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Full text of "Condensed milk and milk powder, prepared for the use of milk condenseries, dairy students and pure food departments"

DilitltiiHHeHiitiilHBiii' 




^tntt Cfjalbge of Agriculture 
At Olornell amoEtaiti) 

3tljara, H. f. 



C ornelL University Library 

SF 259.H8flB| 



Condensed milk and milk powder, prepared 



3 1924 000 001 291 




Cornell University 
Library 



The original of tiiis book is in 
tine Cornell University Library. 

There are no known copyright restrictions in 
the United States on the use of the text. 



http://www.archive.org/details/cu31924000001291 



TO THE MEMORY 

Of 
MY FATHER 

This Volume is Dedicated 



COPYRIGHT, 1 920 
O. F. HUNZIKER 



Condensed Milk and Milk Powder 



THIRD EDITION 

REVISED AND ENLARGED 



PREPARED FOR THE USE OF 

Milk Condensenes, Dairy Students and 
Pure Food Departments 



By 

OTTO F. HUN2IKER, B. S. A.. M. S. A. 

Author of "The Butter Industry" 
Formerly Professor of Dairy Husbandry, Purdue University 

and 

Chief of the Dairy Department of the 

Indiana Agricultural Experiment Station 

LaFayette, Indiana 

Now Manager Manufacturing Department and Director Research Laboratory 

Blue Valley Creamery Co: 

Chicago 



PUBLISHED BY THE AUTHOR 
LA GRANGE. ILLINOIS 



920 



PREFACE 



This book treats ol the \'arious phases of the coiKleiised milk 
and powdered mill< iii(histr\-. It discusses ever\' step in the 
process of niamifacHire, following the milk from the farmer's door 
lo the finished ]jroducl in the |jantr\' of the ci:nsun)ei\ The ])roccsses 
of condensing and desiccating milk', skiiri rjiilk", hnltermilk' and wliey 
are given special attention and the defect- of tlie jiroduct, their 
causes and jjrevention ai"e explained in de-tail. 

'Idle inception of this piihlicalion i- the result ol iniiumerahle 
and ])ersistent ctdls for delmite and reliable infcnaiiation on llie suli- 
ject of condensed milk aiirl milk ]i<jwder, from mtinuf.acttirers in this 
counlrv and in fin'eign kuids ; from jiarties contemjdating emljark'ing 
in the business; Irom naliontil and state experiment stations which 
arc oftentimes called upon to im-estigate condensed milk defects; 
from dtiiry schools desiring to gU'e instruction on the subject ; from 
national and state jjure food departments, seeking informatioti con- 
cerning the possibilities and limita.tions of manufacture, in their 
efforts to formulate and enforce standards and laws; and from com- 
mercial chemists in nc-ed of reliable methods of ;m;Ll)'ses of these 
special dairy products. 

The information contained in this \-olunie represents the au- 
thor's exjierience, co\'cring a period of twelve \X'ars, in (lie ]iractic,al 
manufacture of condensefl milk, as expert advisor to milk condens- 
ing concerns in the United States, Canada and .\ustralia, and as 
visitor of c<jndensed milk' and milk powder ftictones in this countrA' 
and in l{uro|)e. 

ft is the tiuthor's hope that the informatiiin contaiited herein 
may serve ;is a guij-le to manufacturers, investigators, teachers and 
food authorities, alike ; that it ma\' assist in a better understanding 
tiiid wider dissemination of the princiijles, phenomena and facts in- 
volved in the jjrocesses of manufacture; and that it may lift the 
obstructiipg veil of unnecessary secrecy which h<as hovered over these 



industries since llieir lie^'inning, curtailing" their development and 
depri\-ing ihcni r)f much of the light of advanced science to which 
thev arc justh' entitled and wliich they need for their greatest devel- 
opment for (he lasting henelit of the producer, manufacturer and 
consume!' alil:e. 

O. F. HunzikEr. 
Purdue University, March, 1914, 

PREFACETOR THIRD EDITION 

Since the issuance of the First and Second Editions of this 
treatise nianA- changes ha^e taken place in th.e various phases of the 
Condensed JMilk Industry. Old processes have been modified and 
ioTproved, new ])rocesses haAx- been invented, the equipment used 
for manufacture has undergone changes, new tests have been de- 
vised for the determination of the composition of the finished prod- 
ucts and the entire status of the industry has yielded to an unex- 
]iected. iinforeseen and important evolution. 

Oi the m.ost outstanding new features in this edition may 
lie n'lentioned the cha])ters on Direction.s for the Standardization of 
the Sterilizing Process, Evaporated Milk Control, LTse of the Mojon- 
nier Viscosimeter, Manufacture of Condensed Buttermilk and But- ■ 
termilk Povcder, New T-'atents and Processes for the Manufacture of 
Milk Powders. Important additions have also been made to the 
cha|)ters on History of the Industry, A'olume of Output, ^Markets, 
Exports, Imports, Cost of Manufacture, vStandardization of Con- 
densed Milk, and Prevention of Condensed Milk and Milk Powder 
Defects. 

In ]ir!;p.-iring this Edition, the author has endeavored to coni- 
]ileleh,' rcN'ise the old edition, incorpoarting iri the revised edition the 
many chrmgcs which tlie tooth of time has wnjught and to bring this 
treatise in all its im])ortant phases up-to-date. 

O. F. HlTNZIKKR. 

Chicago, 111., ,Se])tember, 1''20. 



CONTENTS 



PART I 

CONDENSED PdlLK 

(ibapkT I 

Definition 

History and Development — Divention of process; development of in- 
dustry; annual output in U. S., i899-lt!2(); annual output in olher 
countries; list of condenseries by -stales Pages 17-20 

Chapter II 

Essentials of Suitable Locations for Condenseries — Milk suppP, ; water 
supply; transportation facilities; sev/age disposal, 

Building and Ecjuipment — Material of cosissructioii; floors, vvidJs and 
ceilings; ventilation; drainage; general plan of factory; list of 
equipment; economic arrangeinen! of macbinerj ; sanitary ar- 
rangement of machinery Pages 29-43 

Chaijler Hi 

Milk Supply — Basis of buying nulk; comparaiive prices paid for milk in 
1914 to 1918 in the four large condensing territories in U. S.; 
quality; control of quality; inspection at condenscry; acid tests 
of milk; boiling test; sediment test; fernientalion iests. 

I-\ictory Sanitation — I^ffect on patrons; on wholesomeness of jiroduct; 
on marketable propjertics; how to keep factory in sanitary condi- 
tion; can washing; care of milk in faetoi-y prioi- to condensing 
.- Pages 43-58 



■ PAlfT II 

MANUFACTURE OF SWEETENED CONDENSED MILK 

Chapter IV 

Definition 

Heating — Purpose; temperature; manner; a(i\;'iitages and. disadvan- 
tages of different methods. 

Addition of sugar — kinds oi' sugar; beel sugar; quality and amount of 
sugar; mixing the sugar i'ages 50-68 

Chapter V 
Condensing — Description of vacuum pan; types of coils; ari-angeraent 

of coils for maximum rapidity of evaporation. 
Condenser.s — Surface condenser; barometric condenser, Avet-vacuum 

spray condenser; care of condenser; expansion tank; catch-all. 
Vacuum Pump — Science and piactiee of evaporating in vacuo. 
Purpose of condensing in vacuo; relation of pressure to boiling point; 

relation of altitude to atmospheric pressure; relation of steam 

pressure in .jacket and coils, water in condenser, temperature in 

pan and vacuum, to rapidit>' of evaporation. 
Starting the Pan. 
Operating the Pan. 
Prevention of accidents , . .Pages <:)8-96 



ChaiJter VI 

Striking or I-'ini.shing tiie li;ili-li — Definition; r;ilio of concentration; 
metliods; appearance lo eye. 

Beaumc liydrometer; temperature coi-reelion of Beaunie; specific grav- 
ity of sweetened ccuulensetl milli at dilferent degrees Beaunie; 
sampling the Ijatcii; drawing oli' ttic condensed milk. 

Cooling— Metliods; e(|uii)inent; ell'ect on product Pages 96-110 

Cliapter VII 
Filling — In barrels; in cans; tilling rnaeliines. 

Sealing — Kinds of seals; soldeiing devices; solder; soldering flux; gas 
supply Pages llO-llti 



PART III 



MANUFACTURE OF UNSWEETENED CONDENSED MILK 
EVAPORATED MILK 

Chapter VllI 

Definition 

Quality of fresh milk; slandai'dizing milk. 

Heating the Milk. 

Condensing. 

Striking. 

Beaume h>'drometer; tem])ci'atiuc correction ni Beaunie; calculation 
of specific gi-avity from Beaunie reading; standardizing evaporated 
milk Pages 117-124 

Chaptei- IX 
Homogenizing — IHii'pose; principle of honuigenizer; Gaulin homogen- 
izei'; Progress homogenizei'; Viscolizci'; operation of homogenizer 
Pages 124-129 

Chapter X 
Cooling — Holding tanks. 
Filling — Filling machines; venthole cans. 
Sealing — Sealing machines; can testers Pages 129-13G 

Chapter XI 

Ste)-ilizing" — Purpose; sterilizei's; loading the stci'ilizer; uniform dis- 
tribution of heat; cans with tell-tale thermometers; temperature 
and time ex|)osare; <|ualiiications of ])rocesser; rapid and uniform 
cooling; fractional sterilization; standardization of projierlies that 
influence beiiax'ioi' of e^•aporated milk toward heal of sterilization; 
Mojonniei' metliod of cvapoiated milk control; Mojonnier equip- 
ment; ineparation of bicarbonate of sodium solution; preparation 
of sample cans for slerilizer; stei'ilizing sample cans; testing 
sample cans for viscosil\-; Mojonnier viscosimeter; importance of 
proper viscosity; factors thai inlluencc the viscosity and their 
correlation lo sterilizing process; the correct viscosity for evapo- 
rated milk; adding sodium bicarbonate to batch; adjusting steril- 
izing process to dilferent sizes of cans; Should bicarbonate of 
soda be used? 

Shaking — Purpose; nicthods; speed of shaker. 

Incubating Pages 13C-162 



Chapter XII 
Plain Condenseil Bulk Milk — iJeiinition; qLialii> of IVesh milk; heat- 
ing; condensint,'; supeihcating; striking; I'atio of concentration; 
cooling ■ Pages 162-166 

Chapter XIII 
Concentrated Milk — l)elinition; apparatus needed; ojjeration of Camp- 
bell process; advantages and disadvantages oi' ]jrocess. Pages 166-16S 

Chapter XIV 
(Condensing Milk b\ Conlinuous Process — l;ullo\ak rapid circulation 

evapoiator; descrijjtion ; operation, 
The Continuous Concentrator — Description; operation. 
'Idle Ruff Condensing l-C\'apoiatoi' — DesciiiJtion; oiieration; (jualily of 

prorluct from coidinuous macliines Pages 168-170 

Chapter X\' 

Condensed Buttermilk — (Composition oi Inittermilk; manufacture; re- 
moval oi' v.lie.\ h.\ i;i'a\it\ ; concentration h\ centrifugal separa- 
tion; evapoi'alion in \'a(Li(i; equipment necessar\-, 

Opei'ation — Ripening of hidlermilk; ]))-eheatiiiK; condensing; concen- 
tration; testing for deirsit\ : condensing buttermilk \>y film pro- 
cess; packing; storage; com|josition of condenseil buttei'inilk; mar- 
kets; annual outi)ut in I'. S. 

Oindcnsed ^\'he\■ oi' Priniost •■ Pages 176-]8o 



PART IV 
FROM FACTORY TO CONSUMER 

Chapter XVI 

Packing — Stamjjing and inspecting of caiv->: labeling; labeling ma- 
chines; wrinkles and iList spots on labels: cajiacitN- of labeling 
machines. 

Packing in (Jases — Maikin^ the cases; casers; jnicking foi' ex- 
port . Pages 185-101 

Chapter XVII 
Storage — Purpose; ellect of stoi'age temperalme; advisahilit>' of stor- 
ing. 
Transpoidation ■ I'ages 191-104 

Chapter XVIII 
Markets — ConsumiJtion of condensed milk and lluid milk; market 
prices; exports anri imi)orts Pages 194-200 

Chapter XIX 

Chemical Composition and Standards of Condensed Milk — Sweetened 
condensed milk; water, solids, fat, proteids, milk sugar, sucrose, 
ash, specific gravity. 

Evaporated I\Iilk — Water, solids, fat, proteids, nnik sugar, ash; compo- 
sition of milk fats in evaporated milk; soluble and insoluble curd 
in evaporated milk. 

Plain Condensed Bulk Milk. 

Condensed Milk Standards Pages 200-211 



Ghaptei' XX 
Sanilary Purit>' of Condensed i^Iilk. 
Digestibility. 
Vitamine Properties. 

Water-soluble Yilaniines — Fat-soliible vilainines; anii-scorbutic vita- 
niincs; ctlect of heat of process on vitamines Pages 211-217 

Chapter XXI 

Cost of Manufarlui'e — Ceneral di.scussioii; cost of sweetened con- 
densed milk; cost of evaporated milk- ■ Pages 217-222 



PART V 

CO?vDE\SE.D MILK DEFECTS, THEIR CAUSES AND PREVENTIONS 

Chapter XXII 

Classes of Defects. 

Defective Svv-eetened Contlensed ?.lilk — Detailed discussion of the fol- 
lowing defects: Sandy, rough or grilt>', settled, thickened and 
clieese, h!rai)\', white and yellov.- luittons, l>!o\vn oj- fermented, 
rancid, putrid, brovyin, metallic Pages 222-2.52 

Chapter XXIll 

Defective Evaporated Milk — Detailed discussion of tlie following de- 
fects: Curdy, grain>', separated or cl-.urncd, blown or ferniented, 
brown, gi'itty, metallic Pages 2.52-270 

Chapter XXIV 

Adulterations of Condensed Milk — Skimming, addition of animal and 
vegetable fats; imitation condensed milk; annual output of; addi- 
tion of commercial glucose; addition of bicarbonate of soda and 
other alkalies, addition of cream of tartar, addition of starch 
• ■ ■ Pages 270-275 



PART VI 
MANUFACTURE OF MILK POWDER 

Chapter XXV 

Definition 

Kinds. 

History and Development; Annual Production. 

Description of Different Pi'occsses — Doug-dr>ing processes; "Winuner 
process; Cami)bell process; Film-drying processes; Just process; 
Hatmaker process; Calhmann ijroeess; Passburg prf)cess; Eken- 
bcrg process; Covers process; Rullovak jjrocess; S!)ra>'-dri,ing 
processes; Percy process; Stauf ])rocess; McLachlan process; Mer- 
rell-Merrell-Gere process; Rogers process; Gray processes; Dick 
lirocess Pages 275-.S03 



Chapter XXVI 
Commercial Manut'atture of Milk Powder by Spra\- Fnjcess — Preheat- 
ing; precondensing; heating of air; spraying and desiccating; 
desiccating chamber; spray nozzles; spray pumps; hot air intake 
and discharge; recover\ of desiccated milk; bolting, packing 
: Pages 203-315 

Chapter XXVII 
Composition and Properties of Milk Powders — Chemical composition 
of milk powders; factors affecting composition; solu- 
of manufacture; markets; annual output Pages 315-330 

Chapter XXVIII 
Dried Buttermilk — Composition of buttermilk powder; annual output; 

manufactvu'e; markets. 
Dried Whey. 
Malted Milk — Histor>- of malted milk industry; manufacture of malted 

milk; keeping (|uality; markets; annual output. 
Federal Standards for Milk Powders and Malted Milk. . .Pages 330-335 



PART VII 



STANDARDIZATION, TESTS AND ANALYSES OF MILK, CON- 
DENSED MILK AND MILK POWDER 

Chapter XXIX 
Standardization — Purpose; standardizing fluid milk; standardizing the 
finished product; standardizing the sucrose in sweeteneil con- 
densed milk Pages 335-342 

Chapter XXX 

Chemical Anahses — Milk; specific gravit> ; total solids; ash; total 
nitrogen; albumin and casein; milk-su.gar; butterfat. 

Sweetened Condensed ililk — Specific gravity; total solids; ash; pro- 
teids; milk-sugar; butterfat; sucrose. 

Evaporated Milk — Specific gravity; total solids: solids tables; ash; 
proteids; milk-sugar; butterfat. 

Milk Powder — Total solids; ash; proteids; milk-sugar; sucrose; butter- 
fat ■ : Pages 342-365 

Chapter XXXI 
Mojonnier Test for Fat and Solids — Equipment; directions; determina- 
tion of per cent fat and total solids in milk, skimmilk, buttermilk, 
sweetened condensed milk, evaporated milk, condensed bulk milk, 
milk powder and malted milk • -Pages 305-374 

Chapter XXXII 

Bacteriological Analyses — Sampling; dilutions for numerical counts; 
plating; media for total counts, acidifiers, liquefiers and yeast and 
molds; incubation; making counts; qualitative determinations. 

Legal Standards for Dairy Products by States. Pages 374-379 



ACKNOWLEDGMENTS 



The author desires to express his appreci-ation and 
gratitude to Borden's Condensed Milk Co. for cuts show- 
ing portrait of Gail Borden and interior and exterior 
vietvs of milk condensing factories; to the Alpine Evapo- 
rated Milk Co. for cut showing portrait of John B. Mey- 
enberg ; to the Helvetia Milk Condensing Co., and to Hor- 
lick's Malted Milk Co. for biographic data relating to the 
early history of the industry; to Mr. IVni. T. Nardin, 
Attorney, for extensive statistics on milk prices; to Mo- 
jonnier Bros. Co. for "valuable data relating to the manu- 
facture of evaporated milk; to Mr. C. E. Fenlon, Vice 
President of the Rico Milk Products Co., for valuable in- 
formation relating to cost of ina)iufacture and details of 
operation; and to the manufacturers and dealers of ina- 
chinerv and supplies related to the industry, for their 
many cuts for illustration in the text and for their 
generous contribution of advertisements, whose kindly 
and active co-operation made possible the issuance of 
this publication. 



Complete Milk Condensing Unit 

for 

Dairy Schools 
and Experimental Laboratories 




^Wi^- 






Ji 




^ jj^*^*- ■ 



r/jc dairy school is the manufactory of dairy 

knowledge, the clearing house of dairy 

thought, and the distrihutory of the 

dairy gospel 



PART I. 
CONDENSED MILK 

Ci!.\i''n:i; I. 
DEFINITION. 

C'liiideustd Jiiilk ir- C'w'^ fresh lllill^ frdin which a cniihidcr- 
aljlc [iijitifiii ijl tlie water has IjCcii ex'api iratcd and Ui wdiicli 
sucruse ma\' eir may imt lia\e Ijeeii added. 

There are chieliy twj classes 'if ccl]ldcn^ed nidk. ri.amel)". 
sweetened a.iid unsweetened. IjOtli reach the marl<et m herniel- 
icall}' sealed tin cans intended, frir ihrect ci m^umiitiun. and in 
Ijulk, intended n^r leakers, ci infecti( uiei's and ice cream mann- 
factui'ers. 

A portion nl the ciinden^c(l mdk < m the market is made 
from the cliiel ljy-])rciducts nf mid;, si.:im n.iiU-: andi buttermih^. 
Confhriised skin.i milk sii])rilK-- tlie same markets as cmidensed 
udi'.ile milk ^old in Ijidk. Ci indented Iniltermilk furnishes a 
valuable hoi;; and chicken feed. It lias, alsci, been recommended 
for medicinal purposes, and of late years it has fotuid extensive 
use in bakeries and for the riianufacture of diverse prepared foods. 

HISTORY AND DEVELOPMENT OF INDUSTRY. 

Invention of Process. — Cnndensed milk is the child of the 
nineteenth century. ' It.^ (jric^an dijes nut date kiack far, and its 
innovation and r,a|)id de\"elMpment stand in sharp coiitra.-t to 
those of the manufacture of butter and cheese, industries tn 
wdiich reference is made in the ' dd Testament' and the exulutiiiii 
of which has fjecn very i^q-adual Xi 't withstanding" the newness 
of this priiduct. its manufacture has assumed such [jr. i])i ntiijiis 
that toda}' it occupies a pruminent ;ilace amnn;^- tlic leading 
branches fif dairv manufactures. 

The coiiflensed milk industr\' i\as introduced at almut the 



1 I:;ook of Genesis. C. IS, V. S: "Ana he took butter and milk and tlie calf 
he had dressed and set it before tVieni." 

Book of Job, C. to, V. 10. "Hast thou not poured rne out like milk and 
curdled me like cheese." 



18 



History and Development 



same time as tlie factory s}'stem of the butter and cheese indus- 
try; although, fur many years l)ef<)re the invention of a suc- 
cessful process of condensing milk, methods had been sought 
to preserve milk. 

The American, T.ail P>orden, the in^■entor of the manufac- 
ture of condensed milk, is said to ha\e experimented some ten 
years before he finalh' decidefl that a semi-fluid state, produced 




Fig'. 2. Gall Borden 

by evaporation in \acuo, was the liest lorm of preser\'ation. 
He first applied for a ]iatent in 1X5,^, but it was not until three 
years later that the Patent ( )ftice ap])reciatcd tlie originalit\' 
and \'alue of his claim sufficieiitl\' to grant him a patent. In 
August, \i<5f>, he was awarded a patent on his process, both b\' 
the United States and by I'jigland. 

In his a])])lic,ation ^Ir. I'lordon savs:' 

"1 am aware that sugar, and \arious extracts, ha\e been and 



1 "A Brief Sketch of Gnll Borden," by S. T^. Goodale, Secretary Maine State 
Board of Agriculture, ISI'2. — Oourte.sj' of Bordeii'e Condensed Milk Company, 



History and Development 19 

are now concentrattd in \acuii under a ]i>\v fk-yrt-e nf iTcat, t" 
prevent disc(jloratifjn fjr hurnni.L^-. J du )iMt claim CMiicentratin,^,^ 
milk in a \'acmim pan for svicli a purpn-e, m\" dhiccl lieinc,'' to 
exclude the air from the be.L^iinnn,;:,'' nf the pmce^s tn the end. 
to pre\-ent incipient decrimpnsition. 'J'his is inipijrlant and 1 
claim the flisco\-erv." 

The claim, I'nited States Patent Xn. 15,35,\ Auy'u>t K'. 
18:'6. is ill the fi i]l(i\\-ini^r \\-(ii-fls ; 

" Pri idiiciiiL,'' ci inceiitrated ^w eet milk In- t•^-a|)Mratil ni m \acuf', 
siiljstantiall}' 'd^ ^et forth, — the ^ame lia\inL;" ni i siiL;ar or other 
foreign matter mixed with it." 

Since the introduction of the lu'oce^- of milk coiiden>in!_;\ in- 
\-ented and patented ]>\ lionleii, numerous modilications of the 
process, as \vell as eiitireK ditterent proces'-c-, ha\e been in- 
\-ented in this country an<l abroad 'Idle most characteristic 
amiiiiL;' thc^e are: condensation bv retri'_;'eration. b\- centrifugal 
force, by boiling under atmos])heric jiressure. b\- pa^sino- hi,t ;iir 
over or through milk, etc. .Most nf these new proCessfs haxe 
not pro\'ed ccinimercialb- satisfactorx", with the result that the 
princijde of the process, originall}" iii\eiited b_\" Cad f'lorden, 
and which consists of condensing the milk in \ actio to a scnn- 
fluid liquid, is still made use of in the manufacture of the great 
bulk of condensed milk produced, both in this conntr\' and 
abroad. 

While the claim of the patent granted 'lail I'.orden was 
that oi "prrjducing concentrated sweet milk b}- e\aporation in 
vacui> \\'ithout the admi.xture of sugar or other foreign mat- 
ter," records show that (".ail iVirden manufactured swettcned 
condensed milk, sold under the famcius Eagle f'.rand label as 
earh' as 1856, The first ad\'crtisemeiit b}' Corden iif unsweet- 
ened condensed milk \\'as reccirded in beslie's W'eekh', Mav 
22, 1858. It reads as follows; 

"Borden's Condensed Milk. Prepared in Litchheld Count^•, 
Conn., is the onl}- milk exer concentrated without the adinix- 
ture of sugar or some other substance and remaining easih- 
soluble in water, ft is simply Fresh Countr^' Milk, from wdiich 
the water is nearly all CA'aporatcd, and nothing added. The 
Committee e)f the Academy of Merlicine recommeiifl it as 'an 



20 



History and Dijvklopment 









•'■'^-^'^ci^'*-. 



f 



article, that, ffir purity, durability and economy, is hitherto un- 
equalled in the annals rif the milk trade.' 

"One quart, b)- the addition nl" water, makes twcj and a half 
quarts, — equal of cream, fne (|U.arts rich milk and se\'en quarts 
o-ood milk. 

"For sale at 173 Canal Street, nr deli\ered at clwellins^s in 
New Yrirk nr Brooklyn at 25 cents per quart." 

Development of Industry. — The be^innini;- was siuall, the 
process crude and the ]U'oduct imjjerfect. ?\iit until the stren- 
uous vcars of the v>^ar of Secession did the \alue and useful- 
ness of condensed milk as a com- 
^.■fcOjA*^,. modit\' become full_\" recoi^'iiized. 

r)urinL;- the Cixdl A\'ar lliere was 
a great demand for this product 
and from tliat time on the indus- 
tr}- grew \\-ith great rapidit}-. 

The fir^t factory \\'as operated 
1)\- (Tail Ei'rden in \\"olcott\"ille, 
IJtchfield county, Connecticut, in 
the srimmer of 18.^6, btit disap- 
pointed in not obtaining means, 
nothing" was accomplished. A sec- 
cmd attempt o-as made at Burr- 
\-ille, fiYc miles distant, in IS.^r. liy a ci"im])an_\' ccmsisting of the 
ow-nei's of the patent. A small rpiantit}' of milk was here suc- 
cessfully condensed and its introduction into New Ycirk began. 
.\lthough admitted bv all tii lie siq^enor to an}- before made, it 
\\'as slow in meeting with sales |irnp(Trtional in magnitude to 
the expenses incin-red. A'ielding to the monetar^" rexuilsion of 
that year the company sus];)ended operations, leax'ing Mr. Bor- 
den liable for bills dra\vn, on which he was sued. 

It was not until Feluuiary, 18.^8, wdien Mr. Borden I with the 
other owners of the patent) associated himself with Jeremiah Mil- 
bank, Esq., wdio ad\'anced money to re\'i\'e the business, that he 
could be said to enjoy adecpiatc means to dexelop his invention 
and at wdiich time the Xew \'ork Condensed }ililk Compan^' was 
formed. yVbandoning llurr\illc, the new conqiany cstal^lished 
work on a more extensiA-e scale in W'assaic. 1 Hichcss county. 
New ^^ork, in 18h0. In 1865, extensi\-e Avorks were erected at 



Fig-. 3. 



The first condensed milk factory 
In America, 'Wolcottville, Conn. 



History and Development 



21 



El,c;iii, Illinois, f '.< .i-ilrn'- Cmnleii-e'l Milk I'actMrie- t'ida_\" mini- 
IxT upwards df I'lfiy, exleiuliii-" fmni Maine to \\'ashinL;'t' in State- 
as well as intn Canada. The Xew \^irk Condensed Milk Com- 
pan}- wa^ incurporated in Xew Jerse\- in 1 ST.O a.nd in Xcw Yend-: 
in IS/O. Thi^ crmipaij}" wa^ succeeded ky Rnrden's Cimdensed 
-Afilk Compan\- winch was incurporated in Xew Terse}' in IS'i'J. 
In the sn\tie-^ mi" the last century, the Anedo^Swi-;- Con- 
densed Milk (_'(iiupany wa- la'-anized in Switzerland under tlie 
leadershi], nf Charle- A. I'a^c, then I 'nitcfl States Consul at 
Zurich, S\\itzerland, anfl hi'- krnther ('.vdv^t Ik l'ai;x-. and wdth 
the a-sistance nf Swis- and k'.n;^"l)-h ca]iitak ddie fu'-t factra-\- 
■ if lh;0 cnm]):niy was kuiit and 'ij.erate'd in IS'.k, at kdiani. l^ake 




rig'. 4, Factory of Borden's Condensed Milk Co., Randolph, IT. T. 



ZuLf, Switzeidand. under the directi^'U nf Ge(ir,i;e H. r'aye, wh-'' 
'.N'as its president until Ic''!^, when he died. 

This cnmiian}' ])ri)spered and ^rew I'a.pidh" in Eur'ipic. In 
the eighties of the last cenliu-y it in\-aded the L'nited States. 
where it built and ojierated se'.eral lar^e fact'iries iu_ X'ew" A'cirk. 
\\ iscrjnsin and Illirniis. The .\mericau factories ^vere manag'ed 
b}' DaA'id I'a^e and W'illiaiu P.. I'aye, brothers of Cjeortce H. 
Page. In VJ02 the Anglo-Swiss Ccjudensed Alilk Company sold 
its entire Amtrrican interests, f.actories and business, tcj Borden's 
(Jnndensed ]\lilk Ccjni])a.ny. , in 1"'04 thi: .-\nglo-Swiss C'cm.densed 
Milk Comi)an_\- cnnsi ilidated w itii Ileni-\- Xestle, 'if AAwcw Lake 
Ciene\a, Switzerland, anijther succfssful manufacturer of con- 
den-ed milk. The cnnipan}" which is u.iw knnwn as tlie X'estle- 
Cham Condensed ?\lilk C'impan\-, is uperating sdme twent\' lar:_;'c 



22 



History and Dkvrlopmknt 



cniidcnsed milk- factories in Iviirdpean cmintries, witli lieadfjuar- 
ters at Cliam, Switzei'land. 

L'p ti) tin- early cii;iiticb ni tlir last cciitur_\-, sweetened con- 
densed milk was tlie iin\\ eimdensed milk that was put im the 
market and sdld in liernieliealh' sealed cans, while nnsweetcned 
condensed milk' was mannlactnred and siild npen, lart;elv direct 
til the crmsumer, in a similar wa\- as market milk'. 'IMic jmrity 




Fig 5 Pan Room In Factory of Boideu's Coufleusecl Milk Co 



and keepmy (pialitx' "I this unsweetened condensed milk", Imw- 
e\-er, were yreath' superior tn market milk. 

Early in 1SX3 the lleh'etia Milk (.'< mdensin^' I'cimpanv was 
ortjanized at 1 ! i;.;"hland, lllinnis. '^lll^■, company cmdined its 
efforts exclusi\'el_\- {o Ihe mannlacture nl' exapdcated milk (un- 
sweetened cinulensed milk, sterilized ]>\ be.it and suld in her- 
meticall)- sealed cans). While, l'(ir se\ei"al \-ears hel'nre the (U"- 
^'anizatidu (d' this ciim|iany, the pd^sildlities nf produciiiL;- a 
sterile unsweetened condensed milk" were essa\'cd in labm'atnry 



History and Development 



23 



inA'estig'ations li\- M:ifnti^t~, aiul \';liile -imultaneuu-h" with the 
c(jmmenceinerit 'if operation^ 'it this company, iexeral 'ither com- 
panie.- experimentei:! on this form "f c.^Klense'd milk, the Helvetia 
Milk C' iridensinc^- C'lmjiany A\-as the first firc^aiiization that suc- 
cecdeii iri pr'iclu'.inc;" a marketable unsweeteiie'l C'andense''l milk 
that was ,^teri]e an'l wiuM keep indefmitely. 

The rudiments "f the 
process of e\-aporated, steril- 
ized milk \'-,'ere iiitrridticed 1;\" 
Air. Jolm Fj. Heyjnl.ierc^', a 
nati\"e f'l Switzerland, who 
formerh- was rijjcrator in the 
mother )j!ant '<! tlie An^d'j- 
Swiss Condensed Milk C'j. at 
Cdtam. Switzerland. Mr. Me\- 
enherc(, heinc^' a man with an 
in\-cnti\-e turn <:\ mind, ex- 
])erimented '.m the e\a]jora- 
ti'iu and sterilizati'iii "f milk, 
durin,;^- the years \i<HO tu 1883. 
As the result '.if these experi- 
ments he decided that it A\-a^ 
])'"issil.)le t' i j)reser\-e milk, 
without the aid oi su,L;"ar. 
Migrating' to this countr_\', he 
a]"jplied f'lr, and A\"as t^ranted 
a ];atent on his idea of pre- 
ser\-in,y; milk by sterilization, 
by the United States Go\-ern- 
ment in 1884 (Patent Xo. 
,308,422), and a.oain in 1S87 
(Patent Xo. 338,213). Air. 
Meyenberg was also granted jjatent rights f Patent X^o. 308,421; 
on apparatus for jjreserving milk. 

/Xttracted. to llighland, Illinois, ]>x reas'^m fif its large Swiss 
]jOj)ulati'"jn, rm the rejjresentations 'af ^ilr. ,\. j. Pagan, a leading 
Highland citizen, wlio brriught jMr. Mevenjjerg to llighland and 
introduced him t'l the cammunit}-. Air. ?vle\'enberg associated 
himself with Mr. JMin AX'ildi, then a merchant of Highland, who 




Tig. 6. John B. Meyenberg 



24 History and Development 

at once trick a IcadiiiL,'- part in the organizatiini of the Helvetia 
Milk Condensing;- Cci., carl)- in the year 1885. Air. Meyenberg 
ser\-ed as the technical n-ianagcr frir the first year, after which 
lie se\'ered his connectiims with ]-iis conipany and became en- 
gaq-ed in the ])r(-iniotion uf ntlicr c\-a])orated milk factories in 
the n-iiddlc \\-e,st, and (in tlic I'acihc Coast. Mr. Meyenberg- died 
ni 11)14. 

During llic fir.st ^'car (if its existence, dperations of the llel- 
\-etia Afilk Condensing Ccim]>any \\erc sn'^pended a nnml)er (jf 
times, both on account of difliculties enciiunlered in the technique 
of successful manufacture and al^o for financial reasons, fn an 
endea\'or t(j place the cim-ipan}' on a technically and commer- 
ciall}- successful fjasis, tlie biiard of directors took charge of the 
work with Mr. Louis I_,atzer as technical mai-iager, and the first 
half of the second 3-car \\-as mostlv de\-oted to exjjerimental 
work. During the third _\-ear, n-iterruiiticnis in the ojjerations 
were oid)- slight and after that tlie comjiany operated continu- 
ously and successfull}- until the panic of 1<S'.)3, which marked 
the last suspensi(jn of busines.s and which w-as <lue to the strained 
commercial cjnditions tJ-iat pre\-ai!ed throughout the countrv. 

The first board of directors of this company was composed 
of Dr. Knoebel, John A\'ildi, C,e(:)rge R(-ith, Fred Kaeser and 
Louis Latzer, with Dr. Knoebel as ]:)resident and Mr. W'ildi 
as secretary- and treasurer, aiid business manager. In 1S88 ~\It. 
Latzer fjecan-ie president, \\-]-iich ]-)Osition he is holding to the 
present day. In ]"'07 Air W'ildi se\-cred liis connection and 
organized the John W'ildi K\-a])(-)rated Alilk Co. with headquar- 
ters in Columlnis, Ohio. Mr. A\'ildi died in DIO. 

The early de\'elopment and the \-icissiUides through \\-hich 
this pioneer companv in the e\'aporaled milk lousiness passed are 
mr>st instructively expressed liy its ]H-csident, Mi'. Latzer: 

"\'T-ry little of the product titrned out tlie first two years 
w'f.iuld now pass as standard goods. About the third ^■ear, after 
i-nore knowledge of the ph}sical and chemical ]iropertics of n-iilk 
and after the introduction of the jiracttce ol" fractional steriliza- 
tioi-i, had sohed the ]<eeping properties and had inq)ro\-ed the 
physical condition of the prcidnet, we felt that the inditslrii' had 
cui-ne to stay. After we had gained more knowledge and expe- 
rience, and a lower standard of the ]jroduct was ad(-)pted bv the 



History and Development 25 

influstry. the practice ■ >f fractional - terilizatn in \\-a< aliandrincd 
for economic reasons. 

"The commercial part I'f the Imsines^ alsn had its trial"; and 
triliidations in introducing; a new and comparati\'cl}" inferior 
product of comparati\-ely hi.L;"h cost, and to ri\-crcomc the prej- 
udices of both the trade and the medical pri ifessii in, 

"The p)riiljlem thus confr< intiiiL:" the crimpa.ny was tr. 'm- 
prcn'e the product, decrease its ccisl and inijiro'.r ^cIHiil:; methods 
at tine least ]:)ossil)lc cost." 

At first this unsweetened ciniden^ed milk', of rehiii\-e]}- thin 
consisteiic}- and prcL^nant \vith the conlycd tla\or resulting',' from 
its exijosurc to hi.L;h sterilizing'," tem])Ci"atnres, failed to apjpeal 
tci the pnldic. who had liecome accustomerl to tlic use rif the 
sweet, thick and semi-fluid sweetened condensed milk. But fif late 
}'ears the flcmand for, and the niami factiirc of this piroduct. 
e\'aporated milk, has increased ra])idl\', until tridaw in this 
country, its outinit li}' far exceeds that of s\^;eetened ci-n- 
densed milk. 

Ori^'inalh' this uns\\'eetened sterilized condensed milk AA-a^ 
labeled and sold under the name of " E\-aporatcd Cream." The 
Federal Food and Druy's Act of IC'Ori caused the name "Fvapo- 
ratcd Cream" to be changed to "E\aporated Milk." 

A further important step in the de\-e]opment cif the manu- 
facture of condensed milk occurred with tlie introduction of 
the Continuous Concentrator, which machine was de\-eh"iped b}- 
the Ry-Products Recox-ery Co., of Toledo, Ohio. This ccimpau}' 
was organized in l''l,i and their machine and ]irocess are covered 
k)y numerous United States ])atents. Tlie ]irinci]">le ujion which 
the Contintious Concentrator is constructed anfl operates is as 
follows: 

"To rapidly mo\c a film la\"er formation within a cylinder 
having a heated surface, haxdng means ior escajiing \'apors and 
means for keeping the surface bright ancl clean, circumferentialh- 
and from the point of inlet to the ])oint <"if outlet." 

Anotlier type of the film prmci])le of continuous concentra- 
tion is represented in the Ruff Condensing lA'aporator, manu- 
factured bv the Cream Productirjn Co., I'ort Iluron, Midi. 

The Continucius Concentrator in its |)rescnt improxed fcirm 
has reached a state of |)eriection that renders thi^ machine apipili- 



26 



HlS'l'ORY AND DEViaOPMENT 



cable fur the ci 'mniercial mamifacturc I'f the fli\-erse forms of 
condensed milk and milk liv-products. 

The sim[)licit\' and ecnionn' of the ei;|ui]jnient inAoK'ed, the 
simplicity and rapidit^' of the pr("iccss and the fact t'lat no \'i-ater 
is ref|uired for condensing" the esca|iinL;" \apors, are decided ad- 
\-antaq"es o\'er the cijndensation in \acno. Already the demand 
for these C(3ncentrators anionic" condenseries and ice cream fac- 
tories is \'er\' i;;i'eat. This process lends itself adniirabl}- t' i the 
establishment and o])eration of small local c mdensei'ies and milk 
shippini;' statiiins where milk is condensed and then shijjped for 
])ackinf^- and sterilization to concentration jilanls. 

Annual Output of Condensed Milk in the United States 
1899-1919, Inclusive. 





Total 


Sweetened 


L'nsweetened 


Years 


Condensed 


Condensed 


Condensed 




Milk 


^U]k 


Afilk 


1S99— 








Pounds' .... 


18r,021,787 


C) 


('■) 


Dollars^ 


1 1 ,888,792 


i') 


(') 


1904 








Pounds' .... 


308,48,^,182 


108,355.180 


110. 12' 1.003 


Dollars^ 


20,149,282 


13.478.376 


6.670.*'06 


1909— 








Pounds' 


494,79r,„^44 


214,518,310 


280.278,234 


Dollars' .... 


33,56.3,129 


17,345,278 


10,217,851 


1014— 








Pounds- .... 


8S3, 112,901 


C') 


(■'') 


Dollars^ .... 


,^8,011,r,77 


(■') 


(■'■■) 


1017— 








Pounds- .... 


075,000,000 


(■') 


(") 


Dollars' 


100,000,000 


(■'■) 


{■•) 


191 R"— 








Ponnds 


1,675,034,234 


507,053,451 


l,lo8,,'^80.783 


Dollars 








1919"— 








Ponnds 


1.077,454,805 


674,184,225 


1,303.270,580 


Dollars 









1 United States Census Report for 1010. 
'- United States Dairy Division, by Correspondence. 
3 Value estimated at $3.40 per case. 
' Value estimated at IfB.BO per case. 
» Not reported separately. 

"Potts, E. C.. TI. S. Bureau of Markets, Pebruarv 17, 1920, and "The 
Market Reporter," U, S. Bureau of Markets, Vol. 1, No. 13. March 27, 1920. 



History and Development 27 

In thi^ C'ilintry, as well as in ('anada. I'.nia iiie. Au-lralia and 
-\ew Zealan.d. ihe cindenseil milk indn-tr\' c;r{->'; iTiiiidlw E\x-rv 
succeedinii- decarle marked the rirpanizai i^n r,f new cwmy^anies 
and the erection of new factorie- until t'ida;/. there are milk con- 
densinc;' facti"]rie> in nearh- e\"er\^ ci-.-ilized ';"nntr\- \\ithin the 
dairy belt. 

The aboxe fi^nre^ ma_\' ^er\-e to emidia-i/e the ra]nd i;rMwth 
wdiich the cjiideii-ed inillc inf!n^tr\" in the I'm'ted States ha> 
enjoyed dnrin-- tlie la.^t decaile. The t^tal nut]jiit ■.!' CMiulen^eJ 
milk in 1'']'^ hnth ^\\ cetiniedi and un-.\\ eetened, iml n'lt includ- 
niL;' "hlled" ei.nden-cd null-; -uch a- cinilen^ed Lj^mrN ni'Mdified 
with \-evetalde fat^, ruir cunden-ed Inittermilk a.nd iiiic. mdensed 
sterilized i-anried mills, xsa^ 1 ,''/ 7.4."4,sn.^ pMuniN, at an e^timaterl 
\-alne <<i ajjin-i i>:imatel\" SJljij/ir/J/jOf). ( 'alcnlatniL' the ratio of 
concentratii in at _'.3 to 1. thi^ (intpnt re]ire~ents ihe utilization 
of aiJ]jro.ximatel_\- 4.' '-I4.r:00.f;00 pr.mid- ■■i linid milk. In l')17, 
wdieii the total ontiiut of i-onrlen-ed milh: w a- ' V .^■.(KJO.OfJU jj^-nnds. 
representing^- the utilization of abriiit 2.4.^7.' ;(¥). 000 pounds of 
tluid milk, the total prodnrl ii in e-f milk m the I'lnted State:- 
was estimated at almnt X4,0l 1 ,.^s( 1 0(JO pomuU of which 2,0 per 
cent were ma,mifactured into roiidensed millc. RcTahle ti^ures 
are not as i,-et a\"ailalile ol the t'ltal jirod.nction o| mdk in tlie 
L'nited States for the year l''l'^. It is estimated howexer, tci be 
about ''0,000,000,000 pounds. Mn the basis of the aboxe esti- 
mate, alji.iut ,^,-1 ]ier cent of tlie trital mill; jiroduced in the 
L'nited State- duriny, llic \ear I'dOi vras main'facttired in to con- 
densed milk, 

.\ new aiul tiniirccedented mijietus was yn'en the condensed 
milk industry in .\mcrica b_\- the arbcent of the World War, The 
concentration o| the prorbict, its wdiole^onieness and hi.uT food 
N'alue, the ser\'iceableness of it^ packa,L;"e and its L;reat keepint; 
ipialitv rendererl it iiidispen^alile as a food tor the arm}" and na\"v, 
as well as lea' the cixiba.n ]iopulati'in fif the warrim;" naiieins in 
its dire need for fmid. In this y-reat crisis in which the food 
supply of the nations ol the earth was ]da}'inL:- a most impiartant 
role, confleiised milk has pro\-ed its \\oi-th and the demand for 
this commodity has increased to tremendous ])roportions. This 
demand has lieen readil}- responded t(.i b}- ihe industr\- i.iii the 
American continent and has resulted in a \ast increase of the 



28 History and Dl{vi-;loi'Mi{n'i' 

ciutput of cninlenseil milk and in the frection of man)' new and 
larqe factories \\-itIiin tlie slKirt sjian iif tlic war. 

The treniendi m^ increase in the xailume of cnndensed milk 
niannfactiired in this conntrA' in I'H'i is due in part also to tiie 
rapidl}- gro\\"i!i_L;' consumption of ice cream and soft be\'erag'es 
of A\diich ice cream is a c( uistituent, as the I'esult of national 
prohibitic'H. Consei"\ati\e estimates ])lacc the increase of con- 
densed bulk milk supplied to ice cream factories at 15 to 20 per 
cent o\er pre\dous 3'ears. 

In bS')'-', there were in (iiicratii ni in this conntr}- about lift)' 
factories manufacttiring' condensed milk, distributed n\'er four- 
teen different states, Ne\\- York and Illinois leading the list by 
over 50 per cent. In 1904, the Government estimated the total 
number of condenseries in operation at ei,ghty-se\-en. In 1'"'14, 
there were in the United States (ner two hundred milk condens- 
ing factories, distributed over twenty-three different states. And 
in 1918 (lo^ernment statistics place the total number of con- 
denseries at 6-2, distributed o\'er 30 different states as shrnvn 
on the following table: 

Distribution of Milk Condensing Factories in United States' 

in 1920. 

Number of Number of 
States Factories States Factories 
.Vlabama 1 Missouri 3 

Arizona 3 Nebraska 2 

California 8 New Flampshire 1 

Colorado 5 Ww Jersey 5 

Fli irida 1 New York 68 

Idaho 2 Ni irth Dakota 1 

Illinois 31 Ohio 30 

1 ndiana 11 < )regon 5 

Iowa 2 l\'nnsyl\'ania 37 

Kansas 5 Rhode Island 1 

Maine 1 Utah 3 

Maryland 3 Vermont 5 

Massachusetts 2 \'irginia 1 

Michigan 24 W^ashin.gton 19 

Minnesota 2 \\^isconsin 40 



Total 30 322 



Potts, R. C, U. S. Bureau of Markets, 1920. 



EsSIiNl'IALS OF SuiTy\BLK LOCATION; 



29 



( )tlKT crinnti'irs in which the ci 'ndeiised mil]-; indnstr}' lias 
made rapid ijro^^ress arc : Canada, Australia, X(\v Zealand, 
Switzerland, C,ernian_\-, Iui'_;land, Ireland, Hrdjanfl, Sweden, Nor- 
way, i'Xustria, Japan and India. Idie annual output nf .-rime of 
these countries is I'epr.rted helow-. 



Annual Output of Condensed Milk in Different Countries. 



Couutr)' 


"liear 


1 'ounds 
Condensed Milk 


Australia 


1916 

1918 

1902 

1911 

1918 

1914 
(1914 
/1918 fest.) 

1919 


43 r,04,,S9; 


Canada 

France . . 


79,807,0/1 
4 601,046 


[apan 


1 ,''00,054 


New Zealand 

Norway 


6,205,400 
,1." 000 riCiO 


Switzerland 

United States 


121,25.1000 

55,1 15.000 

1, 077^454.805 



C (I AFTER II. 



ESSENTIALS OF SUITABLE LOCATIONS FOR MILK 
CONDENSING FACTORIES. 

Unlike the estalilishnient I'f creameries and cheese fac- 
tories, the hnildiiiL'; ol c 'iideicseries and tlic insta.llim; ijI the 
necessary nFTcliinir\- inxuUe the imestnient nf la.ri^e capital. 
There is need nf a sub^lantial huildinp; and uf e.';pcnsi\-e machin- 
ery. The supplies aj-e uumenius anrl must Ijc |)urchased in larger 
quantities hefnre the returns fmm tlie ;^ale nf the manufactured 
product are a\ailal>le. It is cstinia.ted that it takes Ir.im three 
to six months hefnre the cnndeiised inill: reaches the ci'ii-timer. 
This hidds true eS|)ecialh' in the ca^e rii canned ;.4"'ir]ds. The 
hxed ex])eiises also are ci imjiaratixeh- Ilea\^^ and dn imt mate- 
rially ciiaip^e \\'itli a decrease in- increase in the milk supplv. 

All of these facts enipliasize the im])ciriance of locatiu'^ the 
factory in a territor_\' must suitahle for econiimic manufacture. 



Pirtle, T. R., Stattstlclan, U. S. Dairy Division, February 12, 1920. 



30 Essi;ntiai,s of vSuii'ablk Locations 

t(i L^'uard against lica\\- 1' iss wliicli wrnild naturally result in local- 
ities unfa\-(:irahle t" tlie industrw 

The chief facturs tn he ci nisidered in this connection are: 

Milk supph' 
Water su|)pl} 
Transportation facilities. 
( )ther conditii )ns. 

Milk Supply. — A larLje supply i if milk with possiljilities for 
extending;" the milk sup|)l)' territ<ir\' is the lirst essential. The 
condenser}' must lia\e milk tci dij business. The localit}- in wdiicb, 
it is located must he adajited inv the ]'rc)ductii m nf lart^'e quanti- 
ties of milk; it must be a dair}' countr}' Avhere reasonaV)ly large 
herds are ke|)t ()ther thiu!_;s Ikmul; ei|ual, tine larg-er the milk 
supply, tlie l(i\\'er the cust of manufacture. Where the milk 
supply drops belo^-/ hfteen thousanrl ]iouuds of milk daily, pro- 
fi(a1)le manufact>u"e liecomes diflicidt. Territories of o-athered 
cream creameries are usuatl)- nnt \'ery desirable. The farmers 
generally ha\-e small herds and are imt inclined to haul their 
milk dail}'. They ])refer tn take their cream ti i the creamery 
once or t\\-ice per week, nr whenc\'er it is cnn\-enient for them ti i 
do so. Again, the)- ap])reciate the feeding \aluc of the skim 
milk and depend im the skim milk ti > raise their ^•oung 
stock and pigs. When they take their milk tn the C(indenser\-, 
there is no skim milk nnr buttermilk left fur feeding purposes. 

The |.)resence of wdiole milk creameries and cheese factories 
renders a localit}- most attractixe for the establishment of milk 
condenseries. The farmers usurdly hax'C reasonabh- large herds, 
they are accustomed to take reasonable care of their milk and 
to haul it to the factor)- dail)-, .-md the enudenserx- prices are 
generall)- high enough aho\e the creamer\- or cliecse factor\- 
prices to induce the farmers to ])atronize the condensing factor^'. 

Territories in close proximit)- of 1,-irge consuming centers, 
though dair)iug m,-i) ha\e reached a high state ("if development, 
are nc.it desii'able, owing lo the continuous and grcTw ing demand 
for fresh milk. Competition of this kind means high prices, 
which ni> business tactics arc capable of modif\-iug. 

Water Supply. — The \alue to the milk- condensing plant of 
a generous and ne\'er-tailing supph of clean, cool water cannot 



ESSICNTIALS 01' vSuiTABLE LOCATIONS 31 

be o\'erestimatefl. The l"iill\- of crcctinu' ci indeiisei'ies witluiut 
first ascertaining;" the water mi|)])1\- lia^ in ^I'lne instance^- i' im- 
pelled milk conden^iiii^ cnmiianies ti > aliandnn ci-\\" plant-.. merel\" 
because of lack of water. 

In addition to the water used in the bnilei's and for wa^li- 
in<4' purposes, lari^'e amounts of water are necessary for conrlens- 
ing- and for coojiiii;- the eondensed milk. It i^ estimated that ihe 
condensation of ijne pound of fre^h. milk |-'-ip:ires about three 
(^■"allcins of water at ordiir.ir\' temperatur..', aitlioni^h this amount 
of water may be considerabh reiluct-d b\ tlic use of eondeiiser- 
of maximum efficiency. 

The water must 1)e pure. In spite of all precautions, it will 
come in contact, more or les^, with tlie milk. Though all appar.a- 
tus and utensils ho'diuL; and con\-e\-inL:' milf: and condensed milk 
may be thoroui^'hly steamed after rin-iuL; with water, there are 
untrild channels thromdi which the milk ma\' become contami- 
natefl with polluted writer. bre(|ueiitl\-, while tlie milk i- con- 
rlensiii!,'-^ tP^' \acuum pump accidentalK" sto])s. If the ])rocessor 
fails to immediatel}- shut oft the water su]jpl\'inL;- the condenser, 
water will p(;ur back irom the condenser into liie milk in the 
\'acuum pail. In the case of lilth}-, polluted water, the entire 
batch may be ruined, -\L;aiii. the |)an is u^ualh" rinsed lietween 
Ijatches and, if the water used is unclean, il will contaminate the 
milk of the succeediuL;" bath. I'lnallw wlien the hea\"\" 4f)-(piart 
cans filled witli condensed milk are set into the coolin;,^' tank, 
water frequently sfdashes o\er into the i-ans. Ilere ai^ain the 
quality of the crjndeiised milk in jeopardized, unless the water 
used is pure. 

The water must be cold. The colder the water the more 
satisfactory is the ripci'ation of the \"acuum ])an and the smaller 
the \'olume of water required to condense a Ljixen \"o]ume of 
milk. If the temperature of the water used in the condense]- 
rises much abo\'e 6,s dei^rees Iv, the process of condensing' ma\- 
become difficult, accordin.t;' to the type of pan and condenser used. 
Cold water is essential, also, t(.r the prompt .and pro]K-r coolint;' 
of the condensed milk. 

Transportation Facilities.- -It is essential that the factoid- 
ha\-e access to one or more railways lines. 

While, forreas<ins discussed under "Alilk ,^u])ph-," it is not 



32 ESSKNTIALS OF vSuiTABLK I^OCA'I'IONS 

ad\-isal)le tn creel a faetnry in ten > eln^e |)r(ixiiiiit\' lei larcj'e eoii- 
suminp' i u- ra!l\\a\' eenlers, it i'^ e'liially iiiidcsiralile t" elioose 
a eein(leiiser\- site wlicia' ti-ans|ic irtatii in I'aeililies are jmeir. 

Where aeecss tn one railmad unlx" ean lie liail, the laei:(7ry 
is at tlie merev nf iliat mail. ]v;|'erienee lias sliriwn that monop- 
oh- of transportation usually means a Inw standard of effieiene}- 
of service and hio'h freiq-ht rates, ' <")n the other liand, competi- 
tion in\-ol\-es a strnp;f.;de for the snr\■i^•al of the fittest, and it 
offers the public all the inducements that business inpfenuity and 
enterprise can prudnee. W here t\'.-o nr riinre transportation com- 
panies are after the business nf the same manufacturini^" concern, 
they \\-ill ^''-''ler.allv lea\'e ncthing' undnne in the way nf accom- 
modations and low rates to jdease the manufacturer. The result 
is that the manufacturer enjo3's the adcantasjes of efficient ser\'- 
ice. o-fiocl acci imuK^idations and rcasnnalde freii^"ht rates. ^ 

This is a factor which the condensery cannot affnrd to o\-er- 
look, as the freight charges are a \'er\- ci ins])icui uis item in the 
expense .account of the milk condensiuL'; bnsine-s. A part of tlie 
fresh milk may hai-e to be shijiped to the factoi-y by rail, all the 
finished product mtist lea\-e the factory bv rail and the eonelens- 
ery is dependent on the railway for its raw materials and sup- 
plies, such as suLjar, tinplate, solder, bc^x shooks, barrels, labels, 
oil, rosin, gasoline, coal, etc. Prompt and efficient transportation 
is essential. Undue dcla}'s ma\- cause the condenser\- serious 
incon\-enience and 1(tss, and ma}' result in the cancelling;" of im- 
portant orders. 

Other Conditions, — The remo\-al of the sewa!,;e of the fac- 
te)r_v is important, ft may be ])ossible for the factor^• lo connect 
with the town or cit}' sc\A'er, in which case the problem is easih- 
soh'ed. Where this is not iiossible, a site aloii;^- a creek', ri\'er, 
pond or bake ma}' ofier effecti\e means to take care of the con- 
denser}' se\va,L;"e, A\diere no such natural dellosilor^■ is awailable, 
the e!e\-ation o1 the site should be sufficient to carr\- off the sew- 
■Aisc far enou'jh Inmi the factor}' to insure the plant aqainst foul 
odors and uiisanitar\' conditions, fn the alisence of all of these 
a\'enues for the disposal o| the sewage, a properl}- laid-out s^•s- 



' Tlie matter of frcipht rntes is now largely regulated by the Federal De- 
partment of Transportation. 



Buii^DiNG AND Equipment 33 

tern rif septic tanks witli efficient filter Ijerls ma>- ser\-e the 
purpose. 

Where possible, it is advisaljle to take afh^anta.c^e of hillsides, 
affording- natural means to arrange and operate the factory on 
the gravity plan. 

BUILDING AND EQUIPMENT. 

Material of Construction. — Since the e-tahli-hnient oi a milk 
condensing factor}' in\-(jl\es the im'estment r.f con-iderahle capi- 
tal, those willing tcj in\-est must ha\-e faith in the ])ernianeni;_\' 
C)f the business. Frir a permanent Ijusines^, a bnildiuL;" substan- 
tially constructed is the most economical. Most of the facturic^ 
belonging to the mrist reputable concerns are built \X'ry sub- 
stantialh'. Idowexer, tliere are in this country- condensing fac- 
tories in the conslructif'n of which cheapness ^\•as the goA'ern- 
ing factor. 

It is beyond the realm of this A'olume to furnish detailed 
specifications and plans for the construction of condensed milk 
factories. Such information would be of coniparati\-el}- little 
value, as such details must of necessity \'ary ^vith locality, ca- 
pacity of prospecti\'e plant, type of equipment, s\'stem of (ijiera- 
tion and preferences of indi\'idual owners. Such details are best 
decided on and worked out for each indi\-idual factory separate!}' 
and when needed. There are a few fundamental principles, how- 
ever, which applv t<'i all factories and to which attention ma}' be 
briefly called here. 

Floors, Walls and Ceilings. — Stone, brick, crmcrete, concrete- 
steel, according to availability, are satisfactor}- materials o\ which 
to construct a condenser}-. Intersecting walls or jjartitions are 
best constructed of similar material. If constructed of wood, 
they should rest on concrete, brick or stone, built up at lea^t 
two feet from the floor, cjr the lower two feet of which ])arti- 
tions should be wainscoated with an approx'ed cpialit}' of cement 
plaster. 

All floors of the main building should be of cenient, great 
care being taken that the foundation of these floors be of uni- 
formly hard material, thoroughly tamped and avoiding soft spots. 
The concrete bed should be at least four inches in depth, con- 
sisting of one part of cement, two parts of sand and f(jur parts 



34 P)UII,r)JNC. AND EoUIPMItNT 

of gra\i-l. The sand slmiilil he sli:ii-p huilclinf^- sand and llie ,^ra^•c1 
shonld l)e \\a<-lR'd |ii'l.'l)les. |-anL;'iiiu'; in -^i/e frnni (inc-lirdf t' i one 
inch. The t'i]> ch'essin^" shduld 1}e mit less tlian erne ineli thick, 
ceinsistini;' dl nne iiart i'[ cenienl and iine and onc-liaU" ])arts oi 
sharp hnilih'n^' sand. It shduld lie tarried n[i on tlie walls and 
partiti("ins at least Iwm inches, furniinL; a s.'uiitary cox'C. j\fter 
linishinQ-, the llours shi add he rdlnwed to hai'den for at least 
two weeks. This will ^reath- pmk.nc;" their life. It is advisaJjle 
til nse cement hardener such as 3,1 aster llnilders' cement, or 
Lapidolith, etc., which will helj) to make th.ese llciors nuire neai'ly 
wear-, water-, dust- and crack-pri lol. Tt is difficult t("i keep the 
CI )ndenser_\' in sanit.ary crmdiliim and to prutect the prriduct 
against ci intann'nation, mdess the llemrs of the factory are and 
stay free friini cracks and holes. 

Ventilation. — A ]iroper .and eftecti\"C system of A^entilation 
is another \"er^" im]inrt.ant and t("ir> ollcn entireh' neglected factor 
in the planning ct] the condensed milk factory. This applies to 
all pjarts rif the plant where Avnrk" is lieing done, fnit it is espe- 
cialh' essential in rimms w here free steam escapes. The A'cntilat- 
ing' SA'Stem should lie adccpiate to afford rea(h" and i|uick escape 
of steam, to remii\-e frail air and to facilitate the regulaticm of 
temperature. Unless free steam does prr.rnpth' find an exit from 
the lactorv rormis, it condenses im the walls and ceilings, mak- 
ing them sweat ivrufusely, causing corrMsinn nf the walls and 
ceiling, deteia'i )i-a tion nf niriltirs .and otlier similar eipii]mient, 
and m'llding nl sup])lie^"; this is especiall\- the case during the 
winter mdiitlis. Tlie rcmnwal iif fdul air and the Cdntod of the 
lemperatm-e ijf tlie ,iir are essenti.al frn- the Cdinfdrt, health and 
e'fficienc\' df the emi>lo\-es. 

The system dl \ ciif ikatinn I hat will accomplish efficient \'en- 
tikatidU will dl necessity \,arv with the t\"jic df ]dant and arrange- 
menl iil e(iin])iiient. ('.rasitx' \ entikatidu is, under axcragc con- 
dilidiis, inaderpiale td prdduce satisfactdr\- results in factdries, 
lik'c milk' C( ludenseru-s, where llu'rc is lidund td lie much escape 
of free steam. The excliange df air is nut rapid cndtiL;li tci remd\-e 
the steam liefdre it Cdudenses dii the walls and ceilings, espe- 
ciall}' in Cdld \\eatlu'|- It is, llurefdre, a<l\isa1de to priwide for 
some form df forced vcntikatidu. I'nder certain Cdnditidus nf 
constructidn an air Hue Cdunccting with the siiidlce stack may 



BuiLDiNt; AND Equipment 35 

furni'^h all tlic A'ciitilati' ni ncc'Ied.' Uiidui- man}" Mtlicr ci'iiuli- 
tions, ho\vc\er, it i'; iK'i-e-.sai-\- tc) hijorl that equipment from 
\\-hich free steam escapes in larcre \'ilinne, such a^ can Axasliei's. 
and can sterilizers, hot wells, etc., and to draw the steam awa)- 
throiif^-ji ducts of ader|nale si/e Ija' one or inoiaj mcil.nr fan'- 
located in the outside wall oi- ceiliiic;-. 

Drainage. — All floors nf the manufacinrinL;' rorjms shoidd 
sloiK' to facilitate rapid •!raina':,;;e. A fall of one-eiL;'lith in'di 
per foot is nsualh" suffi-cicnt. hari^x- w,ater--ea.lerl flor,i- (Irain- 
should be sufticientK" numerous and \-,"ell ]ilaced in all njcjms to 
rapidl\' carr\- off waatei'. The surface of tho^e llm.r drain~ shrudd 
1)e ahout one-half incdi below ihat of the .adjoiniuL;" lloor, so as 
to catch the water readib/. In the lar-ar rM.ims open drain- 
flitches in the cement lb inr, ^ix to ei^dit inches wide and co\ered 
AN'ith perfcirated iron plates, are preferable to bell-traps. The}' 
ma_\' be jdaced alon^- the walls or elsewhere. The}" should be 
not moi'c ih.an fort}" feet ajiart and l:a\e a fall of cine-ei^hth 
inch to the foot, \\u'th the lloor sloping- tow;ird tliem. It is tjener- 
allv most conwenient to h,a\e all the drain ])i])es enter into one 
larp;e se\^ei' pipe not less than ten inches in diameter, t(jr a. con- 
denser\- i-ecei\in,i^" about !ifl}' thousaufl ]MiUnds cif milk dail}', 
wdiicli shordd dispose of all the factor\- sewera^'e. It is adxds- 
able to jilace the main sewer ]):pe outside the buildiiiL;" aiul to 
have it tcrmin.tite in a "cIe<an-out." This will atlord more read\- 
access in case the sewer is stopjied u]i. 

General Plan of Factory. — Most of the eondensini;- factories 
arc either rme- or two-stor}- buildings. In the case of two-stor}- 
buildings the first llocir is usuall}" de\oted to the boiler and 
engine rooms, \at roiiin, well njom, Idhng, sealing and packing 
rocims. ( )n the second lloiir are in-tailed the ])an room, store 
room for sugar and bo.x shoob's, the tinshop and possibly the 
offices. A basement is sometimes ]jro\nded ;md used for the str]r- 
ing I if CI mdensed milk. 

b'ig. 7 illustrates a lloor ]dan of a milk condensing factor\' 
with a capacit}' of fift}' thciusand pounds of milk daih". .Ml 
operating roiiuis are located cm r<nc tlcKir. The arrangement of 
machiner\- permits of the handling of the milk' em the gra\it\- 



i]n tills ca.se. there should be an Inner and outer staek with an air space 
between which connects with tlie air flue. 



36 BuiLDiNc, AND Equipment 

plan or with pumps accrirding" to the topograpliy of the site 
and the ele\-ation of the rooms. 'J"he receiving' room floor and 
the platform which acciimmodates the \-aciium pans, should be 
seven to eight feet abo\e the main floor. In order to take care 
of storage of water, sugar, tin cans, l^arrels and box shooks, 
there should be a second floiir o\ er the well room and the filling, 
scaling and sterilizing ri:>om. The ceiling of these rooms should 
l)e not less than sixteen feet al)0\e the floor. 

The rooms are so arranged as to necessitate the minimum 
expenditure of machiner}', con\-eyors and labor. All work rooms 
open on the raihva}' switch, and the storage rnom is accessible 
by two elex'ators. The well .room, where most of the steam is 
needed, is next to the builer room, so as td minimize condensa- 
tion in the steam pipes. If the main steam pipes are properlv 
insulated, this arrangement should furnish the ^'actnlm pans with 
dry steam. The floor in the boiler room should be two feet 
Ijelow the main floor, in order to gi\-e additional fall for the con- 
densation water from jacket and coils of the vacuum pans to the 
boiler feed tank. 

The partiticm between the receiving roum and testing room 
is equipped with a cabinet, opening on both sides so that the 
sample bottles can be placed on the shehes in the receiving- 
room and taken oft the sheh-es in the test room. 

From the weigh cans on the receiving platform the milk runs 
direct into the hot wells, which are sufficient in number to con- 
v-eniently di\'ide the milk into batches and to heat the milk with 
the least possible delay. The capacity- <if the vacuum pumps is 
augmented by their close pr(jximity to the vacuum pans and the 
hot wells and by the fact that the water supply tanks are over- 
head. The space to be evacuated is confined very largely to the 
\-acuimi pan only, the milk has to be lifted by the vacuum pump 
but a few feet and the water runs into the condenser by gravity 

From the vvell room the condensed milk is transferred to the 
tanks on the platform o\'er the filling machines. The evaporated 
milk is pumped from the cooling coils through the wall and the 
sweetened condensed milk is raised to the platform in ten-gallon 
cans on the elevator, or is forced by a pressure pump into the 
tanks feeding the filling machines. The sealing benches are 
equipped with self-heating soldering coppers. In the place of the 



Bi;ir,iJi M. AND Ivjrii'M i:.\T 



37 



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38 Building and Equipment 

soldering- benches and hand cuppers, aulcmiatic sealing- n-iachines 
ma_y be installed. The sterilizers anrl shakers arc con\enient!y 
placed to take care of the sealed exaporated milk. The tin cans 
for the sealing- room and the box slmoks for the jiacking room 
are bronght dii\\'n from the stni-agc room o\erhead on the cle- 
^'ator. l^he labeling and packing roor-n, cf|uip]icd A\ith the label- 
ing and box nailing machii-ies, pro\'ides fcjr c( jnsiderable storage 
of the finished product. Additional stdi'age at a moderate and 
uniform temperature might be pro\ided for bv a Ijasement under 
the packing room. A label stock room furnishes satisfactory- 
storage for the labels. 

In case the factory n-ianufacturcs its own tin cans, a tinshop, 
equipped with the necessary machinery fsee list of machinery 
and equipment) should be located in as close and convenient 
proximity to the tilling and scaling room as possible. A suitable 
place is directly opposite the filling room with the railway track 
separating the latter from the tinshop. The tinshop should have 
two outside doors, opening out on the track, and its machinerv 
should be so arranged that the tin plate can be unloaded from 
the car at one door, is moved back through the machinery- and 
appears again in the form of finished cans at the other door, 
directly opposite the fillin.g room and ready for the reception 
of the condensed milk. Instead of erecting a separate building 
for the tinshop, the latter may also be con\-eniently installed in 
the second stor\- directly o\-er the filling room. 

Where natural gas and gas from munici|)al corporations is 
not a\-ailable. one or more gasoline gas generators should be 
installed. These gas generators cmtain inflammable n-iaterial 
and should, therefore, be located at a reasonable distance irom 
the main building. 

The tendenc}- in factoi'y construction toda\- is to do away 
\\-ith all partitions between operating rooms, haxing all niaTiu- 
factin"ing- and packing roonis in one large space. In this case 
it is customary and economical to ])lace the \-acuum pan and 
condensed milk storage tanks on an elexated jdatforni and in- 
stalling the hotvvells, coolers, \acuuni pump, milk pumps, 
homogenizer, filling and sealing machines, sterilizers, labeling 
and packing- machines on the main lloor, xvhich also i)ro\ides 



Building and EQuiPiir.xT 39 

the iiecc^sar\- space fr.r the stuck of siipphcs and ni caiuu-fl 
S"oods. 

List of Equipment. — 'I'lie folloAvins is a list of the [principal 
niacliiiier\- and e<piipment needed in an up-to-date condenser}' 
with a capacitA- of fift\- thousand pounds of milk dail}' : 

BOII.EB BOOIVI 

I'.oilers with a total ca])acity of 400 11. 1'. 
1 boiler feed taid\ 
1 holler feed pump. 
1 boiler water heater. 

ENGINE BOOM> 

1 40 II. r. en-ine. 

2 well pumps. 150 c;'allons per minute each. 

1 XO li,L;ht dynamo. 

PilK' and thread-cuttin;^ .tools, auAil and for,t;"e. 

RECEIVING BOOM 

2 1000-pound Avei^h cans, "low- down" style. 

2 0-beam milk scales, or other weii^hinc;' arranc^e- 

ment. 
1 can-washiipi;" machine with steam and water jets 

and air blower for dryin;:;' the cans. 
1 milk sample bottle i-ack. 

HEATING AND CONDENSING DEPAETMENT 

30(X)-pound. capacit}- jacketed Icettles with re\ol\- 

in.L;' ayitators anrj superheating' de\ice. 

1 0-foot \-acuum pan "^ 

1 7-foot \-acuum pan V or continuous cmi-entrators. 

2 \acuum inimjjs J 

2 5C0-ii;allon standardizing A\ats on scales. 
1 0-c\din(ler honiogenizer. 

1 internal tube cooler, capacity 5000 to 8000 pounds 
])er hour, for cording' e\'aporated milk, or 

1 submerged coil cooler, or 

2 ,30-can cooling vats \vith cans, cross bars and pad- 

dles complete, or 



I In case municipally generated electricity Is available, there Is no need 
of a Dynamo and much of the equipment may be supplied with direct drive 
by motors. This would obviate the installation of a steam engine. 



40 Buii,DiN(;. AND EouiPArriN'i' 

2 50(lO-lbs. circuhir cuflinj;- wits with \-ertical cnils 
for ciioling" sweetened cuiidenscd milk, or 

1 stil)nierg"ed cuil cooler witli liit^h iiressure i^ump 
and two SOOO-palli m .i;lass enameled hr)lding' 
tanks with acjitatrirs. for ])oth e\'aporated milk 
and sweetened condensed milk. 

1 wash tank. 

1 elevator. 

1 2-beam platform scale. 

1 truck. 

FII.I.ING, SEAIiING AND STEBII.IZINO SEFABTIlEEM'B 

4 200-gallon condensed and e\'aporated milk \'ats.' 

2 filling' machines for sweetened condensed milk. 
2 filling machines for evaporated milk. 

4 soldering benches, ?x20 feet, with 10 self-heating 
soldering coppers each, or 

1 or more sealing machines with can-testing baths, 

tiie number depending on t} pe and capacity of 
machine used. 
2000 wooden trays holding 24 16-ounce cans each. 

2 sterilizers, capacity 7S to 100 cases each, com- 

plete with iron trays. 

1 double shaker. 

2 trucks. 

I.ABi:l.ING AND PACXINa DEFARTUEKT 

2 labeling machines with casers 
2 nailing machines. 
2 trucks. 

TESTING BOOM 

2 24-bottle l>al)Cock testers, w\i\] rme gross of stand- 
ard milk test bottles and accessories, complete. 
Equipment for chemical and bacteriological analyses 
of milk, milk products and sugar. 

OFFICES 

Usual e(|uipmenf. 

TOIIiET BOOKS 

Usual e(iuipment. 



Not needed If well room Is equipped with large holding tanks. 



Building and Equipment 41 

OTEBHEAI) STOBAas BOOM 

1 30//)0-,i,fallon A\^atf:r tank. Tl'ii;- tank i- prcferabl}" 

Iricatcd outside of fact'ary. 
] 4-1jr'ani platform <-cale for sugar. 

ADSITIONAI. EQUIPMENT 

1 gasoline gas generafa- ( criuifiletc i . needed ui ak- 
sence of access to natural ga- e,i- municipal ga';. 

1 k"-ton ammonia cf im[ircs^or, \N'itli ammonia and 

krine |>ipe line^, circulating |)mnp anrl Indne 
tank. 

TIN SHOP 

Xeedcl in ca^-e can^ are manufactured at the factfir}'. 

2 sfjuaring shears. 

2 kod}' cutting maidnnes. 

2 lock ■-eamers. 

(i pressc-. 

2 ci'imping machines. 

2 soldering hoats. 

1 can tester with \acunm |)tnnp. 

1 can wipeic 

1 latke with tool-. 

1 ga-nline gas generator, ci'm])lele. 

1 25 II. 1'. engine ' iv motor. 

200 can crates. 

Economic Arrangement of Machinery. — In the arrangement 
and c'lnr.ectiMU of the machinery eccir;cim\' of manufacture and 
sanitation <ji the prriduct shnuld recei\-e scricms crinsideration. 
The mac]iiner\' ^hiiuld be sci an-anged a-- to rerluce tci the mini- 
mum the space, |)imip'-, pif)es and con\-eyors needed. Pump^. 
ccjiu'evors. pi])es and fittings are expen--i\"e, and the space saA^ed 
In' judiciotis arrangement I'f the staticmar}- machiner\' mav be 
used to ad\'antage for nther ])urpi")ses. 

Human muscle is the mi:>t expensi\e ff.irm of motU'e power. 
A\'here\-er muscle can be i'e|)laced by machinery and wdiere, bA- 
intelligent arrangement nf the machinery, uimece-'-aiw steps and 
iianfllin;; can be a\iiided, the cn-t nl manufacture i;, reduced. 

'i'he matter (<\ in^ulati('n of anioKjuia, krine, steam and water 
pipes is an impi>rtant item as related in the econoni}- >>i fuel. 



42 Building and Equipment 

For proper and tcoiioniical insulation the following types of pipe 
covering are recommended : 

Ammonia and Brine Lines. — 

1st layer rif tarred felt. 

2nd layer of 1" thick hair felt. 

3rd Ia3'er of tarred felt. 

4th layer of 1" thick hair felt. 

5th layer of tarred felt. 

6th layer of \vo\'e-felt paper. 

7th la3'er of 8-oz. can\as jacket, sewed on. 

8th layer of sizing and one coat of lead and nil paint. 

Each layer of hair felt must be securely wuund with twine. 
Each layer of all material should he coated with hot asphalt, 
applied ^vhile hot, excepting la}'ers, f>, 7 and 8. 

Special seals must be made at all flanges and fittings, and 
such flanges and fittings must be insulated independently. This 
arrangement will prevent damage to adjoining co\erings, should 
fittings spring leaks. 

Before applying i:)itch or asphalt, the necessary ])recautions 
must be taken to ha\'e the pipes thoroughly dry and the asphalt 
or pitch must be hot. 

Steam Lines. — Air cell asbestos co\ering, or covering of 
equal insulating and lasting quality, one inch thick on pipes, 
and fittings, to be built up of asbestos cement to a cc>rrespond- 
ing thickness: smoothly finished and neatl}' can\'assed, with 
metal bands at 18" intervals. Jiefore putting on the metal bands 
the covering should recei\-e two coats of asbestos cold water 
paint. 

Cold Water Lines. — Coxering of wool fell, tar paper lined, 
sectional, one inch thick on |)ipes ; fittings to be built up to a 
corresponding thickness with one inch hair felt, the entire line 
should be neatly finished with a graded nii.xtnre of Portland 
cement and asbestos cement, and caiuas-jacketed and etpiipped 
with metal bands at 18" inter\als. Ilefi.ue putting on the metal 
bands, the co\ering should rccei\e two coals of asbestos cold 
water paint. 

Sanitary Arrangement of Machinery. — Milk pumps, milk 
pipes, milk troughs and other milk conveyors are, at best, enc- 



AIiLK Supply 43 

inies of sanitati' in. TheA- should he a\ Glided \\here\'er pf")S^ib!e. 
The g"ra\-ity system fii con\-e}-in;4" mill< -hould Ije used in pref- 
erence to the jnimijinQ- -}-stcm. Milk [njie- -hriuld he short and 
accessible; all \-at'- sould lie of tjmitar}- ri in^tructicin : wooden 
jackets should not he tolerated; all '-eani- in the A'ats and ket- 
tles should he well flushed \\ith -older; milk pumps -Ip'uld he 
brass lined; all milk pi|)e« slmuld be of black ir^on pijte made 
smooth on the inside ]>}- sandblasting', oi- (,f gah'aiuzed iron or 
copper hea\-il}- tinned nvcr cm the inside; lung lines of milk 
pipes should he efjuip];ed with unifiiis at -hurt distances; crosses 
or sanitar}- cou]dings shriidd he used in place ni elbciws, in 
oi'der tij render all secticins of the milk pipes easily accessible 
to flue Ijrushes. 

ChAPTI'R III. 

MILK SUPPLY. 

Basis of Buying Milk. — The prices \\dTich the condensery 
pa}'s the patrons are not usuall\- gOA-erned by an}- board cjf trade. 
They do not e\"en necessarily fol!oA\- the i|untations of the but- 
ter and cheese market, thou.Lih the}- naturall}- hear a more rir less 
definite relation to them. In normal times condenser\- prices 
a\'erage from about twent}- to fifty cents higher per hundred 
pounds of milk than those paid by creameries and cheese fac- 
tories. 

The relation Ijetween cijndenser}- prices on the one hand 
and creamer}" and cheese factor}- p'rices on the other, \-aries prin- 
cipally \\-ith the market demand for the finished pjroduct and 
the season of the }-ear. 

The g-reater the demand and the brisker the market for 
condensed milk, the greater usuall}' is the difterence in price 
for whole milk. Thus, during the \\-ar the ex]-jort demand for 
condensed milk was A-er}- great. This resulted in an extreme 
rise of prices which condenseries offered for milk o\-er those 
paid Ijy creameries and cheese factories, at least in so far as 
exportation AA-as not too greatl}- limited b}- shortage in shipping 
facilities. 

It is customary for the condenseries to pay the highest dif- 
ferential over and above creamery and cheese factory prices in 



e 



44 Milk Supply 

* 
winter, during the time nf low supply, and to drop prices very 
close (c those of creameries and cheese factories in summer, 
dm-ing the flush of the milk producing season. Nardin\ assem- 
bled comparati^■e milk prices ]iaid bv condenserics and cream- 
eries and cheese factories in the foiu" main condensed milk-pro- 
ducing sections of this countrw Illinois, New ^'ork and Penn- 
S3d\'ania, A¥isconsin, and the I'acific Coast States, for the years 
1''14 to 1918 inclusi\e. These |)rices ha\e been summarized in 
the following table. Thev slujw that in some instances condensery 
prices exceeded creamer}- and cheese factory prices by over one 
dollar, while there were times in summer wdien condenser}' prices 
even dropped slightly below creamery and cheese factory prices. 
Formerly condenscrv prices ^\•ere announced by the respect- 
ive concerns from three to six months in advance. Of late 
years this practice has been more and more abandoned and C|U0- 
tations are issued in ad\-ance for one month only. The Midwest 
Milk Manufacturers, representing the milk dealers, market milk 
plants and condenserics in the Chicago milk district and the 
middle western states, confer on the price to be paid for milk 
for the succeeding month, toward the close of the preceding 
month, and announce these prices inv the coming month. 

Generall}- speaking, and as Nardin points out, "the price 
in Illinois is subject to prices of fresh milk distributed in Chi- 
cago and St. L.ouis. I-'rices in Xew ^,"ork and Pennsvh-ania 
ha\'e Ijcen sui^ject to the influences of the New York Dair-\'men's 
League, and the iirice of fresh milk for distribution in the Citv 
of New York. The Wisconsin price is most largely influenced 
by butter and cheese prices. The Pacific Coast is, on account 
of freight rates, somewdiat isolated from the rest of the coun- 
try, and the production of exaporated milk on the coast has been 
larger in proper to the demands for fresh milk for distribu- 
tion in coast territory, than jicrhaps in any other part of the 
countr}'." 

The milk condenserics, as a wIkiIc, h.a\c been slow in adopt- 
ing the butterfat content of luillc as their basis for jiayment. 
E\en up to a few years ago most condcn.series were paying 
for the milk on the one hundred weight l)asis and some factories 

' Nardin, Wm. T., Memorandum on Federal Trade Investigation of Milk 
Manufacturers, 1918. 



Milk Supply 



45 



Comparison of Whole Milk Prices Paid by Milk Condenseries in 
the Four Large Condensing Territories in the United States, 
with Whole Milk Values Based on Market Prices of Butter 

and Cheese. 









1 










u 




J 


~ 


Sections of Country 


C 


2 


„ 










% 


■= 


^ 


"t: 


rn 


by Yf-ars 


= 


i- 


t 


" 


>, 


^ 


>. 


£' 


-l 


_3 


^ 






A -^ 


r'. 


Q. 


^. 


X-_ 


X 


-S 


X 


■i y. 'i- 


1914 


























Illinois: 


























Mean condensery price . 


1 , 96 


1.87 


1.72 


1.52 


1.31 


1.22 


1.45 


1 . 56 


1 . 00 


1,77 


1.79 


1.82 


Value in butter <t cheese 


1,34 


1.27 


1,25 


1.17 


1. 14 


1.12 


1. 10 


1.19 


1.17 


1,15 


1.21 


1.21 


New York and 


























Pennsylvania: 


























Mean condensery price . 


1.96 


1.76 


1,73 


1.41 


1.24 


1. 19 


1.35 


1 . 50 


1.64 


1,89 


2.01 


1.90 


Value in butter & cheese 


I.. 34 


1.27 


1,25 


1. 17 


1.14 


1.12 


1,10 


1. 19 


1,17 


1,15 


1.21 


1.21 


Wisconsin: 


























Mean condenscry price . 


1.87 


l.,S2 


1.79 


1.62 


1.40 


1.28 


1,43 


1.47 


1 , 50 


1,72 


1.77 


1.80 


Value in butter & cheese 


1 . -.u 


1.27 


1,25 


1. 17 


1, 14 


1.12 


1,10 


1. 19 


1, 17 


1, 15 


1.21 


1.21 


Pacific Coast: 


























Mean condenscry price , 


1.7.3 


1 . 69 


1 , 66 


1 . 58 


1.42 


1.45 


1.51 


1 . 65 


1,74 


1,69 


1.71 


1.61 


Value in butter & cheese 


1,34 


1.27 


1,25 


1.17 


1.14 


1.12 


1.10 


1, 19 


1, 17 


1, 15 


1.21 


1.21 


1915 


























Illinois: 


























Mean condensery price . 


1.8.5 


1 . 83 


1,72 


1.51 


1.27 


1.20 


1 , 35 


1.47 


1,50 


1 , 66 


1.77 


1.81 


Value in butter & cheese 


1.2.5 


1.26 


1, 19 


1.21 


1.20 


1. 15 


1.10 


1 . 03 


1,07 


1, 13 


1.24 


1.40 


New York and 


























Pennsylvania: 


























Mean condensery price . 


1,9.0 


1,75 


1,72 


1.41 


1.19 


1.15 


1 . 30 


1 . 52 


1,01 


1.87 


2 . 00 


2.05 


Value in butter & cheese 


1,2.5 


1,2G 


1, 19 


1.21 


1.20 


1.15 


1. 10 


1 . 03 


1,07 


1.13 


1.21 


1 . 40 


Wisconsin: 


























Mean condensery price . 


1,82 


1,82 


1,70 


1.45 


1.30 


1,22 


1.40 


1.43 


1,48 


1 . 65 


1.74 


1.72 


Value in butter & cheese 


1,25 


1,26 


1.19 


1,21 


1.20 


1, 15 


1. 10 


1 , 03 


1,07 


1. 13 


1,24 


1.40 


Pacific Coast: 


























Mean condensery price 


1,51 


1,51 


1 35 


1,30 


1.22 


1,29 


1 . 3S 


1.39 


1,41 


1 . 50 


1..54 


1.59 


Value in butter & cheese 


1,25 


1.26 


1.19 


1.21 


1.20 


1,15 


1.10 


1 . 03 


1,07 


1.13 


1.24 


1.40 


1916 


























Illinois : 


























M'ean condensery price . 


1.S2 


1.74 


1 . 63 


1.04 


1 . 46 


1 , 34 


1.52 


1.67 


1,67 


1.98 


2 1"^ 


2.25 


Value in butter & cheese 


1,37 


1.42 


1.46 


1.42 


1.27 


1,21 


I.IS 


1 . 28 


1,47 


1.57 


1^87 


1.86 


New Yorlc and 


























Pennsylvania: 


























Mean condensery price , 


1.94 


1 . 93 


1.74 


1 . 50 


1.36 


1,27 


1 . 43 


1.62 


1 , 80 


2,42 


2 , 53 


2.57 


Value in butter & cheese 


1.37 


1.42 


1.46 


1.42 


1.27 


1,21 


1.18 


1.28 


1,47 


1 , 57 


1.87 


1.86 


Wisconsin: 


























iVIean condensery price . 


1.78 


1.72 


1.69 


1.67 


1 . 52 


1,42 


1 , 50 


1.60 


1,67 


1 , 95 


2. 15 


2.35 


Value in butter & cheese 


1.37 


1.42 


1.46 


1,42 


1.27 


1,21 


I.IS 


1.28 


1,47 


1.57 


1.87 


1.86 


Pacific Coast: 


























Mean condensery price 


1 . 65 


1 . 06 


1.64 


1 . 53 


1.52 


1,47 


1 . 52 


1.62 


1 , 69 


1.80 


1.92 


1.98 


Value in butter & cheese 


1 . 37 


1.42 


1.46 


1,42 


1.27 


1.21 


1.18 


1.28 


1.47 


1.57 


1.87 


1.86 


1917 


























Illinois: 


























Mean condensery price 


2. 25 


2.12 


2 . 05 


2,37 


2.13 


1.92 


2,20 


2.38 


2,52 


3.00 


3. 18 


3.28 


Value in butter & cliccse 


1.76 


1.84 


1 . 99 


2,04 


2.02 


1,88 


1,93 


2.01 


2,21 


2.19 


2. 14 


2. 19 


New York and 


























Pennsylvania: 


























Mean condensery price . 


2.49 


2.44 


2.32 


2.24 


2 21 


2,12 


2,39 


2.83 


2.91 


3.00 


3.77 


3.52 


Value in butter & cheese 


1.76 


1.84 


1.99 


2.04 


2^02 


1,88 


1.93 


2.01 


2.21 


2.19 


2. 14 


2.19 


Wisconsin: 


























Mean condensery price . 


2.36 


2.25 


2.12 


2.29 


2.21 


1,93 


2 27 


2.45 


2.43 


3.19 


3.32 


3.22 


Value in butter & cheese 


1.76 


1.84 


1.99 


2.04 


2.02 


1.88 


1^93 


2.01 


2 21 


2.19 


2.14 


2.19 


Pacific Coast; 


























Mean condensery price . 


2.06 


2.01 


2.02 


2.09 


2.14 


2.19 


2.32 


2.27 


2.58 


2.67 


2.67 


2.81 


Value in butter & cheese 


1.76 


1.84 


1.99 


2.04 


2.02 


1.88 


1.93 


2.01 


2.21 


2.19 


2.14 


2.19 


1918 


























Illinois: 


























Mean condensery price. 


3.28 


3. 15 


2,95 


2.67 


2.10 


1 . 90 


2.32 


2. -SO 


2.98 


3.42 


3.74 


3.83 


Value in butter & cheese 


2.24 


2.40 


2, 16 


2 . 00 


2.01 


2.01 


2.11 


2.19 


2.48 


2.78 


2,77 


3.09 


New York and 


























Pennsylvania: 


























Mean condensery price . 


3.90 


3.68 


3.40 


2.66 


2.61 


2.00 


2.29 


2.85 


3.16 


3.78 


3,96 


4.17 


Value in butter & chcesa 


2.24 


2.40 


2.16 


2.00 


2.01 


2,01 


2. 15 


2.19 


2.48 


2.78 


2.77 


3.09 


Wisconsin: 


























Mean condensery price . 


3.28 


3,13 


2.88 


2.59 


2.21 


2.07 


2.32 


2.80 


2.98 


3.40 


3.74 


3.84 


Value in butter & cheese 


2.24 


2.40 


2.16 


2.00 


2.01 


2.01 


2.15 


2. 19 


2.48 


2.78 


2.77 


3.09 


Pacific Coast: 


























Mean condensery price . 


2.84 


2.81 


2.66 


2.35 


2.27 


2.28 


2.. 50 


2.81 


3.12 


3.30 


3.41 


3.51 


Value in butter & cheese 


2.24 


2.40 


2.16 


2.00 


2.01 


2.01 


2.15 


2.19 


2.48 


2.78 


2.77 


3.09 



46 



Milk Suppia' 



were still oliii--iii,<4- tn the custemi of Iniyiii.y milk 1>>' the quart, 
usinf;" the yardstick for remnant cans. ( )ther factories paid a 
stated price per himdrcd weif;"ht for all milk testing;' say 4 per 
cent fat and ii\-er and made crin-es]"ii nidino- rednclirms for milk 
containini;- le's than 4 per cent fat. Still nthei's ])aid a premium^ 
for milk testing" alio\e 4 ]ier cent fal. .\ few concerns only 
houydit milk nn the strai,L;'ht liuttei-fat liasis. 

As far as the condensers- is concerned it is entireh' feasifde 
to pay for all milk strict]}' on the hutterfat basis. Milk rich in 
fat, and therefure rich in sulids, ^delds more condensed milk than 
milk ]")rior in fat. To ]>:'\ hv the hundred \\'eic;dit, re£;'ardless of 
(|uality is a practice ^^dlich disci'iminates in fa^'or of breeds of 
low-testint;' milk and at^ainst breeds of hiL^ii-testinq- milk. This 
practice has, in fact, had the result that in the milk su]jply ter- 
ritory of these C( mdenseries the breeds and indiyiduals of cows 
producing' low-testing milk weve encouraged and deyeloped until 
the}' largely predoniinated, at the expen^ie of breeds of co\^'S pro- 
ducing high-testing milk. This situation in turn was responsible 
for the popular, though erroneous impi'ession. that milk from the 
]-Iolstein, Ayrshire and Brown Swiss breeds is better suited for 
milk condensing purposes than milk from the Channel Island 
l)reeds. 

AVithin the last half decade, during which the condensed 
milk industry- has experienced sO' great a de^'elopment, the great 
majority of American condenseries ha\-e abanrloned their old 
way of pa}'ing for milk by yolunie, or Ayeight only. Tslany con- 
densing concerns are now buying their milk ini the straight but- 
terfat basis and nearh- all of the other ci mdenseries pa}' for their 
milk on the Ijasis of a standard fat cinitent, penalizing the farmer 
by loycer |")rices frir milk that falls belnw ;i s])ecilled jier cent 
of fat, and gi\ing hini a bonus for milk in which the per cent 
of fat is (j\-er the standard ligure ^pecdied. Thus lur example 
the ]jrice (!U<iled ma}' .'ipl'l}' td 1(10 lbs. of .y.^ ]ur cent milk with 
an added differential of sa\- 4 cents for each one tenth per cent 
fat abo\'e 3..^ ])er cent and a dedncled dili crenlial id 4 cents for 
each tenth yier cent fat below .y.^ ]ier cent. 

fn CMimtrics wdiei'c ime breed oNerwhelmingl}' ])redominates 
or where the predominating breeds .-ill }ielil milk of similar rich- 
ness and where the freshening of the majority of coa\'S is fairly 



Milk .Supply 



47 




c\-enl\' flistriliutcfl i)\er tlic twche nioiitb- rif llie \-ear. the milk 
c^enerallv crintimics to Ijc biiu^in (jn tlie liasi^ of it^ \\-eip-lit ^t 
\'o!ume, and not 1)\- test. L'ndei' tlic-e conditions tlic ribjcctiiin 
rif not paN'inij; on the Imtterlat lia^is i-, in |)art at lea--t, remo\ed. 
The ,L,rreat Indk of the milk sn|j|il}' I'eaclies the eemden^er}- 
]>y Wd'j^on or ]>}' muten" truck. Usual]}' ])a.rt of the cost of trail'-- 

Ijoi'tation is h'l'ne ]>y tlie factor}- and 

»fi ji ^m part l^y the farmer. Some milk con- 

densinc^' concern- e.pei'ate cnncenii'ation 
pi lints to wdiich the milk i.~ hauled hy 
the iiatroii^, and fri mi which it i^ h.auled 
^~— til tile factor\- in lai-^e L;"las--lined tank- 

rig-. 3. iiiiiunted on nuitiir truck-. Shifiiiient- 

Glass-llnea steel tank on hy '''''-il Site le-^ Conininn in tlli-^ djuntr}-, 
truck for tranapo-rting: jj,,. i,iu-ertai n t\- of rail transportation, 

flirid milk to con- ■ i ■ - i i ■ i • 

aensery wni] it-, treipicnt dek-i}-s. jeopardizes 

Courtp.sy of Tlie Pfaudlur Co the i|ualit}- uf the milk. I'a}-ments fcir 

tlic milk are i^cneralh' made monthly. 
Quality. — The ipialit}- nf the fre-h mdk is the hrst and most 
importaiit factnr tn he c iiisiderc-d. ddie milk ci niden-niL;- factfir}'. 
icj-noriuL;- this fact .'iiid acce|.>tinL:- milk fri nil un-aiiitar\- dairies 
and careless dair\nien. i- hiamd to ]i-i\' tlie penal! \- for such 
neg-leet scioner or later. 

]-'olliiled milk and milk- tliat has nut keen cmiled proniptl} 
and til a reascniahh- Inw temperature mi the farm, ma}' pas- 
throui^'li -the prcicess succes-lull\', if it i- mil t' '■ i -inir. The con- 
densed milk made from it, thuULdi. i-. infei-inr in Ikn-or and keep- 
ing rjnalit}-, and u-uall}- ^Iion'.s -ign-^ nf deteri'iralii m and deca}- 
before it reaches the c.-iusumer. Tlie risk oi li.-indliiu;' ^ucli milk 
is xerv great; it ma}- result in tntal In-s to the manufacturer. 
The triiuhle mae and iiftcn dues begin before the- ])rocess is com- 
pleterl. L'nclean, abnornial, nr ]-)artl}- fermented iiii'k, when sub- 
jected In the ])riices-, is |-iriiiic tn ciinlle and wlie}' nft; tlie con- 
densed milk bieci lilies luni])}- ami -hnws ntlier defects. This is 
especiall}- true where sn|ierli''alirig is practiced aiul where e\'a]-)- 
orated milk is made. 

Milk that has recen'ed the be-t i if care on the farm niae be 
(letrinienlal to the interests nf tlic condeii-er}-. if it ciiiiies from, 
cows less than thirty da^-s belnre their partnritiiin, • ir froni fresli 



48 Milk Supply 

cn\vs \\ithin the first se^'en da^'S after calving, or from cows 
otherwise in abnormal condition. Such milk is often abnormal 
in its chemical properties, and, when subjected to high tempera- 
tures, undergoes changes that make its manufacture into a mar- 
ketable condensed milk difficult. 

Control of Quality. — Every well managed milk condensing 
factory plays the part of an educator in the production of sani- 
tary milk. The condensery usually issues a set of rules, setting 
forth specifically the conditions under which the milk coming 
to the factory shall, or shall not be produced. Copies of these 
rules, which are generally a part of the contract, are placed in 
the hands of all patrons. The condensery employs one or more 
dairy inspectors \vhf)se business it is to see that the rules are 
rigidly enforced. These rules co\-er, in general, the following 
principal points : 

1. Cows. — The milk must come from healthy cows. jMilk 
from cows that are diseased, or that ha\e a diseased udder, or 
that are otherwise in poor physical condition, \\ill be rejected. 

2. Feed and AA^ater. — Do not feed weeds, roots, or other feed 
stuffs possessing strong and obnoxious odors, such as onions, 
garlic, turnips cabbage, wet distillery slops, decayed, musty or 
sour silage, or other fermented feed. 

3. Lactation Period. — Reject all milk from cows less than 
thirty days before, and of the first seven days after calving. 

4. Milkers and Milking. — Milk with clean, dry hands into 
clean utensils and remoAe the milk to the milk room immediatelv 
after dra^^'n. 

5. v'^training. — i^train the milk in the mill< room through a 
fine wire mesh strainer (80 to 100 meshes to the inch). Do not 
use cloth strainers. 

6. Cooling. — Cool the milk to f^O degrees F. or below and 
keep it at that temperature until it reaches the factory. Do not 
mix the warm morning's milk with the cold night's milk; cool 
the morning's milk befnre mixing, or send it to the factory in 
separate cans. 

7. Care of Utensils. — ^Kinse with cold water, ^\■ash with 
\varm water and \vashing powder, and rinse «'ith boiling water 



Milk Supply 49 

all milk utensils thoronghl}^ after use ; keep them in a clean ijlace 
between milkinc,^s. Do not store the milk <:,n the farm in cans 
that ha\-e not been «-ashed by the factor}-. 

8. Stables. — Whitewash the stable tA\-ice e\-ery ^■ear and re- 
mo\-e manure daily. ( Some condenseries furnish spra\- pumps 
for applying ^^d^ite\^-a=h. i 

Inspection of Milk at the Condensery. — At the condenserv 
the milk is sulyiected tcj rigid inspecti'jn by a man avIio is. or 
should be. an expert 'in milk inspection: e\-er}- can is examined. 
Warm milk and milk that ib tainted, or smells slightly sour 
should be rejected. 

Inspection of Alilk b}- Sense of Smell and Taste. — In most 
cases the milk is inspected with reference to odior. The inspector 
Cjuickly raises the coAcr of each can t'^i his nostrils. The odor in 
the co\'er is t}-pical of that in the can. If it is "off," the can is 
rejected. -\n exj.ierienced man cin the platfi.irm can, \)y the use 
of this method, tell with much accuracy, wdiether the milk sliould 
pass or not. 

Inspection cif ^lilk According to its Temperature, — The 
temperaturc is also noted. Idiis need n<jt l)e done with the ther- 
mometer in each case. lj_\' pdacing his hand rai the brid\" nf the 
can, or by noting tlie A\'armth of the air and cd^r in the ciiver 
immediately after renio\ing it, ';>r l^}- th.e ]M'esence cr absence of 
small particles of butter fjciating cm the surface "f the milk, the 
inspector can readily tell if the milk has or has licit lieen jjrciperl}- 
cooled. rV correct thermcimeter should always fie on the jdat- 
form for guidance. 

Inspection of ]\Iilk by the Use of Acid Tests. — Since the 
degree of acidit}-, or the -\veetness of the milk, i^ ciiic of the 
chief factors that determines its fitness for condensing purposes, 
tests that rapidl}' and accurately determine the per cent cjf lac- 
tic acid in the fresh milk, are of great ser\'ice. 

Slime concerns hax'e adopted a definite acid standard iif milk, 
rejecting all milk containing more than the maximum per cent 
of acid of their standard, and the}- test e\-er}- can of milk recei\-ed 
with an acid test. This method insures sweet milk in the fac- 



50 Milk Suppi^y 

tory, provided that the alkaHne solutirms used are correct. This 
work involves considerable expense, howexer, and unless the 
solution is carefully prepared and made up fresh often, its use 
may yield misleading results. Again, when the acid test is per- 
formed on the milk of each can, the acceptance or rejection of 
the milk depends altogether on the per cent of acid it contains. 
Although milk may l)e otherwise unfit for use, it will pass, as 
long as it is low in acidity. Experience has shown that, while 
it is necessary for the condensery to decide on a maximum acid- 
ity of milk abo\'e which all milk be rejected, the nose and the 
palate of the experienced inspector are better criterions tnan 
the acid test alone, as to- the fitness of milk for condensing. Acid 
tests are valuable in the case of. uncertainty and suspicion as 
to the qualitj" of any given can of milk. All milk containing .IS 
per cent lactic acid or more is dangerous for condensing pur- 
poses. 

Acid Test for Daily Use, Where Each Can of Milk is Tested. 

Stock Solution. — Weigh out two hundred grams of sodium 
hydrate C. P. and add distilled water to make U[) one liter. 
Keep tightly stoppered. 

Solution for Daily Use. — Mix 4 c.c. of stock solution with 
991 c.c. of distilled water, and add 5 c.c, of phenolphthalein indi- 
cator. The indicator is jjrepared as follows: dissolve one gram 
of dry phenolphthalein in 100 c.c. of 50 per cent alcolTol. Each 
cubic centimeter of the prepared alkaline solution neutralizes 
.01 per cent lactic acid, 18 c.c, of the prepared solution, there- 
fore, neutralize .18 per cent lactic acid, when a 17.6 c.c. pipette 
is used for measuring out the milk. 

Making the Test, — With the Babcock pi]xnte, measure 17,(i 
c.c. into a white cup. With a small dipper, holding exactlv 18 
c.c, pour IS c,c, of the prepared solution into the cup: stir or 
shake. If the mixture remains fainth' pink, it ciintains less than 
.18 per cent acid and will pass; if it turns white, it contains more 
than .18 per cent acid and should be rejected or subjected to addi- 
tional tests. 

The stock solution should be standardized by a chemist. 
The prepared solution should be made up daily. Both solutions 



Milk Supply 



51 



should be kept in L^'la^s boltles. tigiitK- ciirkcd. The Ijijttle con- 
taining the stock sohiti'"in should be qiass-sto])pered. 

The Boiling Test. — In-pection b\- Ileatingv The heating t<:' 
the boiling point of sam]")le< of sus|)icious milk furnishes a most 
reliable means to fletermine the fitness of such nulk tor condens- 
ing. In many instance^ milk ma\' satisfactririly pass the rather 
tests and yet it may not be in conditirin to stcmd the heal to 
which it will be subjected in the iirocc^s. If it curdles, wdien 
boiled, it is ob\'iouslv unfit for u^e. This test shows mure than 
the acid test above. I'}' its use the ciperator is able to detect 
inilk otherwdse aljnormal, such as milk cnitaining colostrum, etc., 
or the ijroteids of \\'hich are unstable for otlier reasons. 

}ilaking the Test. — The l:>Miling te<t i'- simple and can be 
manipulated rapidl\'. A saniple of the que^tionaljle milk is taken 
intC) a small di])per. Tlie dipj.ier is held up against a steam jet 
turned down into the milk. r)irect .^tearn is turned into the 
milk until it comes to a boil. If flakes or specks of curd cling 
to the sides of the dip|(er, the milk i-^ unht for use. 

An alcohol lamp or ga^^ burner on the platform ma_\' be used 
for heating the sample. In this case a few cubic centimeters 
of the milk are discharged witli an ordinar}- pipette into an orui- 
nary test tube, such as are in common use in the chemical labo- 
ratory and can be rilitained from the drug stnre. The tube is 
held over the flame and the milk comes tn a b)oil in less than 
a minute. If the milk i^ in goC'd condition the sides of the glass 
tube remain perfectly clear. If it curdles ujion heating, the sides 
of the tube show fine specks of the curd. The appearance of 
these specks condemns the milk. 

In the ca'^e of milk intended for e\-aporated milk, the boiling 
test is not sufficiently severe to reveal the fitness of the milk 
for the sterilizing ]")rocess. Fr.r the reliable detectii'm of unde- 
sirable milk for this purpose, the use of the pilot sterilizer or test 
sterilizer is recrnumcnded. Suspicious ^amides cif milk are filled 
intcj tins, the tins are sealed and placed into the pilot sterilizer 
where they are gi\'en the same process oi sterilizatir)n as is 
used for the finished product. Milk that A\-ithstands this sterili- 
zation can be depended upon to also pass safely through the 
process of manufacture. yiWk that curdles in this test steriliza- 



52 



MiivK Supply 



tioii (."ibviLiusly shows its unfitness, the cause of \\'hich sliould be 
promptly inxestigatcd and remo\'ed. 
Fig, 9. 

The Sediment Test.— Tliis 
test shows the relati\'e anidunt of 
dirt present in milk. ()ne-hall 
|)int is passed through a smah cir- 
cle of absiirl)cnt cotton and the 
amount rif mechanical impurities 
present in the milk is indicated Ijy 
the color of the cotton after filtra- 
tion, fn order to hasten the filtra- 
tion, the milk is forced through 
the filter under slight pressure; 
this is accomplished by a rubber 
Indb attachment to the ajiparatus, 
as shown in the accompanviuL;" 

Fio-. I) Pig-. 9 

■^ Tlie sediment tester 





rig-. 10. Cotton Filters 
Clean mili Dirty mUk 

If the cutton retains a white or creamy color, the milk is 
relati\'ely free from filth. Milk produced under unsamlary con- 
ditions stains the rotton liro>\n or black. 

'I'liese co'ton lilters m.ay be pasted on a sheet of paper similar 
to a milk sheet, arrrniged i-n thai the cii'cles arc placed opposite 
the respecti\c patron's n.amc or mmdier. When shown to the 
])atri:'ns who come to the lactor\-, the}- furnish a most eliective 
object lesson to them. When the milk reaches the factory on 



j\lji,i-; Supply 



53 



route wagijiis (ir 1")_\- rail, cards -irnilar tr; iMLnire 11 mav he 
maik'fl I'j tile patriiii-. The c-N-idciice i- ^o ciinrlnsn"e tint e'/eii 
the must riljstiiiate ]iatrriii caiuint licl]' adiniltiiiL;' liis vnilt and 
can nsualh' lie induced tn "ilean vv.' 



MIL-K CONDENSING COMPANY 

SEDIMENT CARD 


Name 


/ 

/ 
/ 

THIS 13 THE AMOUNT OF DIRT 1 fJ 
ONE PINT OF YOUR MILK 


Address 
Date 


No. 



Fermentation Tests. — Tlie-c tests are of -reat ^-alue in the 
rapid determination "\ the hind. , ,f ha.ctei-ia with wdnch the mill: 
from individual ]iatrons is cuHtaminalcd. (.dass tuhes are filled 
one-half full "i milk frriUi each ]iatr..ii. Tliese tubes are set in 
a constant \\-ater hath at 100 de-rets !•'. and the chan-es which, 
milk under,;j-i:es are noled after -ix, twelce and tweniy-fciUr liours. 

A solid curd witli a clear \\hie_v indiicates that lactic acid 
bacteria are the chief orc'-ani-ms and th.at the milk lias been 
produced under cleanly conditions. Tiicse or-anism- arc bulled 
when the rnilk rs heated in the hot wells. Such milk therefore 
is safe, unlc-s it contains cxi-essi\'e acid, as shuwn f)}- acid test. 

A curd wuth gas IimIcs, or tliat which i- tiirn In pieces in the 
tubes, shciws the presence of '^.as-] irodueinc; .qerms. These come 
larc;'el\' from manure ..ind other lilth. -\mong" these are I'.acdlus 
cob communis, the natural inhabitant nf the ccibm oi the animal, 
and butvric acid. oreani.~ms which, are s]irire l;earers. 'Idle latter 
esijeciall}' may .gi'-'e rise to scrinus milk- d,efects, causing "swell 



54 P'aCTORV vSANri'ATlON 

licads." I'alrcins ^cinlitiL; such milk ^lifjuld 1)6 looked after at 
once. 

]f the curd disMiK'cs, ^ i)- im curd is formed and the milk 
changes into a traiisjiarent lii|uid, it u^uall}' is ccintaminated f)y 
i^'enns frnm Ihc dust iil Iia\' and lieddiii;4', nr ])iilhited \\ater. To 
this class of oi'f^anisms lielonL;' I'.acillns suhtilis, Hacillus fliiores- 
ccns lifinifaciens, 1 'lectridinni fnetidnm, llacillus putrilicus, etc. 
Some of these are \iiilent ^as ]n-odiicers and most r)f them are 
S|)ore-l)carers. The\- ai'c the cause of ilic most disastrcjus milk 
defects. kJairies fi'oni wddch such milk ciimes slioidd l)e \dg'or- 
ously insitected and all milk' from them sin add be rejected, until 
the patrons ha^e learned how tn furnish sanitary milk. 

Milk that remains unchan,L;'ed for t\\ent}--foiir hours when 
suljjected to the fermentation test, su^'qests that it contains some 
preservative, ft is possible. ho\\X'\er, for milk ]iroduced under 
ideally sanitarv conditions to remain mirmal and unchanged even 
at these hi,gh temperatures for se\-era] da^■s. A\diere milk comes 
to the factory in l)ulk as is the case in the condenscry, samples 
shoying" abnormal keejiing ciualit\- should be regarded with sus- 
picion, and the res'iectiA'c dairies should receiA-e immediate and 
thorough inspection. 

Tests for Eutterfat and Specific Gravity. — In the factories 
where the milk is not paid fur on the 1.)Uttcrfat l^asis, composite 
samples should he taken daih', to he tested for fat and specific 
gravity, at regular inter\-als of from two td four Aveeks. in order 
to detect possible adulterations by skimming or by the addition 
of water. For specific directions for the P.abcock test, the use of 
the lactometer and tests for pi-eser\-ati\-es see Chapter XXX 
"Chemical Tests and Analyses of Milk and Milk Products." 

FACTORY SANITATION. 

In the preyious paragra]>lis, s]K'cial emphasis was placed on 
the great impr)rtance of a gnod fpialily of fresh milk. It is equally 
e.ssenti;il that the factory be kept in cxemplarA- condition as to 
cleanliness and sanitalinn. This is necessar\- because of its eiTect 
on the ;patrons and on the w In ilesomcnrss and marketable prop- 
erty of the finished ])roduct. 

Effect on Patrons. — It does nnt take the watchful e}e of the 
intelligent patron, whu daily cuines to the factor\', \evy long to 



Fac'i'okv vSanita'i ion 



55 



learn, whether the mariiifaeturer gives his milk as Qood care as 
he pa\-e it rm the farm. ,\ n^-ood example set by the factory will 
mean much Inward instilling" the fiatron with ambition to do 
likewise on the farm. Sliiftles^ness is a rnntaL;"i' m^ disease, to 
wh.ich the a\era;_;e fai'mer is \-ery suscejitible. ft i^. therefore, 
inconsistent for the factor)- t^ i is'^ue and enforce rules of sanitation 
for the dairy farmer wdieu. within its own walN. all jirinciples 
of sanitation are \iolated. 

EfTect on Wholesomeness of the Product. — Uncleanliness 
and hlth interfeix- with the wdirilesomeness of the rimduct. Con- 
densed milk made in a hict'ir\' ii^morinc:" sanitatirm, ma\' cimtain 
certain jiroducf- of deca\- which are [joiM.nous to the human 
s}'stem, Ayain, it ma\" cntain i^erms of infectious diseases and 
thus become the caus^- of widespread epidemics of these diseases 
and possibly claim many \ ictims. As a matter of common decenc^■ 
and of dut}- tri the comnionwealllT, the condenser\- sliould pav 
close attenti'ju to deanline-s in all (ipcratunis. 

Effect on the Marketable Property of the Product. — Again, 
uncleanliness in the factor\- is bound to Ijring financially dis- 
astrous results. 'Hie seriousness of the disaster is grcath' aug- 
mented b}' the fact that the consequences of neglect are usually 
not apparent until after the gijods ha\X' reached the market. The 
]")ollution of cijurlensed milk with imjairilies and lilth in the 
factor}', shrjrtens t!ie life of the jjroduct Such condensed milk 
is of A'ery poor keejiing" (|ualit\\ It nla^■ reacli the mark'et and the 
consumer in condition that causes it tc: lie rejected, resulting in 
a ci:implete loss to the ma.nufaeturer. The manufacturer allowing 
such conditions to exist, is usually the last man to I'ealize and 
admit that he is at faidt, which i-enders attem[)ts U' lr)cate and 
stop such defects e.xceedingh" difficult, lAirtherniore. instead 
of helping to build uji the ti'adc and to adwertise the brand, he 
demorali/;es it. 

How to Keep Factory in Sanitary Condition. --Cleanliness 
in the factcuw is abs.ihilel}" essential. The milk \ats should l>e 
rinsed with plent\" of water and scrubbed and steamed thrir- 
oughly, as s,-Min as jiossible after use. The copper kettles and 
vacuum pans shiiuld be rinsed, then seciured with sand|iaper or 
emery cloth, then rinsed and steamed thoroughlw The milk 
pipes sliould be sci.iured b_\- running tlr,e brushes through, flush- 



56 Factory v^anitation 

iiiL;' tlifiii with clean watri- and ^KaniinL;" tliciii until they are 
scaldinc;" hut. In the c:i^o nf mill-; ])i]ics mT c'xcessi\-e len:;'th, tliey 
^himUl he well Unfiled with h^i alk'ahne water. ".Mdk inimps 
shuuld ho taken a]5art e\eiw da\- and freed thi na )U[i'hl}' from all 
remnant.'^ cd' milk-. The water m the cmdin^^- tanks shrnild he 
cli.:'.nL;ed as (.d'tcn as is nceessai w hi insure elean water in them 
at all times. The In imeieeni/cr shduhl )-eeei\"e special attenticiu, 
all its Aahes slmnlil he tin irnuLdil)' ch-aned, and steamed daily. 
The cocilinc;- coils sin add he scalded hefdre use. The hlliiiL;' 
machines for e\apeirated milk' shiaild he freed fnim all milk, 
rinsed and steamed tin iri >UL;'hK- and m i remnants nf milk should 
he alldwed to stick tn the \al\es. The TdlinL;' machines for 
sweetened condensed milk should he emptied and comiiletely 
washed, at least mice per \^■eek, and juaitected from dust and flies 
bv covering- them when m't in use. The tin cans should he steired 
in a clean room and eA-er\' jirecautiou slnauld he taken to guard 
against their defilement frum dirt, dust, imsects and mice. Wliere 
possildc thcw should In- sterilized liehare use. 

All \ ats kettles milk ci in\-e\(jrs, \acuum jiaiis, milk ]nimps, 
and all maehinery cnmiiig in ciuitact with milk, slmuld he ilushed 
and steamcil again in the morning, as sixin as the condeiiser\' 
opens. The sugar chute slmuld he ke])t clean, care hciiig taken 
that nc) dam]"! it \>et sugar remains in il. Special attention shnuld 
l)e gi\'en to the w,-isliiiig id' the farmers' cans. .Vfter ^\■ashillg 
wdth hrush and hot water ciuilainin;; simiic gM(:id washing jniwder. 
the_\' slnuild he thordughly rinsed,, then steamed until the\- arc 
h(jt. If ])Ossil:ile tliCA' should he dried h\- an air blast. 

The flours and walls ed" the facl(ir)- ^Inmld be kejU in saiiitar\- 
condition. .\ccuniu!ated rubbish slnmld be rennwed and sewers 
aiifl drains shnuld be disinfected at regular inter\;ils. 

Can Washing.- .\in-dlier extreniel}- impm-iant. and often 
w-(aefnll)- neglected feature, relatiiiL: tn die erfecti\e management 
nf the ji.atrnn li-nni the st;ind])i liiil i>\ liiL;h (;uaht\" nf milk, is the 
condition of the milk cans wdiicli the fattniw returns tn the ]iatrnn. 

'idle ])ati-nn is hniind tn Inse his inlen-st ui t.aking painstaking 
care of his niill< when the cans returned tn him b\ the factnr\- are 
lillhy and h inl-snielliu"-. Xnr need the f,-ictnr\' expect the milk, 
it recei\a-s in such cans, tn be either n] liiL;h ipi,alit\' fnr cmidens- 
mg ijr wdn.d.esnme. And _\'et an a>|nundini; |)rn]>nrlinn nf cnn- 



FArTom' Saxitatiox 



denser)- cans reacli tin- fa.rnier in ri.indiiiun, unfit li) receive a.nd 
shi|.) milk in. 

l'ro|icr can wasiiinci' cnnsi-t- mi' f'.nr e-~ential i'i])i/ratir,ns, 
naniel}-, \\-a-ln'in^\ rin-in^'. '-U:aniin!_;- ami dr\inc;. 

The cans ^liiadd lie AWifdied until all la-riinant-. of milk a.re 
remu\-ed. Tliey sliduld kc rin^etl w-itli kct water tmlil all ••^ tlie 
dirty wash water is 'lucked "in, Tlif),- slirmld ke vteann-d initil 
"piping'-hnt." and tliey slmnlf! ke drie^l nntil 'dione-drw " 

1 liin'e I- niiw a.dnn.rakk- efjin]imeiit a\"ailalde Mn tke market 
ftir accfinipk-liiiiL'' tlie.-e Ukav im])'irt:uil jcLU-pi i;-e-.. aff'irdin;^- ade- 
quate facilities- ''1 enakle tlie candeiwrj-x- ]•■ r'-tm-n tr. tke jiati-'ni 
cans tkat arc clean, sterile and dr\'. 

Care of Ty'Iilk in the Factory Prior to Manufacture. — ddie 
prriklem i jI sc kandlinL;" tie.- mi'f: in tke factiMW, fmrn tke time it 
arri\x-s untd it i- lieatcd ijre]iara'a a'X' t" c a.]jisra.ticin. i-. an im- 
portant one. tlia! lias rerei\"cd mti^'k careful consideration k}" tke 
fcjremost ciinflciwcfl niiij-: men. Since kacterio]o^ical rinah"scs 
ka\'c sliown tkat, undt-r fa\'orakle temperature conditio ins, the 
micro-orL;,anism'^ ])ia;-sent :n ntill; are ca])a.klc cif ilnuklinr:^'" in 
nundjer once e\'ery t\ver,ty minute-, it i- essrntial tkat tke milk 
eitker ke keaced to kir/k enou,L;'k tempiei-atures tci li-estrrjy o'erm 
life, or ke c-ookal t'l a temperature low en'ai.^k t^ -tc-ji L;rciWtk 
and multipkcat'' 'U, as -or,]i ,-i- p.o,--iklc. 

k.ritk iiractice,- are feasikle. kiit 
to keat tlie kir.'je \"o]ume- c,f milt; tkat 
arrive at tlie factory, all witkin a few 
kour-;, \\-i-aild ta.x tke equipment of tke 
factor\- under a\'ei\aL;"e conditions \-er\' 
kca'.nh'. And unle.-s tke condeiisery 
were ei|ui]iped witk \ er\' larue wacu- 
tiui j.riu cajiacitw mucli ^ a' tlii- keati-il 
milk would ka\ e to lie idle in ike 
lore\'.^arn"icr'-. lea- kour^, aeaitirii; it^ 
rig-. 12. turn lor ciudensatnan. ddiis woidd 

Glass-lined tank for cooling- ke unde«irakle ami mi-k t prox'e karui- 
and holding- null!: before ^ i 

manufacture inl tii tke qu.alit^' cif tkc finisked 

Courtesy of The Pfaudler Co. product. 

I'diorts lia\"e, therelijre, keen made. es];)eciall\- \'i-itkin recent 
years, tc) proAide a practical and eccninmical metkod of cciolin^' 




58 



FaC'I'OR'i- v'-lANITATIOr 



tlie milk as soun as it arri\'es ami of linldin^ it at a Inw tempera- 
ture until I'cady fnr licatiiiL;" and ci mdensinc;. Tliis lias led tri 
di\ersc practices, sncli as laimiinL; the milk ri\er a surface coil 
cooler into a jacketed tank', or co(jlinL;" it li_\' running;" it into a 
large taidc e(pn'])pcd with cold air Mowers, or cooling the milk in 
large \'ats e(pii]i])ed with re\'ol\ing coils, etc. 

One of the later methods for refrigerating the milk consists 
of the use of large, ttsnalh- circular, glass enameled steel tanks. 
These tanks are coniideteh' surrounded on their sides and bottom 
])}■ a cidd water ur hrine jacket and are equipped with a milk 
(listrihuting (kwice that causes the inflowing milk to he sprayed 
h)' grax'it}' against the top df the sides of the tank and to per- 
colate in a thin l-i)'cr down the sides, Tn this manner the cooling 
is in.stantaneous, the entire sides of the tank- 1 icing surrounded 
by the cooling mediuru, Tt is aime<l to cool the milk to al)out 
40 to 43 degrees F. and to licild it at this tcm[)erature until ready 
for manufacture. 

These glass ecjaiueled tanks ha\e man\" adwantages ; the\' 
minimize the initial ccist of the necessar}' equipment, reducing 
the number of costly wacuum fians, and forewarmers, required; 
they cut do\vn labor cost, because tlie\' reduce the equipment to 
fewer pieces to ojierate and to clean : the^- .are '4 such construc- 
tion that they are easil}' and rpiickh' cleaned and readih- kept in 
proper sanitar}- condition, the smonth and ]ieii-c-free enamel \'ields 
more readily to the brush than copper surfaces: the\' axaiid all 
])ossibilit}' of chemical action of the milk on metal and, therefore, 
are a reliable safeguard against thc^ development of metallic 
Ha\-or in the milk. 

also facilitates the 



tan 



'I he use of these large holding 
standardization 'if the luilk fur fal and xdids not f.at. h'or detailed 
directiniis nn standardizing see L'luqiter X .\ 1 X . 



PART II. 

MANUFACTURE OF SWEETENED 
CONDENSED MILK 

Cji-\i''ii.r IV . 

DEFINITION. 

S"\\'cetcned c iiirlense'l milk i'- c.ha's niil!<. ri iikIch^l-iI at tli'.- 
ratio of 2l[. to 2'-y^ parts nf froli milk to 1 ]5art crindcn>ed milk. 
It contains ciinsiclerablc f|nantities uf <ucr>isc. usualK- abrail 
40-p£j" cent, trj ]ir(.-scr\c it. It i> ' if ^crni-nmfl cijn>i^tcnc}^ and 
reaches tlie maid<et in iiiTmeticad}- -ciled tin cans, \ar_\nnL:" iri 
size from cii^dit ounces to r,n(: L'-allcin. and in barrel^ similar tn 
td.ncose barrels. liwldniL; Ir^'m ikrcc linnd.red ti i ^e\"en liund.i'cd 
ponnds (if crindenscd milk. Wlun made prupcrl}'. -wcetencd 
condensed milk will keep for man}- nionllis. but i.^ best A\dien 
fi'esh. 

HEATING. 

Purpose. — The fir^t ^tef) m tin- ])riieess is to heat the milk to 
near the boilinc;' point, d'here are three chief reasons for A\hiidi 
the milk is heated, namcK'. to destroy mo-t of the bacteria. }-east. 
mrilds and other orii'anized and nnorgani/ed ferments, to facilitate 
the sohition C'i the suci'risc. and 1o pre\eiit the milk froni burnin,L;' 
on to the heatinL;" surface in the \acunm \>i\n. 

Destruction of Ferments.— -W hen. the fresh milk ai-ri\"es at 
the factor\- it contain? micr(j-orL^aiiisms in \"ar_\'inc;' nnmliers and 
of different specie^;. Tn so^me cases disease-|n'oducinL;" fjacteria 
may be present, renderini;" the milk dan^a-rous to the health and 
life of the ceinsmiler, were it not hea.ted tij temperatures hi,^ll 
enough to destroy the^e i^erms. Again, milk ma\- contain liac- 
teria, A'cast. molds and enzymes that eaust- it trj iindergrj un- 
desiral.ile fermentations which, il allo\\ ed tci ])ass into the ccin- 
densed milk. ma_\' tend to sliorlen the life and impair the wdiole- 
someness and mark'etable in'operties of tlie latter. 



60 SwKi'.TivNi-'.D C()Ndi-:ns1';i) Milk — Hka'i'ing 

Solution of Sucrose.-' Tt is nct}- essential tliat all the cane 
sni;ar which is added tn (he milk be cnm))letelv dissnl\-ed, in 
iirrjer ti i les-en the tendency cif the sui^ar td fi irm lart;"e crystals 
in the linislied |ir(idnct. IhidissuKcd sucjar crA'stals in condensed 
milk act in a physical way nuich as bacteria in fluid milk do in a 
bacterii di laical wa\', Thev mnltiiiK" rapidlx', and such cnndenscd 
milk nsnalh' ]-ireci|iitates its sn^ai" befnre the pi"i"iduct reaches 
the market. The presence of excessively large sugar crystals 
mal-res the product l^"ritt^' and causes the fnrmatinn nf a sediment 
in the Ijottimi of the cans; this is objectionable to the consumers. 
AAdien the nulk is heated tci -the ]")rii])er temperature fiefore con- 
densing, the sedntiiin rif the cane sugar is facilitated and the 
tendency toward grittiness is minimi.zed. 

Prevention of Burning Milk on Heating Surface. — If cold 
milk Climes in crmtnct \',-ith a steam-heated surface and is not agi- 
tated vigori/usly, it bakes nr Imrns unto this h.eatmg surface. The 
mill: in the \acunm iian is heated, or kejjt h.ot lyv means of the 
steam jack'ct and enils. These radiators are charged \\'ith steam 
under jiressiu'e aufl c<"insefiuenth- gi\"e riff a high degree rif heat. 
If crihl null-: is di-awn into the \acuum pan, tlie milk remains 
caln.i for a considerable length of time. Drndng this time it is 
bounfl to bake or bui'n on the hcatin.e: surlace, gi\"ing the product 
a bui'nt llaNCir, causing- it to cont.ain bro^vn specks and retarding 
the iiroccss of e\aporalir,n. If the milk is licit \\dien it enters the 
pan, the reduced nreshiu-e in th.e ]>an causes it to boil \-iolentlv at 
once, a\oiding- all dang;er of sticking to and burning on the heat- 
ing siu'face and making possible maximum |-ai)idit\' of e\-apora- 
tion. 

Temperature. In mo^l factories the milk is heated to from 
1X0 fleg|-ees b. to .510 de!.;'rees h\ This tcmperalure is sufficient 
to accoiuplish the three ]inr]ioses. Mealing !he milk' to the 
lioiling ])oint tends pi gi\e i( a r.alher prononnced cooked lla\'or, 
\\hi(di is objection.able. Ibi\\e\cr, in the case ol d.aneer of con- 
tamination of the nnik wilh resistant t\pes o|' undesirable bac- 
teida, it nia\ becimie neecss,ar\" io ]i|-:ietice boiling- tiie milk. 

Manner of Heating. — 'I'horon-h, efficient and rapid heating 
of large \ohimes of luillc Io temperatures near tiie boiling point 
is a problem thai requires careful consideration, 'J'he tendency 



Sweetened Condexsed ;Milk — Heating 



61 



of the milk to =tick to the heating surface i5 a permanent obstacle 
and efforts to o\-ercome this frequentl}- restilt in sacrificing th'or- 
oughncis of lieating. 

A \ririet_\- of methods and immer'ivi^ riifferent types of ma- 
chines are used for this purpo-e in the differer.t milk condensinc: 
factories. Some use large cojjper kettle- in v.hich the milk i- 
heated Ijy turnin'r -team direct into the milk. ' )thers u-e iacketed 
copper kettle- equipjied \-'.-ith a re\-<ik.-ing agitator. 'Die milk i- 

hi-ated 1)\' tin'ihng -team under 
liressnre int" the jacket and the 
Inu-niiig I. if the milk is ]jre\ented hv 
keeping tlur milk in con-tant motion. 
In tlii- ca-e the milk is usualh' 
heated tn al.Mut 170 degree- F. l.y 
the jacket and fr'jm there on the 
temperature is raised tr, that de-ired. 
h}- turning -team direct int''' the Ivot 
milk. Still others are heating the 
milk h}- means of large cmitinuous 
]ia-teurizers in wdiich ca-e hot water 
'ir -team -er\"e- as the heating medi- 
um. The milk passes in a thin la^x-r 
between twn water-heated surfaces, 
i^ine of v.diich is rCA-oih-ing. In some 
factories the milk is fi.irced thrMugh a ,-eries cif pipes inclosed in 
a hot Avatcr or steam iacket. 

Finalh', in some cf inden-eric- a omliinatii ni nf the ccju- 
tinuous pa-teurizer and the plain > ']■ jacketcfl kettle i- u-ed. The 
milk is heated to near!}" the dc.-ired temperature in the pasteur- 
izer. From there it lluw- int'i the kettle, where the heating is 
completed. This methnd in-ni"e- efficient heating and, at the 
same time, if operated ]irMperl_\". it pre\ents -ca'ching i if the 
milk on the heating -urfaee. 

Advantages and Disadvantages of Different Methods of 

Heating. — In mcist factiirie> in this cwnntr)- the fn-st named 
method is used. Steam is turned direct into the mi'k until it 
boils up. This is the oldest and nm-t |..iiniitive method. Wdiile 
\'er}' simple in operati'in, this method has some objections. At 




Fig-. 13. 
The hot well or forewarmer 

Courtesy of Arthur Harris & Co 



62 



Swi'.IiTlvNI'D CONDKNSKD MiLK — HEATING 



best, mucli df the steam used condenses in the milk, increasing 
thf amount of water that has to be evaporated. It, therefore, 
prolongs the process of condensing and increases the cost of 
manufacture. This is es|)eciall)' true where the boilers arc 
located at some distance from the hot wells and the steam pipes 
are not well insulated, causing the steam t<j be "wet," and ^^'hen 
the milk to be heated is cold. It is estimated that the amount 
of extraneous water thus added to the milk increases the bulk 
of the milk by about one-sixth of its original vohnne. The steam 
is often associated Avith impurities, such as cylinder oil from 
the engine, boiler compounds used in the bcjilei's, scales from the 
inside of the pipes, etc. These various impurities cannot possbih- 
improve, but may seriously injure the quality of the milk. It is 
generally conceded by those who ha^■e g"i\en this matter careful 





Tie- 14. steam rosette for heatingr milk 

Courtesy of Arthur Harris & Co. 



thought, that the turning of steam direct into the milk shortens 
the life of the product and causes it to develop a stale flavor, 
which may degenerate into an oily flavor. The same defect is 
noted also when cream is heated by turning steam into it. The 
prolonged exposure of the milk to the condensing process, as the 
result of the additicm t(.) the milk of considerable cjuantities of 
condensed steam, is an additional objectitm. 

Krum the abo\e discussion it is olnious that the heating of 
tbe milk by bringing it in direct contact with free steam has 
sf^me objections. Just to what extent this practice jeopardizes 
the Cfualit}' has not been very conclusi\'ely demonstrated. But 
it is recommended that the heating with direct steam, if it must 
be practised, be confined f' the last stages of the heating process, 



vSwiiliTUNKD COXDKNSHIJ AIlI.K AdDI'IION' OF SuCAR 63 

that is. that the milk lie heated In pasleurizin^- tem|")erature. 
170 degrees V. or thereabout, b}' the use of a continuous pas- 
teurizer, or a jacketed kettle, or other similar means, and that 
from there on only tri the flesircd temperature, direct ^team be 
used. 

ADDITION OF SUGAR. 

Considera1)le quantities r,i sucrose are added to the cmi- 
densed milk for the pur]jose rif fireserxini;' it. 

Kinds of Sugar. — fn order to con\x-v to the milk preser\-ati\e 
properties, that kind of su;.^ar must be u-ed which dcies not readily 
under£',Ti fermentation and A\diich has the p'lwer of inhibitiiiL;" bac- 
terial acti\-it}' \\hcn fli';-ol\-ed in a concentrated soluti'in. rducose 
could be purchased at a AX-ry low cost but it is not suitable for 
this purp)ose, since it is, in itself. \'erA' unstable and fermentalde. 
It has no preser\-ati\"e fpialities, e\"cn in crmcentrated siihitions. 
Sucrose, saccharrise, or cane snp;ar, C].,kL,„0„. projierh- rehned, 
ferments with difficult}- in concentrated solutions, and has the 
power of retarflinQ' the iO'owth of bacteria anrl rjther ferments 
ordinaril_v pre^etit in sweetened condensed milk. It is. tlierefore, 
\-ery satisfactor\' and useful in this coimection. 

Fleet su,^"ar, which is chemically indentical with cane su,L;'ar, 
is used in European countries \-ery lar^-eh' in the place of cane 
su,L^ar. r)n the continent the beet sui^'ar indu-^try is an important 
factor. A\'ith the climate adapted to the n'riiwing- of sugrn" lieets 
and the lal>or relati\-(dy cheap, beet su.c^ar can be secured by the 
Kurf)pean condenseries at Icivcer cost than cane su,c;'ar. In America 
wdiere the annual suc^ar cane crop is lari;e and where the hiL^h 
cost of labor renrlers the C-xjiense of i^-rowint;' su,L;-ar beets relatix'e^ 
Iv hiL:"h, there is practical!}' no difference Vietween the price of 
cane su,G;ar and beet supar. Wdien _\merican beet suLjar was 
used in the condenseries during' the infanc}- rif the beet su,i;"ar 
industry, this suc,'"ar A">'as found undesirable, often g-iyina- rise to 
fermented condensed milk. It ^-as then su])piosed by the con- 
densed milk men that beet sugar contained \-ery resistant spore- 
bearing Ijacteria, which followed the beets from the soil into the 
refined sugar. This ccmclusion is highly improbable, as the 
temperatures and chemicals employed in the process of beet 
sugar making are prohil3iti\'e fjf the passage of li^-ing bacteria 



64 SwriK'i'KNP.n CoNDTiN.si{D Milk — Addition of vSticar 

from the soil to (lie fini^bcfl sng-ar. It is possiMe, IioweA'cr, that 
tlie standard of relincmciit of American hect suL;ar, during the 
earlier days rif its manufacture, T\as low and tliat some of the 
heet sugar on the market ma\' ha\'e contained small amounts of 
acid, iuA'crt snqar and other impurities, ingredients rif such a 
nature as to render the sugar ])ri"ine to gi\'e rise to fermentation 
and. therefore, condemn its use in the milk condensery. 

While the 1)eet sugar on the market today appears to ha\'e 
reached a very high state of refinement and is, accordin,g to the 
best authorities, equal in purity to cane sugar, it is still shunned 
hy the y\merican condenseries, \\diich insist that nothing Init 
cane sugar will do, Ho\-\-e\"er, \\dienever a shortage occurs of the 
sugar cane crop in the AA'cst Indies. ra\\- European beet sugar is 
imported into tlie United vStates and it all emerges from our sea- 
board refineries as "piu^e cane sugar." It is not improbable, there- 
fore, that the sugar supph' of many American condenseries today 
consists at times largeh' of beet sugar, though it is purchased 
mider the name of cane sugar. 

There is no good reason win' the best refined beet sugar, 
manufactured today in this Cduntry and else"\\diere, should not 
gi\'e fully as good results for condensing jjurposes as the same 
qtiality of cane sugar. Tests marie at the California Agricultural 
Experiment Station"' led to the crincliisinn tliat the two kinds 
of sugar, cane sugar and beet sugar, were e<pialK' A-aluable for 
canning and identical in their lieha\'ior wdien of the same fineness 
of crystallization. 

Beet Sugar Cannot be Detected from Cane Sugar. — While 
the raw sugar frnm the twn difterent sources, the sugar cane 
and the sugai- beet, takes on the character of the impurities from 
wdiicli it has not )'et been freed (the raw product of the sugar 
cane is pleasant in fla\cir, the raw ]")ri"luct from tlie sugar beet 
is acrid and disagreeable in Ha\i'r), the sucrose or so-called pure 
cane sugar, can be and is crystallized out, and in e\■er^• case the 
sugar is identical in chemical ci imposition, appearance and ])rop- 
ei'ties. "i'.y no chemical test can the pure crystallized sugar 
from these twij different sources be distinguished. "- 



1913. 



' C'aUfornia Agricultui\al Experiment Station, Circular No. 33. 

^ United States Department of Agriculture, Farmers' Bulletin No. 53fj 



SwEETKXHD Coxi)i-;xsi{i) AIji.k — Addition' oi- vSui.ar 65 

Quality of the Sugar. — Since ilie siii;ar, sucrose, is added frir 
the purpose of Dre~.er\-iiic;^ the cjiidensed milk, it i- i"'l)\"iiiu- that 
none Init the best ipialit\' of refined sucrri'^e i^ adnii^^ilile, Ijiw 
grade sucrr.sc i=. a priiduct dan;^er'Tn- t-"- ilie rinideii^ed milk- 
business. It is a]jt tiT cnntain sufficient quarititie-; of acid and 
ins'ert sus^ar, to L^iy-t; bacteria and \'ea~t an oppio'tumty to -tan 
fermentation. A\'hen once started, tlie destruction of the product 
is almrist inevitable. In A'cars cif lailure of the cane su^ar crop. 
wdien the prices of sucrose sn-ir hi,L;'h. cond.eiiscries \'ield trequent- 
1}" to the teniptatioM of IniAuii',;" Iriwer p'r.ades irf sUL;rir. The result 
in\arial.)ly is an abiiormalh- larc^e rjutput of condensed milk that 
"goes \\Tong." 

It is A'ery important that the sugar in tlie lactory be stored 
wdiere it will keep dr\". Sucrose has liygrrisc^ ^pic priipertie-. 
W'ben exposed to an atnic.sphere saturated \cith moisture it ali- 
sorbs water. In rlamp stcjrage it is jirone to become lumpy, 
moUh' and freqnenth' sour. A\dien these nrecaiitions are neglected 
there is danger of defecli\'e condensed milk, causing the cans un 
the market to s^-ell, due to gaseous fermentation. 

Adulteration rif sugar with foreign admixtures, such as white 
sand, white claA-. starch, or lime dust is rare, and occurs usually 
only in ptihx'rized sugar. Fiii* tlie detectiijii c,f these adulterants, 
add a spoonful rif the suspicious sugar lo a glass of hot \\'ater 
and stir, I'ure sugar will fliss(il\-e conqdetel}', \\hile nii ist I'f the 
common impurities are insoluble and wiU settle to the bottom. 

The purchase of coarseh" granulated sugar is an eftecti\'e 
safe.guard, insuring freed'">m from these adulterants. Powdered 
sugar should not be used in the ciTudenser}", 

Amount of Sugar, — The aniiunt i")f sucrose used \-aries m 
different crnintries. with dilTerent manufacturing concerns, in 
different factories of the same cfimpaii}- and at different seasons 
of the year. The ncjrmal \ariations range between twelve and 
eighteen pounds of sucrose fjer one hundred pounds of fresh 
milk. 3iIost factories use aliout 16 per cent. 

It is not advisable to o\-erste]> the limits alio\'e indicated. 
Condensed milk ser\-es as a suhjstitute for fresh milk. The more 
sucrose it contains, the greater is the difterence in composition 
and properties Ijetween the condensed milk and the fresh milk. 



66 



v'-!wi",i';'ri{Ni',ii C<)NI)i-:nsi{i) AIilk — Addi'i'ion of Sucak 



Sucrose is iidl as rcailil\" ili^estcd as the 'itlier niL^redients, of 
milk; thei-cfdrc, tlie |)resciicc 'if cxce-si\r aninuiit^ nf cane su,£;'ai- 
in condensed milk tends to reduce its diL;estil)i!it\' and its vvbole- 
si:)meness as a food, \ri-aiii, wdiile normal milk rs a well-balanced 
forxl in itselk tile ])resence ol larjjc ami units of cane snt^'ar in 
it causes this equilibrium to be disturbed, the condensed milk 
beiuL;' excessi\-ely rich in carbi ih_\'drates and relali\'el_v poor in 
proteids. These facts are specially ^i^'uilicant wdiere condensed 
milk is used for infant feedins^' and b_\' persons with \\'eak 
digestion. 

On the other hand, sweetened condensed milk dejiends for its 
preser\-atioii on the sncmse. This class of conden.sed milk is not 
sterile and is ])re\'ented from rapiwd deterioration by the pre- 
ser\'ati\'e action of the sucrose onh'. Therefore, the smaller the 
amount fjf sucrose it contains, the greater the danger from the 
acti^■ity of ferments and the lower its keeping quality. 

The relative prices rif cane sugar and of fresh milk also 
go\-ern the amount of cane sugar ti'^cd in manv factories. In 
summer, milk prices arc low and sugar ]u-ices are hi.gh, Avhile in 
winter the relati\-e prices are re\'ersed. 1 lence there is a tendency 
on the part of the manufacturer to use less sugar in summer than 
in winter. 

Again, the amount of cane sugar used x'aries according to 
the kind ol market lor wliich the condensed milk is intended, 
Milk put on the market in hermeticallv sealed cans is generalh' 
exposed to more un fa\rirable conditions and is older b\- the time 
it reaches the consumer than milk sold in barrels. It is cllstllmar^• 
to use about sixteen ])ounds of cane sugar for e\"er\- one hundred 
pounds of fresh milk for canned goods, and about tweK'C to four- 
teen ]jounds (if cane sug.ar for barrel goods. 

Innalh', there is a strong ten<leiic\' in some localities for 
sweetened condensed milk made in M,i\ and June, to thicken 
rapidly and become cheesy with age. This can easih- be pre\ented 
by the use (jf luore cane sugar in the milk manufactured during 
these months. (See Chapter XXII on "Condensed !\Tilk 
Defects.") 

A more accurate method of determining the amount of sugar 
that should be added to the original milk in ijrder to secure a 



SwEKTKXKU CONIJI'.X^IID AllLK — AuulTlOX OF SuGAR 6/ 



definite desired ])erceiita;;e i if eane .■-ni^ar in the iini^lied prrjfluct. 
is tn acetiratelA' test and standardize tlie Mri^nnal tliiid milk feT 
fat and solirls nut fat and tlien caleulate llic jMiunds ^f ■-nL;"ar to he 
added on the 1)asis ni the t'jtal pounds nf fat ^r nf si 'lids present. 
For dietailed directi' iii-- sec Chapter XXIX "Vi " Standardizatiem." 

Mixing the Sugar. — The ^u^ar is adrk-d tei the hot milk he- 
fore the latter enters the Aacutnn pan. In ^ome factories a 
seiiarate tank is jirMxifled for this jjurjiM^t-. Small jiorti'ms rif 
tlie hut milk are alluwed to Hi i\v into this tank'. Tn these the 
suu;ar is arlded. Thi:^ tank is called the ^UL^ar ^\■^■\\. It i- usualh" 
equi])])ed with a nieidiamcal re\rrsililc -tirrcr, ni' i\-iiiL;" to and Iro 
on an eccentric, to facilitate the siilntitui of (he sii,Lj;ar. The milk 
from the heater and from the suyar well run- into a tank ^nnk 
into the lloor of the well roiam, the l^touui"! well, frcmi which the 
mi.xed sweetened mill; is drawn into the \"acuum pan. In other 
factoric- tlie ^ui.'ai" wcdl ,-md Liiaiund well are riue and the same 
tank, into which the milk- ruiw direct from the heater. In this 
ca.-e it i.s ad\isalilc X' • -et a wire mesh strainer I ^ixtx' to eiL;ht\" 
meshe^ to the inch I oxer the ^ULirir A\"ell. 'i'he suui'ar i^- ])laced 
into this strainer, a little at a lime: the hot milk from the heater 
[tassiiiL;- into and thrnuo-h the strainer di-snhes the -^u^-ar. A 
padflle or stick <hciuld be used to stir the stn^'ar in the '^trainer. 
For greater coineniencc and economA' oi labor, the stic^ar I)arrcls 
and scales are [daced on the floor ewer the \'.ell room The 
suq-ar is transferred to the strainer lielow thri"mL;h a sucrar chute 
which ma}- be equipped at the Ni\\-er end \\-ilh an ad)ustable cut- 
off to req'ulate the suqar coming;" down. ( )r the kettles, hot 
w.-ells or su;';ar wells in which the suL;'ar is added to the niilk, 
are sunk into the flijor sufhcientl}- to facilitate the empt}-ins- rii 
the sugar Ijarrels direct frcmi the flrxir into the milk. In this 
case no sugar cluite is needed, (')ther factories dissol\-e their 
sugar in boiling w-ater in a se])arate tank, and draw- this syrup 
into the \'acuum ])an together with the hcit milk. This is a \-ery 
commeiidable practice, as it mininuzes the danger of undissoh-ed 
sugar crystals escaping into the pian. Mi-ireox-er. this watetA- 
svrup) can be briiled withinit danger of gniiig the rnilk a cooked 
fla\-or. 



68 



Swi'iiTivNiU) Condensed Milk — Condensing 



Ciia!'T];r V. 



CONDENSING. 

l^'roni the grciuncl well in tlie well room the sweetened milk 
is drawn into the wiciuim pan, where it is condensed under 
reduced pressure. I'he \acuum pan is usually located on the 
second floor over the well room, or in the well itself, in which 
case it is ele\ated abo\ e tlie floor six to eight feet. The ^•acuum 
pan is connected with the \acuum pump, which should be in- 
stalled near the pan. 

Description of the Vacuum Pan. 
— The \acuum pan is a retort in 
which the milk is heated and evapo- 
rated in partial \'acuum. The origin 
of the term "pan" has not been 
satisfactorily ex]ilained. Tn the early 
and experimental days of the manu- 
facture of condensed milk, the milk 
was e\'aporated in open kettles, 
called pans. It is probable that the 
name of this primitive apparatus 
\\-as passed on to the more perfected 
machinery now* in use. 

The \'acuum pans are construct- 
ed of copper, iron, steel or bronze 
r^racticalK' all of the \-acuum pans 
used for condensing milk are made 
of cop[)cr througlKTUt; the^• are of 
\ari(ius styles and sizes. The pre- 
dominating size used in milk con- 

denseries is the "six-foot pan." By the term six-foot is meant a 

retort measuring six feet in diameter. 

There are two general t\]>es nf \ .icuuin pans on the market; 
pans that .are relati\el\' wide in ili:imeter and shallow in depth, 
and [jans oi relatixely naii-ow diameter and which ha\'e a deep 
l)od\', I'poth t\'pes ;ire claimed, b\' their respectix'e manufacturers, 
to ha\e special ad\ antages, such as ease of o|)eration, uniformit\' 
ijf actiiiu, econoni)- of fuel aurl of water, and rapidit\' of ex'apora- 




Pigr. 15. 

Vacuum pan and condenser 

OourUsy of Groen Mfg. Co. 



vSvvki;ti-;ni'.d Condknsku Milk — Condensing 



69 



tiriii : the ii|)inion^ of the users nf these ]i;iii^ .'ire als'i at \ arianrc 
Cdiicenihig their i'elati\'c merits. 

Tlie ad\-iicates f>i tlie wide, shallow pan claim that this t}-pe 




Tig. 16 

Vacuum pan and condenser 

'Vourtr'S\- of 
Arthur Harris & e"o 



Tig. 16-A. Coveringr and insulation for 
vacuum pans 

Courtesy of Arthur Harris & Co. 



70 



S\vi-;i-'.Ti-;NKi) Condi;nskd jMilk — Condensing 



iif ])aii inal<c,^ pi i-^sililc such an arraiigcniL-nt ut the heating" sur- 
face as til take caia- nf lhe maxinmni anicnnit of milk with the 
niinmiuni depth i'<\ nnll< user tlie heatini;" surface and that this 
arrangement is most desirable. 'riie\" Imld that because the wide 
and shalluw pan nffcrs a larger area nf e\ap()rating' surface, it 
therefdre makes ])i"issible uk ire rapid e\'ap( iration than the narrow, 
dee]) |)an. 'riie\- further em])hasize that in the \\-ide, shallow 
pan, the milk boils more ipiietl)', is under better cuntrol and is 
less apt til be carried o\-ei' into the condenser and lost, than in 
1he narrnw, deeji jian. 

The ad\'oeates of the 
narrow, deep pan claim that 
their tvpe of pan increases 
tlie rapidity of e\"apr>ration 
liecause it causes the milk 
to pass ri\'er the heating' sur- 
face more rapidl}'. A\dien 
the pan is in operatiem, the 
lioiling milk tra\-els from the 
center rif the botti im toward 
the peri])her}- where it rises. 
)-iiIls '>xvv the criils, and re- 
turns t( I the center. It is 
claimed that a pan with a 
shallo\^- jacket, such as the 
narrow, dee]i pans ha\'c. 
causes the milk to roll o\-er 
lugher, especially if the coils 
.are close t<") tlie periphery 
and lea\e ]dent>' of vacant 
space in the center of the 
|jan. This, in turn, means 
mure rapid circulation of tlie 




Pig". 17. Vacuum pan and condenser 

Courtosj' or Mrijonnier Bros. Co. 



milk, causing it ti > ]iass ii\er the heating suriace at greater speed, 
and oftencr, wliich ii.alnr.ally enables the milk to utilize more heat 
and, theri.d'( ii'e, In e\a]iiirate mure ipiickly, I'.ecause in such pans 
the milk rrjlls n\ er higher, the\' reipun/ a deejier btKh-. 

Kxfjerience ha.s denv msti-.ated that Inr maximum rapidity of 
e^■aporatil m, nther faclm's being the same, m.aximum rapidit\- of 



Swi'j'.Ti'.x i:i) Conjjkxsi:ij l\rir,K — CoxoKxsixn 



71 



circulati' 111 nf the milk 'i\-cr tlic licatiii'j; -urface i- iiKh-iicn-aMe. 
It i- further 'lixiriti- ihat llie ra|jiilu\" "i e- aji' -ratr iii i- in direct 
relation tn the area ^f tlie lieatiiiL;' -urface. 

RapiditA' III' eirenlati"!! '>f tlie milk deiiian_d- iliat there be 
nri liinderiiif;- cnnnter curi-ents and that the milk he ]iermitted 
tc> circtdate ^Adth maximum treed' im in riiie directiini. ddii-^ can 
best be acceim]dishi,-d 1a- lea\anL: a !arL;e eiijen space in the center 
fur the milk t' > retmai to the biitturn after it lias Imilcd up and 
u\'er the ceiils f ri im the pei'i]dier\'. 

Ill urflei- to ha\"e the cfjils so ar- 
ransx'd as to jiermit thi^ maximum and 
unhindered circulati' ni nf the milk, the 
pan must ha.\-e a certain liei,c;dit i a' 
de])th, sii a^ to admit the neces>ar\" 
heatinc;" -surface. 

W itli tlie qa-ijwiipq" reci ignition iif 
the^e ]ninciples, A-acuum pan manufac- 
tiirer- are thercfnre mure and more 
tending;' toward the ^t}de of pcan vcith a 
tall bod\- in jircipi n-tion tn its rliameter. 
ddie \-acuum pan consists of four 
main |)art^. namel\", tlie jacket cjr bi it- 
tiiui, the h<-<(\v rir \-apMr belt, the dome 
and ihe cnnden^er. 

ddie Jacket form.- the l.nttiim of 
the ])an. Tlu- inside wall is C'lyiper. the 
iiiit^ide cast iriin. It c;"enerall\' is ci m- 
ca\"e, the cin-\-e wai'A'iiiL;" in different 
t\"]jes I if pan- fri mi a rlepth iif a few 
inches tn twn and niie-half feet, ddie 
-team sfjace in the jacl^ec between 
uiner audi miter walls is about two 
inches wide. It i- equipjied witli twn 
steam inlets and mie nr twn steam 
'lUtlet^. In ^("inie j.'ans some nr all rif 
the steam riutlets of the cnils alsn ex- 
liau-t throuL;ii the jacket. 
In the center of the bottom there is an opening-, frniu t\\-n 
to three inclies in diameter, for the discharii-e ni the cnndensed 




Tig. 18 
■Vacuum pan and condenser 

Courtesy of C. E. Rogers 



72 SwiiETl'NI'.D CONDI'NSI'D jMiI.K CoNDI'.NSTNr. 

milk, fitted with a \al\e. Iti the case uf ]);ms that lia\-e no 
s|:)ecial "strikiiii; " nr sampliiii^" cu|). this discharsje is equipped 
with t\\-ri' \-a1\-es and a slicirt nipple between \-alves, to make 
possiljlc tlie sampling' <if the crmdensed milk while the pan is in 
operatic)n. 

The Body or Vapor Belt represents the main part of the 
pan. It is cylindrical, of var)nng heitjht and is ecpiipped with 
copper coils wdiich liaAe their outlets either through the jacket 
or the \valls of the Ijodv. Their upper ends ci'mnect, through 
the bodv of the pan, with the main steam line. Most pans are 
e([uipped ^\■ith two to three or more coils located at dift'erent 
elevations; Since steam should be turned into the coils only ^vhen 
they are covered with the milk, it is desirable to have seA^eral 
short independent coils rather than but one large one. This 
will gi^■e a larger range of the quantit)' of milk that can be con- 
densed and increases the s]}eed I'f e\-a]ioration. The coils A"ary 
in diameter frum afjmit three to si.\ inches. The upper and outer 
coils are the larger ones. The diameter and length of the coils 
necessaril}' vary with and are limited by the capacit}' of the pan. 
The shorter each individual coil, and the greater the number of 
independent coil sections and the greater the total heating sur- 
face; consistent Avith maximum rapidit}' of circulation of the 
milk and with eas}- access to all parts of the jacket and coils, 
the better. Other things being equal, the more square feet of 
heating surface, the less steam pressure, ])y the gauge, is required 
to furnish the necessar}' heat for maximum e\-aporation. This 
is important liecause high steam pressure in the jacket and coils 
means exposure uf the milk to high tem]K=rattu'e, which is un- 
desirable. The jieating surface should be sufhcient to make 
possible the complete cnidensation iif the steam in the jacket 
and coils. If the heating surface is inade(|uate, more steam has 
to be turned into the jack'ct and coils, in order to secure the 
necessar\' heat ioj- i-a])id exaporation, than will ccTudense; free 
steam will l.'low throu!_;h and out of the coils, resulting in un- 
economic and wastcfid use of fuel, and jeopardizing the (pialitv 
of the product, 'hhe presence of numerous but short coils also 
increases the intensity of Jieat-transmission, as practically all 
of the steam is condensed in the uppermost convolution of each coil. 
There is a considerable vai'iation in the area of the heating sur- 



SwiiliTKNEI) CoNDHNSED i\IlI,K — CoNUENSING 



73 




Tig. 19. Steam coils in Harris pan 

Couit'-sy of Arthur Harris t^ <_"o. 



face in different makes nf pans, ranging from abrmt 120 to ZCi? 
sqiiai'e feet, in ilie case of six forjt pans, 

fn the latest improvement 
in cnils each independent ciil 
makes onh" one turn in the pan 
and tb.e inner and outer cciils 
ha^"e the same inlet and dis- 
charge and are j)laced on the 
•^ame lc\'el. This [K-rmits i if 
the installation of a larger 
nuniher (if independent coils, 
(-■ach phiceil at a different le\'cl. 
In this manner the coils can he 
utilizefl to better adxantage. 
This is es[)eciall}' significant 
wlien the \T'lume of milk in the 
])an is \-er)- small, making pri^- 
'-ible the opei-atinn nf the lower ci ids inde])endent i if the upjicr 
coils and tliereb}- a\-iiiding the danger nf Imrning the milk, which 
inevitabl}- occurs wdieii the lie.ited cnib^ are imt c im])letel\' snli- 
mergcd. This airan cement increa-^e^ the heating efficienc}- "f 
the pan, heat can lie turned on the luwc^t cnil alnid^t immcdiatel}" 
after starting uperatii in, and tnward tlie end iif the batch, wlien 
the milk again fjnils low, sunie nf the ciil- are still cio'ered and 
can be used. The shorter length rif tliese cnils fmni inlet t" 
exiiaust also make^ possible the simultaneon-- utili-'atn'in cf a 
greater \iilume nf steam. Idiese crimlnned feature? materiall}- 
increase the rapidit^' of e\api iraticm and :tngnient the capacit}' 
I if the pan. These impnoed ceiils have tlie further ad\oantaL>;e 
that their exhausts do not ha\e to be carried through the jacket, 
but pass through the body of the pan. 

Jacket and coils are cnnnected independentl}" with the direct 
steam main from the Itoiler. h'ach connection at the pan should 
carri- a Aalve and a ^team gauge un the pan-side of the \"ah'e. 
The main steam line and connectinn^ leading to pan should be 
propcrl}' insulated li_\' proper pi]ie co\erings, in rirder to supply 
the pan with as dry steam a> po-siiile. 

Idle drips or discharge ends of the jacket and ceiils are cini- 
nectcd AA-ith tlie boiler feed A'.-ater tank. If the pan has sufficient 



74 



vSwi'.etknkd Condp.nskd Milk — Condensing 



heating" surface and is (iperated pniperh', the dri]) ends of the 
jacket and ci'ils slmnld discharge i\'arni water on!}, and not free 
steam. Tlie jacket and cuils should lie free at the drip or dis- 
cliarge ends so that all condensatifin water may l^e C|nickly and 
CI intintiously rcmoA-cd. This is necessary in order to make the 
miist economical use of the steam and to secure high efficienc}' 
of c\"a])oration. In order to guard against liack pressure the 
di'ips may lie etpiipiied with suitable check \-al\-es. 




rig. 20. steam coils in Sogers pan 

0<:n.irteH,\' iiT o. K. Rogers 



Through the walls of the liod\' of tlu' nan also enters the 
milk draw fiipe. 'J'his ]ii]ie connects with the hot well and through 
It the milk laishcs into the |ian. I mme(li;ittd\- outside of the 
)")an the milk' pipe sliouM he eipiip]ied with a \ ah'e to regulate 
the inllow. 'i'lie size of the milk draw ]iipe and \ .-'.h e is go\'erned 
by the capacity of the |ian : usually two to tliree inches in di- 
ameter, Lnside ol the i)an the mill.; pipe should be turned down, 
ff this i)rr)vision is not made, the nn'lk shciots straigjit across the 



Swi'RTKNKD Co^M.)I•:^•sl{lJ Milk — Coxdensing 



75 



pan atrjiniziiiL;- iiitn ;i dense sjiraw wliicli i^ parth- drawn over 
intn the ce^ndenser can^ini;' I'i^- "f milk. 

The l)ei(ly (il the iiaii al^ii n.^nallx" cai'ide^, near its I'lwer 
portion, a sampling cup, nr strihin'.; eii|i, winch facilitates tire 
samplin,^- and testing;- fur d,en-it\-, "i the c. intent- m| the pan 
wliile the ]ian i> in nperatinn. 

A suitalile. in-rmanent ci i\ eriiiL!' '^hoi.ild he pnaidrd fcir tlie 
hody iif the jian lur insulation a^nainst heat r.uliatmn. This will 
iii't cmly eciiiii'nii/e Inel and ^|ieed e\a])i ir.atii 'H. hnl it will al^u 

assist in keeping" the ])an n h nil 

rea^iinalih' ckjI. 

Idle Dome re^ts mh tup of 
the ].)od\- (jf the pan. It is eijuip- 
|jed with a manln'ile,' nianhnle 
cii\er, thermometer, \"acuum 
i;"au,i;'e, si^Tt L,dasses, liL;hts, 
hh i\\--d' iwn \-al\"e or 
wicuum lireakcr. Idle £ ^ 
in a n h 1 1 1 e measures 
a li II u t il mrteen to 
eighteen indies in di- 
ameter. It is elc)scd 




rig". 21. Vacuum g'aug'e 

0(iui'tt.-s\" of .\i-Uiur Ha.r) is ,^ ( 'u. 



li\" a Si ilia lir.ass eo\-er 
with a well-^lttinc,^ ground surface fiance, ddie cnx-er 
carries a fi\e-incli spy-;4-las> or sight-L;lass thrnugh 
wdiich the nperatnr watches the hoiling milk in the 
pan. ddie stem of the thermometer is enclo-ed in a 
brass casing and reaches to near the hottum oi the 
pan. Snme processnrs jjrefer a short thermometer 
which registers the temperature rif the \-apors instead 
cif that of the milk. As hoth, the milk and the \apors 
are suljjected to the same jiressure, their rcspectiA'c 
temperatures are tlie same. The \-acuum gauge con- 
nects with the interior of the pan, and indicates the ^^^z 

number of inches uf \-acuum. ,-\ mercur\" cohimn ma\" ^ 

rio- 22 
he used in the place of the vacuum gauge. In the 

I - '- Mercury 

rear of the dome there are two sight glasses. Thmugh column 
these the interior of the pan is illuminated In- mccan:- c.^e. Rogers 



76 



SwiiKTl'lNl-".!! CriNDF/NSED MlI.K CoNDENSINT, 



I 




Pig-. 22 

Tlieiinometer 
for vacuum pan 

( 'ourtfSy of 

Ai'tl"ilir Harris 

& Co. 



I if lamps, gas or electric lights. The "l)lci\\'-do\\-n " vaK'e, or 
N'acumn breaker, ser\'es tn admit air into the pan in order to 
"break" the \'acinim. This is necessary for readily . 

drawing off the Finished conrlcnsed milk, ft is 
further needed to prc\'ent the contents of the ^'acu- 
um ])an fi'om being drawn o\'er into the condenser, 
\\hene\er the milk rises abo\'e a safe le\'el. 

.\ further accessory of the dome may be an 
autiiniantic milk sampler. The sampler tube is 
carried through the wall of the dome and extends 
til near the Ixjttom inside of the pan. A\'here this 
I il c prnjects through the dome it is equipped with 
motor, ])iston pump, striking cup and hydrometer. 
The striking cup at it? upper end terminates in a 
small chamber equipped ^vith a sight-glass through 
which the operator notes the position of the hydro- 
meter. 

The Condenser. 
— 'I'he condenser is 
that portiiin of the cnndensing ap- 
paratus in which the \-apors, rising 
fi'iini the l)oiling milk in the pan, are 
ciindensed to water. The condenser 
is attached tn the dome of the pan. 
There are three t^•pes of condensers 
in use. the surface condenser, the 
barometric cnndcnser and the wet- 
\aciuim s]ira\" condenser. 

The Surface Condenser consists 
I if .a tnlie c\'linder I'dled with brass 
tubes, miiunted on a i'ecci\er. The 
w.ater used foi' conling circulates out- 
side I if the tubes and the vapors pass 
Pig.. 24. thi-(iugh the tulies, where they are 

Vacuum breaker or blow-down chilled and cnndensed. 'I his con- 

dcnsei' h.as ihe ad\antage of enaLiling 
the I'perator to note tlie amount of 
condensation and to measure the amount of water actually con- 
densed. The recei\er at the bottnm uf the condenser should be 



valve 

Courtesy Arthur Harris & Co. 



Sweetened Condensed Milk — Condi-:nsix(; 71 

so arrani;'ed tlnat it can he ilrained at will ami witlKnit iiiterlL-riiiL; 
with rir retiirdint;' the npcratii in ^A the ]ian. 

The Barometric Condenser CMn-i^t- >a a \crtical c\dindcr (A 
iron or lirass, equipiJt-d with a ^[ira.\- ict, thr'iUL^h which tin- ciml- 




Pig'. 25. Vacuum pan with dry vacuum barometric condenser 

Courtesy of Artlivir Harris & Co. 

int;' \\'ater enters the condenser. The xapnrs heing" drawn w\er 
from the \'icdenth- hnilint^ mdk in the ;")an, are condensed \)\ 
passintf through this spra\' (A cold water This condenser dis- 
charges its water into a tight cistern m the ^rrmnd. The con- 
denser is placed so that its bottiim flange is about thirt_\'-fi\'e 



78 



SWKF.TEN I'D CONDKNSICD AIll.K CoNDBNSINC, 



feet al.)(i\-e the water le\'e] nf the cistern in wliich the discharge 
|iipe from the crmdenscr terniinates. The lieight i^ii the condenser 
depends on tlie liaronietric pressure cf the location wdiere it is 
installed. The lnwer the altitude and, tlierefore, the higher the 
atmospheric pressure, the higher mn^-t the condenser l)e above 
the cistern. ^Vt the sea le\'el, tlie ;itni()S])heric ])ressnre sustains 
a "water colunm alxmt thirty-four feet high. This water column 
in the discharge pi])e seals the \'acuum and at the same time 
l>erniits the \\-ater fnim the sprav and I he condensation water 
to escape automaticall}'. The ci-^tern in "which the water column 
terminates slioukl be of suflicient size tc) hdld abi)ut one-third 
more water than the ca])acity of the entire length of the discharge 
pipe calls for and should ha\e a large rwerno\v into the sewer 
When the pan is in operation and a uniform \acuum is main- 
tained, the le\'el i if the water column remains cijnstant and the 
excess water from the condenser o\'erllows frijm the cistern into 
the sewer. 

The Wet-Vacuum Spray 
Condenser consists of a huge 
hollow cylinder of brass or iron, 
usually, but not necessarily, 
horizontal. 

The horizontal spray con- 
densers are usually equipped 
with a perforated sprav pipe, 
placed lengthv\-ise in the cyl- 
inder. This spray pi].K' should run close ti i the tup side of the 
cylinder, s(j as t' > ,gi\'e the spray th.at escapes frnm the Imles on 
the upper side of the spra^■ ]npe a ch.ance to strike the to]i of the 
horizontal cylinder \\-illi foi'ce .and to become atomized. The 
spray pipe connects at th<' end nearest the pan with the pi])e 
supplying the ciioling water. When the ii.an is in operation. 
a shower of cold water issues forlh from the perforations of the 
spray pi]:)e as the result of the redMced ])res^nre in pan and con- 
denser. The loree with which the w.ater escapes these jierfora- 
tions is further .augmented b_\" the f.act that in most cases the 
water supply tank is loc;i1ed higher tliaii the condenser. The 
iiot \-a])ors arising from the boiling milk in the pan are drawn 
o\'er into the condenser, wdiere the\' come in contact with the 




Fig-. 26. Wet-Vacuum liorizontal 
spray condenser 

( 'ourtes>' of Arthur Harris & Co. 



vSwEETKNKlJ COXDKNSKD AIjLK — CONDENSING 



79 



cold water s])ra)- and arc cniulen^ed. Tlic lM.tti>ni 'if the rrm- 
denser cylinder, at the end tartlicst imm the ]ian i^ connected 
wth the sucticm end nf the vacuum ])unip throui^li wliich the 
water and the condensed wapors in the ccmden^er escape. Man- 
holes with co\-ers should be T)ro\-ided at the top and end of the 
condenser cylinder to facilitate the cleaning; out of the condenser. 
In the \'ertical spiray condenser the crmrlenser cylinder i- 
uprii;'ht. located either on tiip of the pan or at ^c,me di'itance. a- 
is the case, lor instance, where a catch-;dl is installerl between 




Tig. 27. Diag'onal spray condenser 

c'ouriirs}' of ^[ojorinier Bros, Co, 

pan and condenser. The ulterior arraii::enient of ilic \ertica' 
condenser \-aries somewhat with the different makes. ( ine t}'pe 
of ^■ertical condenser wideh" used in -\nicrican conrlcnseries con- 
sists of a double iiisidated \a])or tube ristini,;' cm top df the pan°. 
This insulated tuhie is surrounded b\" and ci")iiiiects with a spra\' 
chamber, which terminates at iis id]) in a pci'forated metal plate. 
and which has an opening;' in the sid.e near the bottom that ccin- 
nects with the \acuum ])um|i sui)])I}-iii-' the su,ction and that 
permits the escape ol the condensed ^-ajior^ and coiilim;" water. 
The coolint^' water enters at tlie to]i of the condenser. Immediateh- 
underneath the water inlet it -tribes a iiielal cone i.r umbrell.a 
wdiich pre\-ents the water from ruiinin-- into the \-a|)or tulie. and 



80 



vSvviUiTi'NKD Condi-:nsi';d Milk — Condensing 



(li'^triliiitcs it f\enU' i'\-er the pi rfin-alccl -^iji-ay |)late. The vapor 
rises iiitu the \apMi- tu1)e nt the eimdensei- and is dra\\'n over 
into tlie spra\- ehanil)er siirroinKhiiL;- it, where the vapor is crm- 
densed bv the spray of water issninj^- from the perforated spray 
phite which tops the spra^' clianil)er and wliich contains a larg-e 
nnmlicr of verv small holes. As tlie water falls throu.Sfh these 
openings h\ p;ra\-itv, the sjjra}' is nnifumi and constant and does 




Pig'. 28. Vertical spray condenser 

Courtesy- ot C, E. Rogers 



not depend on the anidunt nf water nsed, nor does it require 
water pressure on tlic condenser. A complete sheet of spray al- 
ways is fi)rmed, thmugh wdiich the sajjors must ]>aSs, regardless 
of the amount of water used, a fact which assists in the efficient 
use of the A\'ater and in ra|)id and ciim|)lete condensation of the 
\'apors. Manholes with co\'ers ,-ire hjcatcd at the top to facili- 
tate the cleaning of the spray plate. 



SwEIiTKN i;d CuNDliNSKl) ^MlLK — COiN'UKNSING 



81 



In another tyi>e ijf \ertical ^pray condenser the insulated 
\'apor tube in the center is surrniuided ))V a sprav chamber cif 
much greater width, and the water si)ra\' starts near the Ijijttoni 
of the chamber f n an perf'iratii m^ in a circuUir coib The per- 
forations are so lucated that the .sjiray shants u])ward and iiut- 
ward. As it strikes the perijjhery (jf the condenser, it is deflected 
downward and tnward the center. It is claimed that in this 
case two sheets of spra}' are formed, thmugli wdiich the vapors 
must pass. Raflle i)late-- extend dcwnward and i'ut\\"ard from tlie 
to|) of tlie \:ipiir tuljc prc\entin'j; any df tlie s]iray from entering 
the \-ap(ir tube. Manhnlcs with cii\-t:rs arc prii\ided at the sides 
ti> make pnssible eas\- clcrininL; 'if the ci ind,en<ei'. 

Instead of the Cl;nden-^er lieiuL:' attaclied direct tn tlie diime 
of the \-acuum pan, the cundenser ma\- f(.irm a part of tlie x'acuum 
pump. This arrauLiement is feasible l)(illi in the case of tlie wet- 
x'acuum ^]ira}' ciindenser and m tlie ca^c mI the surface cnndenser. 

The chief ditterence between the \\et-\acuum cciudeuser and 
the barcmietric ciinden>er is that in the wet-\acuum condenser 
the water fmm the cundenser passes through the \acuum pump, 
wdiile m the baoimetnc cmideiKer th.e "\\ater doe^ not pass 
through the \acuum puni]), but g' les diri'ct intii the sewer ;ind the 
\"acuum is sealed, b\' the barmnetric water cnhimn. Si > far as 
practical e.\f)erience has sli(i\\n, there i^ no material difl'erence 
in the efficienc}- between the-^e two tviic- cit condenser-. The 
water column nf the fiammetric condeU'^er lieljis somewhat to 
maintain a unifnrm '.-acrLum. It necessitates, howe\er, the in- 
stallation of the pan incon\-eniently high and ref|uires somewhat 
more expensi^-e machinery- than is the case with the wet-\-acuum 
condenser. The chief ditterence between both cif the:^e systems 
and the surface condenser is that, in the wet-xacuum and baro- 
metric condensers the condensed \-apors mix with the cooling 
w^ater, wdiile in the surface condenser the condensed \'apors are 
collected and carried oft separately and withmit mixing with 
the coolin,g water. In the case cif condensing liquids, the vapors 
of wdiich are of commercial value, the -urface condenser must be 
used. The surface condenser, li(iwe\'er, is cif relati\"elv small 
capacity and the cooling water cannot be utilized as ecniiDmicallv 
as in the case of the other systems. A\diere large quantities of 
vapors are to be handled and the \'apors ha\'e no commercial 



82 



SwiiKTENKn CONDI'NSED MlI.K — CoNDlCNSINr, 



value, as is the case in condensing' milk, the barometric and wet- 
vacuum condensers are best suited ; if properlv constructed, their 
operation utilizes the coolinf^- water most economicallv. 

Care of the Condenser. — Tn the operation nf the spra)' and 
jet condenser, special attention should I)e paid to the condition 
of the spray pipe, or spray plate. F'spccially, when the water 
used contains much organic matter, as is the case with water 
from a creek, pond or lake, there is a tendency of the s])ray equip- 
ment becoming filled and coated with slim^• organic matter, 
causing the perforations to clog. This renders the distribution 
of the spray irregular and the control of the ])an difficult. It 
causes great waste of water because much lyf the water is dis- 
charged from the condenser and liDst withe mt coming into direct 
contact with the \apors. The water is. therefore, not utilized 
economically and the difference between the temperature of the 
vapors and the discharge of the condenser is excessive. In order 
to avoid this the condenser should be cleaned out thoroughly at 
least once a week, or oftener if necessary, t(j keep the pores of 
the spray pipe or plate free from obstructions. It is advisable to 
install condensers e(|uippcd with a manhole, properly located, 
otherwise access to the spraying arrangement is not sufficiently 
convenient to insure frecpient inspection and thorough cleaning 
by the average operator. 

The Expansion Tank, Catch-All, or Milk Trap,— This is a 
tank frequently installed between 
the dome of the pan and the con- 
denser. Its purpose is to collect and 
reclaim any milk that may be carried 
over from the pan and to pre\'e.nt 
its escape and loss through the con- 
denser. 

If the pijje through which the 

milk enters the pan is turned down 

and its end is carried to near the 

bottom of the pan, so as to avoid 

the formation of excessive milk 

spray, if the pan is operated care- 

fullv and if the milk is kept at a rig-. 29. vacuum pan with miuc 

' trap 

reasonably low level, there is very courte.sy of Arthur Harris & Co. 




SwEETF.NUD CoNDENSKD ]MlLK — CONDENSING 



83 



little daiig'er of milk bcint( carried o\-cr into the condenser in 
quantities sufficient tri 1;e of an)" ci mseqnence. I'nder these 
■conditions the installatirin of a special milk trap between the 
pan and the condenser ffir the purpose of collecting the escaping 
milk spra}- and carrying it back to the pan is, therefoi'c. an 
unnecessary expense. 

If the pan is small in ci"im])arison to the amnuiit <if milk to 
be condensed, and if it is forced beyond its intendefl capacity so 
that the milk boils up high, there usualh" is considerable loss of 
milk, as indicated by the fr'amine-s :nid milk\- color of the ex- 
haust of the \-acuum pnm]). In such cases the mechanical loss' 
of an a\'era,S"e size batch may amount tri se\'eral hundred pnunrls 
of milk. In rirder to not lose this milk, a milk tra]) nr catch-all 
may be installed between the pan and the condenser. The vapors 
laden with the milk s[ira}- enter the tra|j near the tM|i. The 
spray drops to the bfittom of the trap, wliile the \apijrs are flrawn 
over into the condenser, wdicre they are condensed as usual. 
This trap may lie constructed I'i suflicient size so as to ser\"e 
as a reser\"oir to collect all the milk that is carried M\-er. and at 
the conclusion of ihe process the contents nf the trap are drawn 
from the bottom and are condensed ivith the next liatch ; or the 
bottom of the trap may be connected with the pan so that the 
milk thus carried o\'er flows back into the pan automatically. 
In this case a small trap only is necessary. 

It should be understood that the milk tra.]) is only a remedy 
and not a preventive. Where the capacity of the pan is in pro- 
portion to the amount of milk to be crindensed. as it should be, 
and where the pan is operated prriperly, the trap is imnecessary. 
The trap is an additional piece n\ ap])aratus to be kei)t clean. 
Unless it is so constructed that acce.'Js can be had to all i>arts 

of its interior and unless it ^g^^'i^apfe, 

really is kept clean at all times, t^JS^im^: 

it may become a serious source 

of ccmtamination. 

The Vacuum Pump. — The [i^ 

vacuum pump is, strictly speak- 
ing, not a part of the A'acuum *^-..lI^,^^.^.^,^ 

pan, but its intimate connec- 

1 Fig. 30. vret-vacnnm pump 

tion with the pan makes it courtesy of Arthur Harris & Co. 




84 



SwiiETriNiin CoNDKNSiiD Milk — Condensing 



necessary to briefly ci insider it at this puint. The suction end 
of the \-acuum pum]) is crmnccted ^\itl] the condenser. The 
vacuum pump exhausts tlie pan, forming a partial \-acuum. 
There are principalh- two t>'pes of \-ricuum pumps used in 
the milk condenser}', the drv-\-acuuni ];)um|j and the wet- 
vacuum pump. The dr_\--\-acuum |iump is used in the factories 
with the dr3'-\'acuum s\-steni, i. e., \\liere the cfioling water 
and the condensation water escape to the sewer direct 
and without passing thnmgh the \acuum pump, as is tlie case 
with the surface condenser and tlie f^arometric condenser. The 
\vet-\'acuum pum|is arc used with the T,\'Ct-\'acunm system, where 
the cooling \\ater and the condensation water ])ass through the 
cylinder of the pump. The flrv-\acuum |)um])s ha\'e the advan- 
tage of permitting the ripci-atii m of the machine at a higher 
piston speed than the \\-ct-\-acuum pnm])s in wdiich the water 
must be displaced at the end <>i each stroke. The C)dinders of 
the dry-"\'acuum ])um]) are cooled by water jackets. The initial 
cost of the dr^■-\"acu^uu puni]is. howex'er, is greater than that 
of the wet-\'acuum junujis. 

The efhciencv rif the \'acuum n])paratu< de|)ends \"erv largeh' 
on the A-acuum jnuuf). Ra])id ewajioi-ation at a relati^'eh' lo\\- 
temperature necessitates the maintenance of a high \-acuum. The 
type, material, construction, wiirkmanship, installation and oper- 
ation of the \'acuum jjumj) sliould be sucli as to insure the maxi- 
mum efficiency. 

The pump should be placed on a good foundation and as 
near the \'actuuu ])an as jiracticalile in order that the full benetll 
of the A-acuum may be realized. The suction itijie and all con- 
nections must be tight. The suction ]>ii>e must be i>f the size 
directed by the manufacturer, as short as possible ami with few 
and easy bends. I^he grade iif the auction ]iiiie should lie uni- 
form in order to avoid air pockets. 

T!ie water should be turncvd into the condenser before the 
vacuum pump, is started. Tin- |)um|) should not run at a higher 
speed than is necessary lo secure the i"eqnired A'acuum. Kxces- 
siye speed means high steam ccinsumptiou and hea\-y wear and 
tear on the pump. Tlie amount of water supplied to the con- 
denser shoidd be regulated to suit the reipiirements. Ordinarily, 
and witl: a vacuum of twenty-fi\'e to twenty-six inclies, the 



Swicetf.xiuj Condexsi-:d AIilk — Coxdknsixo 



85 



temperature I'f the ciinderj-er di^charL'.c -b'liiid lie al)'"'Ut llti de- 
grees ]' . A liiwer teni]jcrature w^add i a.u-e exi:e^~i\-e and uiv 
econnniic use r,f water lude^- tlie axailalile water has a temfjer- 
ature hawer t'la'^. is tlie i:a-e in tlie axeraL'e Vmerican cemden-er\' 
i ?0 to ')0- P.I. 'J'he lia^m lan the •,'a.cnuni CAdmder ^li^idd be 
kept Idled wa'th water to ]ire\i-iit adrni-.^ii in of air to the c\dinder 
throu,L;di the "-tuffinL;" box, and the "j'ra}- pipe, jet, rir ^jtra}" ]date in 
the coiiden>er ^h< luld be iii-]iei ted often to make ~ure that the 
perforatioris are n(t clovi^ed. The ^tuffin.L;" bi.ex oi the c\dinder 
should, be well paeked with a L'.oorl fjuality rjf jiackin:^" and the 
.^team e\dinder well i.okd. Start tlie pnmp .-low 1\ . Kelt-drixen 




Tig. 31. Wet-vacuum pump 

e'<jurtes,\- oC [.^hImu .^iiL-urn I'lnnp Co. 

pumps, e>pecially those equipiwd with :i tly-wheel, insure i^aa.-ater 
uniformit}' of s|)eed than direet-actin;.;', --team-flriv en ]iumps. 
Steam-dri\"en ]riimps -honld l.ic- Inrnisheii with a hi.i^h ;^'rade .t^'0\-- 
ernor. The \acuum piini]i should lia\"e a capacil\" i.jreirj'-'rtionate 
to the size of the Aaacnum jian, amount of heatm.L; ^ui'faee. steam 
pressure and temperature ni conden-^iipg water. 



Science and Practice of Evaporating in Vacuo. 

Purpose of Condensing" in Vacuo. — ddie im|)ortant ad\'aii- 
tages gained by ewaporating milk under reduced jiressure, or in 
\-acuo, are: eceiiieinn- of e^'aporation, rapidity lof ewapciration. kaw 
temperature and large capacity r,f apparatus. All of these features 
are essential in the successful condensing of milk 



86 SWEK'I'KN'KD C0NDKNSI",D MiLK CoNDKNSINC 

]\.apid e\-apiiratiiin caiinut lake i)lacc until tlic milk is brought 
to the boiliny point and is kept there until e\-a])(iratii in is com- 
pleted. Under atmospheric pressure and at the sea level, the 
boiling point nf A\ater is 212 degrees 1"".. the boiling point of milk 
is very slightly higher, about 214 degrees F. E\-aporation of milk 
under atmospheric pressure isi an o])en kettle, hr)^^■e^■er, is a 
relati\'ely slo\\- jirocess, requiring a long time and large appara- 
tus. Furthermore, ex])osure of the milk to 212 to 214 degrees 
F^. long enough to complete e\'aj)oration would render the prod- 
uct unsuitable for market. The properties of some of its ingre- 
dients are altered, the j^rciduct wTjuld assume a dark color and 
a marked cooked fia\-or as the result of the efi'ect of heat. All 
of these objections are minimized and partly a\oided b}'- lower- 
ing tlie briiling point of milk. These objections, hcjwever, do 
not apply to CA'aporation under atuKMspheric ]:)ressure by trim 
treatment, as is the case v;ith the Continuous Concentrator de- 
scribed in Chapter XIV. 

Relation of Pressure to Boiling Point. --The temperature at 
which milk boils depends on the pressure to which it is exposed. 



.SVVEKTKNKD CONDKNSJ'.D MiLK CoNDI-.NSIXG 87 

The table liel(>\\- slmw'- the IiMihiiL:" p'lint "f water at pres- 
sures ranging from atmospheric pressure at the sea level (14.72 
priunds per square inch) tn a cnmplete \acuuni. 

Boiling Points of Water at Different Vacua.' 




1 By courtes\- of the Buffalo Foundry & Machine Company. 



88 Swi-.IiTKNI':!) CONDKNSI'D MiLK CONDENSING 

Tlie pressure ' ii', edrrccth' s|ieakiiiy, tlic \acuum, is expres- 
sed ill tei'ir.s III' iiiclies nf merciir\' wliioli the atmosplieric pressure 
sustains, 'i'lie nicreurA' cnliimii is imt a direct measure of the 
pressure, l3ut it shows tlic difterence Ijel. weeu the atmospheric 
pressure and the alisnhite i>rcssurc in the \acuum cliamljer. The 
atmosplieric ])rcssure at the sea !c\ el is 14.7 pounds per square 
inch. Tt sustains a nicrcur\' crilnmn in an absolute vacuum of 
of) inches at ('>2 decrees V., and nf 2'l'i22 inches at 32 dei^rees F. 
The absrilute -Naciiuni may lie calmilated b}' multipl3-ing the 
atmospheric pressure b\" the factor. 2.04. In case there is only 
a partial \-acuum the mercur}' culumn sustained is lowered to the 
extent of the absnlute pressure in the \acuum j'an. The absolute 
pressure ma^' be calculated as fitlliiw!-: 

Example: The actual \acuiun in the ]ian is 2.^ i'nches at the 
sea leA'el. \\ hat is the alisnlute jiressure? 

14.7 X ^30 — 2.M , ,- , . , , 
:nr = -.4.1 pounds lit alisdlnte fjres'^ure per sq. inch. 

Relation of Altitude to Atmospheric Pressure. — At altitudes 
lii,c;her than the sea le\el, the atnn .^jilieric pressure is reduced 
and the mercury cnlumn i^- lowered, thi"iL;li the absnlute pres- 
sure in the wacuum pan ma}" be the same. Therefore, in factories 
located at hi,:.;h .altitudes the mercur^■ cnlmnn will show fewer 
inches nf wacunni at a gaxen temperature and with a gi\-en 
absnlute pressure. 

The tnllriwing table slinw<; the i-.an'imetric reading- in inches 
nf mercur}- cnlumn and tlie atmnspheric pressure in pounds per 
square inch at different altitudes: 



w^\\'i-;in'i:xh;ii C'()xiii;.\> 



Al II, K-- C'nXDI'.XSIXl 



8') 



Barometric Reading Corresponding with Dift'erent Altitudes. 



Barometric 
reading in 


Atmospheric 
pressure in 


Altitude 


Barometric 
reading in 


Atmospheric 
IJressure in 


Altitude 
al30\-e sea 


inches of 


pounds per 


le\-el in feet 


inclies of 


IJOunds per 


leyel 


mercury 


square inch 


mercury 


square inch 


in feet 


30 


14.72 





23.5 


11.54 


6412 


2y.7 


14.('»0 


2(i4 


23.0 


11.31) 


6977 


I",).':- 


14.47 


441 


->-> T 


11,05 


7554 


29 2 


J 4.35 


710 


22 


lO.S'O 


814^ 


29.0 


14.23 


890 


21.5 


10.56 


8747 


28.7 


14.11 


1163 


21.0 


10.31 


9366 


28.5 


13.' '8 


1347 


20.0 


0.81 


10648 


28.2 


13.86 


1025 


I'l.O 


9.32 


11994 


28.0 


13.74 


1812 


18.0 


8.82 


13413 


27.5 


13.50 


2285 


17.0 


8,33 


14914 


27.0 


13.26 


2767 


16.0 


7.84 


16,^06 


26.5 


13.02 


- M57 


15.0 


7.35 


18201 


26.0 


12.77 


r^/^S. 


14.0 


(').86j 


!'")')(, 


25 5 


12. ,^3 


-)2(.8 


13.0 


6.37 


218'il 


25.0 


12.27 


4787 


12.0 


5.88 


23886 


24.5 


12.03 


53 IX 


11,(1 


5.39 


25981 


24.0 


11.78 


5859 









By courtesy of the lJiilT;ihj Fui_iin.li\" t^- ?v(urli 



90 vSwK.i"ri;Ni-;i) CdNni^NSKi) Mu.k — CoNDi'.NsrNG 

In tlic ti 'lldwinj^" table ma)- ]iv fnund the altitudes (if \'ari(jus 
cities in the I'nited States: 

Altitude in Feet of Various Cities in the United States. 

l!y Ciiurtesy nf L'nited States I )e|)ai-tnient nf Agriculture. 

Akron, Ohio 040 Los Anoeles. Cal 267 

Albany. X. ^' 22 Louisville, Tenn 433 

Atlanta, ()a 1032 Memphis, Tenn 2.36 

Baltimore, Md 02 Milwaukee, AVis 593 

Birming'ham. Ala 000 Minneapolis. Minn S12 

Boston, Mass 10 NeA\' TIaven, Conn 10 

Buffalo, X, ^' 3X3 Xew (')rleans. La 

Burlington. Vi 112 Xew York City 34 

Butte. Mont 3333 (Oklahoma City, < )kla 1197 

Charleston, S. C 12 < )maha. Xeb 1016 

Chattanooga. Tenn 072 Philadelphia. Pa 42 

Chester, Pa 22 Phoenix, Ariz 1082 

Chicago, Jll 300 Pittsburgh, Pa 743 

Cincinnati, Ohio 400 Pro\-idence, R. J 11 

Cle\-eland, C)hio 382 Richmond, Va. 51 

Dayton, Ohio 740 Rochester, X. ^' 310 

Denver, Colo 3183 St. Louis, Mo 433 

Dallas, Tex 430 Salt Lake City, L'tah . . . .4238 

Des Moines, Liwa 805 San Francisc(i, Cal 13 

Detroit, Mich 388 Santa Le, X. M (i';32 

Duluth, Minn 600 Seattle, A\'ash 10 

Houston, Tex 46 South Bend, Lid 717 

Indianapolis. Ind 708 Spokane, W^ash I'lQX 

Ithaca, X. Y 41 1 'i'ampa, Fla 15 

Kansas Citw M<i 750 W'ashingtun. D. (_" 2? 

Knoxvillc, Tenn 800 Wichita, Kan 1204 

Lexington. Ky 035 X'icksliurg. Miss 106 

Little Rock, Ark 2()4 



SWEKTRNKD CONDKNSI'D MiLK — CoNDI'.NSlN'G 91 

AcciirdiiiL;- tn Kent' tlic relatinn . if altitu'lc tn atniM^|iheric 
pressure per scpiare inch !■- as fnllnw^: 

IVniiid-. I'l-essure 
Altitude Per Sijuare Inch 

At sea le\'el 14.7 

■} mile abo\"e sea le\-el 14.02 

i mile al)0\-e sea leN'el 1 .v3,S 

-;} mile al)Ci\"e sea le\-el ]2f)(< 

1 mile abo\-e sea le\-el 12. CU 

1] miles abo\-e sea le\-el 1 1.42 

1 J miles abri\-e sea le^-cl 10. NS 

2 miles abo\'e sea le\"el '"'.XO 

"For a rringh appro.ximatii in anc may ,a>sume that the pres- 
sure flecreases one-half prmnd per 'square inch fur c\"cry 1,000 
feet of ascent." 

'idle absolute jii'cssure in the pan nf a lactiir\" located at 
r)maha, XeV).. A\ith an altitude nf 1,010 feet almye sea lc\-el, and 
condensing" in an actiud \acuuni nf t\\eiit}'-fi\'e inches, \\'ould 
then be as f( dlows : 

Atmospheric pressure = 14.7 — .5 = 14.2 prmnds per square 
inch. 

Absolute vacuum = 14.2 ^- 2.04 = 28." '7 inches. 

14 2 ■■ (28.07 — 23) 
Absolute pressure = -' -,„ g- = l''-"" pounds 

per srpiare inch. 

Relation of Steam Pressure in Jacket and Coils, Water in 
Condenser, Temperature in Pan and Vacuum, to Rapidity of 
Evaporation. — The temperature i if the \a|)iirs in the \-acuum pan 
depends direeth- u])iin the pres,-^ure nr \acuum under wdiicb they 
are generated. The nmre nearh- complete the xacuiim and, there- 
fore, the len\-er the pressure, the lnwer is the temperature, and. 
other conditiiuis being the same, the mure rapid the CA'aporation. 
The jjressure in turn is gdx-erned l)y the capacity nf the A'acuum 
puni]), the tightne.-s . if the jnints. the steam pressure in jacket 
and coils and the amcunit and temi'ierature ijf the water in the 
condenser, 

' Mechanical Engineer's Pocket-Book. p. 581. 



92 



Swi':eticni';]> Condivnskd Mii,k — Condensing 



With a luw i-apacit)' A-acnum pump, or a pump running 
irregularis', or ti'm sldw, nr loo fast, and s\'itli leaks' joints, the 
\acuuni will always lie low, and the pressure and temperature 
relatis'ely high. Ihuler these conditions the pan is difficult to 
iiperate and e\apriratii"in is slow. 

\\\t]\ the al)0\-c crniditirms under control and pro]icrly adjus- 
ted and \\'ith a giA'en area nf heating surface and arrangements of 
it for i")r(";per circulation of the milk, the temperature and the 
rapidity of e\'aporation depend cn\ the steam pressure in the 
jacket and cnils and on the amriunt and temperature nf the water 
used in the condenser. 

'J\\'ent3'-fi\-e pounds nf steam jiressure in the jacket and coils 
has lieen found to he a1")out the maximum that can safely be used. 
With this steam pressure the milk coming in direct contact tt'ith 
the heating surface is expi.scd to about 2('i7 degrees F. and there 
IS a tendenc)' for S(ime of it to bake or binai nn, Avliich is unde- 
sirable. The walls of the jacket and cnils arc also subjected to 
considerable strain, since tlie\' are surrinuided b)' an almost coni- 
|)lete \-acuum Then again, if the pan has the prnper amount 
I if heating surface the ca]"),acit}- r.f the condenser and the Avater 
su])ply are in most cases insufficient to tak'c care of and condense 
the A'apors arising from the boiling milk in the pan, when the 
steam piressure in jacket and coils appmarhes or exceeds twenty- 
li\-e pounds. Most condenseries operate their ]ians with t'we to 
lifteen pounds of steam jiressure in jacket and cnils. Tn the oper- 
ation of some [lans not mnre than abnut h\e pnunds steam ]^res- 
^ure can be used ecnimmically in jack'ct and cnils. because the use 
nf more steam causes the steam tn blnw through and out of the 
coils. 

Aside frciui the principle iif ci nistructinn the capacity of the 
crindenser used in nndk ci nidenscries is \ cry largeh' de|)endent on 
the water sup]ily. W lienexer the cniidenser is forced 1)eyond its 
capacity, by using e.\cessi\'e steam in jacket and coils, the \-acuum 
tirops, the temperature ri^cs and the )irncess nf e\'aporation is 
retarded. 

The liiLdiei" the \acunni the nmre rajiid the e\ai|H iration. A 
rise in the steam jiressure in the jacket and coils increases the 



SwEijTENiiD Coniii-:nsi';u ]\1ilk — Condensing 93 

rapidity of eva|)oi'atiiiii (<u\y as lont;' as enous'h water passes 
throuqii the condenser to maintain a lii,L;'!i \acnnni. As soon as 
the steam ])ressure in the jacket and ciiils reaches the j^riint where 
the \\'ater in the condenser faii< tci promptl}' rednce tlie \'apors, 
the \'acuum drops, the tem];ieratin-e in the pan rises and e\'apora- 
tion is checkech - 

Idle e( nidensiii;^" i .f milk requires immense (piantities i if water : 
experience ha^ sliown that it takes from one to tliree Lialloiis of 
water to condense one ponnd i if fre-h milk, the exact amount 
depending' on the construction i if the condenser and tlie temptera- 
ture of tile water. The water hU]"i[)h" is one of the weakot links 
ill most crnidenseries, so tluit econon^^- rif \\-ater is one 
of tlie important factors to he con-^idered. Idle steam pressure 
in the jacket and coils shrmld, therefore, lie sfi rei^iilated as tei 
make it possible to maintain the maximum \acinim consistent 
with reasonabh' economic use rif water. Wd'th a wacuum of 
t^^■entv-l^\■e inches the temperature in the pian is ahout 1.^."- de- 
Screes F., the tein|)erature A-aryinc;' somewhat with the altitude 
of the factciry. In some condenseries the temperature of the ]:)aii 
is kept at 130 de.qrees F. ddiis practice may ecoiicimize the water 
a trifle better, but the rapidity of evaporation is considerably 
lower. 

Condensin,i;' at temperatures hjwer than 130 de.ci'rees F., with- 
out reducin,!.'," the steam pressure in the jacket and ciiils, increases 
the rapidity of ex'aporation. but taxes the water sujiid}- beyond 
the reach of most condenseries. ?o mnch water has tri l)e used 
in the condenser that it is not used ec im ■micalh-, as is shown l)y 
the relativel}- low temperature of the water discharL;"in,i;- Irom the 
condenser. The temperature of the condenser discharge bears 
a direct relation to the temperature of the \a])ors in the pan. 
Observations made in warion^ factories- and under ditferent con- 
ditions b}' Ilun.ziker and others showed that the condenser dis- 
charge was anywhere from 5 to 2.^ degrees F. lower in tem|")era- 
ture than the Aa]iors in the pan. tlie difference a\'eraL;-in,g afxjut 
1,T degrees F. 

Tlie smaller tlie difterence in temperature l.ietween the con- 
denser discharge and the wapors in the fiaii, the more economic 
is the use of the water and vice \ersa. Tt is not advisable under 



94 SwKETENCD Condensed Milk — Condensing 

average conditions to so (ipcrate the pan that the temperature 
of the ciindcnser discharge dro|)s l:)eli)W 110 degrees F., because 
of the wasteful use of water under sucli conditions. 

The condensing of one j^ound of milk requires about one 
pound of steam and ten to twenty-five pounds of water. The 
number of heat units used for condensing in vacvuim is practically 
the same as that required by e\a])orating in open pans. In order 
to use the steam economically the pan should be so operated as 
to make possible its complete condensati()n by the time it leaves 
the jacket and coils. AMieiuner so much steam is used that it 
blows through and out of the jacket and coils without being con- 
densed, there is great waste of fuel. For further details on this 
point see "Description of the Vacuum Pan." 

Starting the Pan. — Before drawing the milk into the pan, the 
pan should be thoroughly rinsed with water, then steamed until 
the temperature rises to about ISO degrees F. or above. Then 
the manhole cover is put in place, all the air \'alves are closed, 
water is turned into the condenser and the vacuum pump is 
started. When the vacuum gauge shows over twent)' inches of 
vacuum, the pan is ready for the milk. 

Operating the Pan. — The valve of the milk pipe leading to 
the pan is now partly opened. The milk enters the pan auto- 
matically as the result of the reduced pressure in the pan. \A'hen 
the milk covers the jacket, steam is gradually turned into the 
jacket. As each coil becomes submerged in milk, the coils are 
charged with steam. At no time should steam be turned on the 
jacket and coils when they are not completely co\ ered with milk, 
as such action would cause the milk to slick to and burn on the 
heating surface, the milk would assume a burnt f^a^•or, it would 
become permeated with black specks and the e\-aporation would 
be retarded. On the start, but a fev.' pounds of steam pressure 
should be used in the jacket and coils, tC) avoid burning, owing 
to the presence in the milk (if considerable air. As the milk 
becomes more concentrated and settles down to uniform boiling, 
the steam pressure may be gradually increased until it reaches 
the maximum. The ma.ximum pressure permissible must be gov- 
erned by the amount of heating surface, the capacity of the \-acu- 
um pump and the temperature and amount of water a\'ailablc for 



Sweeten Ki) Condensed Milk — Condensin<. 95 

use in the condenser. L'nder a\'era,c;e cijiirlitions alu'ut lifteen 
pounds of steam ]"iressure ma\- 1")C safeK" u-cd. 

During; the earl\- stages r.f the ]">rMce-;'-, when the milk is i:if 
low density, the ewajM 'rati^■e dut}- 's high, pnihahh' ahrmt twenty- 
h\-e to thirt}'-fi\-e piiunds per sfp.iare fcjut nf heating surface with 
ten rjounds of steam pressure. This ,L;T.aduah\" decreases and is 
lowest toward the end nf th.e process. 

When enougli milk is in the pan tr) CMinplcteh' C(i\-er the 
jacket and coils, the milk intake should he reduced and regulate<"l 
in accordance with the rate nf e\-a])oratinn. 'Plu- milk is drawn 
into the pan ccntiiun lU.-^h', hut onh- a^ fa-t a- it e\'a])i irates. It 
should be ke])t a-; much as jxwsihle at a constant le\el, and this 
level is preferahly as Inw as is ci ir.-iistent \-,-ith cnmplete cm'enng 
I if the upper most coil. 

In order tn secure ma.ximum rapidit}' "i exaimratiijii, the 
N'acuum pump should run at the iiroper speed and its nperation 
should be uniform, a uniform wacuum and temperature should 
be maintained and the milk should be pirexented fn im rising- to 
an abnormally bigdi le\'el in the pan. 

Prevention of Accidents. — The opera tnr shnuld pay strict 
attention to the pan in nrder ti > a\'C)id h^iss .if milk due to acci- 
dents. Me should watch the water supply a.nd ^nxern its use 
according-Iv, If the water sup]jlv becnmes c-xhausted, air is liable 
to be drawn intu the ])an through the cindenser. This will cause 
the milk tij dnq") siuldenh' and then rise in a biith-, threatening 
to escape through the cnndenser. \\ henexer air in considerable 
cjuantities is allnwed ti > enter the pan wliilc in nperatinn, be it 
as tlie result c.f lack nf water, nr through an\" other cause, or 
when the ^'acuum pump is allciwed tci stnp aiul li\e steam is 
turned intcj the milk in the ])an, as is the case when the milk 
is superheated, the escape iif milk ma}" lie ax'nided. b\- immediately 
shutting- the steam inlet to the jacket and cnil-^. ]>v clnsing- the 
milk intake and b}- slightl}- opening- the blnw-duwn \'al\-e when- 
e\-er the milk rises dang-ercatsly high, T',y skillful t-i-iai-ii]nilation 
of the blow-down \-ah-e until the milk again settles do\\-n to 
uniform boiling, leiss can be a\-oided and the process can be con- 
tinued in the normal way. 



96 SwEKTENi'i) Condensed Milk — Striking 

I'lV the time :ill tlic milk is in the pan, ciMndensation is nearly 
completed, and from ten 1(i twenty minutes further boiling" usu- 
ally g-ives the milk the desired density. Triward the end of the 
process the steam pressure in jacket and coils shfiuld be reduced 
to about five pounds or less. \A'hen the milk approaches the 
desired density, it is ciimparati\-ely hea\'y and viscous and boils 
less \'igTirouslv. Jt therefore is more direct!)' exposed to the 
heating surface. In the case of excessi\-e steam ])ressure, its 
quality is ieo]iardized. If the batch is small so that the level 
of the milk drops belo\\- some of the coils, steam to the exposed 
coils should be turned off entirely. 



Ch.\ptER VI. 

STRIKING OR FINISHING THE BATCH. 

Definition. — When the boiling milk in the vacuum pan ap- 
proaches the desired degree oi concentration, the batch is 
"struck." The term "striking" is a])plied to the operation of 
sampjling the condensed milk and testing the sample for density. 
I'his term \-ery probably referred, originall}', to the meaning of 
"striking the batch right," that is, stopping the process at the 
proper time, or \\-hen the milk is neither too thick nor too thin. 
It then expressed the result rif the rij^eratiiin, vhile now it is 
used to mean the operation itself. 

Ratio of Concentration. — Sweetened condensed milk intended 
for canned eoods has a specific ;.;ra\"it}' rif 1.28 to 1.30. This 
densit)' is reached usually wdien the ratio of concentration is 
about 2!.t:1. i. e., 2.? parts of fresh milk are condensed to one 
part of condensed milk, assuming that about si.xteen ])ounds of 
sucrose Jiave been added to e\■er^' one hundre<l pcjunds of fresh 
milk. 

C Jccasionally the ratio of concentr:ition is based on tlie pro- 
portion of water evaporated, in which case it is ol>\-iouslv much 
higher than when based on the amount of milk recptired to make 
one pjound of ci)ndensed milk, l)ecause the added cane sugar 
takes the place of its own weight of water, and thereby acts a^ 
a diluent of the condensecl milk. Thus let us assume that 16 



Sweetened Condensed RIiek — Striking 97 

pounds ("jf cane su,y"ar are added to e\-ery 100 prmnrls of fresh 
milk and that it takes 230 pounds f'f fresh milk to make ICHJ 
pounds of s\\-eetencd condensed milk, 100 pounds of s\\-eetened 
condensed milk, tlierefore, contain 10 ;■'' 2,3 = 40 pounds of cane 
sugar. Using tlic sugar-free linislied iirciduct as the t.>asis frir 
calculati(jn, then, tlie ratii' rif cdncentration «ijn]<l be; 

250 

4.17 to 1. 



(100 — 40) 



Instead nf gi\ing the rati' i i if d mcentratirm, tliis 1)asis nf 
calculation determines the ratin nf e\ api iratiiui only. The results 
are, therefnre, erroneous and misleading. It does not materiallv 
matter whether the diluent in tlie condensed milk is water or 
cane sugar, or Ijoth ; the reallv important factor is tlie per cent 
milk solids in the condensed milk as compared ^\-ith the per cent 
solids in the original fresh milk, and this relation is sr>lelv deter- 
mined by the amount of fluid milk required to make nne pounfl 
of condensed milk, or l)y the true and actual ratio of concentra- 
tion. If it takes 2v. pounds of fresh milk f(.ir e\-ery pound of con- 
densed milk, then the ratio of concentration is ol)\-i(;iusly 2.? to 
1 and not 4.17 to 1, 

Methods. — Tij know just when the j)roper degree of concen- 
tration has been reached is diffictilt and requires experience, Tt 
is here "wdiere the processor can easilv make or lose his ^\■ages, 
There are various indications reminding the ol)ser\-ant processor 
that the milk in the retort is nearly "done," \iz,, time consumed 
for condensing, time elapsed since all the milk has Ijeen "drawn 
up," amount <if condensed milk left in the ])an and, most of all, 
the appearan.ce and bt-lia\ ii r 'if the boiling milk itself. Milk 
that has been sufficiently condensed a'-sumes a glrissy, .glistening 
lustre, it boils o\'er f ri mi the periphei"y towards the center, form- 
ing a small nucleus cir ])ud(l!e of fnam in the center of the pan. 
An experienced and obser\ant operator knows within a few min- 
utes when the milk is condensed enough. This does not mean, 
howei.'er, that he shcmld wait until the last minute before he 
"strikes" the batch, for e\en the most skillful and experienced 



98 Svvi;i;TiiNKiJ Condensed Miek — Striking 

processors are easily deceived by the mere appearance of the con- 
densed milk thi^ongh the sight glass. 

The degree of Cdncentraticm may be more accurately deter- 
mined by taking a sample from the pan and testing it by various 
methods, such as by weighing a definite quantity of condensed 
milk on a sensiti\'e scale, by the use of a resistance apparatus, 
or viscosimeter, or by the use of a specially constructed hydrom- 
eter. Of these the lleaume hydrometer has been found the 
most suitable tu use under a\'erage factory conditions. 

Mechanical de^•ices and instruments, such as abo\'e enumer- 
ated can be depended upon, when all conditions influencing the 
specific gTa\ity of the product, such as chemical composition 
and temperature, are under control. Their successful use ren- 
ders careful and accurate standardization of the milk for butter- 
fat, solids not fat, and sucrose indispensable. \A^ithout standardi- 
zation (.if the Component ingredients of milk the result of the 
use of these de\ ices ma}- pro\e erroneous and misleading. 

The ojieration of these de\'ices must also be simple and rapid, 
for when the boiling and rapidly evaporating milk in the pan 
approaches the jiroper densit}', quick action is essential. One 
minute o\er or under condensing may cause the milk to be 
either too thick or too thin f<.ir the market, and may necessitate 
the "rerunning" of the entire batch. 

In the absence of a satisfactory instrument for rapid deter- 
mination of the concentration, and ]iarticularly in the absence of 
a carefully standardized product, the experier.ced eye and the 
good judgment of the processor are all essential. The following 
factory methods ha\e been found applicable and reasonably 
reliable. 

Determination by Appearance to the Eye. — ]3raAv a sample 
from the pan into a tin dipper, lower the dipper into a pail of 
ice water or sm.iw. Stir the condensed milk with a metal-back 
thermometer until the condensed milk is cooled to 70 degrees F. 
Note the thickness of it. Or, finish the batch at a constant tem- 
perature, say 120 degrees F. Draw a sample into a tin cup and 
note the thickness by examining the milk when pouring from 



SwURTENKl) CONDENSKI) MlI.K — STRIKING 



99 



4 




Tig. 32. 
BeaumS hy- 
drometer for 
sweetened 
condensed 

milk 

Courtesy 

C. J. Tagliabue 

Mf g-. Co. 



a ttaspoiin. The transpareiic}- of the milk when thu^ 
held against the liglit and the niannei- in whieh the 
milk piles up in the cnj) furnish a praetical index to 
its densit}'. The last methrid is preferable because 
of its greater rapidit^^ Fnr best results the use rif 
a Beaume h}-di'("imeter. especialK' cemstructed for 
sweetened condensed milk, graduated to frrmi 30 
to 37 degrees B and with sul">di\'isions of one-tenth 
degrees is recommended. 

Use of Beaume Hydrometer. — P.eginner? and 
inexjjerienced operators dn well to take numerou.s 
samples from the hatch in the operating pan and ti i 
start sampling early, so as to a\iiid i ixer-cemdens- 
ing. Xo dellnite tigtire at v\-liich the lieaume hy<lrom- 
eter should be read can be stated that ^^•ould sho\\' 
the proper densit}- under all conditiems. 'i'he Beaume 
reafling" ol s\\-eetened condensed milk rif the ])roper 
concentration varies with such factors as per cent 
e)f fat, per cent of sucrc-e and per cent solids, ratin 
of concentration and tem])erature of the condensed 
milk when the reading is taken. llowe\x='r, for gen- 
eral guidance, it may be stated that condensed milk 
of a concentratiiui of 2.? : 1, made from fresh milk 
'if a\-erage richness and cnntaining sucrose at the 
rati(T of sixteen pounds of sugar per ime hundred 
priunds of fre'-h milk, will shov.- a Beaume reading 
of abiout .i.'i..-' decrees B. at hO deiirees I*"., or about 



M deuTee^ 



at 



i') deyrees F. Sweetened con- 



densed skim milk containing appneximatelv 4(J per 
cent sucrose will sho\',- a lieaume reading at 'lO de- 
grees F. (if about 37 flcgrees B., nv aliout .^.^..^ de- 
grees B. at 120 degrees F. If it is intended to use 
more sugar ('44', ) and to limit the per cent milk 
solids to 28 per cent, wdiole milk is condensed until 
the Beaume h}-drometer at 130 degrees F. shows 
3H- degree.^ B. Skimmed sweetened condensed milk 
containing 28 per cent milk solids and 42 per cent 
sucrose tests about 34'( degrees B. at 130 de.grees F. 



100 SwKliTKNKD CoNDKNSTvD MiLK vSTRIKINC 

Correction of Hydrometer Reading for Temperature. — The 

Beaume hydrometers used in American cmdenseries are grad- 
uated to give correct readings at 60 degrees F. If the readings 
are, to be correct, or if it is desiraljle to con\'ert them into spe- 
cific gravit}', the condensed milk should ha\'e a temperature of 
60 degrees F. AVhere this is not convenient, the observation may 
be made at any temperature coin-enient and the reading corrected 
as follows : 

When the temperature is abo\e 60 degrees F, multiply the 
difiference between the observed temperature and 60 degrees F. 
by the factor .025 and add the product to the obserA'ed reading of 
the Beaume hydrometer. When the temperature of the observed 
reading is below 60 degrees F. the corresponding product is 
deducted. 

Example: Beaume reading at 120 degrees F. is 31.2. Cor- 
rected reading is 31.2 -f [.02.5 y (120 — 60)1 = 32.7. 

The specific gravity ma}' he calculated when the Beaume 
reading is known, by using the following formula : 

144.3 
Specific gravity = -,,,-, — rr- ', B. =: Beaume reading'. 
^ -^ 144.3 — 1!. ^ 

Example: Beaume reading, ,-it 60 degrees F. is 33.1. 

Specific grvitv = , , , , — '-———= 1.2976 
144. o — JO. 1 

In the fi:ilIowing table are assembled figures showing the spe- 
cific gra^'ity of sweetened condensed milk of dififerent Beaume 
degrees, \arying from 28 degrees B. to 37. S degrees Ij. 



S\vi{i-;texi;d Coxiii'.xsi:i) Milk — S'iriking 



101 



Specific Gravity of Sweetened Condensed Milk of Different 
Beaume Degrees, 



Beaum^ at 
60 degrrees F. 


specific 
Gravity 


Beaum6 at 
60 degrees F. 


specific 
Gra^■ity 


28.0 


1.2407 


33.0 


1 2')U':^ 


2 


1 .2428 


-7 


1 .2988 


.4 


1 .244'J 


.4 


1.3011 


.6 


1.2471 


.6 


l.,3034 


.8 


1.24')3 


.8 


1.3058 


29.0 


1.2513 


34.0 


1.30X2 


.2 


1.253(1 


-} 


1.3106 


.4 


1.2558 


.4 


1,3130 


.6 


1.2580 


.6 


1.3154 


.8 


1 .2002 


.8 


1.3178 


30.0 


1.2624 


35.0 


1.3202 


2 


1 .2646 


1 


1.3226 


.4 


1.2668 


.4 


1.3250 


.6 


1 .2660 


.6 


1.3274 


.8 


1.2713 


.8 


1.32'") 


31.0 


1 .2736 


36.0 


1 .3324 


9 


1 .2758 


1 


1.3, US 


.4 


1 .2780 


.4 


1 Mil 


.6 


1.2803 


.6 


1.33')7 


.8 


1 .2826 


.8 


1.3422 


32.0 


1.2840 


37.0 


1.3447 


2 


1.2872 


:> 


\M11 


.4 


1 .28''5 


.4 


1 ,3497 


.6 


1.2918 


.6 


1 .y^n 


.8 


1.2941 


.8 


1.3548 



102 



SwHi'.TivNKD C(>Nni',Nsi';i) Milk — v'-l'i'RiKiNf'. 



Sampling of Batch.— Tlie samples can he drawn from tlie 
[lan by operatini; tlie twn valves al the licittorn explained under 
"Descriijtinn nf A'acimni I'an." While the milk is condensing, 
the partial \-acuum in the pan makes ini]-)( issihle the dra\\-ing off 
of the sample 1))' simpl}- (^ipenin^- the outlet. Instead of causing 
the milk to come out, air would rush in with \'if)lent force and 
would cause the milk in the pan ti i be thrown (i\er into the con- 




rig'. 33. A con- 
venient device 
for sampling" 
the condensed 

milk in the pan 

Courtesy of 

Arthur Harris 

& Co. 




rig". 34. A convenient device for sampling" 
condensed milk In the pan 

Courti:-s>' of Artliur llarris & Co. 



denser, besides dangeronslx' julting the machiiier}-. b'or this rea- 
sr)n tlie nutlet is ei]uipped x'.ith twn \-al\es. bnth of which are 
cliised during tlie ci 'iidensinij" pmcess. h'or taking sam]ilcs, open 
the uppei" \al\'e. This allnws the condensed milk t> > run into 
the nipple between the twn \al\'es. X'nw close the u]iper \ ah'e 
and open the hiwer one. The milk will run nut frceh". The first 
sample sliould be rejected, as it may contain water caught in 
the nipple. 

For greater con\'enience and increased rapitlity of sampling, 
especially constructed sample cu|)s or striking cu])s, attached to 
the side of the ))ody of the pan may be used. These striking cups 



SwKirrENKEi CONDI-'.NSEIJ ;\JlLK — CoOLINf, 103 

are nriw made of sucli size that tlie !i\'lr"nT-ter can l>e r,|iei-ated 
in them, rendering' the u^e of a ?e]:>arate li^drrimeter c}-linder 
iinnecessar}-. The latest in\-entir]n for facilitating the samiiling 
and striking is the auti:>matic milk st:-iker flesigncd h}' Mdjcnnier 
Rrcis. Co., Chicagci. This ingeniiius contriw.nce consists cif a 
m'itoi"-dri\-en yiiston rnuiip. The sncti'in tnl.ic carrying the inst'in 
extends from the dume cif the ]ian intci the hoiling milk. Tliis 
tulie projects .at Us n|Jiicr ^-nr] through the wall "f the d'ime and 
o\-erflo\\-s into a In'di'ometi-r c\dind.er. Thi^ c^dind.er carries at 
its upiier end a chamhcr permitting nnhmdcred. m'iti"n cif the 
hydrometer and the end uf this chamlier which faces the operator 
is equipped with a sijdit gla,--s .-nid a liidit. In the c}linder 
reposes a Beatimc h_\Tlri nneter. \\'hene\"er the Mperat'ir desires 
to know the density of the condensed milk" in the ]ian. he starts 
the motor. The pnnip inimediatck." IllK the CAlinder and the 
h}'drometer shows the dcn^it}" ' ir keairnic reading. 

Drawing off the Condensed Milk — .\s sunn as the e\ apora- 
tion is completed, the steam is -Init r,ff frum the jacket and cciils. 
the water A'ah'c is closed, the \acutim ])um]) stopped and the 
\'acuum brolcen ]>y upening the "lih-iw-di iwn ' \-al\e. The man- 
hole cciAer is then rerniii/ed and the wacnnm iiump started again 
in order to remci\"e the In it air ii\-er the mill:. The milk is draivn 
into 40-quart cans cr intu tank^ nr coolim^ \ats. The ccindensed 
milk shcmld he drawn frc'ni the paii as ra])idl}" as possible tcj 
pre\'ent its superheatinLi' while in the pan. Tn sume factories a 
u'ire mesh or cloth strainer is attached t' i th.e c'tttlet of the f>an. 
so that the ccmdenscd milk is strained before it rnns int') the 
cans This practice is unnecessary and ol)ji?cti' ma.lile. as it tends 
to retard the rem,o\"al ^f the milk fn im the ]ian. 

COOLING. 

The sweetened cimdensed milk, as it cnnie.-, frdUi the \"acuum 
pan, has a temperature nf about 113" F. to 130 F. If it were 
allov/ed to cool naturall}'. nr on its own acccird, i. e., if no effort 
were made to C(.iol it prumptl}'. it would superheat and this would 
cause it tc.i become thick and cheesy in a shnrt time. It is, there- 
fore, essential that it be ciMjkd at cmce. I'ormerh' this \\"as done 
by drawing the milk fr'im the pan into 40 quart cans, setting 
these filled cans in tanl-cs with ice water and stirring the con- 
densed milk with a stick. 



104 SwiJETENitD Condensed Milk — Cooling 

This was a vcrv crude method, it in\iil\ed much hard work 
and time, and the quaHtv <A the prnchict was pnor. It was soon 
found tlial the im|)erfect liand stirring- caused excessi\e suijar 
crystallization, which made the milk sand}'. The sudden chillinr;- 
and irrcciular stirrint^- f)f a saturated sn,L;'ar solution like sweet- 
ened condensed milk are favnralile to the formation of sugar 
ci'}'Stals. A\'here the stirring is im|)erfect and irregular, all the 
milk is not kept in sufficient motion to insure uniform and gradual 
cooling. The milk next to the side cif the cans is chilled too 
abrupth', fa\oring the formation of crystals. A'igorous stirring 
in itself is conduci\-e of sugar crystallization. 

Later the hand stirring was completely superseded by 
mechanical stirring, paddles closeh' scra|jing the sides of the 
cans being used. Instead of setting the [laddles in motion, they 
are stationary and the cans reAXihe. The principle is similar 
to that of the vertical ice cream freezer. Ilea^)' ii"on tanks, with 
a capacity of t^^■eh■e to forty-eight 40-quart cans, are used for 
this purpose. The bottoms of these tanks are equipped with a 
system of cog wheels, set in motion bv means of a g'ear at one 
end of the tank. The wJieels lia^-e a diamtter large enough to 
carry one can each. The cans are set on these \\ heels, the paddles 
are inserted and fastened to cross-bars and the power started. 
The cans should be hea\ily constructed tri stand rough usage, 
without suffering indentations. Cans with irregular, depressed, 
or bulged sides cause the paddles to do jjoor work. Such cans 
should be slipped o\-er a wooden horn, or other contrivance, and 
the indentations hammered out ^\•ith a mallet. The padflles are 
held stationary by cross-bars and are forced against the pei'iphery 
of the cans by springs, .\ttention -should .also be jiaid to the 
pi\ots (")n \\'hich the cog wheels rest. If the\- are warped, the 
"\vheels do not run true, so that it is not |)ossiblc foi' the ]^addles 
to scrajjc the sides of the cans pro])erl\-. 

The sweetened condensed milk should be cooled gradually. 
Sudden chilling should be a\-oided. This is ])est accomplished 
by warming the watei- in the cooling tank to about 90 degrees F., 
before the cans are set in. The cans are then allowed to re\-olve 
for fifteen tC) t-\\'cnt}- minutes liefore an\- cold water is turned 
into the tank. .After th.at, cold A\ater is turned in slowly until 
the temperature of the milk has fallen to about 70 degrees F, The 



SwERTENKD CONDKXSI'.D MiLK — CoOI^IXG 



105 




Fig-. 35. Cooling- tank for 
sweetened condensed milk 

I 'ourtL-sy Arthur Harris & Co. 



entire time nf cridlin^;" >li'"iuld la^-t aljnut 
tw'ii hi'nirs. The cans slionld I'eA-eihe 
sliiwl\\ raiMcl stirring enhance^ the 
preci])itatir)n rif suL;ar cr\-stal<. In cirrk-r 
tri scrape the sides nf the cans efhcient- 
h', wlii-n the ca.ns rex'ilxe slijwh', 
(almut f]\'e re\"i ilutii ins per miinitei it 
is aeh'isaljle t'l nse twri ])ad<lles in eacli 
can. scra])inL;' tlie cans at ^ppiisite sides 
\Mien tlie milk is sufficient!}' cooled 
the cans are sti'p]"jed, the paddles lifted 
out. scraped and remo\-ed. and the 
cans taken wut 'if the tank. This me- 
thiid fit coiilmi,;' sweetened condensed 
mdlc is stil! in \-( i^ue in the maillrit^' of 

condenseries. It is i i|-j\-iousl\' crufle. lahnricius and tinie-cim- 

suming". 

In some factoides the cnndensed milk is transferred fn.im 

the pan direct into 

large tanks and is sub- 
sequently cooled ijy 

))umping it with a high 

]n'essure pump through 

a sei'ies of coils suh- 

merged in ci dd water. 

ddiis methiid is laliur 

and tinie-sa\ing and 

the I jljjectionaiile le.a- 

tnres of agitatinn are 

avoided. On the nther 

hand, there is rlanger 

iti tdii rapid clnlling. 

wdiich tends tnward e.\- 

cessixe sugar cr\'stalli- 

zatinn and the pniduc- 

tion of rough, sand}' 

and settled milk. 

Within recent }'ears 

tlip use of circular tanks ^^ rig-. 36. Vertical coil cooler 

tile use 01 eircuiai Lain^s rourtesy of Jensen Creamery Machineiy 




106 vSwEivTi-.NiCJ) CoNiii'.NSi'D Milk — Cooi.inc. 

with jacket and \-crticallv su^]")ciKle(l, rcNnK-int; ciiil, has been 
adoi")tCfl ill nnmerdiis facinrics \vith inr;st satisfactory results, 
and this nictlii^d 'if cnntiu;^- this \-iscruis prridiict promises to 
assist in sohint;' tlic ciHihn^ priililcni. l\cctanc;nlar \'ats with 
horizontal cnils, wliich alsn lia\-c ])ccn tried for this purpose, 
ho\\'e\-er, are less desira1)lc, as the\- tcnrl t" cause the condensed 
milk to ft'am excessiveh'. Tliis fnamiiiL;' is caused Ijy the fact 
that the horizontal cnil re\iil\-es into the milk, heating air into 
it. In the case of the circular tank, the \'ertical suspended coil 
wdien re\-ol\'inL;" mii\es upward, out of the milk, tlius avoiding 
incorporatii m of air and excc-sixc foaming. The circular vat 
with the suspended \ertical ciiil lias the further ad\-antage that 
the cfindensefl milk does not ccime in contact with bearings and 
glands, these parts lieing entirel}- dctaclied from the \'at. 

A still more recent method o'i cooling sweetened condensed 
milk consists rif a ciimbination rif the use of the submerged coil 
and subsequent slriw agitation. The equi|)ment fcir this method 
consists of a \-ertical or horiz.mtal tank. ef|uipped \\'ith a sub- 
merged coil. This coil should ha\-e a diameter of about Iv 
inches and a length of frrmi WO to 700 feet, the length needed 
depending rm the tenqieraturc 1o whicli it is desired to cool the 
condensed milk and the temperature of the cooling water. The 
coil is usually of regular, ^o-called sanitary pipe (copper pipe 
tinned on inside) or it m;iy lie likick iron pi]")e i^ireferablv sand- 
Ijlasted on inside. 

'i'lie sul^mergcd coil connects at itN intake with a high pres- 
sure pump and at its outlet with one or more large enameled 
^teel JKdding tanks (capacity- u^iiall\- -,000 gallons). Kach of 
these holding tanks is ec|ui]i])ed A'lilli a powerful niotor-dri\-en, 
vertically slanting agitator, also enameled. The agitator re- 
\-ol\es at a sjjeed of .about 1 J k !'. M. 

In the o])eration of this methoil of cooling, the hot sweet- 
ened condensed milk is drawn from the \;u-unm pan, preferably 
by grrndty. into a standardizing Aal nionntcil on scales. When 
all the condensed milk of (ine and the same batch has been trans- 
ferred to this tank it is accurately weighed. The weight of the 
original fluid milk is tlien duided li\- the weight of the con- 
densed milk. Tliis yields the exact ratio of concentration. If 



SWEKTENI'.D CONDENSKD jMiLK — CoOLING 



107 



the concentration is in excess nf that f'.esired, tlie product is 
standardized 1j}' tlie additinn of the accni'ateh- calculated nec- 
essary amount of distilled \\ater, 

Fr' iin this >tand- 
ardizini^ tank the hot 
c ' i n d e n s e d milk is 
f' irced li\' means ol the 
hii;h pressure p u m yi 
thn;ui;"h the sulimercjed 
CI iil in the ci ii")lint;" tank. 
The water su|")ply to 
this tank is automati- 
callv regulated by a 
thermostat, sri as ti i 
cool the condensed milk 
to the desired tempera- 




Fig. 37. 

Higli pressure puiup for sweetened condensed 

lull]! 

CiiiurteSN' of Union Steam Pump Co. 



ture ( usuall}' 65 to 75 degrees F.). 

The crmderised milk remains in the snl:)merged coil aVjout 
six minutes, i. e., six minutes elapse from the time it enters 
the coil till it reachc- the exit. From here the now cool con- 
densed milk )l(iv\'s to the holding t.'ink where it is slowh- agitated 
for se\'eral lumrs. 

E.xperience has demonstrated that this method of cooling 
and agitating sweetened condensed milk is A-cr}- ettecti\"e in 
pre\-enting the pruducti'in of sand}' and settled milk. It appears 
that the great T,iscosit\- of the sweetened cr)ndensed milk causes 
the milk, in its pa-s,-i;;-e through the djil, to lie sulijected to the 
least damaging agitatii n. The center n\ the column of tlie 
milk mo\-es forward sli^^lith- faster than the portion nearest the 
\\alls of the coil. This results in a rolling or curling motion, 
producing suf^cient and }-et injt excessi\-e agitation. 

The subseqent slciw agitation of the cooled condensed milk 
in the holding tanks f'>r a considerable periijd of time, further 
assists in the preser\-ation of a smooth product. It enhances 
the formation of \-er}- small crystals at the expense of larger 
crystals, thereby minimizing the tendency toward coarseness and 
insuring" a uniformly sniC)oth product that is not prone to \-ield 
a sugar sediment. 



108 



vSwKETiiNisD Condensed Milk — Cooling 




Sweetened Condensed ]\Iiek — Cooling 109 

The pressure required to pump the sweetened condensed 
milk through the cooHng cjil and up into the holding tanks 
^'aries from about 800 to 1200 pijunds. and the pump used for 
this purpose must be strong enough to develup a pressure of 
at least 2,000 pounds, which ma^• be required to start the flow- 
through the coil after the milk has stolid idle fur some time and 
has become chilled. 

This method, in additi'jn to its labor-sa^•ing feature, and 
to its efficiency in avoiding sandy and settled condensed milk, 
has the further important advantage, that the product is pro- 
tected against contamination with bacteria, mold, and other im- 
purities frrim the air. etc., the pniduct being under seal until 
it reaches the fdling machine, or until it is packed into barrels 
in the case of bulk gcinds. This method, therefore, should be 
particular!}' adapted for efforts tn priiduce an article that does 
not de^'elop "bnttrins" \'.-ith age. See also Chapter on "Defects 
of Sweetened Condensed Milk." 

The chief criticism that may be raised against this method 
lies in the (|ne«tiiin ijf cleaning the coolino- ccjil. From the 
standpoint of bacterial contamination it mav safe!}- l)e said, 
howe\'er, that the danger nf >uch c mtamination is renrnte. After 
the product of one day's make has passed throui^h the cuil, the 
coil is sealed Vjy \-ah'es and there is no reason to doubt that 
the condensed milk remaining in the coil till ne.xt day's opera- 
tion, is not just as well protected against all crmtaminating 
influences, as if it were sealed in tin cans. It is ad\-isable, how- 
ever, to completel}' empt}' and rinse and steani the submerged 
coil at regular inter\-als of say once per week. This is especially 
desirable in the case of a copjier coil, in order to guard against 
an excessi\-e accumulation of copper salts wdiich would tend 
to lend the product a metallic f^a\"i;>r and to jeopardize its whole- 
someness. In the case of a black iron coil, sand-blasted on inside, 
the effect of the action of the acid and sugar of the milk is 
neo-ligible. However, \vhen not filled with condensed milk the 
iron coil should be kept filled with clean water to pre\'ent exces- 
sive rusting'. 



no 



Sweetened Condensed Miek — Filling 



Chaptek VII. 
FILLING. 

The sweetened condensed milk is put on the market in 
barrels and in hermetically sealed tin cans. 

In Barrels. — 1 barrels, similar to glucose barrels, are generall}' 
used. They hold from three hundred to seven hundred pounds 
of condensed milk. New l)arrels should be used for this purpose. 
Barrels paraffined, or coated with sodium silicate, on the inside 
are most satisfactory, as they are more apt to be free from mold 
spores. Old glucose barrels are dangerous to use, as they often 
contain decaying remnants of glucose, which cause the condensed 
milk to ferment. The new barrels are steamed out and drained 
thoroughly. The filling is facilitated by the use of a large gal- 
vanized iron funnel with a discharge one and one-half inches 
in diameter, or an ordinary milk pail with a nipple one and one- 
half inches in diameter in the bottom of the pail, ^^'hen filled^, 
a double layer of cheese cloth is placed over the bunghole, and 
the bung is dri\-en in \eye\ with the sta^-es. The barrel goods 
are sold to bakeries and candy factories. 

In Cans. — The 

canned goods are in- 
tended for the retail 
market. The cans 
used hold from eight 
ounces to one gallon 
of condensed milk. 
Most makes of tin 
cans for sweetened 
condensed milk have 
a small opening, 
three-eighths to three- 
fourths inch in diam- 
eter through which 
they are filled. Tlie 
cans known and sold 
under the trade name 
"sanitary- can" arc 




Pig-. 39. 



Filling machine for sweetened condensed milk 

filled before the top courtesy of Schaefer Mfg. Co. 



SwEETiiNED Condensed Milk — Filling 



111 



is crimped on. Sweetened condensed milk is nf a semi-fluid, 
\-iscous and sticky consistency. The successful and rapid fillint^ 
of the cans without spillintc the milk o\-er the top of the 
can is, therefore, somewhat difficult. If dnne b}- hand the 
work is very slow. For this reason man}" ing-enirius ma- 
chines ha\'e been de\'ised which are m^re nr less efficient 
in "cutting off'" the milk without "slobbering." The filliuL;' 
machines now in use var)- from the primiti\'e liand filler, in 
which the condensed milk is ""round init" b\" the turniuLf of 





Fig*. 40. The solder seal 



Tig. 41. The Sanitary can 





Tig. 42. The Gehee seal Fig*. 43. The McDonald seal 

a crank by hand, to the most perfect frirms rif automatic fiUinc;- 
machines. In these filling machines, all parts cnming in con- 
tact with the condensed milk are constructed of hras=;. They 
usually are equipped with a reservoir, rcceiA-ing tank, or hopper, 
which has an automatic feed, usually a floating de\dce attached 
to a valve, which regulates the inflow according to the discharge. 
The discharge is adjustable to fill any size can with a remarkable 
degree of accuracy, except gallons which are usually filled bv 



112 vSwF.KTKNED CoNDIiNSBD MiLK — SEALING 

hand. MaclTines of this ty]X' will fill fn im tweiitv-fi ve thousand 
to thirt}' thousand cans per day (ten hours). 

These machines are of complex construction and must re- 
ceive proper care. It is best to clean them thoroua;hly after each 
day's work. Pmt. since their inlet and dischartje are ckised her- 
metically, the complete washinj^ maj" he done once per week 
only, without seriously disturbing their efficiency or impairing 
the product. For thorough cleaning, the filler should be dis- 
sected, removing all detachable parts, such as valves, pistons, 
tubes, etc. ^^^hen freed from all remnants of condensed milk, 
the parts should be scalded, dried and replaced in the machine. 
In order to guard against all possible contamination by remnants 
of wash water, it is advisable to reject the first few cans of milk 
of the next tilling. When not in use, the filling machine should 
be covered with clean cloth, or oil cloth, to protect it from dust 
and ilies, etc. 

As soon as the cans are filled, they should 1)e "capped.'' If 
allowed to stand open, dust, dirt and flies, or other insects are 
prone to reach their interior, and the prolonged exposure of the 
condensed milk to the air and light causes the surface to crust 
over and to de^'elop a tallowy flavor. 

SEALING. 

Kinds of Seals. — The seal must be air-tight and firm enough 
to prevent its breaking during the rough treatment to which the 
cans are exposed in transportation. There are se\eral methods 
of sealing the cans, depending largely on the constructi(Tn of the 
can. Most of the cans used are sealed \\ith solder. There is a 
groove, around the opening, the ])eri])hery of the cap fits into this 
groove and the latter is filled \\'ith solder. In the case of cans 
which are sealed without solder, the caj) or the entire end of the 
can is crimped onto the can so as to make a hermetical seal. The 
McDonald seal with the friction caji, the C.ebee seal with the burr 
cap, and the Sanitary can seal with the to|) of the can crimped on 
after filling, are the chief t}'i)es of solderless seals. In the case of 
the McDonald seal, ;i tightly fitting cap \\-ith a wide flange is 
pressed into the opening. The "capped" can passes under a 
series of steel rollers pressing the flange firmly against the top of 



SwEKTENliO CON'DENSKD MiEK — SEALING 



113 



the can. This seal is \-er\- snii])le. Imt is nrit \'ei'y strrtnc;- and 
not hermeticalh- ti;jiit. In the case nf the Gehec >eal, a rim pro- 
jects around the opening" of the can. -Vftei- the cap is insertecL 
it is crimped o\-er this rim 1i\' nieaii'^ I'f a series i<i re\'Cil\-inL;" dies. 
This seal is reasonabh' striiny- hut not hermeticalh- tiu;iit. The 
Sanitary can is entirel}' njien at rine end when hlled. The cnxer 
or end is crimped arijurid the peripher\' ijf the ])ii(\y ni the can 
by means of rexohinn- dies. 'IMns -^ea! i-^ reaMinahly str(:jnn 
and tisualh' hermetically ti,L;"ht. The chief adxantayes uf the 
seals withijut sokler lie in the sa\ inj^" ul lahur and the reducti'jn 
of the cost due to the omi.^siiin of scilder. 

Soldering Devices and Machinery. 

— The sealint^" of all solderless seals is 
dmie li>' speciall}' cijustructed .--ealing- 
machines. 




Pig. 44. Soldering- stove 

Courtesy of Arthur Harris & Co. 

Ki)r seals with solder there are sex- 
eral machines en th.e market l")nt much 
of this work is as }'et drme b}' hand. 
Ffjr this, different t_\"])es nf snlderinL; 
coppei's are in use and the coijfjer ti|)s 
are heated in S( dderini;- strues (ir ]:)Ots. 
Sc>me solderinw coiJ]x-rs ha\-e Imlli-iw 
circular tips with a diameter ecjual to 
that of the cap used. The hollriw tip 
is telescciped In- a rod \\-hich hold< the 
cap in place and the periphery uf the tip fits int(j the groo\-e 
of the opening- of the can, where it melts the snider. A rapid, 
neat and leakless seal can be made with, this instrument. 

Ordinary soldernig" coppers with a blunt point, such as are in 




Pig-. 45. A convenient de- 
vice for soldering- by hand 



114 SwP,eT)!NED Condensed Miek — Sealing 

g-enera! use by the tin sniitli, are not vevy satisfactory. Unless 
tliey are drawn ont and filed do\'\'n into a fine point, tlieir use is 
not conduci\'e of neat ^\■llrk, prot:;ress is con1parati^'ely slow and 
leakers are often numerdus. When gas is available the automatic 
soldering" copper mav l>c used tn ad\'antage. In this tool the 
copper tip, which is long and slender is automatically heated by 
a current of gas passing through the handle and burning at the 
copper tip. The handle of the de\ice is cr)nnected with the gas 
and air pipes ])\' mean.q of flexible rul.'ber tubing. Xo time is 
lust waiting for the cupper to heat and the flame can be so 
regulated that the temperature uf the copper tip is right and 
uniform. This is im])0rtant. because perfect work is impossible 
unles.'^ the coppers lia\-e the [iroper temperature. 

Machine-siildering is miw rapidly replacing hand-soldering. 
The principle of the older ty]ics of soldering machines consisted 
of re\'olving discs mi \\hich the tin cans were placed. The cap 
was held in place hv a \-ertical rod pressing on it. The solder 
was applied b\- hand, the hot soldering copper Avas held over 
the groove in the can while the cans revoh-ed. This method had 
no particular advantage river the hand soldering. There was 
little, if anv, saving of time and the qualitv of the work was not 
much, if any, better. 

There are now un the market newer types of soldering ma- 
chines, most ingeniously constructed and their operation in fac- 
tories with large out|nits ecmiomizes lab("ir and time. 

Solder. — The sdder used for sealing shduld be of standard 
composition, in this country, canning establishments are |)rone 
to use a A-ery ])<ior (pialit_\- of sinlder. It contains from 43 to 55 
per cent lead. Lead is a fjoi'-onous niet.al ; its u.se in the canning 
industry should, therefore, be regulated by law. In C.erman)-, 
the law requires that solder used in tin cans for food products 
must not contain o\er 10 per cent of lead. 

A\'here tlie sealing is done b}' hand the solder is most con- 
xenieiitly used in the form of thin bars or wire. The wire is 
usually benight ahead)- cut up in segments, each segment furnish- 
ing solder enough to seal one can. In the newer types of sol- 
dering machines the solder wire is automatically fed from spools. 



SWEETENKD CoXDENStD AIlLK SliALINi:. 115 

The smaller the ripeniiii^' rif the can, the less srilder is necessary 
to complete the seal. An nix-nin^ smaller than three-eighths rif 
an inch in diameter, hii\\-e\er, cannut crin\-enientl\- he used, owinr,: 
to the difficulty of filling the can with thi-- \-i^cuus jiroduct. The 
essential points of satisfacti ir}' scaling are: ni> "leakers," neat 
work, rapid worjc, small amnunt 'if solder. Aside frrmi the size 
of the opening of the can. the anvjunt "f ^'ilder used depend- 
on the experience ijf the sealer. F.eginners u-.ualh" make an un- 
even seal. ^N'aste much srijder. and ha\'e man}' "leakers." Thi^ 
is largely due to their ignrirance of the proper s'ddering tempera- 
ture oi the cop])er. An exjierienced sealer will use friim t\^"o 
to three pciunds of sadder pel' jhciusand tin cans with moderate- 
sized openings. He will seal from fifteen hundred t' i t\venty-fi\"e 
hundred cans per da}' 

Soldering Flux. — The use of -older rcf|uires the a]:)plication 
of soldering flux, to prepare the surface nf the tin for the solder. 
The flux alwavs precedes the srilder. Wdien the hot solder is 
applied, some of the flux is hound tci sweat thrnugh, lietween cap 
and can. gaining access tci the interi'ir "f the can. 'fhe ccnnmon 
practice of using zinc chloride or other -imilar acid fluxes, \vhich 
are highly poisonous, therefore, cannot he too strong!}- con- 
demned. Their presence in the can ma}' jeupardize the health 
and life of the consumer, as well as the marketable properties of 
the product. There are cither fluxes wliich are abs'jlutel}' harm- 
less, and which, if properly u-ed, give satisfactory results. Dr}", 
powdered resin, or resin di<soK-ed in alccihcd or gasoline, are of 
this class. Ammonium chlnride, while u-ed in nieist tin shops, 
is not as well suited for this pur|)iise. 

Gas Supply.- -A plentiful and stead}' supply of gas is Aery 
essential. Where natural gas or gas from a municipal corpora- 
tion is not a\'ailable, the factury must rel}' on its own generator. 
For the needs of the condenser}' a gasMline gas plant seems 
suitable. Gasoline gas is pruduced b}' forcing atmospheric air 
over or through a bod}' of gasoline. The mixture of air and 
gasoline sapors form- the gasoline gas. The gas generators in 
use consist chiefly of carbureti ir, air pump or Ijlower. and regu- 
lator. The carburetor usualh' has a series cf cells, ccinnected 
with one another by means of a S}'stem of syphon tubes. The 



116 vSwEKTliNRD CONDKNSED Mll.K — SCALING 

interior of each cell is jiartitioiicd off with heavy cotton wicking 
This wicking' absorbs the gasoline by capillary attraction. The 
air, passing through the fine meshes of wicking, comes in contact 
with a large surface of gasoline. 

The following arc some (if the essential points to be observed 
in the installation and operation of gas generators of this type: 
Sink the carlniretrir Irtw enough (three to fi\'e feet below the 
surface of the ground if necessary ) t" permit the gas pipe tci slant 
from the factory to the carliuretor. If the gas pipe is horizontal, 
or inclined toward the factor}-, condensation water may collect 
in the pipe, obstructing the free passage nf gas. This causes the 
,gas either not to be a\ailable at all, nr t(j reach the stoves in 
irregular gusts, \\liicli is ei|ual'y unsatisfactor)'. Where the gas 
pipe slants toward the carburetor, the condensation water flows 
back into the carburetor, causing no obstruction. Use gasoline 
of the best Cjuality only. Cheap grades form a residue and clog 
the generator. The gasoline is best bought in iron barrels; this 
prevents unnecessarj^ loss by evaporation, which occurs in 
wooden barrels, especialh- in summer. The cells should not be 
hlled more than two-thirds full ; too luuch gasoline reduces the 
gas-,generating capacity of the carburetor. If, during extremely 
cold weather, the carburetor refuses to generate gas, the injection 
of a pint of wood alcoh.ol through the blow pipe into the cells, 
usually remedies the trouble. The gas plant and gasoline storage 
should be located in a separate building and at a reasonable 
distance from the main building, in order to minimize danger 
from fire. 



PART III 

MANUFACTURE OF UNSWEETENED CON- 
DENSED MILK 

EVAPORATED MILK 

CitAi'TKR \niT. 

DEFINITION. 

There arc three kinds of unsweetened condensed milk on 
the market, namely, e\'apiirated milk, formerly callerl e\'api:irated 
cream, plain condensed ludk milk and concentrated milk. 

E\'aporated milk is cow's milk condensed in \acuo at the 
ratio of about two to two and one-half ])arts of fresh milk to one 
part of C(Tndensed milk. It is of tlie consistency of thin cream 
and reaches the market in hermetically sealed cans \aryinn- in 
size from ei,:^iit ounces to one i^-allon. E\-aj>orated milk is pre- 
ser\-ed 1)\' sterilization in steam under i>ressure. \\ hen prciperlv 
made, it will keep indetinitel}-, but is best when fresh. 

QUALITY OF FRESH MILK. 

In the manufacture of e\'aporated milk the physiolnc-ical 
normality and the chemical purit\- and sweetness of the fresh 
milk are factors eyen more important than in the case of sweet- 
ened condensed milk. A uniformly satisfactory and marketable 
product cannot be manufactured, unless the milk is normal and 
pure in eyery respect. The reason for this largely lies in the 
fact, that defects the fresh milk may ha\e, are greatly magnified 
and intensified by the high sterilizing temperature to which the 
eyaporated milk is subjected. AN'hile, frijm the biological point 
of yiew, contaminations of this milk are largel}' rendered harm- 
less by sterilization, defecti\e fresh milk cannot be made into 
a marketable product, because such milk usually does not suryiye 
the process. 

It should be understood that an}- condition or factor that, 
in the slightest degree, increases the tendency- or ability of the 



118 Evaporated Milk — Heating 

casein to curdle, tends toward the furmation of a hard, iinshak- 
alile coagiihim during- sterilization, and makes the manufacture 
of a marketal.)le product difficult. Mmurmal milk of this tvpe 
may come from ciiws apprnachinu' parturition, or too soon after 
calving, or milk from c<i\vs suffering from disease, generalized 
or local, or from Cdws in pour and ahnormal ]>h}-sical condition 
which may l)e brought about bv poor care, fixer-feeding, feeding 
the \\rong kinds of feed, or feed in i)oor C(jndition, exposure to 
abnormally hot weather and flies, or any other condition which 
disturbs the ])hysic>logical functions of the animal and thereby 
affects the ]ili}'sical, chcmicrd, and physiological pro])erties of 
the milk: or it may l)e due tv im])roper care of the milk, causing" 
it to l)e excessi\'eh' contaminated with germ life, or to be rel- 
atively high in acid. All such milk renders the quality of the 
finished product uncertain and may result in hea\'y loss. 

In view of these facts it is obvious that the greatest care 
should be exercised on the recei\'ing platform, inspecting ever^- 
can of milk, using the most reliable means, as recommended in 
Chapter III on "Control of Quality," to detect suspicious milk, 
and rejecting all milk that fails to reach the sanitarv standard 
adopted by the factory. 

Standardizing. — ^In order to insure in the finished product 
the percentage relation of fat to solids not fat that meets with 
the Federal Standard or with any other standard desired, the 
fluid milk should be accurately standardized. For this purpose 
each batch of fluid milk must be correctly tested for per cent fat 
and per cent solids not fat. On the basis of these tests, the 
amount of cream or skim milk which it is necessarv to remove 
or to add, as the case may be, can then be readily calculated. 
For detailed directions on standardizing the milk to anv desired 
standard see Chapter XXIX on "Standardization." 

HEATING THE MILK. 

The ec|uipment for heating the milk should be such as to 
enable the factory to heat the milk with the least possible delay 
so as to avoid the development of acid, or to make possible the 
prompt cooling of the milk u]5on its arri\al to a temperature at 
which bacterial development is checked. In the manufacture of 
e\'aporated milk, the batches of condensed milk in the vacuum 



EvAPOEATKD Milk — Condensing 119 

pan must be relatively small. This milk (..ams mwre in the pan 
than the hea\-ier s\\-eetened condensed milk. This factor reduces 
therefore, the capacity of the pan. If the milk is not cooled upon 
arrival, but is transferred immediately to the hot wells, it is 
advisable to use numerous small wells, rather than lint rnie or 
a few laro-e ones. These small wells fill rapidl}- and the milk 
can be heated \\-ithout delay. This s}'Stem makes it possible to 
render the bacteria inacti\-e and harmless practicallv as soon 
as the milk arri\'es, minimizing- the danger of acid fr)rmation.' 
Steam mav be sa\-e(l if the milk is forcwarmcd In' running 
it through coils inclosed in a chaml'er cif exhaust steam, bni the 
coils increase the labor and difficulty of cleaning. It is liest to 
heat the milk to as near the hjc.iling point as possible and hold 
it there fiir five t(i ten minutes. ])rr]\d(led that the caj^acity cjf the 
factor}' ^\'arrants this delay. In this heating the casein rit the 
milk is som■e^^'hat changed. There occurs partial, though in\'is- 
ible, precipitation, and the higher the temperature to which the 
milk is heated, tlie more uronounced is this change. This change 
is desirable, because the casein thereb}' surrenders, to a limited 
xtent, its po\ver and tendenc}' to form a firm curd in the ster- 
Sce also Chapter XI on "Sterilizing." 



ex 
ilizer. 



CONDENSING. 

The same apjjaratus, the \'acuum pan and pump, is used 
for condensing the milk, and the process cif condensing is prin- 
cipallv the same, as in the case cif sweetened condensed milk. 
The fresh milk is condensed at the ratio r>\ two to two and one- 
half parts of fresh milk to one part of condensed milk. In some 
factories it is customary to superheat the milk in the pan before 
it is drawn oft, i, c,, the steam tij the jacket and coils is shut oft, 
the ^^■ater vah'e is closed, the \'acuum pump is stopped and 
"live" steam is passed into ihe condensed milk, Wdien the 
\'acuum has dropped to about six to eight inches, and the tem- 
perature has risen to 180 to 200 degrees V. the superheating is 
stopped, the steam is turned ofi', the A'acuuni pum|> is started 
again, and the condensing is completed. The superheating is fre- 
quently also done after the e^'aporated milk has bieen dra\\'n 



1 See also Cooling Milk and Standardization, 



120 Evaporated Mii,k — Striking 

from the pan. In this case, the process of evri])oration is usually 
carried slightly l)eyond the desired density of the finished prod- 
uct, the evaporated milk is drawn from the pan into an open vat 
or kettle where steam is turned direct into the milk until the 
superheating is com<pleted, \\-hich is indicated by its greater con- 
sistency and the slightly tfaky condition of the curd. Then water 
is added to the superheated evaporated milk to bring the product 
back to the desired density. 

The chief purpose of sui:)erheating is to partly precipitate 
the curd. This minimizes the danger nf the formation of too 
hard a curd in subsequent sterilization. It also lends the body 
of the milk the appearance of greater consistency, gives it a 
more creamy character and assists in the prevention of sub- 
sec|uent fat separation. The superheating of evaporated milk is 
not essential for the production of quality and marketable prop- 
erties, but it is looked upon by many manufacturers as a safe- 
guard against such defects as curdiness and fat separation. It 
is not improbable that its ad^antages are much overestimated, 
and in most factories the superheating ])rocess in entirely omitted. 

The condensing of milk for the purpose of manufacturing 
e\aporated milk ma}- be done also in the absence of the vacuum 
pan, b\- the use of the "Continuous Concentrator," the construc- 
tion and operation of which are described in Chapter XI\' on 
"Condensing by Continuous Process." 

STRIKING. 

The striking, or sampling and testing fur densit^•, of e\'apor- 
ated milk, is more easih' accomplished than that of the sweetened 
condensed milk. A\ hen this product has nearlv reached the 
projier density, it is not \iscous and S}rup\-, containing no cane 
sugar. It resembles in consistenc)- rich milk or thin cream and 
has a specific gra\'ity of 1.0,^ to 1.073 at \5.? degrees C. or 00 
degrees F. 

Samples are drawn from the \acuum |)an as described under 
sweetened condensed milk and the densit\' can be readily deter- 
mined by means of a hydrometer, lieaume hydrometers, register- 
ing from' 5 to 15 degrees B., are generally used. As it is im- 
portant that the determinations be accurate, the hydrometer 



Evaporated Milk — Striking 



121 



should be sensitive and its scale slionld l)e sul)di\ided into tenth 
degrees. The batch should lie "struck" at a uniform tempera- 
ture, say 120 degrees F., so as tu a\'oid misleading readings of 
the h}-drometer, A difference of a few tenths degrees Ileaume 
affects the beha^■ior of the evap(irated milk in the sterilizer \-erv 
appreciabl}-. If the density is too great the pnidnct ma}' badl}- 
curdle during sterilization. If the density is tun luw the e\-aprir- 
ated milk may be below the legal standard. It is adx'isablc for 
the operator to use a pail uf water of the ]")ro[)er temperature, 
when he strikes the liatch, sri that he can adjust the tem|5erature 
of the milk in the h_\dr' .meter jar readily and quickl}-, and need 
not depend entireh- on the tem]ierature nf the milk in the pan 
wdiich may change sc\"eral degrees -while he is engaged in the 
operation of striking. The hydrrimeter jar containing the sample 
of e^'aporated milk is set into the pail of hot water cif the desired 
tem]")erature, the h}"drometer is inserted in the jar and the read- 
ing is taken. 

"While the Beaume hx-dnimeters should be used at the tem- 
Iierature for wdiich they arc graduated, -which is I'tO degrees F., 
tliey answer all practical ])urposes at an}- cither temperature : 
at 120 degrees F. for instance. The chief essential is to take the 
reading at some unifnmi and clcfinite temperature and read the 
I'eaume at that same ten-iperature in the case of e\-ery batch. In 
that way the results are comparable. The operator soon learn^ 
that at a g'i-\-en temperature the e\-aporated milk of proper den- 
sity shows a certain IJeaume reading. When the reading is 
higher or lower, the milk has either been condensed too much or 
not enough. The use of the automatic ''striker" described under 
".Striking Sweetened Conden-;ed Milk," practically soh-es the 
control of the tem])erature of ihe sample taken. 

The same forn-iula, h(iwe\-er, cannot be used under all con- 
ditions. Xo rule-of-thumb method of determining the density 
can therefore be estal.dished. .Aside from the degree of conden- 
sation, the specific gra\-ity ui the milk \-aries with locality, season 
of year, quality of milk. etc. This means that what is the proper 
Reaume reading in one localit}', or at oi-ie season in the same 
locality, may be entirely wrong in another locality, or at other 
seasons in the same locality. If uniformity in the density and 
beha\-ior cf the batches of c\-ai.)orated milk is tu be secured 



122 



EvAPORATF.D MiLK — STRIKING 




Pig. 46. 
Beauiu6 hydro- 
meter for 
evaporated 

milk 

Courtesy ot 

O. J. Tagllabue 

Mfg. Co. 



throughout the year, tlie operator must \\-atch the 
bcliavior of his milk from day to day and from 
season to season and he must modify the Beaume 
reading in accordance witli the clianging conditions 
This is one of the all important stages of manufac- 
ture, where relentless and careful study and watch- 
fulness are indispensable. 

In order to make absolutedy sure that the den- 
sity of the ex'aporated milk is right, it is advisable 
to get it iust as near right as possible in tlie pan 
and then draw the milk from the pan into a stand- 
ardizing vai. large enough to accommodate the 
entire l)atcli or se^•eral batches. The operator then 
tests the milk again and this second estimation he 
can perform more carefully, because he is tlien 
relieved of tlie responsibilit}- of attending to tlic 
o])eration nf the ^•acuunl ])an. If the evaporated 
milk happens to lie a trifle too hea\'y be can dilute 
it with distilled water until the Picaume reading 
is just rit;ht. See also "Standardization," Chapter 
XXIX. For ma.ximum uniformity and accuracy 
< f results (if <lelerminati<.in \\ ith the lleaume ll^•dro- 
meter, nr l)y other means, it is essential tiiat the per- 
centage relatiijn of fat to solids be uniform from 
b.atch to batch. This unitorniit\' requires standardi- 
zation of each batch. 

Correction of Beaume Reading at Temperatures 
Other than 60 Degrees F. — At a temperature of 120 
degrees F. the Beaume reading of the linished batch 
of standard e\aporated milk uku- \ar\' lietween 
about (i and 8 degrees !'>., according to season of 
year and localit}'. .\t ()0 degrees F. the IVaume 
reading is appn i.ximately 1 .8S degrees B. higher. 

If it is desired to record the Bieaunie reading 
at the correct temperatuie, i. e., ()0 degrees F., and 
it is not convenient to cool the evaporated milk to 
that temperature, the reading at any temperature 
m.'iy be corrected as follows: when the tempera- 
ture at which the ISeaunie reading is taken is above 



Evaporated Milk — Striking 123 

60 degrees F., multiply the difference between the temperature 
of the obser\-ed reading and 60 by the factfjr .0313 and add the 
lirnduct to the obser\-ed reading. 

Example: lleaume at 120 degrees F. is fi.S ; what is the 
reading at 60 degrees F. ? 

Answer: 6.R + (60 ;■ .0313) = R.68 degrees B. 

The corrected T!eaume reading is 8.68 degrees B. A\'hen the 
temperature at \\hich the rearling is made is below 60 degrees 
F., multiply the difference between the temperature of the ob- 
ser\-ed reading and 60 by the factor .0313 and subtract tlie prod- 
uct from the obser\-ed reading. 

Calculation of Specific Gravity from Beaume Reading. — In 
order to record the densit}' of the e\"aporaled milk in terms of 
specific gra\'it}'. instead of P.eaume degrees, the follriwing for- 
mula ma}' be used : 

145.5 

Specific "Ta\"it\' = . , , _ -, — ; B = Beau.me reading- at (iJ 

14?..-^ — M *" 

degrees F. 

Example: Bcaunie reading at 6i0 degrees E. is 8 degrees B. 

What is the specific gra\'it}''"' 

145.5 

Si.'ecific gTa\-it\' ^= , , - _ rr ^ 1.0.^82 

14.'^.,"^ — <> 

Standardizing Evaporated Milk. — .\s pre\iiiusly suggested it 
is atK'isable to carr_\' the condeu'-ing pri:icess slightly fjeyond the 
conceiitration desired, so as to enable the (i|)erator tc' readily 
standardize it to the exact pnint desired by the additiini of a 
small amount of distilled water 

As soon as crjuflensatirm is C(;impleted the contents nf the 
pan are drawn into a standardizing' A'at resting on scales. The 
e^'aporated milk is accurately \\'eiglied; the degree of ci'mcentra- 
tion is calculated b\' di\'iding the weight c.f the original fluid 
milk b\' the Nveight of the e\'ai)orated milk, and the ann'iuut of 
water necessar}' to bring the solids and fat to the exact stand- 
ard desired is calculated, and added to the e\'a]3orated milk. If 
it is desired to further check these results, or instead of weigh- 
ing the evaporated milk, it ma}' be tested for fat and solids, and 
the degree of concentration may be calculated Ijy dividing the 
per cent of fat or of solids in the e\'aporated milk b}" the per 
cent of fat or of solids, respecti\'ely, in the fluid milk. F(ir de- 



124 EvAPORATivD Milk — Homocknizinc 

tailed directicms on calculations of concentration and on exact 
method for standardizini^', the reader is referred to Chapter 
XXIX on "Standardization." 

CH.\1■T1^R IX. 

HOMOGENIZING. 

Purpose. — The object of homogenizing is to a\oid the separa- 
tion of the Ijutterfat in the e\aporated milk after manufacture. 

The butter fat is present in milk in the form; of minute 
globules. These fat globules are lighter than the rest of the 
ingredients of the milk. I^he}', therefore, show a strong ten- 
dency to rise to the surface and to form a layer of thick cream 
in the cans. When these cans are subsecjuently subjected to 
agitation, as is the case in transportation, this cream churns, 
forming lumps of butter. This tendency of e^•aporated milk to 
separate in storage and churn in transportation is especially 
noticeable with milk rich in fat and in which the large fat glob- 
ules predominate. In Jersey and Guernsey localities, it is more 
difficult, therefore, to manufacture evaporated milk that does not 
separate, than in Holstein and Ayrshire localities. While sepa- 
rated and churned evaporated milk is perfectly sound and in 
e\'ery way as \aluable as a food, as it would be without this 
separation, it does not sell in this condition. It is rejected on 
the market. 

This tendency toward fat separation can be minimized and 
frecjuentl}' entirely pre\ented by increasing tlie viscosit\' of the 
e\'aporated milk. This can he accomplished bv superheating tho 
milk in the pan or after it lea\es the pan, and b)' prolonging 
the sterilizing process, raising the heat ver_y slowly or stopping 
the reel of the sterilizer at certain stages of the process. How"- 
ever, there are conditions when e\en these precautions do not 
permanently a\'oid separation of the fat. In such cases, the 
proper use of the homogenizer furnishes a reliable means to 
guard against this difficulty. 

Principle of the Homogenizer." — The principle of tlie homo- 
genizer is to force .the milk under Iiigh pressure through exceed- 
ingly small, microscopic openings. By so doing the fat globules 
are broken up so finely that they fail to respond to the gravity 



Evaporated Mii^k — HoMociiNiziNf, 



125 



force, they caniict ri^^c to tlie surface and therefore remain in 
homoi^enerins emulsion. The \-akie of tlie hrimoqenizer hes in 
remoA'ing' the fnndanienfal cause cif this separatiim. It reduces 
the fat gdcil)ules to such smaU ^ize that their f)nii\'ancv, iir grav- 
ity force, is not great enougli to overcome the resistance of the 
surrounding hf|uid. 

The earher thec)ries concerning the action of the hijmog'en- 
izer were that the milk liad to pass through ojjcnings so mi- 
nute, that the fat ghj1)ules, in order to ])e alile to pass through, 
were crusheth torn and di\-ided into much smaller units, lience 
their fine state of di\-ision in the lioniogenized milk. 

Eater stiuh' of the jirinciples of honiogenization has re\'ealed 
facts and pri:;l)al)ilities wdiich do not liear riut the earlier assump- 
tions. JXIen wdio haxe subjected tlie construction and operation 
of homogenizcrs to intensi^-c stud}" claim, that the openings or 
orifices through which the milk passes in the machines in com- 
mercial use when operating at capacity, range in size from afjout 
.003 inch to .01 inch. If these findings ,are correct, then it is ob- 
vious that the fat globules and e^-en clusters of fat globules can 
pass through the homogenizer as entire units and with^iut being 
broken up, for the a^-erage fat globule measures alxuit SXiOl inch 
in diameter. 

It is not improbable that the homogenizing action is \-er}" 
similar in its atomizing cause and efl'ect, as that which takes 
place in the spray-drying process, i-inl}- the homogenizing action 
is more intensi\'e Ivecause of the smaller size of the openings 
through which the milk must pass. The atomized spray in 
the spra}'-dr3'ing process is formed, not in the sjiray nozzle, but 
as soon as the pressure is i-eleasecl, or as so(]n as the milk 
escapes from the nozzle. 

In the case of the spray-dr}-ing process, the atijmized spra}" 
is discharged into a medium of heated air, wdiile in the homogen- 
izing process, tiie atomized spra}- is discharged into a li(|uid 
medium, milk. 

The degree of fineness of the atoms in either case depends 
on the speed with which the li(|uid passes through the orifice: 
the higher the speed the finer and more minute the atoms. And 
the speed of passage in turn depends on the degree of pressure 
and the size of the orifice. IMie greater the ]jressure and the 



126 



EvAPORy\Ti;D AT ILK — HOMOGENIZING 



liner the ( ipenino;, the fastei' Ihc milk tra\'els thrriugli the orifice', 
and in the case of tlic Immogenizer, tlie finer the fli\'ision of the 
fat globules in the hfimooenized milk 

The tendency of fat L^'kibiiles to separate out in homogenized 
evaporated milk is further reduced h^' tlie fact that the homogen- 
izer also alters tlie |;)hysical condition of the casein, making it 
more \'iscous and thereb}' increasing the resistance which the 
fat globides must ON'ercnme in their u|)ward passage. 

The exact changes which the casein undergoes are not \\ell 
understood, but it is not impi-obal)le that either the high pressure 
or the vibration, or both, tc) wdiich the milk is subjected in the 
homogenizer, bring abnut a molecular rearrangement of the 
casein. T'nssibly these factors cause the lactic acid which is 
increased due to the concentration fif the e"\'aporated milk, to 
remo\'e calcium from the casein, lea^■ing a part of the casein 
as free casein which is a solid, and a part of the casein as casein 
lactate vdiich is in a ciilloidal state and wdiich is readilv hv- 
drolized. 

The fact remains that, wdien the liomogenizing is done un- 
der relati\"ely high pressure, nr when done in a homogenizer 
carryin.g a spring-loaded \'ah-e which lends to \dbratc or pound 
the constituents <)[ the milk, the resulting homogenized milk- 
increases in thickness, is mi ire susceptible to the curdling act- 
ing of the heat in the sterilizer and i< more pmne to "feather" 
or curdle when poured 
into hot coft'ee. 

The essential fea- 
tures of an efficient and 
relialde hrmn igenizer 
are: ,'\ high class, high 
]>ressure, sanitary milk 
p u m p, a resistance 
\'al\-e or similar liomo- 
gem'zing arrangement 
made from material 
which will not wear nor 
rust, and a means for 
a c c u r ately adjtistine „. .„ ™^ „ ,. ^ 

-' -' '^ rigr. 47. The Gauliu homogrenlzer 

tins valve. courtesy of Creamery Package Mfg. Co. 




EVAPORATKD ]\IlI,K — HOMOGENIZING 



127 



Kinds of Homogenizers. — There are nt this time three make? 
of homogenizers in use in this ciiuntr\', name!}', tlie "Haulin" 
homogenizer, the "Progress" hiimogenizcr and the "\'iscnlizer." 

In the Gaulin homogenizer, the milk is frirced, 1»}' means of 
single-acting i)umps, against an agate A-ah'e ^\•hich presses against 
a ground ^'al\-c seat. The milk has to pass between the ground 
surfaces of this "\-ah-e and \'alve seat. 

In the Progress homogenizer the IionKjgenizing pi-inciple 
consists of forcing the milk, by means of single acting pumps, 
between a series nf discs with "round surfaces. The discs lie 




rigf. 48. The Progress homogrenizer 

Courtesy of Davis-Watkins Dairymen's Mfg. Co, 



H-I1S73A 



Fig;. 49. 

Homog'enizing' discs 

and screw 

mechanism 



flat one upon the other, they are enclosed in a cylinder and are 
held in place by a rod running througli their center. The discs 
are pressed against each other by a hea\-}- spiral scre\v, which 
regulates the pressure to \\hich the milk is subjected. The milk 
passes from the center to the periphery of the discs. The discs 
used in this machine are of two types. One t)pe has very fine 
irregular grooves. The milk shoots through these grooves 
against hard shoulders. The other type of discs has smooth 
surfaces but their area of contact is narro\\-. The milk passes 
through these smooth surfaces. 



128 



Evaporated jMilk — Homogenizing 




rig". 50. The Viscolizer 

Courtesy of John W. Ladd Co. 



The Viscolizer. — 'Phi,'; lirimo,i;cni/.er is equipped with a cone- 
.'ihaped resi.stance \'al\-c of " N'iscdlitc" metal, thronoh which the 
milk is forced. The 
cdiiical \'al\e has an 
accurately fitted 
n'uide in the valve 
seat, for the purpose 
of liftin,"' s(|uarely 
from the seat and ' 
pro^'iding an open- 
ing I if e(|ual dimen- 
siijns for the entire 
circumference. This 
\'al\'e is regulated hy 
a differential screw 
mechanism in which 
the tra\-el en- ad\'ance 

of this screw is reduced 2S times fmm its normal pitch, making 
j)ossihle a \'ery fine adjustment. One complete turn of the 
handwheel opens or closes the \al\e approximately to .HQl of 

an inch. The milk is fore- 

ed through this \-alve b}- 
a triple pressure pump. 

Operation of the Ho- 
mogenizer. — In order to 
avoid fat separation it is 
necessary to subject the, 
milk to enough pressure 
t<i reduce the fat globules 
to at least one-third their 
original size. If enough 
pressure is applied to di- 
v\de the fat globules into 
much smaller units there 
is a tendency to also 
change the properties of 

the casein to such an ex- Courte.sy of union steam Pump Co. 

tent as tu cause it to gi\'e rise U< co])i(.ius precipitation, when the 
e^■aporated milk is sterilized, and makin;; the finished ])roduct 




Fig". 51. Atomizing' valve and differential 
screiv mechanism of viscolizer 



EvAPORATHD Milk — Cooling 129 

curdy and unmarketable. In this case the cure would be more 
disastrous than the orig'iiial detect. Great care must, therefore, 
l)e exercised, g^uardini;- against the u,~e oi excessi\-e pressure that 
would injure the casein. Ex]")eriments haA'c shijwn that a 
pressure oi Ijetween one thuU'^and and lifteen hundred pounds 
per square inch is sufficient ti:i prevent fat sejjarati'in and is 
practically harmless as far as its nljjcctii inahle effect rm the 
casein in the e\'aporatcd milk is concerned. 

The e\'aporated milk is run thrrmgli the homijgenizer hot, 
just as it comes from the \acuum pan or standardizing tank. If 
the evaporated milk were liomogcnized cold, the fat glolnile*, 
instead of being'; sul.)di\'ided would unite into Initler graiuiles, the 
milk \\-ould churn. The first ]jailful of milk passing thriiugh the 
machine should be returned to the supjdy tank, as on the start, 
the pre-^sure is ni't unifijrm and honirigenization is incomplete. 

The pistons, cylinders, \-ah'es and pi])es of the homogenizer 
should be kept in sanitarv condition. The\' are difficult to clean. 
After honiogenizing, the machine should lie ke])t in ojieration, 
running- water through it, until most of tlie remnants of e\-apr)- 
rated milk are rinsed out; then liot water C(;intaining some 
acti\-e alkali should be ]umiped through; this sliotild be followed 
1)y clean hot water and ^team. Unless this tnachine is ke])t 
scrupulously clean, it ma}- become a dangerous source of con- 
tamination, infecting the e\ aporated milk witli spore forms 
that are exceedingly resistant and winch are liable to jiass into 
the finished product ali\-e, in spite oi the sterilizing process, 
causing the goods to lie a complete loss, due to subsequent 
fermentation. 

ClIAI'TKK X. 

COOLING, 

In the cooling of tlic ewajiorated milk, no attention need be 
paid to sugar crystallization. In this class of goods there is 
plenty oi water to keep tlie nu'lk sug;ar in read_\- solution. The 
e\'aporated milk can, llierefore, lie crmled as rapidly as facilities 
permit. The cooling ma}' be accomjdished in similar wavs as 
are used fc)r cooling fresh milk. From the homogenizer the 
e\-aporated milk is run o\-er a surface cooler, or cooling coil. It 



130 



Evaporated Milk — Cooling 



is advisable to co\er the coils with a jacket of galvanized iron, 
tin 111" copper, so as to a\'<iid undue contamination of the milk 
from dust, flies, and other undesirable agents. In so'---- con- 
denseries the hot evap- 
orated milk is forced 
through double pipes, 
cold water passing l)e- 
tween the inner and 
outer pipes, nr the coils 
through which the milk 
passes are submerged 
in a tank of cc)ld water. 
The onlv objection to 
this system is that the 
pipes are more difficult 
to clean than in the 
case of an open surface 
cooler. AA'here this sys- 
tem is used, the pipes 

Tig. 52. Surface cooler for evaporated mllli 




C'oiirte.'5.\" 



Davis-Watkins Dairymen's 'Mfg. Co. 



shciuld be equipped 
with sanitary fittings 
so that they can be readily swabbed out from both ends. In 
other fact(iries, the e\'ap(.irated milk is cooled in re^•olving cans 
with stationary paddles, similar as described and used for 
sweetened condensed milk, with the exception that cold water 
is run into the cooling tank at once. In still other factories the 
cooling is done in ^•ats or tanks by means of revolving coils 
which carry the cooling medium. If the evaporated milk is not 
homogeni/:ed, it should be cooled as soon as it lea^•es the vacu- 
um pan. 

Holding Tanks. — 7*hc CDnling and hulding of e\aporated 
milk may be accomplished in the same series of equipment as 
descrilx-fl and illustrated under codling of sweetened condensed 
milk, Fig. 38. The tanks for holding this ])ro(luct are preferably 
jacketed, so as t(j make po.^siblc the circulation of cold water 
or brine, in case the e\apfirate(l milk must be held for a consider- 
able number of hours in the hrilding tank. Some of these tanks 
are equipped with |)i"o])ellers eccentrically located, facilitating 



livApORATEu Milk — Ciiolinc, 



131 



the agitation oi the C'.'ntcnt'; and bringing' all iiarf^ oi the milk 
in direct contact with the conlinL^' '-urface. 

In factories where these larqc g'lass-lined tanks are installed, 
each successi\"e hatch r,i exaporated milk- is transferred, at the 
coi^iclusion of the f)ri"ices^ of ex'aporaticin and. hrimogenizatiem, tn 
this large holding and cooling tank, where all the l)atches cjf the 
-.ame day's make are crirded, mixed anfl heh! uniil the last hatch 




Pigr 53. Holding' tank for evaporated niillc 

Coiirte.^>' of Tlie Pfaudlei' <7o. 



is in the tank. The stanflardizatii in nf ihe e\-apiirated milk may 
be deferred, until all the batches .if i^ne and the same da^'s make 
iia\'e reached the holding tank and the entire mixture is then 
standardized ti > the desired ci anpi isitii ui by the addition cif 
distilled \\ater, skim milk-, or cream acciirding to needs. The 
evaporated milk in this tank is usually c,>r>led t' > anrl held at 4(.) 
to 45 degrees F. until next morning, when the filling into tins 
commences. See also "Standardization," Chajiter XXIX. 



132 



Evaporated Milk — Filipino 



It should 1)6 understood that, at this stage of the process, 
the evaporated milk is not sterile, nor does it contain cane sugar 
to preser\e it, neither is it sufficiently concentrated to he pre- 
served hecausc of the absence of moisture. If exposed to heat, 
such as summerheat, or even 
room temperature, its acidity 
will increase rapidly, thereby 
rendering the subsequent 
sterilizing process difficult. 
Therefore, unless it is 
canned and sterilized im- 
mediately after it leaves the 
vacuum pan, or the homo- 
genizer in case it is homo- 
genized, it should be cooled 
promptly to a temperature 
low enough to check bac- 
terial de\-elooment 40 to 4^ ^^e- 54. Hand fllling- macMne for evap- 

' ' orated milk 

degrees F., or below. In the rourt.,sy of Arthur Harris & Co. 

absence of holding tanks or 

vats with refrigerating facilities as described above, the cooled 
evaporated milk may be drawn into 40 quart milk cans, and set 
in the cold room, or these cans mav be submerged in a tank of 
ice w'ater. 




FILLING. 

The cooled e\'aporated milk is filled into tin cans ranging 
in size from eight ounces to (me gallon. The gallon cans are 
usually filled b_v hand. The filling of the smaller cans is done 
by automatic filling machines. 

Of late years much pr(.)gress has been matle in the con- 
st ruction of different t\'p('s of fdling machines for e\aporated 
milk. The openings in the cans through which the cans are 
filled range from the Sanitary can, which is filled with the top 
of the can entirely remo\cd, to the \enth(:ile can with an opening 
of not more than one-eighth inch in diameter. The filling ma- 
chines are constructed to lill by gra\ity, under pressure, or in 
vacuo. 



EvAFORATliD AIlLK FlLLINC, 



133 




These tilling;' ma- 
chines should Ix- tlior- 
ou,!4-hl\- washed and 
freed frrmi all remnants 
of evaporated milk ad- 
hering til the \-al\'es 
and other ]")arts after 
each use. Remnants of 
milk left in any part of 
the filliuL;' machine de- 
compose readily and 
impair the wholoome- 
ness and marketable 
properties of the prod- 
uct. This is an impor- 
tant point and one too 
often neglected. Afuch 
of the s])oiled e\'ap- 
orated milk may be the 
result of the use of un- 
sanitar\- and unclean 
■ hlling machines. The 

fact, that the e\aporated milk is sterilized after it leaves the 
filling" machine, is no excuse for unclean filling machines. The 

operator should liear in mind that the 
milk running through an unclean filling 
machine becomes contaminated with 
millions of bacteria. The more bacteria 
it contains, the more difficult it is to 
render it perfeclh' sterile. I'urthermore, 
sporefcirms are prone to de\'elo|) in 
the deca\'ing remnants of milk: these 
Spores are \erv resistant and recpiire 
e-\cessi\-ely high sterilizing tempera- 
tures to be destroyed. 

In the fillmg of the \enthole cans 
the foaming of the ex'aporated milk 
frequently causes serious annoyance. 
This can be av'oided by ha\ing the milk 



Tig. 55. Venthole filling' machine 

Ciinrtesy f_.f F. G. Dicker.son Company 




Tig. 56. Ventliole can 



Courtesy of 
F. G. Dlckerson Company 



134 EvAPORA'n^D Milk — vSraling 

ai the proper temperature at the time (if hUiiit;". Ex])erience lias 
shown that warm milk, nr milk- with a temperature ak)(i\-e about 
('>() decrees ]\ causes more trouble in this rcsjiect than cold 
milk. 

A\'ith the rapid and j^encral ado|)tion and use among- con- 
denseries of a c(-ild storage s\'sten-i, the ex'aporated milk usually 
h.as a temiierature lietween 40 and 30 degrees V.. \\ hen it reaches 
the filler, and at these ten-i)jeratures the tendenc}- to foam is 
reduced to such an extent that the fdling can be done without 
interference or interruption due to foam. 

In order ti-j economize kjoth sj-jace and time, it has Ijeen 
fijund ad\-isalile to connect the pipe feedin.g the filler direct with 
the holding- tank. The extent of elexation of the holding- tai-ik 
o\'er the filler ob\-ir)ush' ci-introls the gras'ity ])ressure under 
which the e\-a|-)(-n-ate<l n-iilk enters the filling machine. If the 
holding- tank is located at a high ele\-ation, therefore, the speed 
(jf fillij-ig can V)e materially increased. 

SEALING. 

The filled cans should be capped and sealed at c.nce. The 
seal must l-)e hermetical and strong enough ti") withstand the 
strain of the suljsequent sterilizing jjrocess. AX'ith the exception 
I'lf the "Sanitary can," seals w itliout solder ha\'e so far pro\-en 
inisatisfactory in the canning of e\-aporated n-iilk. They are 
f)rone to weaken in the sterilizer and cause "leakers." Alost of. 
the cans on the tnarket ci-intaining e\-aporated milk are. therefore, 
sealed with solder. Sealing eya]-)orated milk cans with solder 
is by far the safest n-iethod. For details of methods of sealing 
see Chapter VII. 

For the sealing (jr ti|)i)ing of fhc \enthole cans an automatic 
ti]jper is usual]}- attached to the Idling machine, so that when 
the cans lea\e the hlling machine, the\- ha\-e also been sealed. 

It is exceedingly im])ortant that the sealing be done per- 
fectly, because e\en tiiinute leaks cause the e\apoi-ated milk in 
the cans to become contaminated cau,--ing s])oilage. In order to 
detect cans with imperlcct sc-als all the cans, as they come fron-i 
the filling- and sealing machine, are carefull)' inspected for leaks, 
Thi.s.n-iav be done by the use of a test bath consisting of a narrow 



Evaporated Milk — Sealing 



135 




oljlong- trougli, filled with iKjt \\ater and throuqdi wIticIi the cans 
pass on an endless ch.aiii. In the case of !eak\' cans, the heat of 
the hot ^^•ater bath expands the air in the cans and causes it to 
escape throtic^ii the leak in the seal and rierc'ilate upward in the 
water, in the form of air buhhles. The iii)eratoi' standinc,"- o\er 
the test trciu.i^h ]iickh the cans whicli expel air hulddes (>ut sci 
that the defecti\'e sieals can he mended. 

Most condenserics manufacturiuL'' e\'aporated milk are now 
usini;" a hot water 
hath for testinu- the 
sealed cans. I'.ut ex- 
perience has shown 
that the hot \\-ater 
liaths built c.n the 
continni lus c h a i n 
principle often fail 
to ,t;"i\'e the desired 
efficicnc}-. This is nut 
the fault I if the ma- 
chine, fnit it is due 
to the fact that it 
becomes \-er\- tiresome fur the mspectcir tij watch the mi'\-inL,'" 
line of cans in the water bath and he suon becumes careless and 
his work inefficient. It has been found tiiat baths c insti'ucted 
and operated i:in the jirinciple of submerijinL;' a whole tra_\' full 
of cans, (nsualh" 24 cans) at a time, ,^"i\e nmrc sati^tacti ir)' re- 
sults, relie\'inL;- the monoton^■ .and prc^erx-ini;' more succe^sfnlh^ 
the keenness of ol)ser\'ation of the in'spectur. 

The \-enthole tiller i>^ simple in conslructicm, ccunomical in 
operation and easih- cleaned and keiit in sanitary Cdudition. The 
milk, from the time it comes within the ranye of the filler, is no 
longer exposed to ci intaminating influences, such as the hands 
of emploves, insects, etc. The cans are unifornd^' filled tu within 
cine gram of tlie guaranteed weight and the \ents or pin holes 
are automaticall}' sealed with the minimum amount of solder. 
Wdiile the quantit^" "f scdder mu'^t nece-saril_\" yhyy with oper- 
ating conditions, it is possible to limit the average amcmnt of 
solder, under proper conditions, tu 5 ounces per ]()()(.) cans. The 



Pig'. 57. Chapman automatic can tester 

I'ourtesy of Scliaeft-r INIfg". Co. 



136 Evaporated Milk — Sterilizing 

fact that the \eiit hole (ir pin hole hllcr operates by c;'ra\-ity, as 
to lioth, the enlpt^■ cans and the inflnwini^- c\ai)orated milk, re- 
duces tlie human and mechanical errnr tn the minimum, ()uce the 
machine is set for operation. 

The acknowled.^ed ad\-anta!L;es of the \ entholc filler ha\e 
made its general adopti(^n and use rapid and it is estimated tliat 
today over 90 per cent of the American c\ap'iratcd milk is 
being caiuied b}' this t^-pe of fillinp; machine. 

Cn AFTER XT. 
STERILIZING. 

The sealed cans are now ready for the sterilizer. If they 
cannot be steribzed \\-ithin an Imur or two the}' should be sub- 
merged in ice water or placed in a refrigerating room until the 
sterilizer is ready for them. This precaution is especially ad- 
^■isable in summer. 

Purpose of Sterilization. — The chief purpose of subjecting 
the e\aporated milk to the sterilizing process is to kill all germ 
life and, therefore preserxe the product pern^anently. When 
the hermeticalh' sealed cans come from the sealing roiim, their 
contents are not sterile. The only means to preser\-e this milk 
is to subject it to tcmjierattu'es high enough to kill all forms 
of ferments, organized and unorganized, \'egetative cells and 
spores. The success of the maiuifactm-e of this product depends 
to a large extent on the ]irocess of sterilization. 

Aside from this, the manufacturer aims to gain another C(~im- 
mercially impoiiant condition, n.amely, to ]ire\cnt the separation 
of the butter fat. Tleliirc sterilization, there is nothing" to pre\'ent 
the fat fnnn se])arating out in the exai'urated milk antl from 
churning in transportation, unless the e\aporated milk was 
homogenized. 'i'jie sterilizing ])rocess hel|is to so change 
the phvsical ])roperties of the milk, that this tcndenc}' of the 
fat to sei^arate is greath' minimized. The sterilizing tem- 
peratures used, further lentl to the e\apcirated milk a creamy 
consistenc\' and veljowi'-h color, gi\'ing the jiroduct a semblance 
uf richness. 



Evaporated 2^1 ilk — vStkrilizing 



137 




Sterilizers. — The predomi- 
natiiiL;- apparatus used for ster- 
ilizing is a liU!_;"e. 1)oiler-likc, 
IkdIIow, ii'i in c"\'linder nr l)ox, 
it opens eitlier at one end 
111' on the side. Its interior ^J.-'„, - . 
is e(pu])ped with a re\-(il\-ing i-ig-. 58. 

framewurk, steam inlet with a sterilizer for evaporated milk 

perforated steam distrilnitin-- rourt.-.sy or Arthur Harris & Co. 

pipe in the Ixittom of the steril- 
izer and extending over the entire length of the sterilizer, a water 
exhaust, a water inlet with a water distributing pipe in the 
top of the sterilizer and running the entire length of 
the sterilizer and a water exhaust. The sterilizer earries mi its 
exterior a steam gauge, a wienuni gauge, a water gauge, a bl(i\\- 
off \-al\e and a high-temperature thernionieter (registering to 
about 2X0 degrees I'".). Tn sunie makes nf sterilizers the interior 
frame-wiirk does not re\"iil\-e on its axis, but muxes back anil 
forth by means 
cif a direct-act- 
ing, s t e a m- 
(lri\en ijistim, 
attached to the 
ijack end i if the 
sterilizer. 'I'he 
]) u r ]) o s e of 
k e e p i n g the 
cans in motion 
while heat is 
applied, is to 
heat the con- 
tents rapidly 
and uniformly, 
and til i:irevent 
the e\-ai)orated 
milk from bak-- 
in,g onto the 
sides of the 
cans. A still 




Pis'. 59. Sterilizer for evaporated milk 

c'ourte.^y of The Engineering Company 



138 EvAPORATKD Milk — Stijrilizing 

other fiirni nf stcrilizri- i^ tlic CDiitiiiunus sterilizer in which the 
inisterilizcd cans pass intu and the sterihzed cans escape from 
the lieatinL'; cliamher ni ci intniin ais pn'cessiun. 

Loading the Batch-Steril'zer. The sealed tin cans are 
placed in hea\\- ir^n ti'a\-s, usnall}' liiddinL;- twent}'-fi'iur 16-ounce 
cans rir six l-v.allun cans. The loaded {i-a\-s are slid and locked 
into the framework in the interi(".r df the sterilizer. The sterili- 
zer is closed, with hea\\' ii'nn donrs and the framework is put 
in motimi. In siniie makes of sterilizers the interior consists of 
a large pei'fdratcd iron Ijo.x re\ail\'in'^" on its a.xis. In this case 
the cans are sin^ipK- piled into this bo.x, no tra\'s being' used. 

Uniform Distribution of Heat. — W here no water is used in 
the sterilizer during the sterilizing |)roeess, it is important that 
there be a free air space between e\-er_\- two Layers of cans, so 
as to allow the steam to circulate freely and to come in direct 
contact with e\-ery can. AA'hen the cans are piled into the ster- 
ilizer SIX to tweK'e kn'ers dee]j \','ithont an\- free air space be- 
tween la)'ers. the cans in the center do not recei\-e as much heat 
as those at the sides, ends, top and bottom. This causes irreg- 
ular heating and imi)erfect sterilization, 

.\ satisfactor\" means of insnring e\'cn distrifnition ot heat 
is to fill the sterilizer about one-thirdful of \xater. sc) that, when 
the sterilizer is in o]ieration the cans pass through this water, 
with each rexolntion.of the frame work'. Water distributes the 
heat uniformK', ra])idh' and there is no danger of the formation 
of air ])ockcts between the can,s.. Since the heat is applied by 
steam under ])ressure, the tem])eratui"e ol the water is eipial to 
that of the steam in tlie sterilizer. This ])rccaution is especially 
necessar\- in the case of l)ai)\'-size cans (eight ounces) which are 
usually piled in staci^s nn a'e th.an two dec]). When sterilizing 
in the absence of watei" there is danger of lack of uniformity of 
the amount of he.at the\- re(-ei\'c. I'lie uniform distribution of 
the steam by the pei'foi'ated steam distributing pipe in the bot- 
tom of the sterilizer is essential for uniform heating of all the 
cans. If the ]ierforations in this pipe become enlarged due to 
wear, or in case of an iron pipe due to rusting, or if the cap at 
the end of the pipe happens to come otf", the heat distribution 
is bound to lack uniformity. 



EvAPORATi'D Milk — Sterilizing 



139 



It is arh'isablc aiul impurt.-int tn estalili^h the efficiency of 
heat distribution in the stcrihzcr by accurate test. F(ir this 
purpii^e the use r)f cans cfiuipped \\'ith automatic thermometers, 
simihir to medical thermometers, but re,L,ostcrin,c;- sterihzinc,'- tem- 
peratures, ma}- lie found practical. Such cans are placed in 
fliffercnt parts in the caf.(es nf the sterilizer at the time the ster- 
ilizer is loaded, and at the Cdiichisii.n of the process these 




Can fitted with Closed Top 
and TeU-Tolo Thermometer 
for Open Bath and Retort 



rig-. 60. 

Evaporated milk can 
with tell-tale ther- 
mometer, complete 



IIH 




rig-. 62. 

Wrench for eealiug' and 
opening' can 



Pig-. 61, 

Tell-tale thermometer 

C^ourtes\' of Taj'lor Instruinent C'o. 



thermometers indicate the ma.ximuni tempei"ature to which the 
contents of the re^^^pectixc cans were heated. UnfurtunateK' 
these thermometers are not al.\va}'s accurate and often they do not 
function properly. Then ai^ain th.e jars to which the^s' are sut)- 
jected in the re\'ol\inL;- cage and again when the trays contain- 
ing these cans are remo\'ed from the sterilizer, fretpientl}' change 
the position of the mercur}- column, rendernig its readings un- 
reliable and misleading. 

Another and \'ery simple aiuj reliable method df testing 



140 EvAPORATijD Milk — vSteriuzing 

the sterilizer f(_ir lieat distributii in is to test numerous cans 
from different ])arts of the sterilizer, after sterihzation, for vis- 
cosity b}' means of the Mojonnier \isci>simeter or similar de\'ice, 
as described under "Tcstinc;- Sample Cans for \'iscositv," see 
this chapter, succeeding- paran^raplis. 

Temperature and Time of Exposure. — When the sterilizer 
is filled with the cans and closed, the frame work is set in motion 
and steam is turned into the sterilizer. In r)rdcr to hasten the 
lieating and e.xpel all the air, the exiiaust anrl safety should be 
left open until the temperature has risen to 212 degrees F. This 
temperature is usually reached in aljout ten to fifteen minutes. 
The exhaust and safet}' are then closed. 

From this point cm, the process m_ust depend on locality, 
season of year and condition, properties and concentration of the 
milk. No formula can be laid dci\\'n which can be depended on 
to !2;i\e uniformly satisfactory results under all conditions. Xor 
does the projier sterilization depend on one particular formula. 
There are numerous ratios of temperature, time of exposure and 
extent of agitation, which when adjusted to local conditions ma}' 
give satisfactory results. The temperature should be high enough 
and the duration of e-x])osure long enough to insure absolute 
sterility of the product and to ,gi\e the milk sufficient bod^■ to 
prex'ent the separation of tlie butter fat in subsequent storage. 
The temperature should not be so high ni)r the duration of ex- 
posure so long, as to cause the formation of a hard, unshakable 
curd and dark color. 

vSome processers use a ^'ery short process with high tem- 
peratures, others raise the heat gradualK- and not tii quite so high 
a degree. The more gradual heating is preferafile. as it gi\'es 
the product a better body and more \iscosily, which is neces- 
sary to kee|) the fat from separating in storage. I'he author's 
judgment in this matter is, that it is not safe to raise the tem- 
perature to less than 230 degrees 1". antl it is advisable to heat 
the milk to 234 to 23fi degrees 1'., |)ro\ided that the milk is in 
condition to stand this heat without fnrmation of too firm a 
curd. \\'here the maxinuun temperatu.re tn which the milk is 
raised in the sierlizcr is 230 degrees F. or thereab<.)ut, the raise 
of the last ten degrees should occupy Imm thirty-fi\e to fort\- 



Evaporated Milk — Sterilizing 141 

five minutes, and this time slujuld be al>out ex'enly distrilnited 
o^'er the last ten degrees. 

Of recent years, the jiractice uf stoppino; the reel of the 
sterilizer, either at inter\als or \\lien the maximum temperature 
has been reached, has been adopted by some of the manufactur- 
ers. In this case, the temperature usually is rapidh' raised to 
about 240 degrees F., and after keeping the reel running at this 
temperature for a few minutes (abnut two minutes) the reel is 
stopped and this temperature is maintained f(")r from 15 to 20 
minutes, with the cans lying still, A\'hen the "hold" is com- 
pleted, the cooling jjroceeds in the usual wa}-. Some condens- 
eries stop the reel for se\-eral mimites nnce or twice wdien the 
temperature has been lowered and before it has dropped to below 
212 degrees F. 

AMien the stop j)rocess of sterilizing is used it is ad\'isable 
also to superheat the e\-aporated milk ti > about 210 degrees F. 
in the \acuum jjan ; then cocil it to about 140 degrees F. and 
drau- It into the standardizing \"at where it is standardized to 
the desired i)oint, then it is homrigenized, filled aufl sterilized. 
The superheating can also be ddue in the standardizing \-at 
instead in the pan, b_\' simjdy blowing steam direct intu the 
e\-aporated milk. 

Mojonnier Bros. Co, recommend that, wdierc the stop proc- 
ess is used, the teni])erature be raised 3 degrees F, higher (or 
to 243 degrees F,), than wdien the reel is kept re\xih"ing during 
the entire process. They further recommend that the tempera- 
ture be maintained at 243 degrees F, fr.)r 15 minutes, during 
the last se\'en minutes nf which the reel lie stopped. This 
refers to a "coming-u|) time" (from 190 degrees F. to 240 degrees 
F. ) of 10 minutes. 

This method of sterilizing, b}' stcipping the reel, has the 
advantage of developing in the cans a soft, custard-like coagu- 
lum, giving the product a \er}" hea\}' consistency and making it 
appear rich and creamy. It represents a form of superheating, 
ho\^■e\•er, wdiich if not done with great care, may pro\-e disas- 
trous, causing the e\'aporated milk ti > sjiontanetjusly thicken and 
become cheesy in consistency upon storage, !Most batches of the 
stop-reel process rerpiire shaking. 

In his efforts to insure complete sterility the operator should 



142 



Evaporated Mii,k — Sterilizing 



understand that the size of the cans may influence the sterilizing 
efficiency. It takes more time and agitation to sterilize gallon 
cans than small cans. y\t a time of the year when the milk con- 
tains micro-organisms of relati\'ely high resistance to heat, as 
is often the case especially in fall avd winter, the per cent loss 
nf gallon cans due to "s\\'ell heads" may become disastrously 
large, unless the manufacturer makes a special effort to adjust 
his process for gallon cans. Gallon size cans recpiire about one 
degree F. more heat on a 15 minute run of holding than tall-size 
cans, and tall-size cans require about one degree F. more than 
family- and baby-size cans. 

The installation and efficient use of automatic temperature 
controllers and recorders is of material assistance for securing 
uniform results of sterilization. These accessories are made use 
of in numerous factories, and have pro\en to be of valuable 
help to the manufacturer. Aside from the fact that they actu- 
ally do facilitate the temperature control, they automaticallv 




Tig. 63. Bulb for automatic temperature control 

Courtesy of Taylor Instrument Co- 

make for increased efficiency rjf the operator. The knowledge 
of the operator that his work is permanenth- recorded and 
checked up exerts a beneficial efl:ect on liis performance. 

The operation of an experimental or pilot sterilizer also has 
proven a great lielp in the accurate determiiiation of the amount 
of heat which the exaporated milk of an\- liatch requires, to 
produce the desired viscosity, body and color and that it will 
stand without becoming hi.ipclcssly curdx-. These machines are 
of small size, accommodating onh- a few cans. 

,\ few sainiile cans of each l>atch are placed in the pilot 
sterilizer and run through the [irocess. I^hus tlie proper process 
to be used for the entire Ijatch in the large sterilizer may be 
adjusted according to the beha\ior of the contents of the sample 
cans in the pilot sterilizer. 

Qualifications of the Processer, — The operator, or the person 



Evaporated AIilk — Stivrilizin(", 



143 



directing the 'Sterilizing- prijcess, shnnld tliornughK' appreciate 
the complexit}' of the product, understand the can:~e and effect 
of the man}' influencing factors, stud}- ihe e\'er-changing condi- 
tions and modify the prricess in accordance with pre\-aihng con- 
ditions. He should know that during the exceedingl}- lint sum- 
mer days, \\dien the cows sntTer frr)ni heat and are pestered with 
flies, the milk will not stand as much heat ^^dthout badl\- cur- 
dling in the sterilizer as under more faxajrahle conditions. He 
should know that ti'ward and during the fall ni.inths the rjro-an- 




Tig. 64. Pilot sterilizer 

Courtesy of The Engineering Company 



isms normall)- i)resent in milk a''c nmre resistant and require 
higher heat to he destro}-ed, than, earlier in the season. 

Rapid and Uniform Cooling. — As snrin as the required heat 
has been giA-en the milk in the sterilizer, the steam should be 
turned oft and the e.xhaust and drain should lie opened. When 
the temperature has dropped to about 220 degrees F., cold water 
should be turned into the sterilizer while the cans are constantly 
in motion, until the cans are cool enough to handle. There 
should be enough cold water available to reduce the tempera- 



144 Evaporated Milk — vSterilizing 

ture to 70 or S'O degrees F. in t\\cllt^• minutes for gallons and in 
ten to fifteen minutes for small size cans. The water pipe should 
he so arranged as to distribute the water uniformly over the 
entire length of the sterilizer. 

If the process is to he successful, the processer must ha\'e 
as nearly perfect control of the heat as possible. This means 
especially, that there must be ])lent}- of water available to insure 
rapid cooling and the water must be distributed o^•er the cans 
uniformly. Insufficient water suppl_\- and une^■en distribution 
of the water in the sterilizer, means that some of the cans are 
exposed to the sterilizing heat lungxr than others, causing' lack 
of uniformity in the smoothness and color of the milk of different 
cans of the same batch. Delayed cooling, owing to insufficient 
water supply, has the further disad\'antage of causing the cans 
to bulge badly, owing to the difi'erence in pressure between the 
interior and exterior of the cans. This is especially noticeable 
in gallon-size cans, the ends of which may become badly dis- 
torted, present an unsightly appearance and their seams and 
seals may be weakened to the extent of producing "leakers." 
Excessive bulging and injury to the cans can be avoided by 
admitting" to the sterilizer a sufficient quantity of compressed 
air at the conclusion of the sterilizing process, to take the place 
of the steam pressure and thereby equalizing the pressure be- 
tween the outside and inside of the cans during the cooling 
process. 

Fractional Sterilization. — In the earh' days of the manu- 
facture of ei.-aporated milk the product was sterilized bv frac- 
tional sterilization. This luethod has nrtw been largely aban- 
doned, but is (iccasionally used when the milk happens to be 
in very abnormal condition. The milk is heated in the sterilizer 
to considerabl}' biwer temperatures than th(~ise stated abo\-e, and 
this heating; is repeated on two or three successive davs. The 
principle i>f this process is to kill all vegetative forms of bac- 
teria during the first healing. This gi\es the s]")ores a chance 
to de\'elop intf> \e,getati\e forms b}' the second and third davs, 
which forms are then destroyed during subsefpient heating. This 
system of sterilization is not practical for general use. It is too 
great a tax on the ca])acit_\' of the a\'erage factory and increases 



K\'aporaii;d AliLK — Sti{kilizix(, 145 

the cost of mamifacture. It shuuU',. therefore, l)e made use of 
onl}' in exce|")tioiial cases, when it is kmiwn that a certain hatch 
of milk cnuld not l)e put thr(iui;ii the hiL;iiei" sterilizini;" tem[)era- 
tures withiiut causing the prdduct tc' l)eciime permanentl}- curdy. 

Standardization of Properties that Influence Behavior of 
Evaporated Milk toward Heat of Sterilization. — In the foregciino 
discussiijn of tlie sterilizing" proces> no mentiim \\"as made of 
methods ti i standardize tlie Ijehaxdor of evaporated milk toward 
the sterilizing heat. It was clearlv ])iiinted rmt that, in the 
absence of such methods, it is impossible to la\' do\\'n any one 
formula for sterilization that would gi\'e unifi irmly satisfactory' 
results under dix'erse conditions nf the product tci be sterilized. 
The chemical, ph_\'sical and physiological pro|)erties of milk are 
e\-er changing, and e\-en slight changes in these properties often 
cause wide \-ariations ni the amount i if heat the product will 
stand in the sterilizer. This in turn necessitates constant changes 
and modifications <A the process, if a marketable product is ti > 
be the result. T( m.i much must be left to the judgment and 
power of obser\'ation of the processer and this situation ob- 
viouslv results in excessi\'e inimbers ni defectixe batches and 
in costly losses and wastes. 

The standardization nf evaporated milk fur percentage of 
fat and solids alone materially assists in narmwing d(")wn the 
range of \-ariations in the behaxior of the milk in the sterilizer, 
but it fails to adequately control those properties which ha\-e 
the greatest influence on the sensiti\-eness of this product toward 
sterilizing heat. This pmblem has confronted the manufacturer 
of e\-aporated milk from the \-ery beginning of the industrw 
Much e.xperimental work has been done in an effort toward its 
permanent solution, but the results ha\e largely been of local 
and temporary success and usefulness onl}-. 

Within recent years the Alojonnier liros. Co. of Chicagrj 
ha\'e de\-eloped and ha\'e furnished the industry with a simple, 
practical and systematic method and suitable ec|uii)ment, inv 
controlling the ijroperties of this complex pr(.)duct x\ith such 
a degree of accuracy that the adoption of a standard sterilizing 
formula has become feasible and practicable. 



146 



EvAi'(jRA'n-;D Milk — Mojonnier Controller 



THE MOJONNIER METHOD OF EVAPORATED MILK 

CONTROL. 

Principle of Method. — This methr)f] V)riefly consists of the 
following oiitstaiuHng features: 

1. The adoption of a standardized process iif sterihzation 
designed and adapted for evai)orated milk of superior cjualit}' 




Pig". 65. Mojonnier evaporated luUk controller 

Oourtrs>' ol' l\roJtni!nc]- l-'.ros. Co. 



for processing. This ])roccss ])r(i\-ides a \ery narrow range of 

N'ariation oi tempci'atnrc and ■.<i time nf exptisure, in order to 

limit the i.)ers(jnal factor «ith its ine\ital)le uncertainties to the 
minimum. 



Evaporated Milk — iMojonniicr Con'ikoller 147 

2. A standard method of determining-, 1]_\- means rif a pilot 
sterilizer, a viscosim.eter and a cijlor test, the proper \-iscosity 
and color that the e"\'aporated milk sh'iiild ha\'c ^^■hen it cnmcs 
from the sterilizer; and 

3. A standard method of determining' the amount of liicar- 
honate of soda that must be added to anv p;i\-en Ijatch to e\"ap- 
firated milk in case its properties are such, that it is unsafe (n 
subject it, without such treatment, to the temperature condi- 
tions that fall within the range of the standardized process nf 
sterilization. 

Equipment for Mojonnier Method. — The ef|uipment designed 
for this method of e\-aporated milk control, is ilhistrated in 
Fig. 65, and consists of the folliiwing apparatus : 

1. One pilot sterilizer with motor, complete 

2. 2 \'iscosimeters 

3. 1 xenthcile sample can filler 

4. Glassware for making up and measurmg sodium bicarbon- 
ate solution 

5. 1 torsion balance 

6. Open-top cups and venthole tin cans. 

Preparation of 10', Sodium Bicarbonate Solution. — The bi- 
carbonate of soda is used in thi> test in the form of a 10 per 
cent solution. This solution is |jrepared as follows: 

1. Weigh empty bottle to .01 ounce 

2. Add 3 ounces bicarbonate to l)i"ittle 

3. Add 17 ounces warm water to bottle. 

Shake thoroughly until the bicar1)onatc is all dissiih-ed. 
Draw out as needed into dispeiT^ing liottle, filling the sante iir.t 
over half full. Keep remainder tightlv corked in the stock bottle 
until needed. Should the bicarbonate cr^'stallize out. prepare 
a new lot. The abo\'e solution contains exactly 10 per cent 
sodium iMcarbonate. 

Adding the Sodium Bicarbonate Solution to Sample Cans. — 

Arrange in a row li\'e oj^en-top cups, marked — X-1-2-3-4 respect- 
ively. These cups are furnished ^\-itli the Crintroller. Cu]) 
marked X is blank, to ^\■hich no l.)icarb(.inate is added. To cup 
marked No. 1 add one charge of sodium bicarbonate from the 



148 EvAPORATRD MlI.K — MojONNIKR CoNTROI^I^fiR 

dispensing- Inirette. This is the amnunt contained l)etween the 
upper two graduations on the l)urettc. To cup marked No. 2 
add two charges, to cup No. 3 add three charges, to cup No. 4 
add four charges. Dispensing burette furnished with the con- 
troller indicates how the aho^ e quantities are to be added; the 
burette is graduated into four separate charges. The unit with 
one single charge contains the equi\'alent of one ounce of sodium 
bicarbonate, to one thousand pounds of e\-aporated milk. Each 
successi\e charge is a multiple (>f tliis unit. In dispensing the 
bicarbonate solution, it is 1)est Udt to fill the bottle more than 
half full. When filling tlie burette, tlie sdlution should be 
allo\\'e(l to flow into it slowly in order not to tra|) in the air. If 
air is trapped into tiie burette, it is difficult ti > remo\e it, and 
in sucli a case it is best to run out \vhate\'er solution may be in 
the burette and to put in a new supply. 

\\hene\er the quality of the milk is \ery abnormal, it may 
be necessary t(.) add more than abo\e indicated number of 
charges of bicarbonate s(.ilution ti.i the sample cans. In such 
cases any multiples of the ab<n-e numlicr of cJTarges may be 
added. The ratio nf ounces of bicarbonate to one thousand 
pounds of milk will remain the same, being increased simply by 
tlic number of charges added to each sample can. 

Preparation of the Five Sample Cans for the Sterilizer. — 
,\fter the five open-toj) cups ha\-e Jieen treated with bicarbonate 
as indicated in the preceding section, they are transferred to the 
Torsion Balance and exactly six ounces of milk is weigh.ed into 
each cup. This can be done by taring the entire set of empty 
cups, anfl then weighing si.x ounces of e\-aporated milk into each 
separate cup. 

One set of fi\'e empty cans is now marked in the same man- 
ner as the cu|)s to whicli tiie bicarbc^nate solution was added, 
namely as follows; X =: can containing no liicarlionate ; 1 = can 
containing e(pii\alenl of one nunce bicarbc^nate per thousand 
pou^ids of e^•aporated milk; 2 =; can containing equivalent of 
two ounces per one thousantl pounds of e\aporated milk; 3 = 
dan containing e(|ui\alent nf three ounces per one thousand 
pounds of e\'aporated milk, and 4 = can containing equi\'alent of 
four ounces ])er one tlii;)usand jjounds of e\aporated milk. 

Next the contents of tlie fi\e o]ien-top cu|)s are transferred 



EvAPORAT]-:!) jMilk — MojoNNiKR Controi,li:r 



149 



to the five tin cans in tlie order alioxe indicated This is done 
by placing' the cans in jiairs, under the two-can \-enthole filler, 
furnislied with the Controller, and the cups with the milk and 
bicarbonate marked correspondirig to the emjity cans, are now- 
emptied into the filler. Care must be taken to keep the cans 
in the proper order. 

After filling, the cans are tipped, using preferably rosin 
solder. Should none of this solder he a\ailalile, then great care 
must be exercised not to let any of the flux from the zinc chloride 
solder enter the cans. Zinc chloride flux has a ^-er_^- bad efl-'ect 
upon the milk, and will completel}' change the results. 

Sterilizing the Five Sample Cans. — The five sample cans, 
prepared as above directed, are now ready for the sterilizer. 
Place these in the cage and fasten the lid securely, and also turn 
down the screws in order tC) hold all of the cans securely into 
place. .Adjust the cage in the sterilizer l.)y means of the thumb 
screw on the right hand side, in order to keep them from ha^-in^ 
end pla}-. Close the sterilizer dorir secureh' so that no steam 
escapes during the sterilizing process. 

Me sure to pro\-ide circulation of the steam through the 
\'ent on the pipe surrounding' the thermonieter. This little A'ent 
should be kept open during the entire sterilization operation. 
Fill the small pilot sterilizer with water to a point half way 



upon the gauge glass, lie 



to turn <'in the switch to start 



the motor in operation. C)pen the "steam start xah'e" and take 
five minutes to let the heat reach I'TJ degrees F. or 3 on the ster- 
ilizer scale. Then let the heat come up gradually from K'O de- 
.grees to 240 degrees F. or from 3 to S on the thermometer, taking 
one minute for each .^ degrees as indicated in the following table: 



Actual Temperature 


Actual Reading- 


Point at ivhich Mercury 


m 


upon 


should be at anv i;^iven 


Fahrenheit Degrees 


Thermometer Scale 


time coming up 


240° 


8 points 


20 minutes 


230° 


7 points 


18 minutes 


220° 


(> piomts 


16 minutes 


210^ 


.1 points 


14 minutes 


200° 


4 points 


12 minutes 


190° 


3 points 


10 minutes 



150 Evaporated Milk — Mojonnier Controller 

Where sterilizing is done \\ith steam only, withotit using 
superheated water, it is recommended to take twenty minutes 
for coming up. The aho\e table is arranged upon this basis. 
The table, however, can l)e readily adapted to a system recjuir- 
ing fifteen minutes for coming up, by taking fi\'e minutes to 
come up to the ])oint marked 10 ui)iin the tal)le, rir to lOO de- 
grees F. 

It is also recommended that in the pilot sterilizer, the sam- 
ples be cooked to 243 degrees F. and that the "jump" from 230 
degrees to 243 degrees be made in Uvo minutes. It is very 
important to knOAv the exact second when the mercury column 
reaches 243 degrees. The milk should be held at this tempera- 
ture for fifteen minutes to the exact secorid. 

Cooling the Five Sample Cans. — The instant the clock shows 
that the samples ha^e been sterilized as indicated above, both, 
discharge A-alve and cold water valve should be opened simul- 
taneously. It is best to cool the fi\'e sam])les to about 75 de- 
grees F. This should take not to exceed fi\-e minutes, depending 
upon the temperature of the \\-ater a\'ailable. This is something 
each operator must judge for himself. 

Testing the Sample Cans for Viscosity. — ,-\s soon as the 
sample cans are cooled in the sterilizer, as indicated above, 
the cans are dried on the outside and are then opened and 
each can is placed in the proper position in the viscosimeter 
rack. It will be noticed that the same scheme of marking the 
spaces upon the ^'iscosimeter rack has been observed as in the 
case of marking the cans. It is \'erv desirable to cool the sam- 
ples lo as nearl}' 75 degrees as possililc. If this is not done, 
the \iscosit}' should be corrected for temperature, using the 
scale of Corrections that is furnished with the \-iscosimeters. 
Make the \-iscusity test as follows; 

(a) iJid'erent sizes of balls are furnished, correspontling to 
the product that it may be desired to tfst for \-iscosity. A special 
\iscosity b;ill is Inrnished in the case of e\'aporated milk, and 
this is not interchangeable with an}' other hall for tiiis purpose. 
Therefore, see that tlie proper ball is Ijeing used. 

(1)) Fasten one end of the wire in the knurled nut upiin the 



EvAPORATiiD Milk — Mojonnii-r Controller 



151 



top of the 1")ent support, and tlie other end in the dial. Adjust 

the vertical position of 

tlie dial l)y raisins;- or 

1 o w e r i n r.', until the 

small lug' on the botti nn 

(if the dial is in tlie 

l)roper p d s i t i o n to 

engage the trip up'in 

the right-hand side of 

the stand. 

(c) Adjust the hor- 
izontal i)risition of the 
dial until zero degrees 
is in a line with the 
pointer u])nn the fr^nt 
of the frame when the 
dial is balanced in the 
air. Center the dial in 
the 0|jcn circle by 
means of the adjusting 
screws on the under 
-^ide of the frame. ?\fake 
a test fill' \-iscosit\' di- 
rectly in the Ijaby-size 
cans. I'roperl}- center 
the can b}- means of the 
automatic arrangement 
pi'o\dded for that pur- 
pose. As alread\' in- 
dicated, be sure to 
watch the temperature 
I actor \ery closelv. 

(d) Lower the ball into the can of milk; turn the dial clock- 
wise one re\-olution : stopping wdien zero degrees upon the dial 
is in line with the ]iointer upon the front of the frame. Hold 
the dial in place by means of the lug and trip. When read\', 
sharply, release the trip, note the degree where the dial stops, 
just before it starts upon the return round. This will occur 




Fig'. 66. Mojounier vlscosimeter 

Courte-sy of Mojonnier Bros. Co. 



152 



Evaporated Milk — Mojonnier Controller 



TO 3tT; TURN IH 
THIS OIRECTIQNl 




NC CAN fe£ TAk^LN 
WHLN RE:LE.A3ED,"Td,r[_cT ftT POIMTER. MAGNlFYlttQ 
DlALt?E.VOLVt5 IN I CLAiS OVLR poiNTtR A5?yRE.i 
This DlRE.CTior-t accuRac-y. 

rig. 67. 

Mojonnier-DooUttle viscoBlmeter dial, 
graduated to 360° 

Courtesy of Mojonnier Bros. Co. 



after the dial has made one 
complete, and part of the 
second revolution. The de- 
<:,''ree at which the dial stops 
will represent the vi.scosity 
of the sample. The greater 
the viscosity, the lar,t;-er the 
degree reading will be. 

Record the viscosity of 
each (if the sample cans 
tested, as indicated above. 
Further instructions will fol- 
low as to the method of ap- 
plying- the infurmation thus 
obtained. 



Table for 


Correcting 


Viscosity 


of Evaporated 


Milk 


to 75 


' F.> 




STERILIZING ROOM 




PACKING ROOM 






Take 




Ada 




Add 


Take 




Add 




Add 


Temp. 


oft 


Temp. 


on 


Temp. 


on 


Temp, off 


Temp 


on 


Temp. 


on 


Deg. 


Deg. 


Deg. 


Deg. 


Deg. 


Deg. 


Deg. Deg. 


Deg. 


Deg 


Deg. 


Deg. 


F. 


R.= 


P. 


R. 


F. 


R. 


F. R. 


F. 


R. 


F. 


R. 


63 


25 


7(> 


7 


86 


24 


60 15 


75 





88 


10.0 


66 


7 :> 


77 


4 


60 


25 


61 14 


76 


1 


89 


10.5 


67 


1'^ 


7,S 


6 


<)1 


26 


62 13 


77 


:> 


')0 


11.0 


6X 


10 


7') 


,S 


62 


27 


63 12 


78 


,■) 


9] 


11.5 


69 


13 


80 


10 


«)3 


28 


64 1 1 


79 


4 


92 


12. (J 


70 


10 


81 


12 


'M 


29 


65 10 


80 


3 


93 


12.5 


71 


,s 


82 


14 


')? 


30 


66 ' ) 


81 


6 


94 


13.0 


72 


f\ 


83 


16 


66 


31 


67 8 


82 


/ 


93 


13.3 


7Z 


4 


84 


18 


67 


M 


68 7 


83 


7.5 


96 


13.6 


74 


2 


85 


20 


U8 


ii 


69 () 


84 


8.0 


97 


13.9 


75 





86 


21 


00 


34 


70 5 


85 


8.5 


"8 


14.2 






87 


-> 1 


100 


.^^5 


71 4 


80 


9.0 


<W 


14.5 






88 


Ti 






72 3 

73 

74 1 


87 


9.3 


100 


14.8 



Importance of Proper Viscosity. — The \ iscosit}- of e\'apo- 
rated milk determines the Ixidy and permanency of the emulsion 
of the fat and other soliil and liquid constituents of the product 
and it further determines the extent to which the e\aporated 



1 Courtesy of Mo.lonnler Bros. Co. 

- R means degree retardation or viscosity. 



EvAPORATKD Milk — jMojonnikr Con'i'rollek 153 

milk may be ex])ectcd to withstand the sterilizing- lieat w^itlKait 
danger of curdhng in a manner that \\iiuld render the ]iriidiict 
unmarketable. 

The purpose of the \'iseosit\' test, of sample cans haxin^' 
passed through the pilnt sterlizer nr controller is. f' fletermine 
whether the ex'aporated milk of the entire batch, without treat- 
ment \\ill safe)}- pass thniugh the adopted, standard sterilizing 
jirocess, or to what extent this process must be modiherl. i^ir to 
what e.xtent the product, bcfcirc sterilization must be treated 
w ith bicarljonate of soda to secure a good l)ody. and at the same 
time insure freedom fr(_im the formation of a permanent curd 
when applying the standard sterilizing |)rocess. 

A certain degree of visciisity in eva])orated milk is ilesii'able 
and necessar}- in order to gi\'e the prr)dnct a good body and to 
pre^•ent the separation of the butter fat. 

Rut. as tlie \-iscosity increases a jioint is reached 1")C}"ond 
which it is not safe to go. because of the danger of the formation 
of a permanent curd that renders tlie product unmarketable. 

The increasing \-iscr)sity is due to a change in the ];)h_\'sical 
properties of the protein constituents of evaporated milk result- 
ing from the action iit heat. The earlier stages of these changes 
are desirable, because the}' resu.lt in a prciduct of good l)ody and 
of increased staljility of emulsion. An excessi\'e continuation 
of these changes precipitates the proteins in the form of \'isible 
particles of curd \\diich, if i)ermanent, spoil the product for the 
market. 

Factors which Influence the Viscosity and their Correlation 
to the Sterilizing Process. — The extent ti > which heat increases 
the viscosity c)f e\-aporated milk is dependent on man}- and A-ar)-- 
ing conditiiins. such as acid of milk, natural stability of protein- 
in milk as related to tlieir behavior toward heat, degree of con- 
centration of evaporated milk, degree of heat applied in fore- 
warmer, amount of extraneous \\-ater in ex'aporated milk, degree 
of heat in the sterilizer, duration of exposure to sterilizing heat. 
The resistance of the prciteins to heat, as aft'ected by these se\-- 
eral conditions and factors, can be modified and largeh- con- 
trolled if necessary, by the treatment of milk that has an ab- 
normalh' low resistance to heat, with definite, small quantities 
of Ijicarbonate of soda. 



154 



Evaporated Milk — Mojonnier Controller 



The \"i^ctisit\' test therelUre furnishes a measure of the 
resistance of any "ix-en liatch of e\'aporated milk toward steril- 
izing' heat. Hilt in order to enable the operator to correct!}' 
inter|)ret the results of this test and to correctly g'o\'ern his 
method of handling the e\-apr)rated niilk' according to these 
findings, he should luu'C a clear understanding of the correlation 
of the sc\"eral factors that influence this resistance to heat and 
that affect the ^•iscosit^'. 

A\'ith reference to the direction 'increase or decrease of 
^'iscositv) in wdiich these se\-eral factors influence the \-iscosity 
and the tendenc}- to curdle the ex'aporated milk, the following 
general facts should be known: 

1. high per cent acid in milk 
-. low stability of proteins 

3. high ccmcentration of e\-a|iorated milk 

4. high sterilizing temperature 
,^. long exposure to sterilizing temperature 
6. high pressure in homogenizer 

^1. low acidity in milk 

2. great stability of proteins 

3. low concentration of e\'aporated milk 

4. lo^^' sterilizing temperature 
3. short exposure to sterilizing- heat 

6, high temperature in forew armer 

7. extranerius water in evaporated milk 

5. low pressure in homogenizer 
'''. addition of bicarbonate of soda 

The exact i|uantitati\'e relation of most of these factors to 
one another and to the \'iscositv of the e^■aporated milk has been 
experimentally determined b}' Mojonnier Eros. Co. for ex'apo- 
rated milk stan.lai'dized to /.S j)er cent fat and 25.3 per cent 
total solids as follows: 

.\ 40 degree retardation or \iscosit\- as determined b}- the 
Mojonnier \iscosimeter corres]ionds to: 

1. ( )ne degree \\ in sterilizing temperature at the holding 
point of _'40 degrees F., when held for 1-3 minutes and with the 
same "coming-up" time as gi\en under "vSterilizing the Fi^•e 
Sample Cans." This means th;it each degree V. abo\'e 240 de- 



Factors that 

increase the \ is- 

cosity and the 

tendency to curdle 

the milk 



Factors tliat 
decrease the \'is- 

cosity and the - 
tendencv to curdle 



]i\'APOKATED Mri,K — ]Mojoxnii-;r Con'i'kollicr 153 

.i^Tees F. under abo\^e ccinditii ms o\ hoIdiiiL;" increases tlie retarda- 
tion rir \■iscn^it^• 40 de^ree-^. 

2. r)ne minute nf time at lioldmL;- iem])erature r,t 240 de- 
grees F. 'I'liis means that eacli minute nf Imldin^' at 240 degrees 
F. longer tlian 13 minutes increases the retardatirni nr A-iscrisit^' 
40 degrees and each minute of holding at 240 degrees F. less 
than 15 minutes decreases the retardatirm rir \-iscnsitv 40 degrees. 

3. Two degrees F. on temjierature to wdiich milk is heated 
in !iot well unrler 212 degrees F. This means that fiir e\-er}' 
two degrees F. Ixdriw 212 degrees F. in the It it wed the retar- 
dation or \-iscosity is increased 40 degrees. 

4. 20 ]i(iunds of extraneiius water per 1000 ]» mnds rif eN'ap- 
orated milk, 'khis means that the addilidu tn nr ])resence in 
e\-aporated milk of 20 pMunds .if extraneous ^\■ater per 1000 pounds 
of ewiporated milk reduces the retardation or \i-cijsit}- 40 
degTees. 

.■^. ( )ne mince rif srilid sridium lucarkionate per 1(J(.M) pound-- 
of evaporated milk. This means that the adflitirm tei the unster- 
iHzed e\'a])orated milk rif ijne ounce of hicarhonate of soda 
])er 1000 ]5ounds of ex'apiirated milk reduces the retardation or 
\■iscosit^■ 40 degrees. 

6. A\ hen using the alio\-e coi-relation r.f facteirs as a guide, 
it should be borne in mind that. A\-irh e\ ajjorated milk of a 
higher degree of concentration the inllnence of these se\"eral 
factors i')n the retardatiein or xi'-cositv is altered and intensilied. 

The Correct Viscosity for Evaporated Milk. — The ex])eri- 
mental stud}' of th.e \'iscosity of e\-aporated milk h}' iMojonnier 
P>ros. Co. has further demonstrated that a consideralde portion 
of the \iscosity, as determined immediatel}- after the evaporated 
milk comes from the sterilizer, is lost during the handling to 
which the product is su1:ijecte(' fri.m the time it lea\es the ster- 
ilizer and until it is ready to leave the shipping department, 
and again in transport until it reaches the consumer. Also the 
extent of this loss of \-isco5ity is go\'erned somewdiat bv the tem- 
perature rif the milk \\drile it is so handled: the higher the tem- 
perature the ,greater the sacrifice in \d5cosit\". 

AccordingI}- it has been found that fcir domestic trade a 
retardation or viscosity of 150 degrees is the correct A'iscosity 
for evaporated milk just as it comes from the sterilizer. For 



156 KvAPORATED Milk — Mojonnikr ConirollHk 

export ])iirpi)ses the \'iscri.sit}' should be higher, around 200 
decrees. 

.V 150 deg-rees \iscosity of exaporated milk immediately 
after sterili/iation is cquixalent to a \i?cosity of from about 
80 degrees to 100 degrees by the time the milk is ready to leave 
the shipping- department, and this represents a1)ont the correct 
\'iscosity for the summer months. For the winter months the 
\'iscosit\' sh.ould not exceed about SO degrees retardation, Kx- 
cessi\e \ iscosity in\ites the "feathering" or curdling of the e\ap- 
orated milk when used in hot cofifee or when diluted with hot 
water. 

Adding Sodium Bicarbonate to Batch of Evaporated Milk. — 
As soon as the controller and viscosimeter tests are completed, 
the batch of e\aporated milk is ready to be filled into the tin 
cans. In case it is necessary to add sodium bicarbonate, the 
fcjllowing" procedure is recijmmended : 

For conxenience sake we will assume that can Xo. 2 in 
tlie test showed the correct viscosity, as represented by a retar- 
dation of 130 degrees. To this can had been added sodium 
bicarbonate on the basis of two ounces per 1,000 pounds of milk. 
The entire batch of milk containing 24,000 pounds evaporated 

24,000 X 2 

milk, hence , „^.^ :t= 48 ounces of solid sodium bicarbonate 

l.OiKJ 

are carefully weighed out. This amount of bicarbonate is con- 
veniently placed into a lO-gallon milk can, a small amount of 
water is added and preferably also a small amount of evapo- 
rated milk. This mixture is then heated to a vigorous boil, 
which can easily be done by means of the steam hose. The 
boiling should be continued until the greater part of the gas 
generated has been e.xpelled. 

The hot mixture is now added to the entire batch of evapo- 
rated milk in the holding tank. It should be added slowlv and 
the evap(jrated milk should ])e kept thoroughly agitated, not 
only while the bicarljonate is added but for from 10 to 20 min- 
utes after its addition. 

Adjusting Sterilizing Process to Dififerent Sizes of Cans. — 

As stated elsewhere in tiiis chapter, difterent sizes of cans 
require ditterent sterilizing formulas to insure complete steriliza- 
tion, and a similar effect has been found also with reference t(j 



EVAI'ORATRD jMiI.K ]\IoJONXII:R CoXTKOLLI'.K 157 

viscosity. Thus, tall size cans require one degree more heat 
on a 15 minute run of holding' than the hahy size cans. Hence 
if the record for a bab}' size batch of e\-a|)orated milk calls for 
15 minutes at 240 degrees F., for tall size cans, the same batch 
would have t<"> be held for 15 minutes at 241 degrees F. 

Irregularities in the Reaction and Results of Sodium Bi- 
carbonate. — Generally S]")eaking the Abijunnier furmula abo\e 
gi\-en fur the use of ]'.icarbf)nate of Soda \'ields reliable results 
There are occasionally conditions, however, when the evai)orated 
milk fails to react mjrmalK- with this ingredient and ma_\- }'ield 
results exactly oi^posite those anticipated. Instead of reducing 
the \'iscosity of the milk, it increases the \-i.-^C("isit\-. Abnormal 
cases of this ty|)e suggest that the pli^'sical and possibly the 
chemical make-up of the casein may ha\e undergone material 
though not as yet well understorid changes. 

Such abnormal conditions may be the result of im|)ri:)per 
lorewarming c)i the milk, the use of excessi\e pressure in the 
homogenizer, excessi\'e heat in the sterilizer, mixture of brine 
with the e^-aporated milk due to leak}- coils in the cooler, or 
unbalanced relation of the protein and ash constituents of the 
original milk. See also Chajiter XXIII. "DefectiA-e E\'aporated 
Alilk" under "Lumps of Curd in Fva])r)rated Milk." 

Should Bicarbonate of Soda or any other Chemical be Used 
at all? — The foregoing directions for the use of the Mojonnier 
Controller and \'iscosimeter should not be interpreted to mean, 
that this volume ad\ocates the use of bicar1)onate of soda in 
the manufacture of e\-aporated milk. In fact the a\-ailabilitA' 
of this equipment and of these tests materiall}- facilitates the 
manufacture of evaporated milk without the use of sodium 
bicarbonate. 

It is important to realize. howe\-er, that the use of sodium 
bicarbonate for the ]nirpo^e of facilitating the process of ster- 
ilization has been prett}' general frir mam' ^-ears prior to the 
introduction of Mojonnier equipment and methods. It has be- 
come a fairly well established practice, acce]ited b^' the industrv. 
Its abuse cannot be too strongly condemned and its promis- 
cuous use in the absence of a systematic, scientifically controlled, 
ccirrect method, is prone to in\'ite its alnise. 



158 EVAPOKATI'.D Milk jMoJONNIER CoNTROLIvTiR 

WMiile, ill ]irinci])k', the use of 1)icarhoiiate oi soda in a 
product siicli as ex-aporated milk caiinut lie unconditionally 
recommended, its ])rn|)ei" and correct use, \\'here necessarjr, has 
pro\'en a decided henel'it to the industry, reducinc,'- the occurrence 
of unmarketable though otherwise perfectly .qxjod batches of 
evaporated milk to the minimum, and thereby a^•r)idino- unnec- 
essary economic loss. It is a matter of chorisintf the lesser of 
t\x-o evils. 

Trrei;ularities in the behaxdor of e\-aporated milk toward 
the sterilizini;- process, that render the product unmarketable are 
laro;eIy due to chaiic;'es and diftcrences in the chemical com]"jo- 
sition and ph}-sical rmd ])h\-si(i|i loical pi'operties cif the milk. 
Some of these changes ai-e under the control of the milk pro- 
ducer on the farm, otlurs are under the control of the manufac- 
turer and still others are uncontrollable. 

The conditions A\hich can and sluiuld be controlled by the 
])roducer refer lart^eU' to sanitation in the production and care 
of milk, prompt and proper cooling', frequency of delivery, pro- 
tection against heat in transit, health of ci:)\vs and rejection of 
colostrum milk. The condensery must insist on cleanly pro- 
duction, on jiroper coi:i!ing of the milk on the farm, on daily 
delix-er}' at the factory (some condenseries, especially those in 
Kurijpe recei\-e their jiatrons' milk twice daily), on the pro])er 
temperature of the mill-; iipmi ai"ri\al at the factory, on the proper 
disposition oi milk fr(jm sick cows and of milk too close before 
parturition, and ido -mm after cahdiig. Much oi this can be 
accomplished by a rigid system of milk inspection on the plat- 
form and frequent \isits b^' the inspector to the patrons' farms. 
In the case of rail shi])ments the milk often is in transit too 
long to arri\i' at the tactor\- in the best condition. 

The factors under control of the factory, wdiich influence 
the beha\-ior of the e\a])(irated milk toward sterilizing" heat, refer 
to sanitation in all de|)artments where milk is handled in the 
|)lant and to uses nr abuses ol the milk in manufacture. All 
ec|uipnient with which milk' comes in contact must be kept in a 
perfect state of cleanliness as outlined earlier in this ^'olume 
under "Factory Sanitation." The handling of t\\o da^'s' milk 
must be discontinued, the e\'aporatcd milk must not be held 
excessixely long' in the storage tanks, and if held at all, it must 



KvAPORATiiD Mii,K— Shaking 159 

be cooled to a low temperature. AH ainises of milk airnig- these 
and similar lines are bound to t'ause triTuble in the sterilizer, 
which is a\oidable and unnecessar}-. 

Finally there are factors ^vhich are nrit under cimtrol but 
which also exert a very marked influence im the lieha\-ior iif 
the product toward sterilizing- heat at times. These are iuA'ari- 
al)ly associated ^\•ith changes in the perif'd of lactation, changes 
in feed and climatic conditions and their effect on the amount and 
pro])r)rtion of the ])rotein and a'-h ccnT-tituents of milk, as ex- 
plained in Chapter XXllI, "Defecti'ce ]'*\ afiorated ]\Iilk, Lumi)S 
• if Curd." These conditinus are not iinl\- ncit controllable, but 
their eftect on the milk is ni't determinable In- an^- no\\- known 
practical n-iethod nf anah-ses. 

Proper attention tn the controllalile ci-mditions will go far 
in making- unnecessary the use rif bicarbonate in c\-aporated 
milk and \\-ill at least cnnfine its use, \\-lien necessary, to ^■ery 
small amounts. AA'hen these conditions ha\e been conscientiously 
taken care of and, in spite of these precautions, certain batches of 
milk, because of the abo\e named effect of unc(-introllable fac- 
tors, recpiire the use of bicarbonate in order to insure safe ster- 
ilization and to a\-ijid loss, then the eniergenc}- justifies and 
sound judgment and birsiness cfticienc\- demai-id recrmrse to 
methods th;it the helping hand nf science has made a\-ailable, 
so long as tliese methods do not inijiair the \A-hi ilesomeness and 
food value of the product, although their ethics, in principle at 
least, canni:it be a|i|)ro\-cd for general ]iractice. See alsri "Effect 
of Relation of Mineral Constituents of ^lilk," Chapter XXIII, 
"Defective E\-aporated Milk." 

SHAKING. 

Purpose. — The purpose of shaking the e\-anorated milk is 
to n-iechanically break down the curd that n-ia}- hax'e been forn-ied 
in the process ui sterilization and to gi\-e the contents (-)f the cans 
a smooth and hon-iogeneous bi'id-s-. 

The high temperatures to ^\-hich the e\apoi-ated milk is sub- 
jected in the sterilizer ha\e a tendencv ti ' cciagulate the casein. 
In the case of normal, fresh milk the casein coagulates at a ten-i- 
perature of 26'' degrees F. In the c\-apoi-ated luilk, made from 
perfectly normal and s^^-eet. fresh milk, the casein curdles at 
much lo\\-er temperatures, and the higher the r.atio of (~oncentra- 



160 



EvAPORATKD Milk — Shaking 




Tig. 68. Evaporated mili shaker 

Courtes>' of Arthur Harris & Co. 



tioii. the lower the temperature re<niired tci precipitate the 
casein. It seems that the concentration of the milk intensifies 
the properties of milk t(i coagulate when sul^jected to heat. This 
factor is prohabi}' in part at least due to the increase of the per 
cent of lactic acid in the e\aporated milk, due to the cr)ncentra- 
tion. If the fresh milk contains .17 per cent lactic acid, a con- 
centration of two and one-fourth parts of fresh milk to <)ne part 
of evaporated milk causes the e\'aporated milk to contain .17 
X 2.25 ^ .38 per cent lactic acid. With this amount of acid 
acting on the casein, it is not difficult tci understand wliv a coa.g- 
idum is often formed in the 
sterilizer. While the formation 
of this coagulum may be partly 
a\oided. under certain condi- 
tif>ns it appears in e\-ery fac- 
tory and there are more batch- 
es, especialh' in summer, that 
come from the sterilizer coag- 
ulated than otherwise. 

In this condition the product is not marketable. Some means 
must be pro\ided, therefore, to lireak up this curd and reduce 
the contents of the cans to a smooth, homogeneous and creamy 
body. For this purpose a mechanical shaker is used. 

Method of Shaking. — The shaker cfmsists of one or more 
hea\y iron boxes, or iron crates made r)f black iron pipes. These 
boxes are at- 
tached to an 
eccentric. The 
t r a }" s filled 
with e\a])orat- 
ed milk cans 
arc f i 1' m 1 y 
wcflged into 
these b o X e s. 
W hen the 
shaker i,s in 
operation, the 

cans are shaken back and forth \ iolently, causing the curd in 
the cans to be l)roken up, 




rig-. 69. Evaporated milk shaker 

(.'ourteyj' of The Enginoering- Co. 



l\VAPORATKi) Milk — Siiakinc 



161 



Speed of the Shaker.--! f the -^l1aker is ti i perf(jrm its work 
[jroperlv, it mu'st ha\ e I'hil;' enuuyh a struke and run fast enough 
to cause most \'ii;'orous agitation. The stroke should be not less 
than about two and one-lialf inches and the eccentric shuuld 
rcx'ohe not less than three hundred ht four hundred times per 
minute. In order to acc(jm])lish this withcmt wrecking the ma- 
chine, the shaker must be fastened securely tn a sulid foundation. 

Fmm !jne-fourth tn twi i minutes' shaking is usuall}' suffi- 
cient to completely break down a soft curd. When shaking for 
fi\-e minutes doc; nut jiroduce a smunth milk, the jiriiduct is 
usual!}- hopelessly curd\- and ni i amount nf additional shaking 
will remedy the defect. 

In some cases it __ ^._ — ,..__ 

has been possible, ho\v- 
c\"cr, to improve the 
curd}- product by shak- 
ing again after a da}" 
or t\M->. Under certain 
conditions, age seems 
to have a slight mel- 
lowing eii'ect on tlie 
curd. 




Fig-. 70. Evaporated milk balanced shaker 

Oourtcsy of .Schael'er Jlfg. Co. 



Formation of Curd not Desirable nor Necessary. — It slunild 
be understood that tlie processor should aim to get only a \-ery 




Fig-. 71. Atomatic shaker 

t.-ourte.s>- of Sctiaol'er Mfg. Co, 



162 Plain CoNDENsrlD Bulk Milk 

sIJL^ht and soft curd in his product, that can be shaken out in 
the shaker in one-fourtli to one-half minute. When the curd 
produced is firm, even prohmtjed shakinj^; will not prevent the 
appearance in the finished product of specks and small lumps 
of curd. Such milk is rejected on the market. 

The formation oi curd during the sterilizing- process is not 
desirable and is not necessary as far as the marketable properties 
of the e^-aporated milk is concerned. It is una\'oidable. however. 
under many conditions and as lony as it can be cr)nfined to a soft 
curd that readily shakes out, no harm is done. 

INCUBATING. 

From the shaker, the cans are transferred to the incubating 
room. This is a room with a temperature of 70 degrees to 90 
degrees F. The e\'aporated milk remains there ten to thirty days. 
The puryjose of incubation is tn detect defecti\'e milk and de- 
fective cans before they leave the factory. If the contents of 
anv of the cans have not been completely sterilized, or if any 
cans have the minutest leak, the evaporated milk therein will 
spoil within the time of incubation. Such milk either sours, 
curdles or becomes scilid, or it undergoes gaseous fermentation, 
causing the appearance of "swell heads." The more nearlv per- 
fect the process nf sterilization and the better the construction 
and seal of the cans, the fewer are the sjxiiled cans. This incu- 
bation process is strictl} a prevcntati^■e measure. It is omitted 
in many factories where the cans are labeled, packed and ship- 
ped to their destination at once, or put in ordinary- storage in 
the factory. 

Ch.aptkr XII. 

PLAIN CONDENSED BULK MILK. 

Definition. — This is an unsweetened cmidensed milk made 
from whole milk, or parti}', or wholly skimmed milk, condensed 
in vacuo at the ratio of about three or four parts of fluid milk to 
one part of condensed milk. It is usually superheated to swell 



Plain Conuicnsed Bulk Milk 163 

and thicken it, and it has tlie ci'nsistency of rich cream. It is 
sold in lO-gallon milk cans to ice cream factories and in milk 
bottles to the direct consumer. I'lain condensed bulk milk is 
not sterile, nor is it i>reser\ ed by sucrose. Its keeping (|uality 
is similar to that of a hi'^h i|uality of ])asteurized milk. 

Quality of Fresh Milk. — The sweeter and purer the fresh 
milk or skim milk, the better will be the (|uality of this product. 
Old milk, or skim milk in which the acid dexelopment has made 
considerable headway, tends t(> form a lumpy jjlain condensed 
bulk milk. Howe\-er. since this milk is n(it subjected tc> steriliz- 
ing temperatures and is used uj) cpiickly after manufacture, the 
(|uality of the fresh milk from wliich it is made, is not of such 
magnitude as in the case of evajxirated milk. 

Heating. — In the manufacture <if jilain condensed bulk milk 
the heating is accnmplished much in the same manner as in the 
case of sweetened condensed milk and e\'aporated milk. The 
milk is usually heated by turning steam direct intt) it; though 
many of the mcjre efficient types of milk and cream pasteurizers 
could l)e used to excellent ad\antage f'lr this ])urpose. 

It is ad\isable, howe\er, tn heat this milk imly- to about 150 
to 160 degrees F. in order ti.> secure a nice "li\er" (coagulum), 
when it is superheated in the pan. If the milk is heated to the 
boiling point in the forewarmers, it does not respond to the 
superheating in the pan as satisfactorily. 

Condensing. — The condensing of plain condensed bulk milk 
is done in tlie \acuum in a similar manner as described under 
evaporated milk, except that the evaporation is carried farther. 
See also "Campbell Process" and "Condensing Milk by Continu- 
ous Process." 

Superheating. — When the condensation is nearly completed 
the milk in the pan is superheated. This is accomplished by 
shutting off the steam to the jacket and coils, closing the valve 
that regulates the water supply of the condenser, stopping the 
vacuum pump and blowing steam direct into the milk in the pan, 
for the purpose of swelling and thickening it. During this proc- 



164 



Plain Condensi:d Bi'lk Milk 



ess the tem|)eratiire rises to 
hetween 1X0 and 200 dc- 
l^rees F. When the milk- 
lias liec'iiiK' sufficientl)' 
thick nr, in the language 
lit the processor, has pro- 
duced the "proj)er li\er" 
(coagiilum) the steam is 
shut ofl", water is again 
turned into the condenser 
and tlie \acuum pump is 
started up. As soon as the 
\acuum has risen to from 
l\\ent_v-fi\-e to twenty-six 
inches and the temperature 
lias dr<)|ii.)ed to aljout l.iO 
degrees F. the process is 
complete, the \'acuum is 
released and the condensed 
milk is drawn off. The 
su];erh.eating" usually oc- 
cupies aljout t\venty-fi^■e 
t( 1 thirty minutes. 
The com])letion of the superheating, or the jioint wdten the 
superheating slujuld cease, nia>' also readily he detected by the 
exam'ifiatidn f)f a sample cif the iiroduct. ,\s snon as the con- 
densed milk begins to sh(i\\' a I1ak^■ coiidilion of'the curd, the 
])urprjse nf superheating has been accomplished. The amount of 
su|jerlieating necessary and that the milk' \\ill stand, will largeh' 
de|jend, aside from the sweetness of the original milk, on the 
extent of the concentration. The lui^her llie ratio of concentra- 
tion, the less superheatiiiL; is required to secure the desired 
results. 

Striking. — The striking, or saniplin;^ ,'ind testing for gra\it\' 
is done with a lieaume hydrometer, the same, or a similar one, 
as is used for e\'aporated milk. The scale should extend to 18 
de.grees I'.eaume. The batch should be struck before and after 
superheating. : '?■■ 

Factories which sUindardize their product to a certain estal)- 




rig'. 72. Superheater 

(^ourte.sy of C. E. Rogers 



I'l.Ai.x Cn.\ui:.\sKj) Hi;lk Mti.k 165 

lislu-d density, usiiall}- cimdciisc tlic mill; to a |)iiint sliL^htly 
l)c\-("iii<l that (lesircfl. Then, ai'ter sti|)erhcatin,L;", they determine 
the aniMunt of water reciuired t' i reduce the finished prdduct, and 
tlien add the required amriunt ()f \\ater hefnre the condensed milk 
is cooled. It is adxdsahle to use destillefl water f("ir this jmrpose. 
Ratio of Concentration.— The ratio of concentration \aries 
lai-pely with the I'at content o|' the milk, although the locality 
and season of _\-ear are also iniluenciuL;' factors. Wdiole milk is 
Cdudcnscd at the i-atio of about three jjarts df milk to one part 
ol condensed milk, wdiile the ratio of coni.-entrati(.in for skim 
milk is ahou.t 4 to 1. The ])niper density \aries somewhat with 
localitx' ,and season of \-ear. l\oui;hly speaking", whole milk has 
I'eached the pro|")er densit\' when the Beaume reading" at 120 de- 
crees !•". IS afjout 10 de,u;rees I!, and skim milk has reached ahou.t 
the ])roper de)lsit^• when ihe lieaume reading' at 120 degrees F. 
IS abi lut 14 decrees M. W hen the ratio of concentration exceeds 
4 to 1, there is danger of gritt}' condensed milk due to the pre- 
cipitation, in this concei'trated product, of crystals of milk sugar 

Cooling, — The plain condensed bulk milk is usually drawn 
into 4(; quart milk cans, placed in cooling tanks containing re- 
\ oh'inv" cogwheels as described in Cha|)ter \'I. under "Cooling 
Sweetened Condensed Milk," and is cooled to as near the freez- 
ing; |joint as facilities permit. 

}\ecentl_\- this crude and laboriou.,-- method of cooling has 
been sujjerseded in main' of the larger condenseries b\' more 
modern w,a}'s. Wdule the plain condensed bulk milk becomes 
t(.o thick and sluggish during the ]}rocess of cooling to make 
possible the use of surlace cmilers. and internal-tube cocders, it 
can Ik- readily crmled in \-ats e(piipped with re\ail\-ing discs, or 
in hijrizontal coil \ats es])cciallv constructed for this purpose 
and in whicli the lower part .;if the \rit is constricted and the coil 
sets x'cry low in this constricted part, so as to agitate the milk 
vigorousl}' and at the same time pre\-ent the incorporation of air, 
by being com])letely submerged, or in circular \ats equipped 
with a \'erticall}' suspended cr)il. The \-ertical coil \-at has the 
further ad\aiitage in that it eliminates from the milk, all liear- 
ings and glands and it e.xpeK. rather tlian incorporates, air, 
from the condensed milk, 

Wh.en. cooled the condensed milk is reach- frjr the market. 



166 CoNci{N'rRATi{D Milk 

If lu'Kl in tin- fact(ir\-. it slmuld he placed in a C"\<\ vunm or 
sliduld l)e ( itlit-rwise iirutected auain-^t tcmjieraliircs '^ufficien.tly 
lii,i;-h t(i cause it Ui Minr. Wdicn kc|it at -10 dcL;rces [' . nv heliiW 
the danger from sotirini;" is larnel}" eliminated. If ti'anspi irled 
lonLj" distances dmanL;" warm \vcatlier, it slmuld be slii])ped in 
reirit^eratt ir cars. 

ClIAl'TKR XTII. 

CONCENTRATED MILK. ■ 

Definition. — Ci mcentrated milk is cnw's milk, either wlmle 
milk, iir ])arth" i ir wlmllv skinamed milk, condensed at tlie ratio 
iif thi'ce to four ]iarts of fresh mdk to one ];.'irt of concentrated 
milk. It is not conden'^ed in A'acnrj, hut in o])en \ats h}- ]>a-sin,n' 
currents of hot air through the milk. It is sold larL','ely in piint 
and (|u;irt bottles for direct consnm])tion. It i^ not sterile and, 
therefore keeps for a limitcfl time only. Its keepiuL;" '|uality is 
similar tt) that of a hij^di urade of properl}" pasteurized milk. The 
|)rocess Ijy wdiich the concentrated mill: is manufactured is 
known as the "Campliell J'rocess," This process was inxented 
h\' J. 11. Campbell of .Vew ^'ork l'it\', in I'-'CO and patented in 
I'JOl. 

Apparatus Needed. — The principal ])arts are: the e\apo- 
ratin^;' \at with hot water jacket and coils, and air blast reL;is- 
ters or nozzles near the l.iottom of the \"ai ; .in ,air blower which 
furnishes the air Idast: an air heater tlirouL^h which the air 
blast passes and from wdiich the heated air is conducted into the 
millc: a water pump circulating' hcit w.ater throui;h the jacket 
and coils; an anxiliar)' e\aporatinL;" taiil< for completin;,;- the 
e\a])oration ; and a spra}- pump) which thro\\s th.c sprax' of milk 
drawn from the bottom of the mam e\ a]M iratin;^ \ at into the 
auxiliar}- tank and for transferrin^;' the ]iarth" condensed milk 
from tank- 1 to tank 2. 

Operation of Campbell Process. — The milk' is lieated to about 
ILO dcLjrees h . and allowa-d lo iliiw into e\a|)( iratint;" tank 1. 
Water at temperatures ranging' from 1(10 to \2? deyrees \' . is 
forced tlirou,L;h the coils an(' jacket. Mot air is then passed into 
tlie milk. The teniperature ijf the air is remilated so as to keep 
the temperature of the e\ ajioratiiiL;" milk down to 120 de,s;'rees F, 



CoNTTNUOUS Prockss Evapokaiors 167 

nn the start, and tn tnnisli tlic e\:i|)rir;i ti"n I)etwccn ''0 and 100 
de<4'rees F. The air Idast is ^o intrcdnced, as t' i keep tlie nidk 
alrinq- tlie licatinq surface ot the jacket and cuils m circidaticni 
anch tlierefrire. ])rc\ent lar^ieh' the lial-dni;' 'if tlie min< on the 
heating- surface. After the milk has keen eNapnraled ti > a certain 
decree nf concentratii mi. '-a\' J:l, it i,- tr.aiisferrefl t' > the auxiliarv 
evaporatinj.,^ lank \\hei"e the ci mdensatii m is cinnpleted. ddiis 
transfer is nut necessarw I ml is resurted ti > sulci}' as a ci'uve- 
nience, in order to ciintinue trealment ol the reduced l)ulk of 
material in a smaller lank and leax'e the lai-'_^x-r tank" free for 
treatim;- a fresh hatch of mdk, and fu.rther, hecanse ihere are 
no obstructing" coils in the au-xiliar\- tain<. niterferinq" with the 
drawiuL'," oft o| the imislii'd and thuds condensed milk'. In lids jjroc- 
ess, as now used, the milk- is iisnall\' first sejiarated and the 
skim milk oid\' is condensed. Tdie cream is snl)sei]uenll\" added 
to lire condensed skim niilk. 

Advantages and Disadvantages of Campbell Process. — ddie 
initial cost ol installing;' the necessary' machinei'v is nuich Icss 
than where \'acuum ex'aporalion is practiced ddie low beat 
ap])liei;l makes it ixi^sible U^r the (inisked in'oduct lo retain the 
properties ot raw ndll-;, leaxini;" ihe albnmenoids and lime salts 
in their original and easih' digestible form and preserxing the 
antiscorbutic \'itamines in actn'c loj-m. 

This proeess is applicable iiiih' in thi.' manubicttire of nn- 
S'.xeetened conrlensed, niillN-. L nlcss sii|isei|uenll\' sterilized, the 
l)roduct will kec]) for ;i short tinii' 'inl\'. Thi- lu'ocess has at th.e 
present time onh' xerx' limiied use. It can liardb' be considered 
as an imporl.'oit branch o| the condcrrsed milk industre. 

ClIAI'Tl'-.K XIA . 

CONDENSING MILK BY CONTINUOUS PROCESS. 

The processes of condensing milk dtsenked in preceding 
chapters, a.re exchisneb' cimbned to the intermitleiit or batch- 
])riiu'iple Ol e \a])oratii in. dd'at r- m the case of the x'acnnm i)an. 
the fresh mill; runs into the pan nn'il the capacit\' of the pan is 
reached and no ciin(iens^.d milk' lea^xes the p;in until the con- 
dciisatii n oi the entire batch is complete'k Then the i)an must 
I'le emptied before more milk can ke draxxn in. In a similar man- 
ner, in the Campbell process, e\'aporation of the entire batch 



168 



Continuous Prockss Evaporators 



must l)e C( 'iiiplet'efl bsldrt- aiiv uf tin; tinislie'l ]ini(hict lea\cs the 
e\"ap()ratint; \ at or tank. Tlie operation in eitlier case is inter- 
mittent and not continuous. 

( )f m(jre recent ^■ears. c(|uipnient and processes ha\ c l)een 
de\elo])ed that make possible continuous operation. That is, the 
-fresh milk enters the machine and the condensed milk lea^■cs it 
simultanei luslx" and cnntinuoush'. So far three t}'pes- of continu- 
(Tus machines have been perfected sufficiently to make them com- 
mercialh' practical and usable, namely the ^.uflo^-ak Rapid Cir- 
culatiim E-\'aporator, in^•ented and manufactured by the Buffalo 
Foundry and Machine Co., Buffalo. .\. Y.. the Continuous Con- 
centrator, in\'ented b}- the Hy-Products Uecoverv Cn., Toledo, 
Ohio, and manufactured b}- the Creamery Package Manufactur- 
ing Co., Chicago, and the f-tuff Condensini'; E\'aporator, manu- 
factured by The Cream Production Co.. T\irt Huron, Mich. 

BUFLOVAK RAPID CIRCULATION EVAPORATOR. 

This t\'pe of 
Evaporator has been 
developed from the 
standard return-flue 
tubular boiler and 
adopted for the spe- 
cial purpose of han- 
dlinq- foamy and del- 
icate li(|Uors. 

Construction. — 
'['he Piufl(.>\ak Rapid 
Circulation E\ apora- 
lor (-(insists of a 
hi irizi mtal cylindric- 
al \-apor bod\-. To 
this is bolted an in- 
c 1 i n e d cylindrical 
steam-chesl. 

The \apor bodv 
is e(juip|)ed w ith a ^ 
baftle i)late which ex- 

ten(l> aclo>s its cyl- rig-. 73. The Buflovak rapliJ circulation evaporator 

mdncal part and c.nrU-s.v of Buffai.. Foundry & Macliine Co. 




CoxTixi'ous Process Evaporators 169 

leaves < i|)eniii;4"S at hotli ends at the \-a|)or Imdy for the xapors td 
escape, the ends (jr heads of the \-apiir body lieinj^ dished ont- 
ward. The \ aprir hocW alsr) carries the milk inlet, \apiir rmtlet 
and sp}- glasses. 

The steam client which is attached tn the lower ])art nf the 
x'apiir l)(id\'. is (li\ided In- a sulid ]iartiti(in into two cnmpart- 
ments. The upper and larger C(im])artment is filled with tulies 
wdiich are e.x]:)anded in the Hue-sheet.s, closint,'- both ends. The 
trdies themseh'es are open at both ends. The\' are two inches 
in diameter and from six to eit;"ht feet lontj. The lower and small 
Compartment, called the downtake, i^ entirel}- open at both end^. 
The steam chest is eipiipped \\-ith a steam inlet, a licjuor outlet 
and a condensation outlet or drip. The steam is around the 
tubes and the milk i'^ inside the tid)es. 

Operation. — Thi> machine is operated under ^■acuum of frr)m 
20 t("i 2.S inches mercur}- column, the \-ap'"ir outlet beinr;- connected 
with a condenser and \acuum ))ump). 

The fluid milk enters the vapor body and flows down into 
the bottom 'A the downtake of the steam chest, from wdiere it 
rises in the tubes and finds its le\el. The le\el of the milk in 
the tubes is kept low. the coefficient of the heat transmission 
beim^" hiLjhest ^\dlen the milk le\el in the tubes is abcuit one- 
third of the tube lens^th abi.i\-e the lower flue-plate, and it is 
re;_;ulated by automatic float controls in the larger machines. 
The steam that is turned into the steam chest, causes the 
milk in the tubes tci boil. The \xipor thu^ arising from the 
milk, tC)gether with a pjorticin <'>\ the milk, rises and passes 
through the upper part of the tubes at a \ ery high speed, 
and is thrown \vith great force against the ribs of the baffle 
plate which extends across the whok- cylindrical length of the 
\-a])or body. 

The li(|uid or condensed milk returns thniugh the down- 
take to the lower part of the steam chest where it escapes from 
the machine. The \-apor passes at Ijoth ends of the baffle plate 
into the \"a])or space abfi\-e and from there through the entrain- 
ment separator for reclaiming escaping milk, and then to the 
condenser attached to the outlet of the \apor liody. 

The upper part of the tubes becomes co\ered with a climb- 
ing film of milk. Thi-- together with the high speed of the 



170 



CnNTINl'()i;s ProCI'.SS En'AI'ORATOKS 



milk ill tlic Uilies (KiO feet per -(.'Cnnd nr mrire I increases the 
capacit\' df tlic lieatini;' snrface, and tlie small amount of milk 
ill circulation, tn^^ctlicr with llie low k-\ el of the milk in the 
tiiiies, reduce^; the ]io^slliilit\- of foaming, conhiiinL'; the foam ti'i 
and hreakiiii; it up in the u|)|nr ]'aii of the luhes where film 
e\a]3oration takes ]ilace. 

The escape of the condensed milk i^ crnitinnous and the 




-ConotriiATIOH OvTLCT 



uoB oyTurr 



Fig". 74. Cross section of Bufiovak rapid circulation evaporator 

(_'ourtewy of lUiffalo Foundry and Alacliine Co. 



degree ol concentration is controlled 1)_\' a xalx'e regulating" the 
outlet. The condensed milk runs Iw' gra\-it\- from the steani 
chest int(i a rescr\oir located nndcr the e\aporalor. In this case 
the reserx'oir must he under tJie same \acui'm as the e\-a])r)rator. 
In some cases it is recommended to lia\e an intermediate ste)rage 
tank renici\-ing the condensed milk from the e\aporator h\ a spe- 
cially constructed steam pump.- 



Continuous r'R(jci{ss Kx'apokators 



171 



THE CONTINUOUS CONCENTRATOR. 

The inflow (if flic fliiid milk and tlu- outlli'W- (,f the crm- 
(lensed milk :ire ci mtinuDiis. The milk is conflcnscd under atmos- 
pheric yire-snre at 2)2 dmrees F. \ i-apidly re\"' i]\-in,L;' agitator 
throws the milk in a thin him ai^ainst the steam-heated and con- 
tiniionsh" |)ohshed [)eri[)her\- .if a jacketed copper drum. llv 
keeping;' the heatiuL;" surface clean and liri^ht, and the milk 
rapiflly moxdnv, fhe power of the milk to ahsorli and utilize heat 
is t^reath' auL'anenled and the rapidit\- of e\-a])oration increased. 

Description of Continuous Concentrator. — d'he continuous 
concentrator consists of a hollow copper drum. The copper shel' 
is surrounded !)}• a stea.m jack'et which is insulated. The space 




^^smmP^., PS^ ?,^MaS:^ 





rig-. 75. The continuovis concentrator with preheater and cooler 

Coui-tes.\" of Creamery- Pack;ig"e :\Ifg. i "o. 

hct\\'cen innci- sliell and jacket is a'.njut one inch. 

This drum carries in its interior, a i'e\-ol\-in;.'; dasher "with 
f.'ur-or more Mades, accordiui^" to the size ni the machine, and 
similar to an ice ci'eam freezer or a tla.sh pasteurizer. The edr;'e 
of these Idades comes in direct contact with the inner surface 
cif the shell which is the heatini;" surface, so that wdien reN'ohdnn;, 
each hlade coustantl}- remo\-es from the heatini;- surface anv 
milk Ihat adheres to it. 

The blades a.i-e pressed aL;'ainst tlie heatiii,L^- surface liy the 
centrilui^'al force that is t^cuerated wdien the machine is in m.^i- 
.tion. The arms to which the hlades are attached are equipped 
witli .-tops that control their pressure a_:,';ainst the heatinv,' sur- 
face so as to insure continuous and uniform pressure. The shaft 
which carries the dashei- passes through the front and rear heads 



172 



Continuous Pkockss 1\vai'okatoks 



i3f the c(>nceiitr;it(ir and carries a piilk} \<;uk nl" the rear head, 
tn whicli the pew er is transmitted. 

The rear of the ci nirentratur terminates in tlie exliaust 
ehamber nf the condensed milk xripcirs. whicli escape throngh a 
S:alva!iized iron flue to the outside. The \a])iirs are not con- 
densed by water, but escajjc intu the atmosphere. The rear wall 
is ccjuipped \\ith the intake of the lluid milk. In urder to permit 
the milk to feed the concentrator by ,L;ra\ity, without necessitat- 
ing iiicon\'enientlv hic;'h ele\-ation of the forewarmer. the intake 
is located at the bottom. 

Tn the front head, in close proxiriiity to the periphery rif the 
concentrator is located the outlet of the condensed milk. Its 
distance from the inside wall of tlie concentrator determines tlic 
thickness of the film of condensed milk tliat is allowed to f(jrm 
on the heatin.G^ surface, a)id the amount of milk that is retained 
in the concentrator. AccordiuL;- tij the amount of superheating; 
intended, this hlni ma^' \ar}- from i to I inch in thickness anfl 
the amount of milk retained in the machine may \ar\ from (> 
to 12 quarts. 

I'he front head is ef|uip|)ed \\ilh a cover which is fastened 
to the rim with screw bolts and w hich carries a spy L;lass through 
wl'.ich the operator ma} watch the process. .\t the conclusion 
of the operation this co\er is remo\ed and the dasher and blades 
are taken out, so that both the shell and the dasher can be 
readily washed. Over the trjji cjf the concentrator extends the 
steam line, a 3 incii pipe, with bi inch laterals, supplying the 
steam jacket, and insuring uniform distribution rif heat. The 
-team line is also eipiipped with regulator and steam gauge. .-\t 
the bottoni rif the concentratrir is located the exhaust and regu- 
lating drip vahe. 

The continuous concentrator is constructed of diverse sizes 
and capacities, the most common of these sizes are the following: 



Diameter 


Length 


Capacity per Hour 
when Concen- 
trating at the 
Ratio of 3:1 

7000 lbs. 
,sOOO lbs. 
2000 lbs. 


Boiler Capacitj' 

Required 

H. P. 


3 feet 
3 feet 
3 feet 


4 feet 
3 feet 
2 feet 


100 11. T. 
XO II. 1'. 
40 II. 1', 



Continuous Process Ivvaporators 173 

Speed of Agitator. — The prijpt-r speed of the coiitiiiuous 
concentrator is expressed in terms of rim speed, that is the 
distance which the blades travel per minute. It lias been found 
that the rim speed wiiich is sufficient ti i ninxe the film oi milk 
in the machine properly, is about 230(J feet per minute. In order 
to insure a rim speed of 25f)0 feet per minute, the blades in a 3 

-'500 _. . 

toot chameter machnie must rex'nlve =: sn? tmies per 

3x3.14 ' 

minute. In a ■^ix fucit diameter wheel, the same rim speed would 

require — — =- 133 re\< ilutii mis |)er minute of the spider. 

ox3.14 

x\t;-ain, it has been fi nmd -that the blades should be not more 
than about 2i feet apart. .\ three U>nt diameter concentrator, 
therefore. rei|uires four blades while concentrators with larg'er 
diameter require a larger number of blades in order tn keep the 
distance between blades within the limit of two and one-half 
feet. 

Operation of Continuous Concentrator. —The operation <i1 
the crinti'iuous concentrateir is simple and the ratio iif concen- 
tration of the ])roduct can be rei^ulated as desired. 

Heating of Milk.--Sinnlar a^ in case i.if e\aporation in 
\'acuo, it; is desirable, if not necessar\ , to heat the milk before 
it enters the concentrator. Thi.s nc>t only increases the capacity 
of the machine, but it also prepares the casein in the milk for 
the superheating ttj .which the milk is ■subjected in the concen- 
trator. Anv method of forewarming or preheating may be used 
for this purpose, but since the milk flows to and through the 
concentrator, in a continuous stream, it i« preferable to also use 
a forewarmer of the continuous tyi^e. The milk should be heated 
to about 185 to 200 degrees F. and the fore\^■arming should be 
so arranged that the milk is exposed to this temperature for 3 
to 10 minutes before it enters the concentrator. 



Condensing. — The concentrator is steamed, the parts of thie 
agitator are assembled and installed in their proper place, the 
cox'er is securely bolted over the ijpening" in the front head and 
the machine is ready for operation, llefore starting the agitator 
a small amount of milk is permitted to flow into the cr)ncentrator 



174 Continuous Process Evaporators 

so as to prevent the blades from runninc; over the dry heating sur- 
face, cutting the copper. Simultaneously with the starting of the 
agitator the steam is turned into the jacket and then the milk 
intake ^■ah e is opened. 

The steam yiressure on the jacket is kept uniform, preferably 
at 40 to 50 lbs. of steam. This machine evaporates the milk at 
atmo.spheric ])ressnre. The temperature of the milk in the con- 
centrator therefore, is practically the same as that of boiling 
water — ^212 degrees F. — at the sea level and varies only with the 
altitude of the location. The ratio of concentration is regulated 
by the rate of the iniilk inflow. As the milk inflow is increased, 
the ratio of concentration is reduced, because the amount of 
evaporation being constant, a smaller proportion of the water is 
taken out of the milk. 

The density is determined bv the use nf the P.eaume hydro- 
meter. If the density is greater than desired, more milk is 
allowed to flow into the machine. Tf the density is lower than 
desired the inflow of milk is reduced. 

Cooling of Condensed Milk. — From tlie discharge spout the 
condensed milk is run over a continuous cooler from A\-hich it 
escapes read}' for packing in whatever form it is intended for. 
The disc continuous cooler has proven very suitable for this 
purpose. 

No subsei'iucnt superheating of tlie concentrated milk is 
necessary. This product can be made of an_\' consistency desired, 
regardless of concentration, according t(T the thickness of the 
film tiiat is allowed to form in the coticentrator. and this in turn 
depends on the distance of the discharge fmni the periy^hery of 
the machine. 

THE RUFF CONDENSING EVAPORATOR. 

Principle of Machine and Process. — In the "Ruft Condensing 
Evaporator," similar as in the "Continuous Concentrator," the 
condensing is accomplished b}' the film iirinciple, but in the RufF 
machine the heating surface consists of one or more steam-heated. 
re\'oIving drums, and atmospheric air is blown through the milk. 
This machine is applicable both, for cimtinuous evaporation 
and for condensing in batches. 



Continuous Process Evaporators 



175 



-The Ruff Cnndensint; F.\ap(jr;it'ir consist-- 




Construction. 

of the follow- 
ing three main 
jjarts ; 

1 . A vat I )r 
tank holding 
the milk to l)e 
condensed, and 
equipped whh 
c o V e r. T h e 
bodv of this 
tank is of steel 
sheathing, lin- 
ed on the inside 
with tinned 
c o p p e r. The 
co\er or ti>p is 
fitted with 
doors. 

2. (3 n e o r 
more s t e a m- 
heated hollow 

cylinders which re\i>he in the tank horizontally. These cylin- 
ders are ci instructed of special steel, highl}- ]}olished. Thev are 
equipped with tinned brrmze scrapers \s'hich remo\e the film of 
milk from the heating surface. The cylinclers are fitted with 
a device f<ir the automatic removal of the condensed steam, facil- 
itating the cnntinumis heating with dry steam and therby in- 
hancing the rapidity 'if e\aporation and augmenting the capacity 
of the machine. 

3. An arrangement for blowing atmospheric air into the 
lower part of the tank, causing it to rise up througli the milk 
and tr> escape from the tank. 

4. Accessories. — The entire unit further comprises such 
accessories as a dial thermometer, high pressure blower with 
pipe connections from fan to e\aporator and automatic return 
boiler feed pump, complete. 

Operation. — The milk is preheated to 145 degrees F. The 
hot milk runs into the tank by gravity, or is pumped in. In the 



Tig. 76. Tile Buff cond*nilng •Tftponktor 

C'lurtesy of The Cream Production Co, 



176 



Condign SKI) But'ii':i<mii,k 



case (i| ciintimicuis c\ aimratii 'ii the milk is key^t at a cmistant 
le\ck the lii\\'er |)art of the rc\i i!\ iiiL', (•\4iiulers di|)])iiii;' into it 
and picking" iij) a fihn which is aiiti miat icalh scra|ierl off with 
every rcxcilutii m nf the cylinflers. 

At the same time air is hlowii thri iii,'_;h tlie hot milk, further 
assisting' in the exapuratinn anrl akso remuxiny ;_;ases and (ither 
volatile substances frdui the milk. 

During- operatiDii the rexclxiuL^ cxlinders are eJiarned witli 
40 pounds of steam and the temperature of the milk is held at 
about 145 degrees F. 

TlriS' process of condensint^' can he carried tn almost any de- 
gree of concentration and the desired degree of density is deter- 
mined in a similar manner as in the case of e\'aporated milk 
and plain crmdensed liulk milk. 

Capacity. — This machine is constructed in several sizes, 
with capacities ranging from OfK.) pounds to 8000 pounds of 
raw milk per hour, based on a ratio of concentration of two 
to one, as shown in tlie following specifications: 



Model No. 
1920 


Number of 

Steam 

Cylinders 


Approximate 
Floor Space 


Gallons' 

Tank 
Capacity 


PolindM Capacity 
Condensing 
Kaw AC Ik 

2 to 1 per Hour 


Additional H. P. 
Required for 
Blower and 

Evaporator Cyl- 
inders 


Required 
Boiler 

Capacity 
H. P. 


2 
4 
6 
7 
8 


2 

2 

2 

4 
6 


3'x5' 
3'xlO' 
4'xl4' 
5'xl4' 
7'xl4' 


175 

300 

500 

600 

1000 


000 
1800 
2700 
5400 
8000 


4 
7 

10 
20 
30 


15 
30 
40 
80 
120 



Quality of Products from Continuous Concentrators and 
Evaporators. — When properly o|)erated and when using a good 
<|uaiity of raw materi.il tliese ciintimnnis concentrators and film 
eva|)orators yield a ])OMhict <if excellent fia\-or and good (pialitv, 
especially suitable fur the manufacture of ice cream, but also 
applicable for the maiinfacture of sterilized e\a])orated milk, 
condensed Imttermilk' .and condensed \\he\'. 



CONDENSED BUTTERMILK. 

The \'alue of Ijuttermilk as a part iif the feed ration for 
chickens, laying" hens, iiigs and hogs has long been recognized 



CONDEKSICD BuTTIiK.MILK 



177 



and its use fnr feeding |)ur]i(ises is ra])idly gniwing. P>iitternii!k 
nnt oil!}' contains iirotein and carbohydrates i if hiL;h quality and 
great digestibility, but it has biolngical jirriperties that stimulate 
growth and gain in weight, aufl it exerts a |)h}'siological action 
that makes for a health}- cunrhtinn of the inteslines, because 
of its lactic acid content. 

Chicken feeders ha\e fciund it invaluable in their efforts to 
accom])lish maximum growth and gain in weight nl the grciwiiig 
chicks, and Ixcause of the superiur cjuality nf the meat nf butter- 
milk-fed fowl. And extensive experiments with laying hens 
ha\e conclusively demonstrated that buttermilk makes for in- 
creased egg jjroduction. 

For similar reasons buttermilk, when properh' balanced with 
C)ther feed, is a most valuable hog feetl. !n_ fact it is the lounda- 
tion of a good hog and is becoming a more and more indis- 
pensable part ("if the ration fcir growing pigs and fattening hogs. 

Composition of Buttermilk.' 



Cunstituents 

in 
Buttermilk 


From Rii>ened Cream 


From Sweet Cream 


Van 

Slyko 

% 


Starch 


Snyder 


Vleth 

% 


Fleisch- 
mann 

1o 


Storch 
1c 


Elch- 
mond 


Water 

Fat 

Casein 

Albumin .... 
Milk Sugar. .. 
Lactic Acid. . 
Ash 


90.6 
.1 

2.8 

.8 

4.4 

.6 

.7 


90.93 
.31 

1 3.37 
4.58 

.81 


90.5 
2 

3.3 
5.3 

.7 


90.39 
.,50 

3.60 

4.06 
.75 
.80 


<n.30 

,50 
3,50 

j 4,00 
.70 


89,74 
1.21 

4.98 
.79 


90.98 
.35 

3.51 
1 ,01 



Specific gravity of sweet-cream buttermilk 1,0331. 

Specific ijravitv of sour-cream buttermilk 1,0314, 

Caloric ^-alue 165, 

Since the great bulk of butter is manufactured during the 
summer season, the main supply of buttermilk is confined to the 
summer mc>nths. In summer the output of buttermilk far exceeds 
the demand for this product and nvuch of it goes to waste for 
lack ,"if a suitable market for it. In \\ inter, on the other hand, 
the output of buttermilk is small and insufficient to supply the 
demand. 



1 Hunziker, The Butter Industry, 1920. 



178 CoNDIiNSHD BuTTERjMII,K 

In iirder t<i stop this waste uf InUtermilk in summer, to utilize 
it econtimicall} and prolitalily and to equalize the supply 
throui^iiont the year, some of the lart;e creameries of the coun- 
try ha\e found it practicable and ])rofitable to cr)ndense the sur- 
plus l)uttermilk. f nforniatirm from chicken feeders and hog 
feeders shows that, when re-diluted to the consistency of the 
oritjinal buttermilk, this condensed buttermilk j:<i\es equally as 
satisfactory results as the fresh buttermilk. 

Prior to the t;Teat war the market \alue of buttern^ilk and 
of Condensed buttermilk was C(jnsidered too limited to justify the 
relati\el_\' hii^li manufactnrint;' expense, incident to the concen- 
tration of buttermilk by e\a|)oratiiig from it a larf^e portion of 
its \\'ater, lint the food and feed shortasje, titgether with the 
high prices liroui'ht about by the war and since the war, neces- 
sitated the more general use of byproducts and raised the valua- 
tion <jf buttermilk to figures that render its manufacture into 
condensed buttermilk highly profitable. 

Manufacture. — There are sexcral methods whereby butter- 
milk can be and is being commercially reduced in volume. The 
uKjst Common of these are: Removal of water bv gravity, re- 
mo^"al of water ]}\ centrifugal separation, remo\al of water by 
c\aporation, either in \acno ()r under atm(.)si>heric ]>ressure. 

Removal of Whey by Gravity. — Mu.ch of the so-called con- 
densed buttermilk that reaches the market is not the result of 
e\aporation of a [Portion of the water contained in the butter- 
milk, but is produced by permitting the curd to settle by gravity 
and then drawing off and rejecting the whev. 

In this case the fluid buttermilk is ]iumped into a wooden 
tar/k, either a horizontal \at or a \ertical sta\-e tank. The tank 
usually Contains several outlets with gates, located at different 
heights, to facilitate the renioxal of the whey. The tank may 
or may not be e(pii|)ped with steam pipes for heating. The but- 
termilk is heated to boiling point in these tanks either bv blow- 
ing li\e steam into it, or ]>\ running steam through the pipes 
installeil in the bank. This heat is maintained for several hours. 
This causes tlie casein to contract and settle to the bottom in the 
form rif hue particles of curd,, leaving on top a clear whev. This 
whe}' is drawn olT thrrmgh the gates located above the stratum 



Condensed Buttermilk 179 

of curd. Tlie residiie, cim^istiiii,'- larL;el\' nt casein, water and 
some lactic acid and milk suijar. rc|)resents the condensed liutter- 
milk. The concentration, or more crrectly speakini;-, the reduc- 
tion in \c.)lume thu< offered, is at the ratio of about 4 tu .^ parts 
of fluid buttermilk to one |)art of condensed buttermilk. It is 
obvious that in this form of concentration all of the \alual)le food 
elements of the buttermilk are not reclaimed. Most of the milk 
su.cfar and much of the lactic acid escape with the \\he\- and. arc 
lost. Ho\ve\er, the equipment re(piired for this process is ^"er^• 
simple and incx):)ensi\e and the process requires no special 
knowled.tre on the part of the creamer}- personnel. 

Concentration by Centrifugal Separation. — For many years, 
efiforts ha\-e been made t<> remo^■e the w atei froni the buttermilk 
by centrifugal separation. Machines are now on the market and 
in use. in which the curd of the buttermilk collects nu the walls 
of a re\iih'iniL;" basket while the \\he\' is centrifuged out. These 
machines are similar in principle to the well-known laundr}' 
centrifuge. They ha\-e been suci-"essfull\- used \i\ creameries 
that are engaged in the manufacture of buttermilk cheese. Their 
operation. ho-,\-e\'er. is intermittent onlw When the l)asket Idls 
up with the curd, the machine must be sto])ped and the curd 
remo\ed. 

For the purpose of handling large \(ilunies (if buttermilk 
daily, these centrifuges are obviously not \\x-\\ adapted. They 
are too limited in capacity, in speed and in \'i:)hmie of per- 
formance. Efforts to de\ ise a centrifuge for continuous o|)era- 
tion. similar to the cream separator, ha^e so far failed. The spe- 
cific gra\'itv of the curd in the buttermilk is so nearly like that 
of the whey, that the centrifugal separator refuses to discharge 
a liquid rich in curd and one of practically clear \\die_\-. F.xper- 
im-ents bv the author ha\e demonstrated that, no matter how 
the outlets of the discharges are adjusted. l)oth liquids ha^c prac- 
tically the same ccmipi isition. 

Evaporation in Vacuo. — This metlnid for condensing butter- 
milk is rapidly gaining in fa\'or and today \ast xijlumes of but- 
termilk are concentrated in this manner. The equipment used 
and the method of operation are princi|)all}' the same as those 
used in the manufacture of condensed milk and CNaporated 
milk, The buttermilk is condensed in the \-acunm pan. 



180 CoNDiiNSKD l-iu'lTHRMILK 

Equipment Necessaiy to Condense from 5000 to 6000 Pounds 
of Buttermilk per Hour: 

2 wooden l)uttermilk storaj^c tanks, capacity lO.OrX^) pounds 
each, for ripcnint,;" tlie Inittcmiilk ; 

] ()-foot \ acnuni |)an witli condenser; 

1 \acuum |)iini|), \acuum cvlinder IX inches diameter and 
20 inches lont;-; if steam dri\en, steam cylinder, 1_? inches diam- 
eter and 12 inches stroke; 

2 hot wells. 3 feet diameter and .^ feet dee|), with ^ inch nut- 
let in bottom, and equipped with brass heater arran,t;"enicnt. 

Moiler capa'-ity. 150 II. V. 

Water rc(|tiirements. 12,^ ^.'illons per minute. 

OPERATION. 

Ripening of Buttermilk. — 'i'he liuttermilk should he sour, 
the sr)urer the better, liecanse : 

1. The acidity facilitates the process C]f manufacture. The 
curfl in sweet oi- only slijditK soiu" buttermilk is \iscous and 
sticky. It adheres to tile coils and siflcs of the pan and its action 
dnrinL; the condensinj.;' process is sln<;\ifish, retarding e\aporation, 
reducin!^ the capacit}- of the |>an and increasing; the cost of 
manufactnie. 

If the buttermilk is sour, these handicaps are greatly mini- 
mized. Upon subsequent lieatin,^" the curd in the sour buttermilk 
contracts, loses much of its \'iscosity and stickiness, and adheres 
less readil\' to coils and sides of the pan. The sour buttermilk 
is more fluid, boils niore \is^orously and therefore condenses 
more rapidh'. 

2. nii^h acid content is necessary in order to gi\e the con- 
densed buttermilk satisfactory kee])ini.; quality. The hnished 
j)rodnct is not sterile, nor is the temperature at which it is held 
in stora.^e sufficiently low to iidiibit bacterial action and prexent 
decomposition. The acidity is essential to i>reser\e this product. 

,1. lliL;li acid is ad\ antai^cous for feeding puri^oses. The 
;icid in the buttermilk keejjs the fowls, |)if.>;s and hoys in healthy 
condition, and makes them thiisty. They drink more water, 
which is a \alnable .asset for ln'St rcsu.lts. 



CoNDl{NSi;u Bl'TTKRMILK 181 

If tlie Inilterniill; CdiiU'-^ irmu >\\<;el cream hutter or from 
neutralized cream cliiirnini^s, it is usualh' nc>t sufhcieiitl}- sour 
for rea(l\- liandlin;^' and rapid e\ -i])! n-atii in, ]i therefore slioiild 
lie allowed to ripen before it is used. Fur this |nir|)ose it is held 
in wcjiiden stnraLje tanks fur .me i a' nidfe da\s. where it aut'i- 
niatically de\-el(ips acidit)" due In the lactic acid bacteria with 
wdiich it is usually teemint^'. For most satisfacti iry operation the 
buttermilk shduld ]ia\e an acidit\- df approximately f> per cent. 
In scime cases it nia\' be necessary to inoculate it with lactic 
acid starter in urder to in-ure the desired acid dexeb ipment. 

Heating the Buttermilk. — F'rum the ripeniuL', tanks the Init- 
termilk is drawn ur ])umped into the li;it wells, \\here steam is 
turned d.irect intn it until the tem])erature is raised to the l)i-iilin^ 
point. This methiifl <<i heatin,!^" alsn keeps it agitated and pre- 
\'ents the cnpiuus scttliuL;" ol the curd. 

Condensing. — Fr^m the hut wells the boiling-hot buttermilk 
i^ drann intu the wacuum |)a.n. The buttermilk is ])referabl}" 
di-;iwn fr. m the liittuui > if the liui wells, sc.i as ti i ci mtinui aish- 
reimnc :i p.irtiun uf the sftthn:.: curd. The buttermilk will 
(b'Mp snnie I if its curd in the hot \'ells. The n])eratiiin mI the \acu- 
um pan liir buttermilk is tiie saiue as Iit milk. loir general 
directiiins tlie reader i-- referred t" Cdiapter A un "C' ludensini;"." 

'flic first ]ians u^ed lur ci indensinu" knittei'iuilk were tin 
coated nn the inside and ha(l tinned cfi]iper ends, sn as to mini- 
mi.ze the action of the acid un the coppjer. The tin cnatincr \^■as 
of \-ery sliort duration. howe\"er, es))ecialh" that on the coils, so 
that it was found inipiractical and trio costly to use tinned \-ac- 
uum pans. The pans now- m use are not tinned. 

In the condensing" of a thick and slu,t;,g'isli liquid, -uch as 
•Inittermilk. it is of the ,o-reatcst importance that the coil arrancje- 
ment in the \aeuum pan l)e such as to insure maximum circula- 
tion of the milk, utherwise the l.iuttermilk is incapaf)lc to absorb 
the heat fast euijut^ii and ti i expin^e en..iu,i;"h surface to evapora- 
tion, to make possible ra]jid eoncentratii m. the l:)Uttermilk fails 
to freel>- boil up, it slui^x;-i-hly bubliles in the bottom of the pan. 
e\-ai)ciration is slow, the ca]iacit\- of the |)an is L;reatl\- reduced, 
and the cost of manufricture is increased. For detailed descrip- 
tion of the p)roper coil arrangement see Chajner \" on "Descrip- 
tion of A'acuum ran," 



182 CoNni'.Nsicn Buttkrmilk 

During the early stages of the ci mfleiisiiig process the l)nt- 
terniilk hoils and heha\es in tlie ])an in a similar manner as 
milk. As the process continues anil th.e huttermilk increases 
in (lensit\', it becomes more sluggish and does not circulate as 
ra])idly. nor hoil as \igorousl}'. 

Concentration. — The huttermilk should he ccinrlcnscd imtil 
it has a concentration (jf n.t least -I :1. Lluttermilk- of a lo\-i-er con- 
centration fails to ha\'e the necessary kee])ing (|uality to with- 
stand the trials of storage fcir se\-eral months at ordinary tem- 
perature. It undergoes decom])osition, usually of the putrefac- 
ti\'e tvjie, tha.t renders it unfit for feeding" purposes. 

Testing for Density. — No accurate meclianical method of 
determining the exact density of the condensed huttermilk has 
as yet been worked or,t. When a concentration of about 4:1 
or more has been reached, the buttermilk is ^"er^■ thick, e\'en 
\\diile hot. It is too thick and \iscous to permit of testing it 
with the I'learmie h\'drometer. The densit^• could be determiiied 
howexer In" i\-eighing a detiniteh" measured \(ihmie or in- the 
adaption of a resistance tester such as the Mojonnier \iscosi- 
meter. ( )rdinaril)-, however, the determination of the proper 
degree of concentration is left to the experienced e\'e and judg- 
ment of the pan ojicrator. If he condenses batches of uniform 
size, the height ol the surface of the condensed buttermilk in 
the pan furnishes an ajiproximate guide. The behax'ior of the 
boiling condensed buttermilk, when the proper degree of concen- 
tration has been reached, is also noted. .\nd samples taken 
Iri.m the |)an and examined for thickness, standing-u]i properties 
and transi)arencv or opacpieness, as described under "Afethods of 
Striking" for sweetened condensed milk, Cdiapter \'l, enable the 
operator lo ,ap|)roach a fairly uniform neiisitv' of the rtnishcd 
product from liatch to batch. 

A\'hen Condensed a1 the ratio of 4:1 the buttermilk at the 
temperature of the p;'.n, or about liO degrees F.. is thick enough 
so that when a sam])le is taken into :i cui> :inil a ]-)ortion of it 
is picked np with a spoon or stick and is .allowed to drop Iiack 
into the cu]) Irom a height of about six inches, it does not readiK' 
difiuse, but "])iles u|)" on the surface of the sam|)le in the cup. 

Condensing Buttermilk by Film Process. — The condensing 
of buttermilk can be and is accom])lished a.lso b\- lihii exajiora- 



COiNDI-'.NSEl) Bu'l'TKRAULK 183 

tiiin as re])resented hv the "Ci mtinui'ii'- C"i 'iict-iitrati ir" and the 
"Rufl' Ci indeiisiiiL;" E\"ai)i n-atni-." These methrjds liaxe |)i-(i\-eii 
a comniei"ciall\' ])ractica,l iin iixisitii m. Expcnnieiits haxe denmn- 
strated that a cnndeiised luittermilk nf \-er\' L'lind quaht}' and o1 
the desired decree fif ci 'ncentrati^n can lie made 1)_\' the n^e ''<i 
these eontiniKms machines. In fa.ct snnie i it the cundensed but- 
termilk (jn the market is their ])riiduct and it is iirnljahle that 
the future will see many nf these machines installed and in u|)era- 
til in in creameries lor the ]nir])iise uf cuiidensiiiL;" buttermilk. 
See also "CondensinL;" .Milk by the Continuous I'rucess," Chap- 
ter Xl\'. 

Packing. - The condensed buttermilk is tilled into barreks, 
holdiuL'; about 'lOU pound.s nl the linished uroduct. Second hand 
uduciise barrels i ir co|)ra liarrcds are L;enerall\" ti^ed fi ir tliis pur- 
pose. I'lUttermilk intended fi n' bakeries, conlectioners and 
other channels of human consumption, should be filled into new 
barrels. The barrels should be thoroui;1il_\- rinsed and steanieil out 
Ijefore use and it i-- ad\is,able to treat them on the inside with 
sodium silicate. 

'J'he barrels are lilled with the condensed buttermilk wdiile 
hot and direct trom the pan or iither cimdenser. If allowed to 
cool, the condensed Inittermilk would be too thick t< i "run." 

Storage. — The Ixirrels killed with t!ie condensed buttermilk 
are stored at ordin?-r\' ware liouse tcm])erature. If made from 
prriperl}' soured buttermilk, condensed at the ratio ("if imt less 
than 4:1, and if the barrels are Idled completely full and sealed 
tiyiitlw the ])roduct will Iceeii in L;'ood condition, without nmld- 
ine; and \\-ithout appreciable deterioration frir many months 
without artificial refrigeration. 

In remnant barrels or in liarrels which are subsec|Uently 
c>pened and from \vhicli a ])ortion ot the cimteius has been 
remo\-e(k the l)Uttcrmilk molds rai)idl3- on the surface and, spoils, 
because of e.\]iosure to .air. 'kliis can be largeK' ])re\-ented bv 
"slappint;'" a ])iece o| hea\'}' pajier ( wrapjpiiiLi" ])a|)eri, largx 
enou,!^h to coA-er the entire ex])osed surface, mi tlie to]) of the 
remaining;' contents. The condensed i:iutteriiiilk beiiis' cif a ]iastv 
consistency furms a ti,L;ht seal \\itli the ])aper. shutting (,ut the 
air, and retardint^' moldiny and decompositiini. 

The al)o\-e statements concerniiii^' the keeping;' ciualit^- of 



184 ' CV)NI)1';nsi':i> P)nT'n';KiMir,K 

Cl)n(lt'n^f(l Kuttermilk rcU'V niiU' |m the prudiict vcsultini;' from 
e\api irntifin ol a ])(ii'tiiin of tlie water, siieli a.s crindensiiif;' in the 
\aciuini pan, nr l>y the ei mtinnniis ci mccntrators and e\'apfira- 
tors. Where the rediictiiui in \iilnme is aeciMmpli.slied \)y re- 
mo\'ini:; a purtinn of the \\'he\', eitlier h\- L;ra\it\' or bv eentrifu;;'al 
separatiiin, the I'inishcd jirndnet laek.s in Iceei^in,!:;' rpiality, it will 
,spoil in a few weeks after nianufactnre, if held at ordinary teni- 
|)eratnres. The reason fur this lies in the fact that \vith the 
remii\-al of the whe}', the finished pri)duet is also depri\'ed of 
much (if the lactic acid. There is not lii;,;li enotti;1i a percentage of 
acid left in it to preser\-e it. 

Composition of Commercial Condensed Buttermilk, 

Total Solids .30 ])cr cent to 40 per cent 

Water 60 " "64 

Fat 1 ■■ •• 2 

I'rotein 12 " "15 

Milk Su-ar 16 " "20 

Acid 2 " " 3 

Ash 2.S " " 3.5 " 

Caloric A'alue 600 to 700 

Markets. — The .ureat hulk of condensed Imtterniilk manu- 
factured in the L'nited States is sold to chicken feeders and for 
hos feeding;'. 'L'he ])rice oliNaously fluctuates with season, local- 
ity and sujiply and demand. Dnrini;" the first six months of 1<»J0 
it averaged about 4,5 cents ])er ]")onnd, 

Consideralile (piantities of condensed buttermilk are also 
absorbed by bakeries and manufacturers of di\'erse prepared 
food products. The ])i"ice received durini^ the first six months 
of 1620, for Condensed buttermilk" sold to bakeries, etc., aver- 
as^ed about X.5 cents i)er |")oimd. 

Annual Output of Condensed Buttermilk in United States, 
— ;\s pre\ionsly stated the manufacture of contlensed buttermilk 
is rapidly ^rowint;. in l''l!^ the total output amounted to 
6,534 02,3 pounds: in I'UO it was 22,535,580 iwunds. 

CONDENSED WHEY, MYSEOST, OR PRIMOST. 

4'he condensiuL; of wdiey is a pr.actice which orioinated in 
Scandinavia, The original process consisted (jf straining- the 



CoNDKNSI-.I) Bu I TERM ILK 



185 



whey into :i kettle nr lary;e upeii ]iaii nver a lii'f. "The alhiimi- 
noim material that ])recii)itates and rise^ t<i the --iirl'aee is <kini- 
mecl dfi.'"' The whe\' is ex'api irated as rapiclh- as |)()s,silile with 
eonstant antl tlmi-ousT stiri'in^'. When it has reaehed ahemt one- 
fmirtli nf its oriL;'inal x'rjhinie the allnnnin prexii iu>l\" skimmed 
nfF is retnrned and stirred thrirnuuhh' tn lireak up all |)r]s<il)le 
lum|)S. Wdien the whe\- has attained the cnn<istene\' lA tliick- 
ened niilk it is prinred (|uiekh- intii a wrioden trriunh and stirred 
with a paddle nntd ennl, tn present the f(irmatiein of larye sut^ai' 
erystals. It ean then he mnldcd mti' the desired form for 
market. 

A more ra])id metlmd "i makin;^ ]innn)st is tn e\"a|ji ii'ate the 
\\die\- in the \aennm |)an. When the s\ru]i has reaehed the 
desired density it 's drawn oti', allnwed t^ eonl and pressed into 
brieks. 'I'he ])rodnet has a ^•eIll iwish-lirr iwn enkn-. L;'ritt\" textnre 
and sweetish taste. The e\api o-ation rif \\dle^" in \aeni'i is as \-et 
a rare practice aiul the demand fur the fniished inaiduct is \'erv 
limited. 

Exfieriments with the "Ci intnuH >ns C' incentrati ir" ha\"e 
flemrnistrated that condensed ^^■lle^' i if ^rood i]naht\' can readd\' 
be prefiared with this machine. The concentratii in can be car- 
ried as far as 1.^ to 1 ; \\die_\' so cnndensed escai)es fn nn the con- 
centrator still in li(|nid fnrm, bnt chani;es tri a sulid n])iin cool- 
inL;', tlie mill: sno-ar in this supersatnrated sciluti^n crystallizing;' 
com|)letelv If made nf snnr whew the product thus nlitained 
has a splenrlid clean and sharp acid Haxiir. This |ir'idnct ]irnni- 
ises to ha\'e excellent dietetic ]ii-o]iertics. and alsd to lend itself 
admirabh" fur fcMk'in;^- ptn'iioses. 



' United Stale.s Ijepai-tmeiil of Agrlrnlture. Bureau of Animal Indu.str"\'. 
Bulletin No 105. 



PART IV. 
FROM FACTORY TO CONSUMER 

CflAI'TI'R X\'l. 

Stamping. — E\crv well rei^'ulatcd ci hkK'hsihl;' faclory. selling" 
condensed milk in licrmeticalh' sealed tin cans, emphiN'S some 
system of ma.rkiiiL;" the cans. This is important lor future 
reference. 

When delecti\"e condensed milk is returned to the factorv. 
the m;irks on the cans tell the manufacturer the date of manu- 
facture, and his own record on hie in the factor\' shows the coti- 
ditions under wliich the defecti\'e milk was made, in this \va\' 
defects can usualh' l)e traced to their causes and the recurrence 
of similar trouble can l)e a^•oided. 

In some factories the hatches of condensed milk are nnm- 
liered from one up, and the cans are stam]>ed \\ith the res])ecti\c 
hatch number. This method is simi)le l)Ut may pro\ e undesirable, 
since it mlorms the competitors also ol the d:ite ol manuiacture 
of com])elinL; brands. In most factories a code of letters and 
lii^ures is used, desiLj'natini^- the factoj-y, the ilatc, and the number 
oi the batcl; of each da\'. 

The cans arc 
usnall\- stamp- 
ed on the hot 
lorn, that is. on 
the end which 
carries the cap. 
The slampinp- 
done ]->\ the 
seder. S m a 1 1 
intcrclianL'eable 
rubber letters 
and liL;urcs are 
used. The 

slampin;.; i n k 
Flgr. 78. Mojonnlei- evaporated milk can polisher i i i . ■ 

r„uvirsy .Vlojonnirv Bro.s, <•„, should CoutaUl 




I^Aiii'.Lixc Cans 187 

a flrier and be waterproof. In small factories the stani|)in,<,'- is done 
li\- hand. It can be done very rapidh'. In lar.ox- factories an anto- 
niatic stanipini;- uulfu is attached to the filling, sealin.t; or lahelini; 
machine and the cans are stamped automatical!}- while the)' are 
being- filled, sealed or laljelefl. 

Inspecting. — The sealed and stam]ied cans are ]daced. witl-i 
caps doA\-n, in wooden tra}-s holding t\\-ent\--four n-iedium-sized 
cans. All tra\-- of one halcli are stacked together. .\ card in- 
dicatin.g nni-idter and date of batch ai-id nun-iber of cans in the 
batch is attached to the ^tack and a co])\- of the same is likd in 
the office. file cans ar(.' placed with their ca])S down in order to 
detect 'Meakers" (cans w-ith defectn-e seals). fJefore labeling, 
the tra^-,s sjinild 1,^. taken down, the cans turned o\-er and exam- 
inefl for leak^- seals. I nless the iactoi-i- is behind in lilling orders 
the cans will ha\-e been in stock at least t\\-entA--four lirmrs or 
usualh- liinger. In the case o1 s\\ eeteiied condensed nidk. if an\- 
seals are defecti\-e, a little coridensed milk will lia\-e oozed out 
liy that time. 1 nex]jerieiiced sealers are jirone to cause a high 
percentage of leaky cans .\ careful scaler ma\- reduce the num- 
I)er (if leakers to .1 per cent. 

In the case of e\-ai>orated milk I unsweetened, sterilized; i all 
cans coming from the incubating i-oom should he iiidixiduall}- 
shaken b\- hand. All cans showing no signs of bulging, and the 
Contents of \\-hich shake w-ith the characteristic sound and be- 
ha\-ior of a liipiid, iiass inspection. If the ends of the cans are 
bulging or the contents do not rcs])ond to the shaking w-ith the 
characteristic s(-)uiid of normal milk, the}- are rejected, as the 
e\-aporated milk in them has either uiidei-gone gaseous oj- cur- 
dling fermentation, and is spc'iiled. 

LABELING. 

Labeling Machines. — In the earl\- da\ s of the n-iilk condens- 
ing indiistrv, the lalieling rif the cans was done b\' hand, in\-(:il\- 
iiig much time and consideraljle expense. Today, especiall}- con- 
structed lalieling machines are aln-iost exclusixeK- used for this 
purpose. 'Idle efficienc}- and qualit}- rif w-ork of these n-iachines 
are such, that the}- haxe become a permanent fixture in I'lracti- 
callv e\-er^- condenser}- selling canned goods. The labeling ma- 



188 



TvAJiKLiNf, Cans 



chnies ai'c adjustalile to N-anHiis sizt^ nl cans ar.d can Kc (i))er- 
atcd h\' hand, nii'i(ir, ur litdt pdwcr 

Principle of Labeling Machines. — The cans arc f)laced into 
a chute from \vliich thev roll intn the machine by i^i'axdt}'. 'I'lic}' 
are caut^ht h}' two endless belts which dra\\- them through the 
machine 'J'he\^ first pass o\-er re\'i il\ in;:; metal discs that touch 
each can \\'ith a trace of "pick-u|")" cement. I'nim here the can 
rolls o\'er the label talile ^vhich is loaded with a stack fif labels, 
face-down. The touch of '"pick-u])" cement on the cans causes 
each can tn pick up one lahiel, \vhicli is automaticall}' wrapped 




Tig. 79. Burt lateling- machine 

Courte.sy of Burt ]\Jac]iine i"o. 

arcjund the can as it rolls on. An endless belt ])as.sinL;" thriiui;"h 
a paste bnx a])plies a small strip i if ]5aste tn the lap i >f the label 
and a curlinu" md stretches the label taut and L;"!\"es its la]i an 
inward curl, makinc;" it ti) crinform to the shape i >f the can and 
ensuring a perfect seal. 

The label table is ec|uip]")ed with an automatic feedint;- ar- 
ran£;ement which jiushcs the stack of labels up as fast as the 
labels are l)ein,g used. 

Wrinkles and Rust Spots on Labels. — In the latest models 
f)\ labeliiic;' machines un paste tnuches the cans ]iroper. The 
"|)ick-np" cement used mi the cans, is nn iistnre-|iroiif and is 
a|jplie(l hot. This is a great ad\antage from the standpoint of 
ensuring freedom from rust spots on laliels. The cement, being 
applied hut, dries instantl)' and ha\ing ua corriisi\e actinn on the 



pACKiNi, IN Casks 189 

can is a reliai)le safeL(uaril against wrinkle^ ami rust sputs, which 
arc- s<_) prone ic a])|)ear wliere jjastc is used exchisi\cly, and whicli 
mar the attracti\eness and neatness cif the packas^e. The hd)eled 
cans which nnw lea\-e the machine ii\er a chute slantin<^- from it, 
can he cased immechateh' witlinut risk. The use of tal)les and 
fans to dr}- the Lahels, often found necessary in the case of 
mechanicalh' apj^hed pa^Jte. is made superfluous, and time. la1)or 
and space are sa^■ed. 

: .Capacity of Labeling Machines. — fn the kitest im|jro\ed 
t\'pes of lal)elin^' machines tlie ca]")acity has heen greatly in- 
creasctl over that of the riUler models. ( )ne ])rijperly (jperated 
hand-dri\en machine will now lal)el on an a\'erag'e from 40,LHJ<J 
to 50.000 cans and a ])0\ver-dri\-en machine will averaj^e from 
r,0.(JJO to 70,000 cans per ten-hour da_\-, 

PACKING. 

The labeled cans are packed in eases Imldini; from six ti.> 
ninety-six cans, aceordint;' to the size of the cans. ( ( )ne case 
holds six l-<4"allon cans: fortv-eiyht 14-, 1,^-, \(>-. and iO-ounce 
cans; or se\'ent\'-t\\'o to ninet^•-six S-ounce cans. I 

The sides, bottom and top of the eases should be of material 
about three-eighths of an inch to one-half inch thick, the entl.-, 
three-fourths of an inch to se\en-eif;hths of an inch thick. The 
cases are usually Ixi'.ight in the "knock-dcjw n " shape and are 
made up in the factor^-. Six])enn\' cement-coated wire nails are 
most suitable for tliis pur])ose. The cases are most econcjmicall)' 
nailed l)v the use ".)f nailing machines, which nail one entire sitle 
or one side and one end simultaneouslw The cans are usually 
placed into th.e cases direct from the labeling machine. In some 
factories. ])acking machines, which |)ack- twenty-four medium- 
size cans in one operation, are used. F('rmerh' condensed milk 
cans were packed exclusi\eh- in wmiclen cases. Within the last 
few vears the use of paste-board and fibre boxes has been adopted 
in man\' eondenseries. These lioxes are |)r(ning \ery ser\'iceal)lc 
for domestic trade, and prior to the price achance on paper ma- 
terial caused by the world war, the_\' made jiossible a considerable 
saving in the cost of the ])ackage. 

Alechanical can easers, operating with the labeling machine, 
are ni'W a\ailable and are used to ad\antage in man\' condens- 



190 



Packinc, jn Casus 



cries. Tin- can cascr rccei\cs the lal)ele(l cans from the laV)elinj:( 
machine, stacl<s them into laAcrs, places the layers uf cans intci 
tlie case an'l automaticalh' pushes nfT the lllled case, while a 
new la\'er of cans is puslied forward. It is olndons that the 
meclianical can caser makes the work of packinf^' the cans easier 
and accelerates its speed. • 

Marking the Cases. — One end cif each case is stenciled with 
the nnmlier of the Ijatcli ; o\er the other end is pasted a case 
label, re])re^enlin54\ enlarged, the brand i.)f the label on the cans 
within. In tlie place of th.e case label, the respecti\'e brand may 
be ])rinted on or bnrnt into the wood. The bnrnt stenciling is 




Fig'. 80. Burt caser 

Couttes\' of Burt Maeluni' Co. 



usually (lone by the manufacturer of the shooks. ( )ne side cif 
each case is usually marked "Condensed Milk" or " F,\-aporated 
Milk," as the case may be; the other "Keep in cool, dr\- place." 
!f sweetened condensed milk is exposed to excessi\e heat for a 
CI insiderable len.gth ot time. ;is is olten the case in storehouses 
or in the hold of steamers, where the cases m.av be stowed against 
the boiler room, it becomes brown, thickens rapidly ;ind develops 
a stale llaxur. l'',\ apor.'ited milk also darkens when e-\])osed to 
heat and depreci.ates in llavor. It should, therefore. Lie kept in 
a cool place. The humidity <if the storage room has no effect on 
the condensed milk j^rojier, the cans being hermetically sealed. 



Storagk 191 

Prolonged exposure to dampness, ho\\e\-er. ^\■ill dampen and 
wrinkle the labels, rnsi the cans and in\-itc the appearance of 
rust and mold spr)ts. 

Packing Condensed Milk for Export. — In the case nf crm- 
densed milk bought l)y tlie L'nited States Cli iNernment, the cans 
are dipped in a solution of shellac befoi'e the} are labeled, or the 
tin plate or empty cans arc bdught liy the manufacturer already 
lacquered. Cans for export trafle and in man\' instances for tlic 
home market, are wrapped into hea\y, soft ])aper, l)earing mi the 
outside a ccipy of the respecti\'e brand. This \\Tap])ing pa]>cr 
takes up the space beetween the cans and i)re\ents the cans 
from being" damaged on tlieir lung JMurney and liy rdugh usage. 
This wrapping is usually done by hand. Some makes of label- 
ing machines, ho\\e\er. ha\e an attachment for wrapping the 
cans so that when the cans lea\c the machine they are \\rapped 
as well as lalieled. The cases are reinforced writh a band <>i strap 
iron around eacli end, \\'here the cases ha\e to l)c loaded and 
unloaded numerous times, a^ is the case with exjjort shipments, 
thev are in danger of being torn to pieces, unless such special 
precautions arc taken. 

CllAl'TKR XMI. 

STORAGE. 

Purpose of Storing, — The purpose of storing condensed milk 
is largely the same as that of storing butter and other produce. 
namelv, to keep the jiroduct from the time of large ■-u])pl}' and 
low prices. t<.i the time of small supply and high prices. In sum- 
mer time, the market is usually Hooded with condensed milk 
throughout the cotmtry, the demaml fcir it i^ at ebl) tide and the 
prices are low. In winter, there i^ usu.alh- a great shortage of 
condensed milk, the dem;nid far exceeds the suppK' and iiriccs 
soar high. The storing of simimer milk ma}' be neces:~ar}-, also, 
in order to enalde the manufacturer to (ill his contracts and su])- 
plv his trade in winter. This is especially true where the fac- 
tories of a concern are located in new territories where the ])a- 
trons produce an excessi\'el\- small amount of winter milk. 

F'lain condensed milk and ccmcetitrated milk which are not 
sterile and contain no cane sugar to prc-erxe them, keep but a 



192 Storage 

lew il;n s at (jr(l!nar\' temperatures and should, therefore, be sokl 
and u^ed as scxm as jxissihle after manufacture. If their storag;e 
is una\"oidahle, the\- shmild he liekl as near the freezint,^ point 
as ]i(issible. F(ir pri)l(>nL;ed stnrage it mi^lit l)e ad\antat;eous tn 
freeze them. Tlowexer. relial)le data nn tliis phase nf the indus- 
try are L^ckinlL,^ 

Mxajioratefl milk, scild in hermetically sealed cans, is sup- 
)i(ised to he entireh- ^terile, and. if made ])rii|)erl}-, will keep in- 
definitely, There is a constant tendeuc}', hi)\ve\er, for the fat 
to sc|)ai'ate nut. which naturally is au,L,mi,ented hy prolonf^ed 
stora,i,re. Ap;ain, the lactic acid in the e\a])(irated milk gradually 
acts on the can. causini.;" the tin]ilate to hecome dull and the 
Contents to acquire a disagreeable metallic fla\or. When stored 
for an excessi\elv long time this chemical action may be suffi- 
cient to cause the e\olution of considerable (|uantities of hydro- 
gen gas. swelling" the cans, 

v^weetened cmidensed milk which is ])reser\ed b}" about 40 
per cent of sucrose, will kee]) a]iparcntly unchanged for a con- 
siderable length of time. It is best, ho\ve\ er, when fresh. Bac- 
teriological examinations ha\e ^Imwu that, while moderate age 
does not change the outward ai)pearance of this condensed milk, 
the bacteria in it gradually increase and the milk gradually de- 
velops a stale tla\-or, \\'liite and yelh.iw "buttons, ' lump-;, or 
nodules of a cheesy texture and fla\'or, due to fimgus growth. 
are alsc) |.)rone to appear in the condensed milk. -\ge, also, causes 
it to become darker in cob jr. These defects arc especially aji- 
parcnt in old milk which has not been kept at a low temperature. 
.Xi^ain, sweetened condensed luilk mafic in Ala\' and lune has a 
strong tendenc}- to thicken with age and to become entircl}' solid. 

In sonic cases a part of the sweetened condensed mi'k made 
during the >ummer months is stored in larg;c c\ lindrical wooden 
or iron tanks sunk' into the ground, or installed in the basement 
of the factor\', where the comU'iised milk remains at an c\en tem- 
peratiu'e. .\s the demand lor the ])roducl increases and the 
suppK' III Iresli milk decrea.ses. condensed milk is drawn from 
the-se tanks to lill the increasing orders. 

Effect of Storage Temperature.-- -Most, if not all the changes 
which condensed milk is ])rone to undergo in storage are retarded. 
if not entirelx' prevented, w^hen stored at the pro]>cr temperature. 



Storage 193 

Temperatures of 60 degrees F. or above are too high for satis- 
factory storage for a prolonged period of time and the higher 
the temperature the greater the resulting defect. 

Temperatures helow the freezing point of water are also 
undesiral)le. The e\-aiJorated milk freezes and while so doing it 
expands sufficiently to s\\'ell the cans. Although this swelling 
disappears when the contents cjf the cans dissoh-e again, yet 
the swelling action tends to weaken the cans and ma}' give rise 
ti3 subsefjuent leakers. Again, the melted e^■aporated milk is 
prone to be grainy as the result <>i freezing. This is due to the 
fact that when freezing, the \\ater\' pcrtinn separates from the 
curd and the latter contracts. When the milk thaws up the curd 
remains contracted and fails to form a smooth emulsir]n with 
the remainder of the milk. 

The sweetened condensed milk does nut freeze, because it 
contains so concentrated a sugar solution that its freezing point 
is usually far belo\^• the refrigerating temperature. If it is packerl 
in solder-sealed cans there is usually nn bad eiiect from cold 
storage. However, wdien packed in cans sealed with the frictiijn 
cap or the burr cap, difficulties may arise. These seals are not 
air-tight. Excessi\-ely l':i\v storage temperatm-es cause the con- 
tents to shrink appreciably. Suction is farmed and air is drawn 
in througdi the seal. When these cans again warm up, the vis- 
cous milk in the cans seals the microsco|)ic openings, the air and 
the liquid expand but the air finds no exit. This causes the cans 
to swell. While the ("|uality of the milk in these cans is not im- 
paired in the least, the swelled cans suggest gaseous fermenta- 
tion, \\'hich means spoiled milk and which is invarial)ly rejected 
on the market. 

The temperature-- at which condensed milk can be stored 
with least objectinnable results, range between 32 and 50 de- 
grees F. 

Advisability of Storing. — A hea\y st(jck of condensed milk 
is a severe drain on the \vi irking capital of the condenserv, in- 
volving the cost of the fresh milk, cane sugar, tinplate, boxes, 
solder, labels, coal and labor. 

Unless the manufacturer has successfullv overcome and 
mastered all of the principal condensed milk defects, and, unless 
his experience justifies him in belie^-ing that his goods will stand 



194 Markets 

the trials of storage, lie Avill find it advisable not to manufacture 
more than he can promptly dispose of. E\'en at best, the con- 
densed milk will be from three to six months old before it is all 
consumied, and, if it is at all suliject to deterioration, the sooner 
it is consumed the better. 

TRANSPORTATION. 

The i)l;iin condensed Inilk milk and crmcentrated milk are 
highly perishable products. If shipped considerable distances 
they should be placed in refrigerator cars. 

The evaporated milk and sweetened condensed milk in her- 
metically sealed cans, and the latter also in barrels, can safely 
be shipped in ordinary- box cars. The cases weigh from fifty 
to six-five pounds, and the barrels from three hundred to seven 
hundred pounds. Care should be taken that the cars used for 
this purpose are clean and did not previously carry goods with 
strong and obnoxious odors, such as fertilizers, as these odors 
are prone to follow the condensed milk to its destination. Strong 
box cars, in good repair only, should be used. Even at best, 
the cases and cans sufter more or less damage in transportation. 
Cars w'ith leaky roofs should be condemned, as transportation in 
them may cause the package to suffer in appearance. If shipped 
on steamboats, it should be specified to stow the cases away from 
the boiler room, as prolonged exposure to high temperatures 
causes the condensed milk to deteriorate. 

Chaptkk XVIII. 

MARKETS. 

A large proportion of the cantied condensed milk, both 
sweetened and unsweetened, supplies localities, territories and 
countries where the dairy industry is yet in its infancy, or 
where geographic and climatic conditions bar the profitable 
husbandry of the dairy cow. Thus, we find some of the best 
condensed milk markets in the tropics, in the arctic regions, in 
the army and navy, on ocean liners and in mining and lumber 
camps. In these markets condensed milk has, in many cases, 
become as great a necessity as fresh milk is to the inhabitants 
w'ithin the temperate zone. The wastage and the decreased 



Markets 



i95 



productic'ii nf diA-erse food products caused l)y the war has 
opened \'ast new markets for, and has caused the demand and 
consumption of condensed milk to grow by leaps and bounds. 
The consumption of canned condensed milk in our home markets 
has, also, been increasing rapidly xvithin recent years, and is 
toda}' assuming astonishing proportions. This increase has oc- 
curred, in ])art at least, at the expense of the consumption of 
fluid milk. Wdiile conclusi\-e 'statistics on this subject are not 
available, the trend toward larger rlomestic cijnsumption of con- 
densed milk accompanied by decreased consumption of fluid milk- 
is suggested in the following taldes, in wd'-dch I'rof. J. O. Jordan,^ 
President of the Internatirmal Assf^cintirMi of Dairy and Milk 
Inspectors, shows the situation in the city of Boston, ^lass. : 



Consumption of Condensed Milk in Boston, Mass. 





Cases 


of Condensed Milk by Tears 


Source of Stati-stics 


1916 
Cases 


1917 
Cases 


1918 
Cases 


1919 • 
Cases 


Business of a firm 
operating chain 
stores 

Receipts according 
to records of Board 
of Trade 


.30.500 
762,446 


52,700 
880,072 


76,500 
1,237,647 


77,000 
1,647,264 



Daily Consumption of Fluid Milk in Boston, Mass. 



Tear 


Quarts of Milk 
actually c o n - 
sumed daily 


Quarts of Milk 
which should 
have been con- 
sumed dally, 
based on esti- 
mated riopulation 
and quarts used 
in 1916 by esti- 
mate d popula- 
tion 


Estimated 
Population 


1916 . 


347,735 
342,244 
342,451 
333,506 


353,209 
358,617 
364,157 


760,400 
772,370 
784 340 


1917 

1018 


1<)19 * 


796,310 



1 Jordan, Address, Eighth Annual Convention International Association 
Dairy and Milk Inspectors, 1919. 

• 1919 flg-ures are for ten months only. 



196 Marki{ts 

The rapid g'r<j\vtli of the ice cream iiidustr)- has further 
developed a s|)lendid and e\'er-increasin£;- market for plain con- 
densed bulk milk. Additional impetus has l)een lent this devel- 
opment since the advent of natir)na! prohibition, which caused 
a vast increase in the Cdusumption nf ice cream and of soft 
drinks of which ice cream coiistitutes an integral part. Manu- 
facturers of condensed milk estimate that this has resulted in 
an increase of their production of plain condensed bulk milk- 
amounting to from 13 to 20 per cent. 

Market Prices of Condensed Milk. — The price of condensed 
milk is not controlled by the general market of dairy f)roducts, 
nor by any board of trade ; there is no consistent uniformity of 
price throughout the country as is the case of l)utter and cheese. 
The price of condensed milk does not necessarily follow the 
rise and fall of the butter and cheese markets, but in the long 
run it is usually affected by alirupt fluctuations of prices of these 
other dairy products, largeh' on account of the influence of such 
fluctuations on the supph- to the condensery of fresh milk. It 
is chiefly go\-erned by local conditions of supply and demand, 
conposition of product and reputation of the individual brand. 
Condensed milk is sold under hundreds ai different brands or 
labels. "W'hile one and the same concern may sell scores of 
different brands, the brand itself has \'er}- little, if anything, to 
do with the <]uality or comp)osition of the contents of the can. 
Each brand usually sells at its own special ]irice, although the 
\'arious brands put on the market b\' the same concern often 
contain the same qualitv of milk and ma}' be filled with con- 
densed milk from one and the same batch. It is customary in 
most factories to fill the cans before they are labeled and the 
orders for different brands of condensed milk are filled from 
the same general stock. The biands ser\e largeh' as an in- 
strument to inci'case the sales and "dodge" competitors. 

Sweetened condensed milk. ])acke(l in hermetically sealed 
cans, sells from about v$,x2.3 to $.3 ])er case of 48 sixteen-ounce 
cans and the cans retail at froiu .^ to 20 cents each, according 
to the size of the cans and market conditi<ins. 

Evaporated milk, unsweetened condensed milk in hermetic- 
ally sealed cans, sells from $2.25 to $4.00 per case, according tq 
the size of the cans and market conditions. 



Markets 197 

l^jiilk milk, l)otlr sweetened and unsweetened, K'^es direct 
from the manufacturer tn the purchaser who ))uys it at prices 
ap-reed upon by the ci mtractinf^- ])arties. The sweetened con- 
densed milk is sold in barrels JKildiiio froni three hundred to 
seven hundred ])ounds (usually about six hundred pounds') to 
cand}- and caramel factories, bakeries and confectioners. The 
price \aries from four to ten cents per pound according- to the 
per cent ()f fat, demand and supplv. AMien there is a j^reneral 
"epidemic" of bad canned condensed milk, this spoiled con- 
densed milk is usually turned into candy shops and bakeries, 
where it is si>ld for "a soni.,'"." This condition has always a 
clepressino' influence nn the ])rice of sweetened condensed bulk 
milk, which, durin;.;" such seasons, nia\- haxe to be suld at a loss. 
Some milk cinidensing' concerns operate their own candy shops 
A\diich take care of the condensed milk that is rejected on the 
market. 

Plain or unsweetened condensed milk is sold in 1-gallon to 
lO-gallon cans to ice cream factories, the jjrice ^•arying from 
twent}'-five to ninety cents per gallon, according" to fat content, 
concentration and market conditions The market for this class 
of goods is not \cry constant, but the profits are generally hig-h. 
It reaches ebbtide in winter when the demand for ice cream is 
small. Limited quantities of plain condensed bulk milk are also 
S(jld in milk and cream bottles for direct consumption. The 
concentrated milk finds the same markets as the plain con- 
densed bulk milk. 

The abo\e range of prices of the se\-eral types of condensed 
milk refers to the market conditions \\diich prevailed while the 
industrv A\as protected against competition with goods from 
abroad by an import tariff of 2c per pound or $1.00 per case of 
condensed milk, and to conditions prior to the advent of the 
European war in 1914. 

In 1913, the United States, by Act of Congress, removed 
the import tariff', ]:)lacing condensed milk on the free list. This 
Act became effective in the fall of the same year. Its immediate 
effect was a rapid increase in the importation of European con- 
densed milk, wdiich \\as offered for sale at relati\'ely low prices. 



198 Markets 

decreased the sale i>f domestic f;<iods and caused the holdings of 
condensed milk to accumulate in large quantities. Condensed 
milk prices depreciated rapidly throughout 1''14 and reached 
the bottom in the fall of that year when financial limitations 
compelled manv concerns to mo\e their goods at any price. At 
that time the bottom prices of condensed milk were approxi- 
mately as follows : 

Sweetened condensed milk per case $2..iO 

Evaporated milk per case 1.90 

The losses suffered by this slump in the condensed milk 
market, caused l)v the influx of cheap foreign goods in the 
absence of a protective tariff, were enormous and caused bank- 
ruptcy of numerous of the financially limited concerns. The 
outlook for the future of the industry looked ^•ery uninviting 
at best, but the situation was sa\ed and market conditions 
reversed by ^-he urgent food requirements of tlie Allied nations 
in the European war, and after the entrance of the United States 
into the \\ar, by large orders for the American army and navy. 

The extraordinary and very urgent demand for condensed 
milk by the U. S. Go^'ernment and by its allies during the war 
and the enormous demiind for exports to Europe after the 
armistice, boosted the prices of this product to a level not 
attained since the Civil ^^'ar. While Government regulations 
tended to hold price advances within reasonable liounds and 
while lack of shipping facilities and other factors caused tem- 
porar)- fluctuations downward, the price advance in general con- 
tinued until the spring of 1''19, and readied the follo\\''ing maxi- 
mum figures per case : 

Sweetened condensed milk per case $9.25 

Evaporated milk, per case 6.50 

Exports and Imports. — Canned condensed milk only need 
be considered here. 

The United States liureau of Statistics reports the following 
imports and exports of condensed nxilk for the years 1911 to 
1919, inclusive : 



Exports and Imports 199- 

Exports and Imports of Condensed Milk and Evaporated Milk 
for the Years 1911 to 1919, inclusive.' 

Exports Impfirts 



i^ears 


Pounds 


Dollars 


Pounds 


Dollars 


1911 


12,180,445 


936,105 


630,308 


46.088 


1912 


20,642,/38 


1,651,870 


698,176 


61,671 


1913 


16,525,918 


1 ,432,848 


1 ,778,044 


135,724 


1914 


16,209,a^2 


1,341.140 


14.500.3,^0 


1 ,089,440 


1915 


37,235,627 


3,066,642 


33,624,180 


2,5.56,787 


1916 


159,577,620 


12,712,952 


18,174,505 


1,515,354 


1917 


259,102,213 


25, 12<),083 


18,375,608 


1 ,746,446 


1918 


553,439,554 


— 


29,926,931 


— 


1919 


852,275,264 


— 


16,509,2,30 


— 



Prior to 1914 the L'nited States exported cnndensed milk 
chiefly to Xorth America, Oceanica and Asia, small quantities 
were also exported to South America. Africa and Europe. .Alxiut 
60 per cent of all the export condensed milk went to cmmtries 
of the North American drntinent. Canada and Panama beinc; 
the leadinj:,'' markets. Durino- the la^t few years, immediate!}' 
preceding' the world war, our expcjrts t<:i Canada had fallen off 
very rapidly. In 1911 the exports to Canada amounted to onh' 
about 15 per cent of the total e.xports of condensed milk to the 
same country in 1908. The rapid development of the milk con- 
densing industry iii Canada, within the last decade was larijelv 
responsible for this situation. From 1907 to PHI there was an 
annual decrease in the total exports of the L'nited States. In 
1907 they amounted to $2,191,000.00 as a-ainst $036,105.00 in 
1911. 

Prior to 1913, the imports of condensed milk intc> the United 
States were likewise very limited. This was largely due to the 
protective tariff on imported goods, which was an eft'ective agent 
to exclude foreign brands from American markets. 

In the fall of 1913, Condensed Milk was placed on the "free 
list." This resulted in an immediate and rapidly growing in- 
flux of condensed milk from European countries, such as Switzer- 
land, Denmark, Holland, Sweden, Norway, Germany and Eng- 



» United states Department of Commerce and Labor, Bureau of StatlstloB 
for 1911 to 1919, 



200 Chijmical Composition 

land. At first the bulk of the influx consisted nf sweetened con- 
densed milk, but later e\'aporated milk also arrived in increas- 
ingly large quantities- causing ha^■oc in imr dumestic markets, 
and an almost unprecedented depression in the industry in the 
F'all of 1914. At the same time, the exports further decreased 
and ceased almost entire!)'. 

In 1915 the fo(jd shortage in the allied countries and their 
need of condensed milk f(ir their armies and na\'ies began to 
counteract the effect of the remo\-al of tlie protective tariff. 
Imports decreased while large and repeated contracts for exports 
to the Allies brought about an unprecedented growth of our 
export trade of condensed milk at attractive prices. Our exports 
were further increased by the fact that the war deprived non- 
combatant countries in South America, Asia and Africa of their 
usual imports of this commodity from the then warring coun- 
tries, opening up the world markets to the United States. 

The exports continued to increase after the armistice was 
declared, the \-olnme exported l)eing limited largely only hv the 
shortage of transatlantic transportation facilities. After the first 
six months of 1919 the increasingly unfavorable rate of exchange 
of foreign moneys commenced to make itself felt and since then 
there has been a steady decline in exports. Early in 1920 iso- 
lated shipments of condensed milk began to arri\e in this coun- 
try, foreign manufacturers being attracted by and taking advan- 
tage of the high exchange \alue of the American dollar, our high 
domestic prices and the absence of tariff' on condensed milk 
imported into the United States. 

ClIAPTKR XIX. 

CHEMICAL COMPOSITION AND STANDARDS OF 
CONDENSED MILK. 

Sweetened Condensed Milk. — Sweetened cnndensed milk 
contains all the constituents of fresh milk and considerable but 
varying quantities of sucrose. Its composition, therefore, de- 
pends on such factors as : composition of the fresh milk from 
which it is made: the degree of condensation and ])er cent, of 
cane sugar added. .As all of these factors xary in milk from 
Hiff'erent localities, and in milk of the same factorv at dift'erent 



CHKiiiCAL Composition 201 

seasons of the year, no hard and fast rule can he g-iven. The 
following- figures mereh' show the a\-erage composition of sweet- 
ened condensed milk as obtained from the results of analyses of 
a large number of different brands. 

Average Composition of Sweetened Condensed Milk. 

Water 26.5 per cent. 

r fat 9.0 per cent. ^ 

■vr-,, ,. 1 J pi'"teids 8..T i)er cent. i -, ^ 

-Mdk solids < ' ' ^ 3_'.6 per cent. 

1 milk sugar 13.3 per cent. ( 

L ash 1.8 per cent. J 

Cane sugar 40.9 per cent. 

Total 100.0 per cent. 

Water. — The water content is largely go\erned by the de- 
gree of condensation and the per cent, of cane sugar. American 
brands a\erage from 24 per cent, ti ) 2S per cent, water. In e.x- 
ceptional cases milk has been found to cc/iitain as low as 21 per 
cent, and as high as 34 per cent, water. 

Milk Solids. — Tlie |)er cent, nf milk solids is largely gov- 
erned b}- the per cent, of milk solids in fresh milk and the degree 
of condensation. In the majurity of brands the solids fluctuate 
between 28 and 34 per cent. ; in extreme cases analyses have 
shown less than 28 per cent, and as high as 40 per cent, milk 
solids. The relatixe prdportimi in which the \arious solid con- 
stituents are present is the same as that in the fresh milk from 
which the cimdensed milk is made, pru\-ided that the fresh milk 
was not skimmed pre\'i<>us to condensing. 

The fact that the l\ S. standard requires not less than 28 
per cent, milk solids and the intr(")duction of perfected methods of 
standardizing ha\e an unniistakal>le tendency toward keeping 
the percentage of milk srdids down to 28 per cent. 

Butter Fat. — The butter fat in sweetened condensed whole 
milk fluctuates from about 8 ti : 12 per cent., according to locality, 
season of year and degree of condensation. Sweetened con- 
densed milk sold in barrels is usually partly or wholly skimmed 
and is, therefore, low in fat. It has been su.ggested that a small 
portion of the milk fat is lost during the process of condensation. 



202 ChI'Mical Composition 

and this theory is frei|ui;ntl_v resorted to by condensed milk men 
to explain why their milk is low in fat. It has been claimed by 
some that the volatile fats (\-olatile fatty acids) are lost during 
the ])rocess of condensation. This claim is not well founded, 
since repeated experiments' ha\e ciinclusi\ely demonstrated that 
condensed milk contains the normal amount of volatile fatty 
acids. It has further been experimentally proven that the con- 
densed milk, when made properh' and from whole milk, contains 
fat equal in amount to that found in the fresh milk used. A 
reasonable allowance should be made, however, for loss of milk 
due to spilling- and wasting in pipes and retainers. Experience 
has shown that this loss amounts to al)out fifty to one hundred 
pounds of milk per average batch under normal conditions. 

Proteids. — The per cent, of proteids in the condensed milk 
varies with the per cent, of proteids in the original milk and 
the degree of concentration. It fluctuates usually between 7.5 
and 9 per cent. The heating previous to condensing coagu- 
lates a portion of the milk albumin and alters the casein to the 
extent that it is not precipitated in the normal way, when rennet 
is added to the diluted condensed milk. 

While, in most analyses of sweetened condensed milk, the 
per cent, of proteids nearly equals that found in the fresh milk 
multiplied by the degree of concentration, there is a tendency 
toward a slight loss of this constituent due to precipitation in 
the forewarmers. 

Milk Sugar. — Sweetened condensed milk contains from 
about 12.5 to 15 [)er cent, of milk sugar, the amount varying 
according to the degree of concentratinn and per cent, of milk 
sugar in the fresh milk. The milk sugar is not known to undergo 
any material changes as the result of the condensing process. If 
condensed milk is recondensed, it assumes a darker color which 
is largely due to the caramelizing of a part of the milk sugar, 
caused by the action of prolonged exj)osure to heat. The milk 
'sugar in condensed milk crystallizes \-ery readily and causes the 
condensed milk to lieconic sandy and settled. Chemical anal- 
yses of tliis sugar sediment show that it consists principally 
of milk sugar. The primary cause of this property lies in the 



' Hunzlker and SpUzer, Indiana Agricultural Experiment Station Bulletin 
No. 134. 1909, 



Chemical Composition 203 

fact that sweetened condensed milk contains so little water 
(about 26.5 per cent.) that the milk siitjar is present in the form 
of a supersaturated solution ; therefore, any condition which 
favors sugar cr3'stallization will tend to produce this defect.^ 
Milk sugar requires from five to six times its weight of water 
at ordinary temperatures for complete solution. In sweetened 
condensed milk the milk sugar has access to only about twice 
its weight of water (12.3 to 15 per cent, lactose to 25 to 27 per 
cent, water). 

Ash. — The per cent, of ash is largely dependent on the 
degree of condensation. It usually x'aries from 1.5 to 2 per cent. 
It is (juite constant in fresh milk (normal fresh milk contains 
uniformly about .7 per cent. ash). The per cent, of ash in 
sweetened condensed milk may serve, therefore, as a reason-; 
ably reliable factor in determining the degree of condensation. 
The heating of milk, before condensing, precipitates and renders 
insoluble a portion of the mineral solids, principally the lime 
salts. 

Sucrose. — The purpose of the presence of sucrose in this 
product is to ])reser\'e it. Most i)f the sweetened condensed 
milk on the market contains from vV to 44 per cent, sucrose, or 
cane sugar. A\'ider variations, howe\'er. are nut infrequent. In 
some cases analyses showed as low as 30 per cent, and in others 
as high as 48 per cent, cane sugar. Cane sugar dissolves in one 
half its weight of water, so that under normal conditions there 
is sufficient water in the condensed milk to keep the sucrose in 
solution. The amount of sucrose in milk does not appreciably 
afifect the power of the milk to dissoh-e milk sugar, nor does 
the per cent, of lactose present materially affect the power of the 
milk to dissolve sucrose. 

\\'hen the SA\eetened condensed milk has a concentration 
of about 2.5:1, the manufacturer usually aims to have it contain 
about 40 per cent, sucrose. \\'hen it is condensed sufficiently 
only to contain 28 per cent, milk solids it is necessary to add 
sufficient sucrose to bring the percentage of sucrose up to aliout 
44, in order to insure the necessary keeping qualit\'. 



• For further details on causes of settled sweetened condensed milk see 
Chapter XXII. 



204 



CnitMICAL CoMrOSlTlON 



Specific Gravity. — 'Tlic spccilic i^'ra\ity oi sweetened con- 
densed milk falls within the limits nf 1.24 to 1.35. Foreign 
brands averag-e snmewhat higher in specihc gravity than Amer- 
ican brands. The specihc gra\ity i)f sweelcnefl condensed milk is 
controlled by the degree of condensation, the per cent, of fat and 
the per cent, of cane sngar. Milk condensed at the ratio of about 
2.3 parts of fresh milk to 1 c|uart nf condensed milk and contain- 
ing about 9 per cent, fat and 40 per cent, cane sugar, has a speci- 
fic gravity of al)0ut from 1.28 to 1.20. 'J'he specific gra\-ity of 
sweetened condensed skim milk may go as high as l.,33, and, if it 
contains an excess of cane sugar, it may be still higher. 

Chemical Analyses of Sweetened Condensed Milk of Eighteen 
Different Brands. 



Brand 



Milk 
solids 

per 
cent. 



Water 

per 

eeat. 



1 "Silver Spoon" 
Hlre^ Condensed Milk Oo 

2 "Eagle" 
Borden's Condensed Milk Co 

" "Reindeer" 
Truro dondensSd Milk Co 

s "Tip Top" 
Bordens' Condensed Milk Co 

' "Challenge" 
Borden's Condensed Milk Co. 

2 "Siveet Clover" 
Mohawk Condensed Milk Co 

3 "A^-row" 
Wisconsin Condensed Milk Co 

' "Blue Bell" 

American Condensed Milk Co\ 

" "Red Cross" 

Mohawk Condensed Milk Co 

3 "Rose" 
Borden's. Condensed Milk Co._...- 
3 "Magnolia" 

Borden's Condensed MUk Co 

» "Rustic" 

Michigan Condensed Milk Co 

" "MlUt Maid" 
Anglo-Swiss Condensed Milk Co. 
■: "Jubilee" 

The Manitoba Dairy Oo. 

' "Export" 
Baldwin Condensed Milk Co..i--_ 
a "Owl" 

CanSda JMIlk Condensing Oo 

" "Nestle" 

mtiiy Nestle 

' "Upper Ten" 
v. 8. Condensed Milk Co ._ 



31,90 
31.^08 
31.23 
36.5V 
31.74 
32.84 
31.1.5 
35.56 
34,78 
30.82 
.31.98 
.30.00 
35.69 
29.40 
,32.24 
31.61 
32.91 
33.65 



28.68 
25.99 
27.33 
21.67 
24.84 
24.07 
26.83 
26.50 
27.14 
24.76 
26.32 
27.63 
25.65 
32.15 
26.69 
30.84 
28.04 
27.88 



Fat 
per 

cent. 



Pro- 


Lac- 


teids 


tose 


per 


per. 


cent. 


cent. 



Ash 


Sucrose 


per 


per 


cent. 


cent. 



8.40 
8.72 
9.56 

10.07 
8.23 
9.31 
8. CO 
9.31 

il.07 
8.88 
8.64 
8.611 
9.6.-. 
9.62 

11.60 

10.61 
8.06 
8.80 



9.12 


12.56 


1.91 


40.38 


8.15 


12.35 


1.83 


42. 9S 


8.32 


13.42 


1.80 


4144 


9.35 


15.00 


2.15 


41.75 


8.67 


13. (.2 


1.92 


43.42 


8.71 


12,96 


1.87 


43.09 


8.49 


12.87 


1.79 


42.02 


9.50 


14.80 


1.95 


37.91 


7,92 


14. C? 


1.76, 


38. M 


8.03 


12.07 


1.81 


42 97 


7.84 


13.60 


2.00 


42 00 


7.07 


12. «0 


1.73 


41.00 


8.78 


15.17 


2.09 


38.68 


8. CI 


11.. 30 


1.85 


J3.45 


8 60 


12.36 


1.80 


41.07 


8.47 


12.40 


1.81 


37.55 


7.68 


16.28 


1.94 


39.05 


8.34 


14.66 


1.85 


38 47 



^ Spitzer. Indiana Agricultural Experiment Station, 1910. 
^ McGill, Inland Rev. Dept., Ottawa. Bulletin No. 144. 1908. 
' Cochran, Special Report of Analysis of Condensed Milk.s and Infants' 
Foods, Pennsylvania Dopt. of Agriculture, 1905. 



Chemical Composition 



205 



Evaporated Milk. — The same factors which control the 
chemical composition of sweetened condensed milk, also govern 
that of the unsweetened product, with the exxeption that the 
cane sugar is absent. 

The following figures represent, in njund numbers, the 
average composition of evaporated milk as obtained from anal- 
yses of a large number of American Ijrands. 



Average Composition of Evaporated Milk 



\A^ater 



Milk solids 



fat 

proteids 
lactose 
ash 



8.3 per cent. 

7.5 per cent. 

9.7 per cent. 

1.5 per cent. 



75 per cent. 
27 per cent. 



100 per cent. 



The chemical and piiysical properties nf the \-aririus ingre- 
dients in unsweetened cfjndensed milk are affected to a greater 
extent than in the case of s\\eetened condensed milk. This is 
largely due to exposure uf the evaporated milk to high tempera- 
tures in the sterilizer. 

Water and Solids are go\ erned Ijy the degree of concentra- 
tion and the relati\e per cent, of the same constituents in the 
fresh milk. The per cent, ni solids admissible in evaporated milk 
is largely dependent on the chemical and physical properties of 
the milk and the sterilizing temperatures employed. Excess 
in solids in this product jeopardizes its marketable properties, 
owing to the tendency of the proteids to form hard lumps of 
curd during the sterilizing process. Exaporated milk \-ery low 
in solids tends toward the separation of its butter fat in storage. 
Analyses show a range of from 23 to 31 per cent, solids. Since 
the per cent, of solids necessary and possible to be contained in 
marketable evajjorated milk, largely depends on the properties 
of milk, and, since these proj)erties again are principally con- 
trolled by localit}-, season of year, crop, feed and weather con- 
ditions and the quality of the fresh milk, the solids in milk from 
any gi\'en seasijn of the year may vary \-ery considerably. In 
some localities and at certain times of the ^-car the best result? 
may be obtained with ewaporated milk containing 2S per cent 



206 



Chkmical Composition 



solids. In other localities it may be difficult at certain seasons 
of the year, to incorporate more than 24 per cent, solids without 
injuring or destroying' the marketable properties of the product.' 

Butter Fat. — The fat varies ^^■itll the per cent, of fat in the 
fresh milk and with the degree of concentration. No fat is lost 
during the process of condensing and sterilizing.- It has been 
claimed by some that in the process of manufacture, the volatile 
fatty acids escape and that the e\-aporated milk therefore con- 
tains less fat than the fresh milk from which it is made, times 
the degree of concentration. If this were true the loss of fat in 
the evaporated milk would not exceed .25 of 1 per cent. Rut 
analyses show that the fat in the e\'a])orated milk is entirely 
normal in composition and contains the same proportion of 
volatile fatty acids as the fat in the fresh milk. 

The Composition of Milk Fats in Evaporated Milk.- 



Date of 

Manufacture 



August, 1908... 
November, 1908. 



Relchert 
Melssl 
Number 



28.48 
29.52 



lodlna 
Number 



33.64 
33.60 



Melting Point of 
Mbced Fata 



33.3 degrees C. 

33.4 degrees C. 



Melting Point of 

Insoluble Fatty 

Acids 



41.0 degrees C. 
41.2 degrees C. 



In the evaporated milk there is a strong tendency for the 
fat to separate out during storage and to churn in transportation. 
This is largely avoided by the proper adjustment of the steriliz- 
ing process and by use of the homogenizer. 

Proteids. — ^The proteids vary with the per cent, nf total 
proteids in the fresh milk and the degree of concentration. 
Similar to the case of sweetened condensed milk, there is a tcn- 
denc}^ of a slight loss of proteids in e\aporated milk due to 
mechanical adhesion of a part of the precipitated curd to the 
heating surfaces in the forewarmers and in the \'acuam pan. 

Most of the coagulable milk albumin is precipitated. Fresh 
milk contains about .16 per cent, of alliuniin that is not coagu- 
lable by heat.'' The relation of soluble and insoluble curd is 



' Hunzlker. Indiana Agricultural Experiment Station, Twenty-flrst An- 
nual Report, 1908, pages 67-68. 

' Hunzlker and Spltzer, Indiana Agricultural Experiment Station. Bulletin 
No. -134. 

' Hunzlker, Indiana Agricultural Experiment Station, Bulletin No. 143. 



Chemical Composiiion 



207 



shown in the follo\ving table which represents analyses of dif- 
ferent brands of evaporated milk: 

Soluble and Insoluble Curd in Evaporated Milk.' 



Brand 


Insoluble Sc 
Curd Al 

Per Cent. Per 


luble 

Dumln 

Cent. 


Total 

Protelds 

Per Cent. 


Gold Milk 


8.44 

7.41 
7.54 
7.37 
7.86 
8.28 
6.49 
8.39 
7.52 
6.77 
7.06 
6.88 
6.89 
7.21 
7.436 


46 
49 

46 
33 
30 
34 

52 
39 
42 
52 
42 
52 
49 
44 
429 


8.90 


Columbine 


7.90 


Every Dav 


8.0 


Gold Milk 


7.70 


Star 


8.16 


Morning Glory 

Carnation 


8.62 
6.91 


Beauty 

Van Camp's 


8.78 
7.94 


Monarch 

Diadem 


7.29 
7.48 


Reindeer 


7.40 


Wilson's 


7.38 


Dundee 


7.65 


Average 


7.865 



The abo\'e figures sho\v that, in the evaporated milk, prac- 
tically all of the coagulable albumin is changed to insoluble curd. 
The brands analysed contained e^'aporated milk condensed at 
the ratio of 2 to 2.4 parts c>i fresh milk ti) 1 part of e\-aporated 
milk. The soluble albumin found corresponds «-ith the albumin 
not coagulable by heat, normally found in fresh milk, times the 
ratio of concentration. 

The casein is largel}' precipitated by the sterilizing heat, 
but is present in the form of \-er_y finely di^•ided particles. This 
is due to the mechanical shaking to which the evaporated milk 
is sul)jected in the sterilizer and in the shaker. In many batches 
of evaporated milk the precipitation of the casein during sterili- 
zation is so fine that the product is perfectly smooth without 
shaking. The casein in evaporated milk does not respond to the 
action of rennet as does the casein in fresh milk. 



1 Hunzlker, Indiana Agricultural Experiment Station, Bulletins Nos. 134 
and 143. 



208 CllHMICAL COMFOSITION 

Milk Sugar. — The milk sui;ai- is i)rest'iit in jjcr cent, corre- 
sponding with that of tile (iri!_;inal milk', times the degree of con- 
centration. A ]>ortion cif it has undergone oxidation (carameli- 
zation) due to the high sterilizing tcm|)cratures. It gi\'es to the 
evaporated milk a yellnw In light hmwn color. The higher the 
sterilizing temperature and the longer the exposure nf the e\-apo- 
rated milk to this heat, the darker is ils colnr. 

Ash. — The mineral cunstituents al^o .are present in nearly 
the same propnrtion to the other snlids. as in fresh milk. They 
are largely rendered insoluble l)y the sterilizing )jrocess. The 
lime constituents frecjucntly are found in the 1)ottom (jf the cans 
in the form of hard, whitish, insoluble granules. For discussion 
(jf relation of ash constituents to staljility of casein, see Chapter 
XXIII on "Lumpy and Cin-d)' Evaporated Milk." 

Since the ash in normal fresh milk is practically constant, 
averaging about .70 per cent., the .per cent, of asli in the evapo- 
rated milk is frecjuently used as a factor in determining the 
degree of concentration. The results may, howexer, l)e ver}' 
misleading, since, w'hen the ash is [)reci])itated in the form of 
granules, it is practically impossible to mix it back into the milk 
in order to o1)tain a rei)resentati\ e sample for analvsis. 

The Specific Gravity I'anges from 1.0.^ to 1.08, according to 
the degree of concentration and the specific graxity of the origi- 
nal milk. It averages aliout l.Ori.s. 

Plain Condensed Bulk Milk is of \erv \arying composition, 
depending largely on the degree of concentration and the per 
cent, of fat present. It is usually made from parth' <ir wholly 
skimmed milk and is condensed at the ratio of 3 to 4 i)arts of 
fresh milk to 1 part of condeiise<l milk. The same fact applies 
to the comp(jsitiou of concentrated milk. 



Chemicai, Composition 



209 



Chemical Analyses of Twenty-four Different Brands of 
Evaporated Milk.' 




^ Hunzlker and Spitzer, Indiana Agricultural Experiment Station, Bulletin 
No. 134, 1909. 



210 Chkmical Composition 

Condensed Milk Standards. — I'^cdcral cruidensed milk stand- 
ards were first assembled in cnnncctiun witli llie l'\'deral Food 
and Drug's Act, passed jinie, 1''06, and wliicli went in force Janu- 
ary 1, 1907.' These standards i)rovidcd that both, sweetened 
condensed milk ami unsweetened cfindcnsed milk shall crintain 
not less than 2X ( tw'erit\--('ii^'ht ) per cent milk snhrls, nf which 
not less than I?.? ( twenty-se\-en and fn-c-tenlhs ) per cent, shall 
be milk fat. 

These standa.rfls ha\e been mcjdilied rejK-atcdly since their 
introduction.'. -, ■'■ The standards which have superseded them 
and their earlier mcidificatiuns. and which are now in force are 
as follows : 

"Sweetened condensed milk, sweetened evaporated milk, 
Sweetened concentrated milk, is the ])roduct resulting- from the 
e\'aporation of a considerable portiriii df the water from the 
whole, fresh, cle;in, lacteal secretion nbtaincd b_\' the crim]3lete 
milking of one nr more health v cows, pro[)crly fed and kept, 
excluding that iibtained \\'ithiii fifteen flag's l.'efore and ten davs 
after cah'ing, to which sugar (sucrnse) has been added. It con- 
tains, all tolerances lieing allnwed f^r, not less than twenty-eight 
per cent. (28%) of total millc Sdlirls. and nrit less than eight per 
cent. (8%) of milk fat.' 

"Unsweetened condensed milk, evaporated milk, concen- 
trated milk, is the pr(-iduct resulting irom the ewqidration of a 
considerable ])ortii'n of the \\ater fi-nm the wliole, fresh, clean, 
lacteal secretion obtained by the complete milking of one or more 
healthy cows, properly fed and ]<ept, excluding tli.at obtained 
within fifteen days before and ten da\'s after cal\"ing, and con- 
tains, all toleiMuces being allowed for, not less than tw'cntv-fi\-e 
and five-tenths per cent. {2?.?[i ) of total .solids and not less than 
seven and eight-tentlis per cent. (/..'>', ) of uiiUv fat.' 

"Sweetened condensed skimmed milk, sweetened evaporated 
skimmed milk, sweetened concentrated skimmed milk, is the 
product resulting from the e\Tiporalion of a coiisider.able portion 
of the \vater from skimmed niill^ to winch sugar (sucrose) has 

' U. S. Department of AKrieulture. Circular No. 19; al.so Hunzlker, Purdue 
Bulletin No. 143, 1910. 

= U. S. Orp.-irtmi'iit ..r .\mi.nUiir,-, Fci.i.J lns|H-ction Decisions Nos. 131. 
1911; 2 158, 1915; ^ no, 1917. 

" U. S. l)eit.-irl nieiit ot .Akii'm I Uirr, I'nud Tn.spcction Decision No. 15S, 
April 2, 1915. 



Sanitary Purity 211 

been added. It cnntaiii^, all tiiler;inces heiiii;" allowed frir, not 
less than twciity-eiL'lit ]ier cent. (2S'; i df milk solids.-' 

"Unsweetened condensed skimmed milk, evaporated skim- 
med milk, concentrated skimmed milk, i^ the product resnltinE: 
from the CA-aporatiijii of a considerable portiim oi the water frr)m 
skimmed milk, and contams, all tolerances lieinj^' allowed for, 
not less than twent\' per cent. (20' r ) of milk solids." - 

Requirem.ents of Condensed Milk for Export to the Allied 
Nations. — Condensed milk shall contain not less than ''.2 per 
cent, butter fat. 

In order to meet the hii^h bntter lat re(|uiremeTit in con- 
densed milk furnislicd t" the .\llies. .\merican condenseries A\diich 
receiA'e lari;'el)' low-tc'^tiipi;" milk are compelled to reinforce their 
pri'dnct with bntter fat. Thi^ i~; doix: either b\- rcmo^-inc;■ a pi'r- 
tic'.n of the skim milk, ( ir bv the addition to the milk o\ butter 
fat in the fi^irm of crermi or tmsalted butter. 

Cll.xrrKi: .\X. 

SANITARY PURITY, DIGESTIBILITY AND VITAMINE 
PROPERTIES OF CONDENSED MILK. 

Sanitary Purity. — Fi-om the point of \ iew of freedom from 
pathog'enic and other harmful micro-organisms, most forms ("if 
condensed milk are superior to the a\'erage market milk. In the 
first place, the manufacture of a marketable condensed milk 
makes essential eternal viiiikmce in the c.introl of the qnalitY of 
the fresh milk. It is safe tci state that in nci milk plants doe^ 
the qualit}' of the fresh milk accepted. recei\"e nutire careful atten- 
tion and a\'era,y"e hi^lier than in the milk condeiisery. The foun- 
dation of the C(indensed product, the fre^h milk, therefore, is cif 
a relatiA-ely liiyh standard cif i.uirity. 

Again, the temperatttre to which, the milk is subiected is suf- 
ficientl_v liigdi to destriy\- tlie geruTs of i)ractically all milk-borne 
diseases; so that, unless the ciaidcnsed milk beccimes infected 
u'ith pathogenic germs alter condensing and before the tin cans 
are hermeticalK' scaled, practicall)" aU damper from disease germs 
is eliminated. In tlie case of e"\-a]iorate(l milk the marketal.de 



= U. S. Department of Agriculture. Food In.spection Decision No. 170, 
Marcli 31, 1917, 



212 Digestibility 

product is free frDiii all forms of germ life. The only exception 
to this rule uould apply tn concentrated milk, in the manufacture 
of which the milk is not heated to temperatures detrimental to 
the life of hacteria. 

Digestibility. — In this discussion of the digestihility of con- 
densed milk it is assumed, that the condensed milk, unless used 
in. admixture with other foods, is diluted to approximately the 
consistency of normal milk. If consumed as a drink, similar to 
milk but without proper dilution, its concentration, and con- 
sequent excessi\'e richness, ^\•ould ob\'iously seriously interfere 
with digestion. A\'hile there are no experimental data a\'ailable 
concerning the digestibilit\- of condensed milk, the results of 
feeding experiments with heated, i)astcin'izcd r)r sterilized milk 
vs. raw milk, may furnish a logical guide as to the dietetic efifect 
of condensed milk. IMilk pasteurized at hi.gli temperatures, or 
sterilized, may 1)e considered comparable, as far as the effect of 
heat is concerned, to condensed milk. 

Doane and I'rice' report the following ex|)erimental results; 
"Raw milk is more easil}- digested when fed to caK'es than either 
pasteurized, or c<ioked milk. Contrary- to theory, cooked milk, 
wdien fed to the cahes used in these ex])eriments, caused \iolent 
scouring in the majority of trials. .\ majority of physicians in 
charge of children's hospitals corresponrled with, favored the use 
of raw milk for infants when the milk is known to lie in perfect 
condition, but fa\'ored pasteurized milk under ordinary condi- 
tions. With one exception all the ph}'sicians corresponded with, 
discouraged the use of cooked, or sterilized milk for infant 
feeding." 

Rosenau* states that "Comparati\e obser\ations upon in- 
fants under the same conditions show that thev flourish (|uite as 
well upon heated milk as upon raw milk. Laboratorv experi- 
ments as well as clinical obserAations coincide ^\■ith the \'iew', 
that hep.ted milk is ijuite as digestible as vnw milk. In fact it is 
now claimed tci be more so. Metabolism experiments indicate 
that the utilization of calcium and iron in the body is more com- 
plete in children fed u|)on boiled cow's milk, than in those fed 
upon raw cow's milk. 



1 Doane and Price, Marvlan<l Ag:ricultural Experiment Station, Bulletin 
No. 77, 1901. 

• Rosenau, United Stales Department of Agriculture, Bureau of Animal 
Industry, Circular No. 1.53. 11)10. 



DiGESTIBIIJTY 213 

v^tutzer' who conducted experiments df artiticial digestion 
reports in fa^-or of boiled milk, while similar in\-esti,i^ations made 
b_y Ellenberger and ITijfmeister- sho\\-ed no ditterence in the 
dit^estibility between raw and cooked milk, 

Rodet" \\di(> experimented \\-ith dnL^s noticed a slight dif- 
ference in favor <>( boiled milk. liruninQ"' fed dogs, pigs, rabbits, 
and guinea pig's ^\■ith ra\\- and sterilized milk and reports that 
all results were in fa^•"r of the sterilized milk. Bruckler's' ex- 
periments with dogs showed that the animals gained more in 
weight on sterilized milk than on raw milk, but that their general 
health, vigiir and \'italit}- was Vjctter when ferl raw milk. \'ariot'' 
(ibserx'ed no difl'erence in the eti'ect on infants between raw and 
boiled milk. 

The foregoing citations suggest that our knowledge of the 
digestibilitv of lieatcd or boiled milk is exceedingl}' limited and 
that the results oljtained and C(TncIusions drawn by the \'arious 
in\-estigati irs are at \-ariance. In experiments with the li^'ing 
rirganisni, and cinhneil tn si i few specimens as seems to hax-e been 
the case in the w"rk repurted, the facturs of indi\-iduality and 
emdrumnent are a constant stundjling bluck, magnif}-ing the 
limit 1 if experimental ei'ror and weakening the conclusi^-eness of 
the results. ( )n the basis of oin- present k'niiwled,ge it seems 
reasonable to conclude that, as far as the fligestilhlit}' cif its 
inherent ingredients is concerned, condensed milk, wdien con- 
sumed in properly diluted form, varies but little, if an_\-. from 
ra^^• milk. The absence in condensed milk of ferments, such as 
enzymes, wdniclT are destro\-ed in the process and wdTich mav 
assist digestion, may tie considered the most important defect 
of condensed milk from tlie point of \-ie\\' of digestibilitA'. 

In the case cif s\^•eetened condensed milk, howex'Cr, the nutri- 
tive ratio of the normal milk is decisiA-ely disturbed In- the pres- 
ence of large cpiantities of sucrose. K\'en ^\dien diluted to far 
beyond the compositiim nf luirmal and original fluid milk, the 



1 Stutzer, Landw. Versuchs-Stationen, 40. p. 307. 

= Ellenberg-er & Hofmeister, Bericht ueber das Veterlnarwesen Koenig- 
reich Sactisen. 1890. 

3 Rodet, Compt. rend. soc. bioL. 48, p. 555. 

» Bruning, Muenchner Mediz., Wochenschrift, Ko. 8, 1905. 

* Bruning-, Zeitsclirift fuer Tiermed, 10, p. 110, 1906. 

^ Bruckler. Jahrbuch fuer Kinderheilk. 66. p. 343, 1907. 

« Variot, Comp. rend., 139, p. 1002, 1904. 



214 Digestibility 

per cent of cane sug-ar is still high, causing the nutritive ratio 
of such milk to he abnormally wide and unbalanced. The carbo- 
hydrates are present far in excess of the protein, fat and ash. 
If fed to infants exclusively and for a prolonged period of time, 
the growing organism is bound to suffer from malnutrition and 
at the expense of muscular de\elopment. 

Furthermore, it is conceded by the medical profession that 
sucrose is not a suitable form of carbohydrates for infants. It 
is not as digestible as lactose, it changes the bacterial flora of the 
intestines, enhancing the de\elopment of butyric acid and other 
gas-forming and putrefactixe germs at the expense of Bacillus 
bifidus, which is the natural inhabitant of the intestine in normal, 
milk-fed babies. 

Sweetened condensed milk is generally highly advertised by 
the manufacturer as a suitable food for babies ; it is frequently 
recommended by physicians and in some instances, it is claimed 
to have agreed with babies who were unable to take care of milk 
in any other form. It is not improbable that in these extremely 
isolated cases of baby feeding, when all other feeds failed, the 
true virtue attributed to the sweetened cimdensed milk, lay in 
the fact that the mothers carefully followed the directions on 
the label for dilution. The directions specify that the condensed 
milk be diluted with ten to sixteen parts of water. The majority 
of cases of digestive disorders in bottle-fed babies are undoubt- 
edly the result of the natural tendency of the mother to feed 
her child too much milk or too rich milk. \Mien we consider 
that the ratio of concentration in sweetened condensed milk is 
only about 2.5 to 1, it is obvious that a dilution of 10 or 16 to 
1 is a great relief to the over-taxed digesti\'e organs of infants, 
previously fed on milk too rich for normal digestion. The im- 
mediate change of the health and disposition of these babies for 
the better, as the result of turning from a prolonged siege of 
too rich food to the xery dilute condensed milk, is therefore not 
surprising. 

The manufacturer of sweetened condensed milk in this coun- 
try is inclined to load his product excessi\'ely with sucrose. He 
does this largely in an effort to increase the keeping quality and 
to guard against de\ elopment of fermentations in the finished 
article that ruin the goods for the market. While a certain 



ViTAMiNE Properties 215 

amount of sucrose is necessary to preserve this milk, _yet, if the 
product is manufactured from a good quahty of fresh milk, as 
it should be, and when the proper sanitary conditions are main- 
tained in all departments of the factory, sixteen pounds of cane 
sugar per one hundred pounds of fresh milk is entirely sufficient. 
He should bear in mind that sweetened Cdndensed milk is 
used and accepted by the consumer as a substitute for market 
milk, and it is the manufacturer's moral duty to retain in this 
substitute the normal properties and composition of the product 
which it is supposed to replace, as nearly as is consistent with 
the production of a wolesome and marketable product. 

Vitamine Properties. — Recent disccjveries by nutrition ex- 
perts\ - have revealed and conclusively demonstrated the pres- 
ence of vitamines, or chemicall}' unknown substances of food 
origin, that are essential for the normal performance of the 
function of animal life. Extensive feeding experiments have 
shown, that before complete growth can occur in a young animal, 
or for prolonged maintenance, or for the prevention of certain 
diseases, the diet, besides being adequate as regards its content 
of proteins, carbohydrates, fats and mineral salts, must contain 
certain, at present unidentified accessory substances, popularly 
called vitamines. 

Hart and his co-workers eiuimerate three of these vitamine 
substances, namely, water-soluble vitamines or antineuritic 
vitamines; fat soluble vitamines or antixerophthalmic vitamines: 
and antiscorbutic vitamines. The absence in the diet of each, 
or all of these vitamine substances causes stunting of growth 
and the development of certain characteristic diseases. 

Water-Soluble Vitamine. — The absence of this vitamine in 
the diet retards and stunts growth and leads to such diseases 
as polyneuritis and beriberi (paralysis). The water-soluble vi- 
tamine is present in a variety of foods and constitutes an inherent 
part of the non-fatty portion of milk. 

Fat-Soluble Vitamine. — The absence of this substance in 
the diet retards and stunts growth and leads to the disease of 
xerophthalmia (an eye disease culminating in blindness). The 



^ McCoUum. The Newer Knowledge of NutrUion, 1918. 
2 Hart, Steenbock and Smith, Studies of Experimental Scurvy, Journal 
Bloloelcal Chemical Chemistry. Vol. XXXVIII, No. 2, 1919. 



216 Vi'i'AMiNK Propi'.rtiks 

fat-s< ilulile \itaniiiie is |)rt'--(-nt ahundaiitlv in a \cry limited list 
I if fdiifls, namely, in butter fat, eL;"t;' fat, cod li\'er riil, the fats fjf 
tlie \'ital oryaiis and in the leax'es of plants. It is not contained 
in ordinary animal fats such as lard, nor in any of the vegetable 
fats. 

Antiscorbutic Vitamine. — The absence of this vitamine sub- 
stance in the diet causes the development of scur\-_y and similar 
scorljutic diseases and skin diseases. The antiscorbutic \'itamine 
appears to be present in many foods, similar to the water- 
soluble \itamine, and it is abundantly present in raw milk. 

Effect of Heat Employed in the Manufacture of Condensed 
Milk on These Vitamines. — The heat to Avhich condensed milk 
is subjected in the process of manufacture does not rob the con- 
densed milk of the water-soluble and fat-soluble \itamines, so 
far as our knowledije, based on data now available, is concerned. 
This api)lies to all kinds of condensed and evaporated milk made 
froni whcjle milk. From the standjxiint of these two fjrowth- 
promoting' and curati\e \itamines, all forms of condensed whole 
milk are, therefore, equally desirable for infant feedincf, for 
children and for the adult, as is whole milk. 

On the other hand, sk-ini condensed milk is not a satisfactory 
food for the g'rowiuL;- young. It lacks the indispensable fat- 
soluble accessor}' and unless sufiplemented by egg yolk, cod 
liver oil or butter, its consumption by the young in the place oi 
whole milk, or in the place of condensed milk made from whole 
milk, will i)ro\-e disastrous to the growth and well-being of those 
who are restricted to such a diet. 

Nor does imitation C(]ndensed milk, such as the "Hebe" 
product, in which the l)utter fat has been replaced by a \-egetable 
fat, supplement the lacking fat-soluble vitamine substance. The 
public should clearly understand that in milk or condensed milk, 
there is no substitute for butter fat and when the butter fat is 
remo\'ed the product no longer can take the place of milk. See 
also "Addition of Artificial l-'ats," Chapter XXIV. ■ i 

The antiscorbutic \itamine. on the other hand appears 
to be destroj'cd in the process of manufacture of evaporated 
milk, as shown by Mart in exi)eriments with guinea pigs. Hart 
found tliat commercial unsweetened condensed ' milk fmeauijig 



Cost of jManufaciurr 217 

evaporated milk), had li'St its aiitiscnrljutic ])r(iperties wlien 
used in quantities ef|ui\-alent tn an amount rif raw milk which 
\\-(iuld prevent scurv}- in guinea Jiigs nn a diet rif rnlled riats 
and dried hav. 

Hart's results agree with tlmse nf manv (jther inxestiga- 
tors in the fact that the exposure 'if milk tci sterilizing tempera- 
ture, deprives the product of its antiscorbutic [iroperties. C)n 
the basis rif these facts e\"aporated milk cannot be recrmimended' 
as an exclusi\-e milk diet for babies and children. If exapo- 
ratcd milk must be used fcir infant feeding, srmie antisci^irbutie 
supplementary food, such as orange juice, sliould be fed in cc)n- 
junction with the exclusive use of e\aporatcd milk or similar 
heated milk product. 

To ^\d^at extent the antiscorlmtic properties oi milk are 
preserved or destro^•ed in the manufacture of sweetened con- 
densed milk, has not as yet been experimentall}" demonstrated. 
This product is not exjiosed to sterilizing temperatures and vet 
it is heated at least to the boiling point. 'J'h.e safer course to 
follow here, too, if sweetened condensed milk must take the 
place of normal raw or pasteurized milk, is to feed it in con- 
junction with a known antiscorbutic supplementar}- food, such 
as orange juice. 

Ch.M'TEr XXT. 
COST OF MANUFACTURE. 

General Discussion. —The cost of manufacture ^■aries, in a 
general wa^', with the organization and size <>{ the factorv, 
capacity of machinery and the ami.iunt ijf the (jutput. These 
variations are further modified by the cost of a\-ailable labor, 
the price of milk, cane sugar, tin cans, box shooks, coal ancf 
other supplies, etc. 

In a properly organized plant the cost of manufacture per 
case of finished product decreases with the increase of the out- 
put, provided that the capacity of the machinery is sufficient to 
take care of such increase. When the plant is forced be^•ond 
its capacity, the factory operates at a disadvantage, and the 
extra labor and possiljle waste and losses tend to increase the 
cost per case, AMien the output drops bebiw ](K) to 1.^0 cases 



218 Cost of Manui'acturb; 

per day, profitable niamifacture becomes difficult, the overhead 
expense is out of proportion with the business, the factory can- 
not take advantage of rebates in the purchase of supplies, the 
factory labor is relatively high, because skilled men have to 
do manual labor, and occasional losses due to spoiled goods 
devour the profits of a comparatively large portion c)f the entire 
output. 

The price iif milk fluctuates with season and proximity and 
strength of competing markets. The pre-war fluctuations em- 
braced a range of from .$1.00 to $2.00 per one hundred pounds of 
fluid milk, or twenty-five to fifty cents per pound of butter fat. 
Maximum war prices and post-war prices up to and including 
January 1, 1920, reached the figure of $4.17 per 100 pounds of 
milk. 

Cane sugar varies in price largely with the season and witli 
the success or failure of the sugar cane crop. Sugar prices 
usually reach their climax in fall and their minimum price in 
late winter or earl}' spring. Pre-war -v-ariations usually fell 
within the limits of $4.00 and $6.50 per one hundred pounds of 
sugar. Since the war and up to January 1, 1920, the price of 
sugar has risen to 17 cents per pound. 

Tin cans vary in price with style of can and whether made 
in the condensery or bought from a can-making concern. Some 
factories are paying more or less heavy royalties for the priv- 
ilege of using certain patents of cans. Cans intended to be 
sealed without the use of solder, but which are guaranteed to 
make a hermetical seal, are generally higher in price than those 
in the sealing of which solder is used. This difference in price, 
however, is ofYset, in part at least, by the cost of the solder 
and g"asoline. Cans purchased from can-making concerns usually 
are more expensive than cans manufactured in the condensery. 
This h(jlds true only where the tin-shop of the condensery is 
properly e(|uipped and efficiently manned. In normal times 
the cost of cans bought from can-making concerns is about 45 
cents per case of 14 ounce cans and 55 cents per case of taW 
size cans, varying somewhat with size and style of can; when 
made in the condensery the price may be lowered from 10 to 
20 per cent. January 1, 1920, prices for cans were about 88 cents 



Cost of Manufacture 219 

per case of 48 14-ounce cans and al)Out 'J'J cents per case i ,f 4S 
cans for tall-size cans. 

The cost of coal \-aries with (|ualit\' and lijcalit}-. L'nder 
average conditions, the condensinf,"^ and ])ackinp of one pound 
of fluid milk recjuires about three-tenths of a pound of coal r)r 
thirty to forty pounds per case. A good (|uality of "mine run" 
can be laid down at the factory in states near the coal region. 
like Indiana and Illii-iois for about $2.50 per ton. or in northern 
states, like A\'isconsin, for about $330 per ton. Tlie cost r)f coal 
per case, therefore, may vary from about three and eight-tenths 
to six and a half cents per case. Where natural gas or refuse 
from lumber mills is available, the cost of fuel may l)e reduced 
materially by the use of these sul)stitutes for coal. Maximum 
war price raised the cost of coal to about 9 cents per case. 

Solder and gasoline for sealing the cans a\-erage about three 
and a half cents per case. I^he price of solder is about twenty- 
seven cents per pound and the solder used per case of forty- 
eight cans, amounts to about one-tenth of a pound. Maximum 
war price raised it to about 7c per case. 

For venthole cans the amount of solder needed is from .3 
to .5 of one ounce per case, making the cost in normal times 
about seven-tenths of one cent for tall size cans. 

In the case of the sanitary can and other cans with solder- 
less seals this item drops out entirely. 

The labels varv in price according to ciualit}- of paper, and 
elaborateness of printing. The average cost of labels is about 
four cents per case. Maximum war price about 8 cents per case. 

The box shocks and nails per case cost about eight to ten 
cents, January 1. 1920, the price of box shooks per case for 14 
ounce cans was about 23 cents and per case for tall size can.s 
about 26 cents. In the case of fibre boxes the cost per case is 
about 18 cents. 

The factory labor for pre-war conditions was about 12 to 
l.S cents per case and the administration expense about 5 to 
10 cents per case, \'arying widely, of course, with the type 
of organization and volume of business. January 1, 1920, the 
factory labor was about 20 to 25 cents per case and the adminis- 
tration expense about 10 cents per case. 



220 Cos'L' OF Manui-acturic 

Under jirc-war ciiiiiliti( jus tlic frei,L;lit and ntlier trans])Orta- 
tiuii ran,L;ed fnmi aliout KJ to 23 cents ])er case a\'era[;int;' about 
12 to 13 cents. January 1, 1920, tlie freight and other transpor- 
tation charges would ax-erage 33 cents per case. 

Before the war the in\'estnient in factdry, equiiiinent and 
operating expense for a ])lant with a capacit\' of about 300 cases 
per day amoinited to ahunt $73,000, placing the interest and 
insurance at alxjut 3 cents per case, January 1, 1020, a factory 
of similar ca]iacity \\i(iuld in\iil\e an inxestment in building, 
equipment and operating expense of alxmt .$173,000, placing the 
interest and insurance at about 7 cents per case. 

The selling expense \aries widely ranging fr(:im less than 
10 cents to 20 cents per case. 

The following tabulated summary may ser\-e to bring out 
the approximate relati\e expense per case of sweetened con- 
densed milk and evaporated milk more clearly: 

Sweetened Condensed Milk. 

Cost per case of forty-eight cans. These cans weigh 14 ounces 

net per can or 42 pounds net per case. The}' are known in the 

trade as 14 ounce cans. 

1913. • 1920. 

103 lbs. milk (concentratiun J<iu. 1. 

2.5:1) @ $1.50 $1.57 (??$ 3.60 $3.78 

16.8 lbs. sugar (16 lbs. per 100)rrt) 5.00 .84 (a 15.75 2.()4 

Tin cans (sanitary) 45 .88 

Boxes (wooden ) (J75 .2i 

Labels 040 .03 

Coal 045 .00 

Factory labor 15 .23 

Administration exjjense 07 .10 

Freight 14 .35 

Selling expense 10 .12 

Interest and insurance on inx'estment 

and on o[)erating ca|)ital 03 .07 



Total cost per case $3.51 $8.54 



Cost of 3vIanufacturiv 221 

Evaporated Milk. 

Cost per case of fort}'-eight tall size cans, \\"ei:4hiii<4" forty-eight 

pounds net. 

1913. 1920. 
Jan. 1. 

106 lbs. milk (^i Sl.,=iO S1..V) (F, So.fiO $3,819 

Cans (vent hole) ."^.^ .988 

Boxes (wood ) 075 .262 

Labels 04 .053 

Solder and gasoline hcnt lir.le cans). . . .(307 .014 

Coal 045 .0^) 

Factory labor 15 ' .23 

Administration expense 07 .10 

Freight 14 .3? 

Selling expense 10 .12 

Interest and insurance on in\'estment 

and (m operating capital 03 .07 

Total cost per case S2.7'^7 $6.0^)3 



PART V. 

CONDENSED MILK DEFECTS, THEIR CAUSES 
AND PREVENTIONS 

CllAl'TI-R XXTT. 

CLASSIFICATION OF DEFECTS. 

IMaiiy are the defeets wliicli caii.^e CMiuleiised milk tij be 
rejected on the niarl^et and mnnenais are the a\-enucs tliat may 
lead to the manufacture nf defectiA'c milk. The milk faults ma)' 
be of mechanical, plivsical, chemical, or Ijacteriological origin, or 
they may he due tn a ciinibinatii ni rif two iir more of tliese forces. 
In some in.stances the defects can lie detected in milk during, rjr 
immediately after the prncess, in A\hich case the}- may be rem- 
edied, or their recurrence pre\'ented. Tint more often, se\'eral 
weeks maA' pass liefiire al)ni:irnialitics de\'clop and l)efore the 
manufacturer realizes that snmething is wr(jng witli the milk. 
In the meantuiie, the cnnditinns which i iriginall_\- produced the 
milk defect niav Iiaxc si > ciianged, that it is excec-dingh- difficult 
to locate the seat nf the nriginal trMulde. 

DEFECTIVE SWEETENED CONDENSED MILK. 

The follcwing ai-c the chief and uio-^t couuhimi defects of 
sweetened condenseil milk : 

1. Sand\'. r:iu;^h i ir L;rilt\- 

2. Settled 

.1. Thickened .ami chees\- 

4. I.umpw white (ir velliiw buttim^ 

,"1. i'liiWu nv Ici-mcnled 

(>. kancid 

7. Putrid 

8. Brown 
y. Metallic. 



vSwEETiiNKD Condj-;nsi;i) j\Iii,k Dei'iiCTs 223 

Sandy, Rough or Gritty Sweetened Condensed Milk. 

General Description. — This is condensed milk in wliicli a por- 
tion of the milk suqar has htcn ])rccipitated in the furm if largx- 
crystals, the size nf the cr\-st:i|s deijeiidiii^' ini the cunditions 
caiisni!,;' crystallizatiijii, h'irst-class sweetened crnidensed milk 
is smcidtli and \-e]\'et}'. Snch milk is ndt entirel_\- free frum smjar 
cr}-stals, 1)ut they are sn niniiue in size tliat the}' (h< nrit itiIj the 
condensed milk rif its natnral ^nii mthness. In sandy nr i^ritt}" 
condensed milk the cr\-stals are xery nnmerons an.d larL^e eminqh 
to innnd lietwecn tlie teeth, smnlar ti i salt crystals in ;_;aatt}' 
Initter. The presence nf these crystals is alsij nriticeahle to the 
naked eye; the milk Inwks candied. 

Causes and Prevention. — The sn,L;"ar crystals which render 
the contiensed milk nmeh and ^.-nnh- cniisist largeh' I'f milk 
snr.;'ar. The solnhility nf nhlk stiyar is relati\el}' lo^^■. ]\[ilk' 
sn,L;'ar reqnires alumt six times its weight nf \vater at nrdinar}- 
temperature for C(ini]di.'te snlntion. C'ondensed milk contains 
from 12. ,T to 15 per cent milk snL;"ar and on!)" ahout 2('>.? per cent 
^^•ater. The ratiia rif milk snyar tn Awater in sweetened con- 
densetl milk, therefnre, is 1:2, while fnr comrilete snlntion it 
should 1)6 1:6. The nnik sng'ai" in this prnduct is ])resent in a 
supersaturated solution ami an\ cnnditinn which fa\"i:irs sugar 
crystallizati(")n stningl}' teuds tn precipitate this milk sugar, 
because there is nieire tif it [)i-eseiit in the milk than the a\'ailable 
\vater is capal)Ie of readil_\- kee])ing in snlutinn. The chief factor 
that prevents the milk sugar from precipitating \-ery hadlv is 
the great A-iscosit}- of the coiiflensed milk. This is largeh' due 
to the caseous matter and the cane sugar. 

Cane Sugar Content. — It has been ai-gued that the large 
ani("innt of sucrose winch sweetened cnndensed milk contains, 
is the principal cause nf sandA' milk and rif sug'ar sediment in 
the Ijottom of the tin cans, and that a reduction in the amount 
of sucrose lessens the tendency rif the sugar to crwstallize and 
the milk to liecome sandy. This line of reasoning is erroneous. 
The presence, in w^ater, of sucrose in solution does not materialh' 
lessen the power cd' the water to dissoh'e milk sugar, provided 
that the sucrose solution is not a saturated one. Sweetened 
condensed nrilk, contains about ,is to 4^ per cent sucrose and 



224 vSwiiKTivNivu CoNDi;NsiiD Milk DhfivCTS 

24 tfi 28 jier cent water. Sucrose dissolves in one lialf its weight 
of water. Tlie sweetened condensed milk does not, therefore, 
contain a saturated solution of sucrose. 

Incomplete Solution of Sucrose. — If the llnished product is 
to be smooth and free fmrn sandiness, it is essential that the 
sucrose wliich is added tn the hot, fresh milk be thoroughly dis- 
soh'cd before the mixture reaches the \'acuum pan. Undissoh'ed 
sugar crystals in a medium as highly concentrated as sweetened 
condensed milk lia\'e much the same effect in a physical way, as 
huve bacteria in fresh milk in a biijjogical way ; they multiply 
rapidl}'. Tlierefore, if all the sugar added ti i the fluid milk is 
not completel}' dissoh-ed, the undissohed sugar crystals give 
rise to \\-holesale precipitation uf the milk sugar in this product 
after manufacture, and since the crystals of undissolved cane sugar 
are relatively large, their presence also gives rise to the formation 
of milk sugar crystals of large size. Hence the sandy condition of 
the condensed milk. Complete solution of the cane sugar can 
best be accomplished liy heating the liquid, milk ^r water, in 
which the sugar is to be dissolved, to the boiling point and by 
boiling the mixture for se\eral minutes ; or I))' placing the sugar 
on a large wire mesh strainer (about eighty meshes to the inch) 
which stretches across the sugar well and allowing hot milk to 
run over this sugar into the well below. In this wa^' the sugar 
crystals must dissolve before they can reach the sugar well. 

One of the safest methods of insuring complete solution of 
the cane sugar is to dissoh'e it in a separate kettle in a sufficient 
quantity of boiling water (preferably distilled water) and boil- 
ing the syrup for five to fifteen minutes. If the s^rup llius made 
is grj^-en a iew minutes rest it should become perfecth' clear; 
by its clearness, the purity of the sugar can also be observed. 
If a scum forms at the top it should be remo\e(l ; then the hot 
sugar S}Tup is drawn into the pan. Care should be taken that 
the milk already condensing in the pan has not l)ecome too con- 
centrated, otherwise sugar crystallizati(.Mi ma^- set in. It is ad- 
visable to inject the sugar S}'rup gradually, rather than to wait 
until nearly all the milk is in the pan. 

Excessive Chilling in the Pan. — The cause of grittiness of 
condensed milk ma)' lie in the ])an itself. \A'here the water used 
for condensing is \er}' cold, and where one end of the spray 



SweiiTENliD CoNDIiNSUD MlI,K DEFECTS 225 

pipe in the condenser is \'cry close to the goose neck of the pan, 
as is the case with most of the A'acnum pans in use, wliich are 
equipped \\'ith horizcmtal spray cijndenser, the chillinq" of the 
\-apors and of the spray of milk rising from the pan is so 
sudden, that sugar cr^'stals arc [)r(-jne to form in the spray and 
along the walls of the pan. 'i'liese crystals either stick to the 
side of the pan, or fall back into the milk A\-liere the}' later mul- 
tiply and cause the milk to become suvarw Trduble from this 
source can be a\'oided by either raising the temperature of the 
water that gcics to the conden-^er \A-hich is, hii\\e\x'r, not practical 
inider most conditions, or l)v clnsing the holes in that portion of 
ihe spray pipe which is nearest the pan. This can easily be drme 
by wrapping a piece cif galvanized ircm or tinplate around the 
portion of the spra)- ])ipe to lie closed, or l)y lilling the holes 
with solder, or l)y replacing the old spray piix* bv a new and 
shorter one, properly constructed. 

Superheating at End of Batch. — Sometimes the manufac- 
turer is pcrsistentl}' trouljled with the apprearance of cr} stals in 
the condensed milk of monstrous size, as large as rice kernels; 
this condition arrives usually \-ery gradually. During the first 
few days after manufacture, only a few of these large crystals 
may appear in some of the cans Tn the course "i a few weeks, 
all of the cans may contain specimen of these ''rice crystals" 
which increase in number until the entire contents of the cans 
are one mass of "rice crystals," rendering the milk unsalalde. 
The direct causes of this particular kind of sugar cr^-stallization 
are excessive concentratinn of the condensed milk, the use of 
too much steam pressure in the coils and jacket wdien condensa- 
tion is near completion, dela_\- in the drawing off of the condensed 
milk from the pan, and leaky steam \al\es in the pipes leading 
to jacket and coils. 

Toward the end nf the CMiidensmg process the milk becomes 
heavy, thick and syrupy, .uid bulls with much less \dolence. If, 
at this stage of the process, excessn-e steam piressure is used in 
the jacket and coils, tlie milk is superheated, often causing the 
precipitation of "rice crystals." .-\gain, wdiere the finished con- 
densed milk is dra\\n fi'om the ])an very slowly, either o\\'ing to 
too small an outlet in the bottom of the pan, or l.iccause the milk 
is forced to run through a strainer attached to the outlet, or 



226 SwiiHTKNED Condensed Milk Defects 

because the finished condensed milk is retained in the ])an as 
the result of an accident, in all of these cases there is danger 
of superheating", and therefore, of the |)r(jdnction of these large 
crystals. This danger is especially great, where the vah'es of 
the steam pipes leading to the jacket and C(_iils are leaking, as 
is often the case. The avoidance of excessi\'e concentration and 
the removal of any conditions that tend to ex]jose the finished 
or the nearly finished condensed inilk to e.\cessi\e heat will 
usually prevent further trouble of this sort. 

Experimental results by C. S. Hudson,' on the solubility 
and crystallization of milk sugar also show that milk sugar 
crystals of large size were obtained bv e\aporation of a solution 
of milk sugar at 95 degrees C. (203 degrees F.). 

Excessive Concentration. — ^In as much as the initial cause 
of the precipitation of a portion of the milk sugar ^\'hich leads to 
the production of sandy condensed milk lies in the fact that the 
milk sugar is present in this product in the form of a super- 
saturated solution, it is ob\'ious that the danger of sugar crystal- 
lization and sandiness in this product increases \\ith the increase 
in concentration. This is fully borne out liy practical experience. 
The higher the ratio of concentration the more difficult it be- 
com'es to manufacture a smooth condensed milk. The danger 
here is further augmented by the fact that in the \cry highly 
concentrated product the tendency of sujierheating is augmented. 
And the superheating gives rise to \'ery large cr^'stals which 
render the product exceedingly coarse. The superheating is 
due to the increased slug''gishness of the v'cry thick condensed 
milk in the pan, it ceases to boil \igoronsh' enough and is there- 
fore excessi^•ely exposed to the hot coils. It is further due to 
the slowness with which this product leaxes the hot yrdu. 

Improper Cooling. — The method used for cooling the s\\-eet- 
ened condensed milk after it leaves the \ acuum ])an is another 
important factor determining the smoothness or grittiness of the 
finished product. The chief principles in\'ol\'ed here are the 
rapidity and extent of co;ding and the amount of agitation to 
which the condensed milk is subjected. 

In order to fully appreciate the importance of strict ntten- 



' Hudson, The Hydration of MUk Sugar In Solution, Jour. Am. Chem. 
Boc, Vol. XXVI, No. 9, 1904. 



SwEETEXED Condensed Milk Defects 227 

tion tri details in the cooling- process of sweetened cundensed 
milk, it should he understoijd, that the f'lrniatinn of large sugar 
crystals in concentrated sfiluticjns is enhanced 1)_\' sudden cliilling 
and by excessi\-e agitation of these solutions. In the case oi 
cooling in 10 gallon cans as described under "Cooling c)i Sweet- 
ened Condensed Alilk," Chapter \'I., the sudden anfl irregular 
chilling rif a part or all "f the sweetened condensed milk in 
the cooling cans is the result of the use of badly dented cans, 
poorly fitting paddles, a warped condition of the pi\'0ts nn which 
the cog wheels in the bottom of the cooling va1 re\'oh-e, too Cdld 
water, and the application of tod much crild water. 

The paddles must scrape all parts of the sides of the cans. 
from toj) to bottcim. This i.s possii)le niilv when the cans are 
intact and their sides are smcM'ith and free from indentations. 
The paddles must he adjusted properly so that their edges fit 
snugh' against the sifles of the cans, the}- must be firmly fastened 
to the cross bars and fi'rced against the sides of the cans liy 
springs. In order that the cans may I'un true the}- must properly 
fit int'i the rim of the c(Tg wdieels in the bottom nf the cooling 
\-at and the |")ivots on which the cog wheels re\'i"ih-e must be per- 
riendicular. If the pi\-i:its are \\-arped, the c^'ig wdieels cannot 
run true and the cans wobble; this ca.uses unc\'en and incom- 
plete scraping of the sides of cans In' the paddles. 

The water in the cooling vat shraild not be cold, but ha\-e 
a tcmfjerature nf about 90 degrees V . wdien the cans, filled with 
tlie hot condensed milk, are set into the \-at. The cold water 
should flow into the \'at sk'wd)- and l)e e\"enly distributed 
thmughrjut the x'dt. This is best accomplished b}* the installa- 
tion cjf a perforated pijjc running' the entire length of the ^'at. 
The cooling must be gradu.'il. See also "Excessi\'e Stirring." 

Excessive Stirring. — The cans should re\'oh'e slowly. Rapid 
re\'iilution causes excessive agitation of the condensed milk, 
which stimulates the formation of cr^'stals. ,-\l)0Ut fi\'e re\'olu- 
tions per minute is satisfactory. In order to make more ettecti\'e 
the proper scraping of the cans by the paddles when the cans 
revolve slowlv, it is ad\'isable to install two paddles in each can, 
touching the periphery of the can on i'>p|)osite sides. 

W'hen the milk has been cocded tn between GO and 70 de- 



228 SwivrvTrmRD CondKnsivD Milk Dkfk.cts 

g'rees F., the water should Ijc fh-a"\vn from the coolins;'" vat, or 
the cans should be rcmo\'ed at once. 

In tiie newer method of coolniq', in wdiich the hot condensed 
milk is forced tuider pressure throucdi a 1:]: to l\ inch coil sub- 
merged in a lank of cold water, there a])pears to he a happy 
relation of rapidity of coolinq- and type of agitation, that assists 
in avoiding the formation of cri,'sta!s sufhcientl)' large to cause 
sandiness. While the cooling here takes place with relatively 
great rapiditj^, the agitation appears to be such as to prevent, in 
a large measure, the production of excessi\'ely large cr3rstals. 
If this cooled condensed milk, leaving the cooling coil, is sub- 
sequently further subjected to slow agitation for several hours, 
the formation of small crvstals is encouraged and the preven- 
tion of a sandy condition of the product is facilitated. For de- 
tailed description of this method of cooling see "Cooling Su'cet- 
ened Condensed Milk," Chapter Yl. 

Warming Up of Too Cold Condensed Milk. — Finally, if the 
condensed milk is cooled to too low a temperature, either by 
mistake, or as the result of the cans of cooled milk standing in 
a verv cold room over night, so that the condensed milk is too 
thick to run through the filling machine, it is best to warm 
it up by simply allowing it to stand in a warm room. The prac- 
tice of setting the cans liack into the ciioling tank and rex'oh'ing 
them in warm water is oljjectionablc, since this stirring of the 
milk, while it is warming, seems in\'aricdily to ]M'odnce whole- 
sale sugar crystallization, and therefore, causes the condensed 
milk to become very gritty. ( Sec also v^ettled Condensed Milk.) 

Settled Sweetened Condensed Milk. 

General Description. — l',y the term "settled milk" the con- 
densed milk man refers to condensed millc which has precipi- 
tated and IhrdU'ii down a ])(irtii)n of its sngai-, fiTrming a deposit 
of sugar crystals in the boltmn nf the can or barrel. This de- 
posit may \';iry in amount from ;i \'er)" thin la)'er to a layer an 
inch deep or more, according to the character and age of the 
milk. The nature of this sediment also dilters in diFferent cases 
of settled milk. It m;iy Ite soft, and upou stirring may mix in 
and dissolve readily, or it may be very dry and hard, in which 
case it sticks to the bottom of the can with great tenacitv, and 



vSvVKl-'.TI'.Ni:!) C()XDI".iVSI;D MiLK DEFliCTS 229 

can l"jc reniONCfl and nnxud intn tlic milk with difficiiltv onl}'. 
Like yi'itt}- milk, settled niill-; is a \-er}' f("inimnn cnndensed milk 
delect, Thom;li it decs nut render the prriduct les? wdirilesrjme, 
it is an undesirahle characteristic. Such milk is usually rejected 
lui the marlcct and results in a fiartial k'ss to the manufacturer. 

Causes and Prevention. — It is (ib\-icius, f^r rcasdiis above 
referred tn, that the c'l iiulitions leading' ui.i to the |)riiduction oi 
settled milk, are cluselv related tn tlniSe that cause milk tn 
hecnme giatt}-. Condensed luilk canmit drop its milk suj^ar, 
unless the latter is present in the Icjrm nf cr\'stals. The abst-nce 
of crystals then, means that Cdiideiised milk \\-ill not settle but 
experience has shin,\-n that it is a ]iractical impossibilit}' to maim- 
facture sweetened cinideiised milk whicln cmitains mi su,yar cr}'S- 
tals. Suc;"ar crystals are alwuA's jiresent in it, ami the fact that 
the milk is nut samh' or t;ritt\'. dues not uecessarii}- mean that 
it ^\'lll not settle. NcAcrtheless, the remowd of cunditions con- 
duciA-e of sandy or i^ritt}- milk", diminishes the tendency" of the 
formatiiin of su^ar sediment. The successful and uniform pro- 
duction of condensed milk that diies not settle, ]io\\e\'er, in\-ol\^es 
additional conditions that arc not controlled b\' the factors 
causing' g"ritt_\' milk. 

Effect of Density on Sugar Sediment. — One nf tlie chief of 
the^e conditions is the dcnsit)' of the condensed milk. The thin- 
ner the condensed milk, the .greater the difference between the 
specific gra\'it\' of the liquid jHirtii'ii and that of the sugar crys- 
tals; therefore, the more readih' A\'ill the crystals sink to the 
bottnm. The viscositv cif thin condensed milk, also, is less than 
that of thick milk", oti'ering less resist.ance to thi.' force of ,gra\'ity 
of the crA'stals. fn the manufacture iif sweetened condensed 
milk that has the luaiper densit}', about 2.? parts of fresh 
milk are condensed into one part of condensed milk. If the 
e\-aporation is stopped sooner, so that the ratio is much less tliaii 
2.3 to 1, the condensed milk is usually ton thin to hcdd its su,gar 
crystals in suspension unless its specific ,gra\-itA" and \-iscosit)- 
are increased by the addition nf niore sucrose. 

Effect of Fat Content on Sugar Sediment.- -The i)er cent of 
fat in milk, also, influences the s[iecific gra\-it}- df the condensed 
milk, and therefore, has some effect on the settling (if the sugar 



230 SwEKTl'NKD CONDKNSKD MlLK DlvFIXTS 

crystals, althougli to a relati\ely slight degree. Nevertheless, 
sweetened condensed skimmed milk will settle less readily than 
sweetened condensed wh.ole milk. 

Effect of Cane Sugar Content on Sugar Sediment. — The per 

cent of cane sugar materially influences the specific gravity and 
viscosity of the condensed milk. Milk with a high per cent of 
sucrose is heavier, more viscous and drops its sugar crystals 
less readily than milk with a low per cent of sucrose. 

Turning the Cans to Prevent Sugar Sediment. — Concerns 
who have been continual!}' troubled with settled milk often resort 
to the practice of turning their cases daily, or at other regular 
intervals. This keeps the precipitated crystals in motion, but 
it does not pre\-ent the settling entirely. Moreover, milk des- 
tined to settle, as the result of defects in the process, cannot 
be prevented from dropping its crystals after it lea\'es the fac- 
tory. Some concerns have stor)ped to printing on their labels 
statements similar to the following; "A sediment in the bottom 
of this can indicates that this condensed milk is absolutely pure 
and free from harmful ingredients." .\dvice of the above de- 
nomination is obviously ridiculous as well as untrue. 

Adding Powrdered Milk Sugar. — It has been explained that 
after the condensed milk is cooled it contains sugar crystals. If 
those crystals are large, their cubic content is relatively' great 
in proportion to their surface. Their buoyancy is, therefore, 
sufficient to overcome the resistance of the surrounding liquid 
and they will drop to the bottom, ffirming a sediment. If these 
crystals are very small and fine they are not objectionable and 
they usually do not cause settled milk, because their gravity 
force is insufficient to overcome the resistance of the \'iscous 
syrup. It has been further shown that the size of the sugar 
cystals is largely determined by the size of the first crystals 
present. Experience has demonstrated that the addition to 
the condensed milk before cooling, of \cry fine sugar crystals, 
such as powdered miilk sugar contains, encourages the formation 
of very small crystals and tends to guard against the develop- 
ment of large and coarse crystals during subsequent cooling. 
Hence sugar sediment may be greatly minimized, if not entirely 
prevented, by adding; to the hot sweetened condensed milk, a 
small amount of powdered milk sugar, at the rate of a tea- 



SwKETKNliD C0NDEi\Si;u ]\IlLK DUFIXTS 231 

spoon full of milk sugar per one hundrt-d pounds of condensed 
milk. The milk sugar must be added as scon as the condensed 
milk comes from the pan, if the milk is allowed tij cool before 
the milk sugar is added, its effectiviness is largely lost. 

In order to insure the full desired actinn of the added pow- 
dered milk sugar, this powder must be transferred to the con- 
densed milk in such a manner as to prexent its fcjrniation into 
lumps. It must be e\'enly and tinely distributed o\er and in the 
condensed milk. The use of a flour sifter has been fotind most 
suital)le for this purprjse. 

Thickened and Cheesy Sweetened Condensed Milk. 

General Description. --The term "thickened and cheesy" con- 
densed milk applies to condensed milk that has become thick 
and in some cases solid. This is a \-ery CDmnmn trouble with 
milk manufactured in late spring and earh- summer. The milk 
thickens soon after its manufacture and continues thickening 
tmtil it assumes the coiisistenc}" of scift cheese, withnut the de- 
velopment of acid. In this condition it usually has a pecidiar 
stale and cheesy rta\-or, disagreeable to the palate. Such milk is 
in-\-ariably rejected un the market. 

Causes and Prevention : Effect of Colostrum on Thickening. 

— It has been suggested that this spontaneotts thickening is due 
to the presence in tlie fresh milk of colostrum milk, Ijecause this 
defect appears at a time when the majority <jf the ccjws supply- 
ing the condensery freshen. This explanation can hardly be 
considered correct and there is no experimental e\idence a^-ail- 
able substantiating it. If the presence rif culostrum milk were 
the cause of it, the thickening would take place during the 
process, as the result of the action of heat (jn the albuminoids. 
This is not the case. This thickening begins some days and 
often some weeks after manufacture and increases as the milk 
grows older. 

EfTect of Cow's Feed on Thickening. — Again, the cause of 
this defect has been attributed to the change in feed, the co\\-s 
being turned from dry to succulent feed at the time wlien this 
tendenc)' of the condensed milk to thicken nccurs. There is 
no reliable e^•idence, ho\\e\er, of ho\v the succulent pasture 



232 Swi'H'i'RNivD CoNDL'.NSi'.D Mii^K Divfivcrs 

tjrasses nn wliich the cows feed can 1)riiin" a1i("iiit tin's tliiclvciiinj^' 
actiiin in llic condensed milk. 

Effect of Bacteria on Thickening. — A tliird and far rnrjre rea- 
sonable explanation is that tbds ihickcniiiL^' is the residt of a 
fermentation process. It is c|uite prohahle tliat the thickeninp; 
of sweetenefl condensed milk is closeh' related to the sweet- 
curdling- fermentation in fresh milk. The sweet-curdlinc;- of 
fresh milk is a fermentation cliaracteristic of, and frequent dur- 
ing- late spring and summer, ft is caused ]>y certain species rif 
bacteria \\dii(di are capable of producing a rennet-like enzyme, 
wliich has the power to curdle milk in the sweet state. These 
bacteria are known to be closely associated ^\ith dii^t and filtli, 
especially from the feces, and gain access tri the milk usu.ally 
on the farms ^\'here the jiroduction and handling of milk is not 
accomplished under most sanitar)' conditions. 

It is further known, as the result of analyses that, in spite 
of tlie large ])er cent of cane sugar ^vhich sweetened condensed 
milk contains, the bacteria in it increase with the age of the 
milk. The thickening of the sweetened condensed milk in early 
summer, therefore, ^'cry probab)ly is the result of a slow curdling 
of its casein, caused l)y enzymes wdiich are pi'oduced by bacteria. 
It has further been demonstrated that condensed skim millc 
tliickens more readily than conclensed T,vhole milk, which may be 
explained by the fact that condensed milk ^\■ithout butter fat 
represents a more fa\-orafjle medium for bacterial gro\\'th. Fur- 
thermore, it has lieen conclusi\-eh' demonstrated bv the writer 
and others that the addition of cane sugar to condensed milk, 
in excess rif that |)resent in noj-mal couflensed milk, greath' 
retards thickening. 1'his fact suggests that the higher per cent 
of sucrose has an inhibiting effect on tlie enz\me-pr(idncing bac- 
teria, and jierhaps, on the action of the enz\-me itself. This 
C(Tnflensed milk- defect can be jirexenled cntireK- b\- using, duriuL; 
the summer UKJUths, eighteen i)(-iinids of sucrose jier one hundred 
l)Ounds of fi-esh millc, so that the condensed milk- contains about 
45 per cent suci-ose. 

Effect of Finishing in Pan With High Steam Pressure on 
Thickening. — Abnijrmally thick condensed milk is also the result 
of (iverheating the condensed n-iilk in the \'.-iciuini prui 1ow',-ird 
the close of tiie process. The batch should be linished with low 



vSwEETKNED CONDENSKD MiLK DEFECTS 233 

Steam pressure in the jnckct and cciils, not to exceed In-e prmnds 
rif pressure, and the milk slicadd lie drawn I'reim the |"ian at once 
after crmden^atinn is eomideted. 'I'he ^ujicrlieatiuL;" to A\diich 
the condensed milk is sulijected in the ]iau. wdien finishing' with 
a hiq-h steam iircssure in jack'et and coils, oi- when the milk is 
not drawn frum the pan jirrimptlv wlien the \-acuum pump is 
stopped, rir when an effort is made tij condense to a A-ery high 
deg'ree of crincentration. is ahiTist sure to cause the finished 
product to s[)Ontaneously thicken A\'!tli age and this tendency 
is especially ]irfin(juuct'd in the spring and early summer. 

Effect of Age on Thickening. — Finall}-, all sweetened con- 
densed milk has a tendencv to thicken with age. I'.xpusure tcj 
high storage temperature (summer heat I hastens this action, 
'fhe rapidity nf thick'ening in steerage increases with the increase 
ill tem])eratui"e. ddiis tendency is \-ery much reduced, therefore, 
1))" ])rotecting" the goods frnm high temper;itures and by storing; 
them below 60 degrees F. (See Chapter X\^II on "Storage,'' page 
191.) 

Lumpy Sweetened Condensed Milk. 

General Description. — Fump< of \-ar_\'iiig denominatiijiis are 
not infrequentlv found in sweetened enndeused milk. The}' ma}', 
be soft and permeate the ciuitents oi the can througlK^ut, or may 
:ippear espccialh- in the form nf a "smear" alnng the seams ol 
the can: r,r again, they ma.}- tLiat cm the surface, in which case 
thcA' are usuall}- hard and cliees}-, and either white cir yellow in 
color. Their jirescnce gives the ci intents nf the can an uiisighth- 
appearance at Ijcst, and in man}- cases, the}- spoil its fla\-or. 
ThcA- naturalh- suggest to tlie consumer that something is wrong 
'with the condensed milk, and cause him to reject the whole 
package. 

Causes and Prevention. — The chief causes of lumpy con- 
densed milk are: ]ioov c|uality of fresh milk, unclean pipes in fac- 
torA', milk from fresh ciiw-s, acid tlux in tni cans, and unclean 
and contaminated tin. cans. 

Poor Quality of Fresh Milk and Unclean Factory Condi- 
tions. — Upon opening the can i:if condensed milk, e\-en shortly 
after it is filled, the lid is co\-ered with large and small lumps and 
specks sticking tci the tin, presenting a very uninviting appear- 



234 SWKI'TI'N'KD CONOF.NSKI) MiLK DKFECTS 

ance. This ciiiulitinn can usually he tract-d l)ack to a poor qual- 
ity of fresh milk, containinj; too much acid. \'ery often, too, the 
cause lies in the factory itself, where it is due to lack of clean- 
liness. A thorous^h inspection rif milk pipes and pumps generally 
shows accumulations of remnants rif milk which f^et into the 
milk of the succeedint^ hatch. Where this condition exists, it is 
noticeahle that the first hatch of the day contains more specks 
and lumps than the succeeding ones. These lumps do not, as a 
rule, grow larger in size nor increase in numher with the age of 
the condensed milk, hut they injure its appearance to the eye, 
and certainl_v cannot add to the wholesomeness of the milk. They 
might easily be accompanied by the formation of ptomains. 
A more rigid inspection of all the fresh milk as it arrives at the 
factory and thorough scouring of all milk tanks and milk pumps, 
pipes and conveyors usually jirexents the recurrence of this 
defect. 

Milk from Fresh Cows. — During early spring there is a 
strong tendency of the jacket and coils in the vacuum pan to 
become coated with a thick layer of gelatinous and lumpy milk. 
This is probably due to the fact that milk during these months 
comes largely from freshened cows and may contain some colos- 
trum milk which coagulates \\hen subjected to heat, or that 
the proteids of milk from these fresh cows are abnormally 
sensitive to heat. This thickened material usually does not leave 
the pan until most of the condensed milk has been drawn off. 
It, therefore, appears in the last one or two cooling cans. If 
the milk in these cans is mixed with the rest of the condensed 
milk, the lumps will appear again in the tin cans. The last cans 
drawn from the i)an should, therefore, be kept separate. The 
contents of tliese remnant cans may he redissolved in hot water 
and should be recondensed in a succeeding batch. In this way 
the manufacturer sustains practically no loss. In order to pre- 
vent these lumps from getting into the cooling cans, some fac- 
tories attach a strainer to the outlet of the pan. This practice 
is as unnecessary, as it is damaging to the milk in the pan. 
The straining greatly retards the removal of the milk from the 
pan, and the milk is held in the hot pan so long, as to cause 
partial superheating which is otherwise detrimental to its quality. 



SwEETIvNED CONDI'NSKD MiLK DEFECTS 235 

Comparative Composition of Gelatinous Coating of the Jacket 

and Coils and of Normal Condensed Milk of the Same 

Batch, Made April 23, 1908. 

Ccating of Jacket Xdrnial Condensed 
and Coils Milk- 
Moisture 24.76 per cent 30.34 per cent 
Lactose 13.12 " 13.16 
Fat 0.50 " 7.44 
Curd 8.14 '•• 7.30 
Ash 1.42 ■' 1.80 
Acid .33 " .40 
Sucrose 41.36 " 40.02 



'^8.63 per cent 100.46 per cent 

The aijo\c analyses were made in order to determine the 
difference in chemical com])osition between that part of the batch 
which, in tiie sprinj:^ of the year, fc^rms a gelatinous coatiny on 
the jacket and coils and that |)art which remains normab The 
figures do not show as great a difterence, as the physical com- 
parison of the t-wo prciducts ^\ould suggest. Possibly the most 
significant point these analyses sliow is that, while the proteids 
in the coating are higher, the ash is lower than in the normal 
condensed milk. 

A large portion of the ash of milk is present in chemical 
combination \\-ith the casein, which does not curdle bv heat, 
while the albumin, which is coagulated bv heat, contains onlv 
a very small amount of ash. Therefore, the fact that an increase 
in the proteids of this gelatinous coating is accompanied by a 
decrease in the ash content, \\<:)uld suggest that the proteids of 
the coating of the jacket and coils consist of more albumin and 
less casein than the proteids of the normal condensed milk of 
the same batch. Since this coating of the jacket and coils occurs 
only in the spring of the _\ear, \\hen most of the cows freshen, 
it is reasonable to assume that this coating is the result of the 
acceptance at the factory of milk too soon after cahing and 
which contains excessi\-e quantities <if proteids and other sub- 



236 vSwiviCTUNiiD Condensed Miek Dju'Ects 

stances which arc highly sensiti\e to heat, such as alljumin, 
colostrum, etc. 

Excess of Acid in Condensed Milk and Acid Flux in Tin 

Cans. — The presence in the conclensetl niill^ dl organic and 
mineral acids, in excess of the amount which imi-mal fresh milk- 
contains, is conducive of the formation of lumps. 

Excessi\'e amounts of acid in condensed milk ma}^ Ix; the 
result of fermentations, usually due to a ])Ofir quality rif sugar, 
or of the use of acid flux in the making and sealing of the tin 
cans. Condensed milk that sho^^•s acid or gaseous fermentation 
usually contains lumps. The acid Avliich it flc\-elo]Ts as the result 
of the fermentation, curdles the casein \>ith which it comes in 
contact. 

One of the most common channels throu;.;h wliich condensed 
milk mav fiecome contaminated ^\•ith acid mechanicalh-, is the 
use of cans, in the manufacture and serding of \\'hich acid flux 
was used. The acid flux gcneralh' used contains zinc chloride. 
The flux precedes the solder and some of it is hound to sweat 
through the seams into the interior of the cans. This type of 
lumps usually has a ])ink iir brownish-red color, especialh* in the 
case of consideraljle cpiantities of acid flux. Zinc chl(-iride is a 
highly poi'Jonous product arid its use m the manufacture of tin 
cans, which are intended for receptacles of human food, should 
be prohibited by law. Aside from its injurious effect on th.e 
health and life cjf the consumer, its presence, e\"en in small quan- 
tities in condensed milk, is a detriment to its market value. In 
such cans there accumulate, usully along the seams, lumps and 
smeary substances which ha\-e been found to ci'usist of casinate 
of zinc. 

Most commercial sifldering flu.xes consist lai'gelv of zinc 
chloride and are highh' aciil, although mam' of these are ach'er- 
tised as acid-free lluxes. In order to a\oid ihe appearance in con- 
densed milk of lumps fr(.im this source, cans sluiuld be used, in the 
manufacture of which ;i strictly acid-free llux is used and ^\■hich 
are sealed with acid-free flux. \)r\. |lo^\■dere(l resin or resin 
dissolved in alcohol ,r gasoline are h.arndess in this respect and 
are just as effectixe lluxes, as ;icul llnx, 



SwiiiiTENtD Condensed Milk Defects 



237 



Buttons in Sweetened Condensed Milk. — Buttims. as known 
to the condensed milk manufacturer, rei>resent a type f'i lumps, 
different from those previously described. Buttons are lumps 
(jf curd of a firm and cheesy consistenc\'. The)' usually float on 
top of the condensed milk in the can or barrel. They are suffi- 
ciently firm units so they can he readil\- remo\ed and \\ashed 
free from the condensed milk. The}- are of \arying sizes, 
depending on the age of the condensed milk and the temperature 
at which it was stored. The (dder the milk and the higher the 




rig-. 81. 

Typical tiuttons of different sizes — All signs of mold Kave disappeared 

Courtesy of L. A. Rogers, U. S. Hairy Division 



Storage temperature, the larger the buttons. Most of the but- 
tons are about one half inch in diameter but frequently the\- 
are of sufficient size to co\'er the entire surface of milk in the can. 

Idiese buttons have a whitish-brown to yello\A-ish or reddish- 
brown appearance. They appear in old sweetened condensed 
milk more frecjuently than in milk that has been in storage for a 
short time only. They are entirely absent in freshlv made con- 



238 SwKKTRNED Condensed Mii,k Defects 

deiised milk. They Iheniselves have, and they give the con- 
densed milk, a cheesy, stale flavor and lend the entire product 
an unsightly appearance. They de]3reciate the market value of 
sweetened condensed milk. 

Causes of Buttons. — Experience has demonstrated that but- 
tons are mosi prone to appear in stored condensed milk, in the 
packing of which no attention was given ti i sanitary conditions 
in the factory and of the cans or barrels, and that the use rif 
clean sterile cans and barrels and a high standard of sanitation 
in the handling of the product before packing greath' minimizes 
this defect. That they are the result of biological action, direct 
or indirect, is fairly obvious, and the fact that the milk during the 
process of manufacture is heated to temperatures destructi^-e to 
most "\'egetative types of germlife, strongly suggests, that they 
are the product of recontamination of the linishefl product. 

Rogers. Dahlberg and Evans' of the United States Dairv 
Division in\'estigated the causes and control of buttons experi- 
mentall}'. They found that the buttons are caused by the growth 
of the mold Aspergillus repens, and possibly b}' other molds; 
that the development of the mrdd colony is restricted bv the 
exhaustion of the oxygen in the can or barrel, and that the button 
itself is probably due to enzyme action, continued after the 
death of the mold. 

These findings corroborate earlier experimental results bv 
the author, who was unable to dcA'elop growing mold colonies 
in normal sweetened condensed milk from inoculations with full- 
grown buttons. 

Rogers and his co-workers demonstrated that the time re- 
quired for the development of the \'arious stages resulting in 
button formation \aries with temperature, amount of air a^'ail- 
able and possibly other factors. The mold colons- usually ap- 
peared in ,^ to 10 days. A'Jold growth is supposed to cease in 
two to three weeks on account of the exhaustion of the air. In 
one month a reddish-brown discoloration became quite evident 
and at the end of two months the 1)utton had usually assumed 



^ L. A. Rogers, A. O. Dahlberg and AMce C. Evans, The Cause and Control 
of Buttons in Sweetened Condensed Milk, Jour. Dairy Science, Vol. Ill, No. 
3, 1920. 



Sweetened Coxdexsed Milk Defects 



239 



definite form. The disiiiteg'ration oi the mold livfthae (hlamentl 
proved to be a slow process, extending o\-er 3 to h months. 

Prevention of But- 
tons. — The prevention 
or control oi hesc Viut- 
tons ma-\" l)e accom- 
])lished b\' : 1 , e.xclu- 
sicm (if contaminatii m. 
2. low temperatm'e. ,v 
exclusion of oxygen. 

Exclusion of Con- 
tamination. — ^Contam- 
inatiiin of the cmi- 
densed milk \\Mth hut- 
tnn-forming' molds is 
most likeh- to occur 
during the conling. 
holding and filling 
operations and as the 
result of contaminated 
cans and barrels. 




rig-. 82. 

Button in growing' state, molds 
still very evident 

Coiirte."!y of L. A. Rogers, U. S. 
Dair>' Division 



In conden«erics \\diere the milk is cooled b}' the old method 
— in open 10-gallon cans, revolving in a cold water tank and 
stirred with wooden paddles — it is not difficult to understand 
the reason for l:jutt(^ns. In this s}'stcm the condensed milk is 
exposed to the air for hours, the 10-gallon cans and the wooden 
paddles are never sterile and are an almost sure source of con- 
tamination, unless special precautions concerning the sanitary 
condition of cc|ui]Mnent and of the air are ol)served. 

In condenseries which use the C(Tntinuous plan of cooling 
and hi^ilding cif the s\\-eetcned crmdensed milk, the product is 
protected against the atmosphere of the factory from the time 
it leaves the vacuum pan until it enters the tin cans, and if 
this equipment is kept clean and is steamed out thoroughly 
before use, which is readily and quickly done with this type 
of equipment, contamination should be A-ery largel}- eliminated 
and buttons guarded against. 



240 SwKTvTKNKD CONDUNSKD MiLK DEFECTS 

The cmjity tin cans in man}' of tlic plants are kept under 
undesirable crniditiiins. Tliev are exposed to diverse channels 
of contamination dnrinq transportation to the factory and dur- 
\nff storage in the factiir\-. If these contaminated cans are sub- 
sequently filled with the condensed milk, contaminaticm is un- 
avoidable and buttons are likel}' to follow. 

The tin cans should thereftire lie iimtected against a\-oidable 
contamination, or better vet. they should lie sterilized before 
filling. 

A practical sterilizer of empty cans may be readily devised 
by permitting the cans to pass bottom-side-up over a series of 
gas flames, under a hood. This method is used successfully 
in some of the Etn-opcan condenseries and has for them solved, 
in a large measure, the prevention of buttons. The caps and 
filling machines ob^•iously should recei\-e such treatment as to 
prevent them from becoming sources of contamination. Barrels 
should be steamed till piping hot and then paraffined, before 
filling. 

]n factories with \\-r)oden floors where the filling and scaling 
is done, the danger of mold contamination is much greater than 
in the case of concrete floors. 

According to Thorn and Ayres"' the spores of the mold Asper- 
.gillus repens, as well as of most other common molds, are killed 
in 30 minutes at 140 degrees F. The preheating of the milk in 
the hot wells, wdiich is done at 180 degrees to 200 degrees F., 
and again evaporation in the A'acuum pan at 135 to 150 degrees 
F. are, therefore, sufficient to destroy any mold present in the 
original milk, so that the cause must be confined \cry largely 
to contamination after the finished ]ir(Tduct leaves the vac- 
uum pan. 

Low Temperature. — The growth of most molds is retarded, 
if not entirely inhibited at low temperatures. This also is the 
case with the button-forming mold Aspergillus repens. Rogers 
et al., state that this mold grows \-cry poorly at temperatures 
(if 68 degrees F. or below. They re])ort that they ha\'e ne\-er 



1 Thorn and Ayres, Effect of Pasteurization on Mold Spores, Jour. Agr. 
Res., Vol. VI, 153-166, 1916. 



SWKRTENKD CoNDENSfiD MlI,K DF.FKCTS 



241 



observed Inittons nn cnndciiscd milk held at ('■S de,[;rees ]\ or 
below. These temperature limits are not enrrribnratcd l)v exper- 
iments hjy Ilunziker, nor 1)\' the expei-ience of the manufacturer. 
In commercial manufacture, the stora.i^e of sweetened condensed 
milk at 68 de.^rces 1^. will slmw C(i]-)ii-)us bultnn furmation, if such 
milk CLintains h)utton-fi irnun- spures. Reasonabh- sure prc\-en- 
tion cif buttons may be seciu'er! ]>y ImldinL;' the sweetened con- 
densed mill-: at about .^0 dei^rees F. or Ijclnw. 

Exclusion of Oxygen. — ]\I(ilds need air b.r their life and 
growth. They cannot de\-eliip in the absence of oxygen. Accord- 




riif. 83. 



rig-. 84. 

Absence of 'buttons in 20-incli 
vacuum 

Courtesy of I^. A. Rogei-.s, JJ. S. Dairj' Division 



Button development uncler 
atmosperic pressure 



ingly Rogers et al., b}' careful experimenting, found that b^- seal- 
ing the cans under a \'acuum of 20 inches or more, Ijutton-for- 
mation in condensed milk contaminated with button-forming 
molds could be entirely preA'cnted. 

It is proljable that a similar effect, if practicable, could be 
accomplished also by charging the cans ^\•ith an inert gas to the 
exclusion of atmospheric oxygen. 



242 ,Swi';i'.ti':ni*.i) Conim'.nsi'.d R'lir.K Di^fivCTs 

Blown, or Fermented Sweetened Condensed Milk. 

General Description. -()ne of tlie moNl disastruus troubles 
in the manufacture (jf s\\cclcuc(l cnndenscd millc is the appear- 
ance of "sweh heads." Tliis term is applied Pi cans of con- 
den.sed milk, the contents nf vvliicli liaAc uuderc.oue gaseous fer- 
ntentatii-n, the residtiui; ]i)-essrire causiui;- tlie ends of the cans 
to bld^e or s\\'ell. and lref|uentl\- tn Inirsi npeu tlie seams. In 
the case of barrel t^ixids, tlie jjrcs^ure ma) cau^e the barrel head 
to blow out. This j^-aseiius fermentation is usually, thou.E^h not 
alvva}-s, accom]).anied In- the dex'eli ipment cjf acid and the for- 
mation of lum])s. 

This fermented mi]]< is worthless for any jnir])ose and means 
a total loss tr) the manufacturer. The loss is jjencrall}' aug- 
mented bv the fact that this trouble does not Ijecome noticeable 
at once; its development requiix's sexeral \veeks, so that large 
rpiantities of cc)ndensed mill-; ma}- ]ia\-e Ijceu manufactured before 
it is apparent that the milk is defecti\e. Some of the goods ma}' 
have reached the market before tlie cans begin to swell, in wdiich 
case the reputation of the ' respecli\'e brand is jecipardized. In 
some instances entire batches ^Imw this defect, while in others 
only a few cans oi* cases of eacli batch are blown. 

Causes and Prevention. — This defect nia_\' Ik- brought abriut 
through warious channels. In most cases it is due tii contamina- 
tion of the milk, on the farm oi- in the factorw witli siJCcific 
micro-organisms which are capal)Ie of fei'nienting one or more 
of its ingredienls, in spite of tlic prcserxatixe .action of the 
sucrose; or the condensed milk' ma_\' cont.ain highly fermentable 
substances such as glucose or im'crt sug.ar, so th.at the germs 
normally prescnf in the corideust'd nnik' becunic aclixc and pro- 
duce gas; or the milk' m.'i\- not be condensed {<> a sufficient degree 
of concentration, or ni.ay not eunl.-iui ,-idei|uate (|uaiitities of 
sucrose, t<j render it immune to tin/ bacteria iiorni.alK' present. 
The cans may also liulge without b.'icterial action, .as the result 
(jf exposure to .a wide ranL;e of tem])(.'ratnres, causing mechanical 
ci'mtraction and e.xpansiim of the contents. 

Contamination with Specific, Gas-Producing Bacteria and 

Yeast. — 'I'liis is by far the most common cause rif bli-iwn milk. 
While the micro-organisms which, undei' normally sanitary pro- 



Swi-;i',ti-;ni';d CoxmiNSivD AIilk DiiFiicxs 243 

duction nf milk and factiir\' ci inditiniis, i^'ain access in the con- 
densed milk, arc lai"t;"el\' inhibited and do not ferment the sweet- 
ened condensed milk, there are certain specdic forms of bacteria 
and yeast \\diose ,L;"rci\\th is not retarded li\' the concentrated 
sngar solution of this jiroduct. Contamination of the condensed 
milk with these specific organisms is nsn.al!}- the result of hio-]ily 
unsanitary conditions in the handlini;' oi the condensed milk. 

The products of ferment.ation depend on the particular t}']>c 
and species of micro-ori^ani^ms in\"ol\-ed. fn most cases the 
sucrose is the chief constituent .attacked, i)Ut the lactose, also, 
is ca]ial.)le of q-aseous fermentation, thciunii instances of lactose 
fermentation in sweetened ermdeu'^ed milk are not common. 

The g'aseous fermentation of lactose is lariielv catiserl 1\\' 
f>acteria, veast and molds wdiich. contain the lactose-splittinc: 
enzA'me 'dactase," whicli has the ])o\\er of hydrolizin/^' the lac- 
tose. \\'hile the '-]iecies of or^j'anisms which cam^e lactic acid 
fermentation from lactose are very numerous, those contairunp; 
the enz)-nie lactase and thereby causini;' ,u'a"^eous termentation. 
from lactose, are less freijuent, at least, as far as then- access to 
milk .and cijudensed milk is concerned. It is generally under- 
stood, thouLdi not e.xperinu'ntall}' pro\-en, that species of ndcro- 
ors^anisms which do not contain the enz}-me lactase hax'e no 
q'as-prodticinL;' action on kactose. 

The i^reat maiorit^' of cases of jjase.ms lermentati("in ot 
sweetened condensed ndlk are the result of the action of niicro- 
org'anisms on the sucr(ise, especiallv those which contain the 
enzyme "inA-ertase." The majority of Acast^ seci'ete in\-ertasc 
and ferment sucrose, pjroducing- .alcohol and carkjon dioxide to 
the same extent as in the case of glucose fermentations. The 
process is considerabd}- sk.jwer, howex'cr, esi>ecially at the start, 
o«dng to the fact that in\"ersiou cif the sucrijse must precede 
fermentation. For thi?^ re.ascm, g.aseous fermentations of s\vect- 
ened condensed milk do not become noticealde until the product 
is one or se\-eral weeks cdd. 

Contamination with Yeast on the Farm, -In most cases of 
veast fermentations oi sweetened condensed milk, the scmrce of 
contamination lies in the factc^ir}-. AMiile such contamination 
ma)' and often dries iiccur on the farm, the }-east cells, tliough 
the\- nia)- be spore-bearing, are destroyed by the heat to which 



244 



SwEUTijNi'.D Condensed Milk Defects 



the fresh milk is ,sul>jected in the fore warmers and before it 
reaches the \'acuum jian. The thei'mal death point of all forms 
of yeast which ha\'e come to the attention of the writer in con- 
nection ^\'ith a \'ast number of in\estii;'ations of fermented con- 
densed milk was jjelovv bSO degrees F. It all the milk is properly 
heated in the forewarmers to 100 degrees F. or over, there is, 
thercfVire, little danger of fermented milk, caused by contamina- 
tion of the fresh milk on the farm with A'cast. If, however, the 
heating is incomidctc, or if some nf the milk passes into the 
vacnnm pan without ha\'ing been properly heated, there is dan- 
ger of milk, contaminated with these yeasts, to result in fer- 
mented condensed milk. 

Contamination with Yeast in the Factory. — As previously 
stated, veast fermentation of cinidcnsed milk can almost in- 





Tig. 85. Gaseous fermentation In 
sweetened condensed milk' 



Tig. 86. Yeast cells causiner 
g'aseous fermentation 

This species is cap.ible of 
fermenting sugar solutions 
containing S5% sucrose.^ 



\'ariably be traced b;ick to cemtamination in the factory. After 
the milk lea\'es the fdrcwai'mers, or hot wells, it is ne\'cr again 
lieated to temperatures high enough to destroy these destructive 
yeast cells. The channels thrnugh \vhich yeast contamination 
mav occur in the f;icti)r\- are manv. 



' Hunzlker, A Study of the Causes of Fermented Sweetened Condensed 
Milk, 1910. 



SwEETliNKD CoNDIiNSIiD MlLK DEFECTS 245 

Contaminated Sugar. — The sucrose itself may Ije contam- 
inated with }'east. This is frequently the case and especially so 
if the sui^ar is exposed to dampness, and if flies, !)ees, ants or 
cockroaches ha\-e access to it, 

A^-ain, the suc;ar may reach the milk throus^-h a sugar chute. 
The lower end of the chute is usually located directly over the 
steaming' milk in the hot well. The A'apors arising" from below 
may 1)C condensed in the chute, causing its inside walls to be- 
come damp, and sugar will adhere to the damp surface, forming 
a crust. If the crust is not remri\-ed daily, its contamination with 
A'cast an.d (jther dangcr(')us micro-organisms is almost inevitable 
and whene\'cr this crust peels off and drops into the milk, the 
cmitamination ma\' lie carried into the finished product, gi\'ing 
I'lst; to gaseous fermentation. 

Contaminated Machinery and Milk Conveyors. — Remnants 
fif milk may lodge in th.e condenser, in the T,'acuum pan, in the 
pipes conx'eying the milk and condensed milk, in the cooling 
cans or cuils, in the sup])]\- tank nf the tdling machine, or the 
fdling machine ilself. These remnants are all subject to con- 
tamiriatiiin and may become the source of fermented condensed 
milk. The strictest attentiim tn scrupidiius cleanliness and cou- 
tinuous inspection of all parts nf c(inA-e\-i irs and apparatus which 
come in contact with tlie milk are the nnh- consistent safeguards 
against trouble from this source. 

Contamination Through "Cut-opens." — It is customary to 
empt}' the contents of sample cans which are cut open for any 
purpose, back into the condensed milk of succeeding batches. If 
these samples happen to be contaminated with the fermenting 
germs, the defect is naturally propagated from batch to batch 
and it is exceedingly difficult ti^j locate the source of the trouble. 
It is ob\'ious that all suspicious "cut-opens" should be rejected 
and that all "cut-opens" that are utilized should be emptied into 
the hot \\'cll where their contents are boiled up again. 

Dangerous Effect of Poor Quality of Sugar, — vSweetened 
condensed milk is not sterile. There is no part of the process 
tliat would render it sterile and, from the time it leaves the 
vacuum pan to the time when the tin cans are hermeticallv 
sealed. it is exposed to contamin~ati(.)n with microbes, even 



246 vSwiviiTKNKD CONDKNSHD MiLK DKFIvCTS 

though the factory obser\es the most rigid attention to scrupu- 
lous sanitation and cleanliness. Most of these microbes are 
harmless and their growth is inhibited by the preservative action 
of the cane sugar. If, however, a poor quality of sucrose is used, 
which ma}' C(_>ntain traces of invert sugar, or acid, etc., many of 
these common species of micro-organisms, harmless in normal 
condensed milk, find an opportunity to develop and cause gase- 
ous fermentation. The presence of invert sugar makes unneces- 
sary the action of in^■ertase in order to start fermentation ; thus, 
microbes which do not secrete invertase and are otherwise harm- 
less, may become detrimental in the presence of invert sugir, 
added to the milk in the form of a poor C|uality of cane sugar. 
In a similar wiay the use in condensed milk of commercial glu- 
cose, as a substitute of a part of the cane sugar, and in order to 
reduce the cost of manufacture, is bound to cause disastrous 
results. Nothing but the best refined, granulated sucrose should 
be used, the best is the cheapest. 

Dangerous Effect of High Acid in Milk. — Acids have the 
power of inverting sucrose. The inversion by acid is especially 
active in the presence of heat. The milk in the vacuum pan is 
condensing at 130 to 1.^0 degrees F. These temperatures are 
most favorable to inversion of a portion of the sucrose in the 
presence of acid. The higher the acid content of the milk, the 
more active is the insersion. vSince invert sugar is the very 
ingredient necessary to cause bacterial action in the finished 
product, it is essential that the acidity of the milk to be con- 
densed, should be held down to the minimum in order to avoid 
trouble from this source. 

Contamination with Butyric Acid Bacteria. — Frequently the 
troublesome microbe is not a yeast, but belongs to a species of 
bacteria highly resistant to heat, and which fail to be destroyed 
by heating the milk to the boiling point. In this case, the con- 
tamination usually (iriginates on the farm. Organisms of this 
kind, which infest the milk on the farm in this connection, 
largely belong to the butyric acid group. The most prominent 
among them are Granulobacillus saccharo-butyricus mobilis or 
Bacillus saccharobutyricus. Bacillus esterificans. Bacillus dimor- 
phobutyricus. The putrefac1ii\e forms of but}'ric acid organisms. 



Swi'HTENED Condensed Milk Defects 247 

such as Bacillus putrificus, Plectridium foetidum. Plectridiuni 
novum, etc., do not seem tij thrive in sweetened condensed milk. 

The contamination may occur from dust of hay and other 
fodder, grain, bedding, or the unclean coat of the udder and sur- 
rounding portions of the animal, nr from milking with wet and 
unclean hands, or from remnants of milk in unclean utensils. 

It is noticeable that the great majority of cases of blown 
milk appear during" late summer and early fall, when the crcjps 
are harvested and the air in the barn is frequently loaded whb 
dust from the incoming crops. Gelatin plates exfxjsed in the 
stable before and during the filling of silos sh(i\\ed an enormous 
increase of colonies on the plates exposed during the filling of the 
silos. Milk drawn under such conditions is naturally subjected 
to excessive Cdntamination, unless special precautions are oIj- 
served. 

A very common source of these but}'ric acid organisms also 
is remnants of milk in pails, strainers, coolers, cans and any 
other utensils with which the milk may come in contact, also 
polluted water used for rinsing the utensils. The cheese-cloth 
strainer, owing to the fact that it is difficult to thor(jug'hly clean 
and that it is very seldom really clean, is a very serious menace in 
this respect. Under average farm conditions, unless a new cloth 
strainer is used at each miilking, it is safe to condemn it entirely 
and to recommend the use of a fine wire mesh strainer cuntaining 
about eighty meshes to the inch. (.)n some farms the milk is 
held in a set of old cans which are kept on the farm and which 
never reach the can washer at the factory. Just before hauling 
time these cans are emptied into the clean cans from the factory. 
These old cans are often not washed properly and sometimes not 
at all. The remnants of milk in these cans breed these undesir- 
able germs and contaminate the fresh milk. It is obvious that 
such a practice is bound to jeopardize the finality and life of the 
finished p)roduct and may constitute a continuous cause of blown 
milk. 

Effect of Amount of Sucrose. — Since the sucrose contained 
in sweetened condensed milk is the chief agent preserving it, 
it is obvious tliat enough of it must be added to insure adecjuate 
preservative action. Experience has shown that about 39 to 40 
per cent of sucrose is required to preserve the condensed milk 



248 vSwEKTF,Ni?,D Condensed Milk Defects 

under a\-craf^c cunditions. A liicjlici ]")cr cent nf sucrose would 
naturally intensify the prescrvatix'e action and inhibit the growth 
of the bacteria normally jiresent more comjiletely ; but if enough 
sugar were added In also inhibit the growth of and make harm- 
less thcise ^■i(llent gas-])r( iducing butyric acid b^acteria and }'east 
cells, which thri\'e in sweetened condensed milk containing 40 
per cent sucrose, the product "■i\-ould be f)bjectionable from the 
consumer's point of view. The bigical avoidance of "swell 
heads" as the result of these undesii'able germs, therefore, must 
ever lie in prevention, rather than cure. The sanitary standard 
of production on the farm and of the process in the factory must 
be raised to and maintained on a le^el \^here the milk is pro- 
tected from contamination with these micro-organisms. 

The writer^ has isolated yeast from fermented sweetened 
condensed milk that produced vigorous gas formation in media 
containing as high as 85 per cent sucrose (600 grams sucrose in 
100 cc. whey bouillon). 

Effect of Too Thin Condensed Milk.— Condensed milk that 
is too thin is, also, prone to start fermenting, since it is deficient 
in the chief preser\'ing agents, i. e., density and per cent of 
sucrose. It is not safe to |:)ut goods on the market, with a ratio 
of concentration much less than 2.3 ;1, unless the amount of cane 
added is sufficient to raise the cane sugar content of the fin- 
ished product to 44 jjer cent or abo-ve. 

Effect of Excessively Low Temperatures. — The cans of 
sweetened condensed milk may also bulge in the case of cans 
with non-hermetical seals, exposed successively to cxcessi\-e cold 
and to room temperature. In this case, the condensed milk is 
entirely normal and unaffected, and the bulging is the result 
of mechanical contraction and expansion by cold and heat. This 
is possible only where the seal of the cans is not entirely her- 
metical. In the case of the Ciel)ee seal with the burr cap, and 
the A'IcDonald seal wdth the friction cap, the seal is not abisoluteh' 
air-tight. While the pores betw'een cap and can are microscopic 
in size, and niit large enough to permit the contents from leak- 
ing out, they arc sufficient to admit air. The cans are usually 
filled with the condensed milk at a temperature of about 70 de- 



1 Hunzlker, Results not pubUshed. 



SwEivTiiNED Condensed Milk Deeects 249 

screes F. Tf the filled and sealed cans are exposed to a A'er}" 
lo\\- temperature, as nia^- lie the case in winter, in store houses or 
in transit, the milk and the air in the cans contract. This con- 
traction is intensified In' the fact that the sweetened cioiidensed 
mi'k dries not freeze. Its concentration is so great that its freez- 
ing- point is usually below the mrist extreme cold storage tem- 
perature. This contraction of milk and air in the cans produces 
a partial A'acuum, causing air to be drawn into the cans through 
the microscopic ofjenings of the seal, \\dien the cans are sul)- 
sequenth' mo\'ed into places with a more moderate temperature, 
the milk and the air in the cans expand, but the milk on the in- 
side of the cans fiorms a seal preAX-nting the escape c<i the sur- 
[)!u.s air. The re-^idt is that tlie ends rif the cans bulge. Thi^ 
phenomenon has been experimentallv determined by the authcir.' 
While the contents of such cans are perfectly nrirmal, the pack- 
age suggests fermented milk and may be rejected on the market. 
It is e\'ident, from the abo\-e data, that the swelling of the 
cans, as the result of exposure tc) exces^i^'ely low temperatures, 
can readih' be aA'oided, either by protecting the cans against ex- 
cessiA-e cold, or b}' using cans that are sealed with solder. The 
solder-seals are hermetical S(} that no air can be draA\'n into the 
cans A\dien a partial A-acuum is formed in their interior as the 
result of the contraction of air and milk. 

Rancid Sweetened Condensed Milk, 

General Description. — Sweetened condensed milk ma}' de- 
\-elop a distinctly rancid flaA'cir and odor, a defect which renders 
it unmarketable. 

According to the best anthorit>\ there are many agents 
wdiich may be actix'e in the production of rancidity. The fact that 
in rancid butter are usually frjund to predominate certain species 
of organisms, such as the fungi of I'enicilium Cdaucum, Penici- 
liitm Roqueforti, Cladosporium but}-ri, (')idiu.m lactis, Actinonry- 
coces odorifora, }'east and various bacterial species, such as Bac- 
terium fluorescens. Bacterium prodigiosum. Bacillus mesenteri- 
cus, etc., and that these species are capable of making butter ran- 
cid, has led to the conclusion that the}- maA- be the cause of ran- 
ciditv, either fjy direct actioi-i, or V)y the seci-etion of fat-splitting 



1 Hunziker, ResuUs not published. 



250 SWKKTHNKD CoNDKNSKD MlI,K DEFECTS 

enzymes. ]t is, tiierefure, tjuite ])ossible that some of these spe- 
cies, or similar groups of species, may be instrumental in develop- 
ing rancidity in sweetened condensed milk. It has been further 
found that the milk products from certain indi^'idual cows, or 
cows under certain physiological conditions are more prone to 
develop a rancid flavor, than milk products from other cows or 
cows under other conditions. 

Relation of Polluted Water to Rancidity. — I'lilluted and 
filthy water is usually contaminated with fungi and bacteria 
belonging to the species enumerated above and whicli have been 
found to be able to produce rancidity. It is, therefore, m.t im- 
probable, where such water is used in the factory in the washing 
of cans, conveyors, kettles, pipes, etc.. in the condenser of the 
vacuum pan and in the cooling tanks, as is frequently the case, 
that the contamination of milk with it may result in the develop- 
ment of rancidity. 

Relation of Climate to Rancidity. — It is frequently claimed 
that condensed whole milk shipped to the tropics turns rancid, 
owing to exposure of this milk, rich in fat to a warm climate. 
Advantage is sometimes taken of this argument, to justify viola- 
tions of the law by skimming all, or a part of the milk before 
condensing. This matter has been thoroughly investigated. All 
experimental results show that sweetened condensed milk, made 
properly and in conformance with the law, and containing all 
the butter fat of the original whole milk, does not turn rancid 
at any temperature. 

Putrid Sweetened Condensed Milk. 

General Description. — Sweetened condensed milk is best 
when fresh. With age it gradually de\-e!ops a stale flavor which 
frequently develo])s into a putrid odor and flavor. 

Causes and Prevention. — The purer the fresh milk and the 
cane sugar, and the more careful the processor, the longer will 
the condensed milk retain its pleasant flaxor, proxided that it is 
stored at a reasonably low temperature. Age, however, will 
cause the best sweetened condensed milk to become stale. The 
appearance of the stale flavor is usually hastened when heating 
the fresh milk with direct steam; also, where the fresh milk is 
not heated to a sufficiently high temperature (below 176 de- 



SwKETENKD CoXDKN'SED MlI.K DkFIXTS 251 

grees F.) the condensed milk will break d<nvn rapidly with age. 
usually developing a putrid llavor and ndnr. This defect rarely 
appears where the fresh milk is heated to IJ^O degrees F. or 
abo^'e. This phenomenun is priibal)l}' due to the presence iu 
milk of active enzymes, such as galactase. gradually decompos- 
ing the proteids. The action of most of these enzymes is 
destroyed when the milk is heated to \7C> degrees F. or aljove. 

Metallic Sweetened Condensed Milk. 

General Description. — Sweetened condensed milk frec|uentl}' 
is pregnant with, a \ery distinct metallic fla\()r suggesting copper. 

Causes and Prevention. — This can usually lie traced back to 
an unsanitary condition of the dome of the \acuum pan. The 
sugar and acid in the boiling milk in the pan tend to cause the 
formation of cO])per oxide and copper salts, on those sections of 
the interior surface of the ]ian which are not dail}' completely 
cleansed. 

The dome of the pan is neglected in many condenseries from 
the standpoint of thorough cleaning. If it is permitted to go 
uncleansed for a considerable period of time, it becomes C(jated 
\vith copper salts and when the pan is again in ()|)eration, the 
boiling milk and its spray wash these metallic salts down, incor- 
porating them in the condensed milk. 

That the copper in the diime is being acted ijii can be very 
readily determined by wi]iing the inside surface of the dome oft 
with a wet sp<)nge, then analyzing the expressed liquid that 
the sponge has absorbed. This licjuid will be found to contain 
varying amounts of copper, according to the state of cleanness 
of the dome. 

In order to avoid metallic flavor in sweetened condensed 
milk, the dome should be washed down daily with similar care 
as is gi\'en the cleansing of the jacket, body and coils, and each 
morning, before the milk is allowed to enter th"e pan, the entire 
pan, including dome and gooseneck, should be thoroughly rinsed 
down with plenty of clean water. 

Brown Sweetened Condensed Milk. 
General Description. — Some of the sweetened condensed 
milk on the market has a brown color, suggesting chocolate pud- 
ding. In this condition it is usually rejected by the consumer. 



252 Unswi'.ivTUni'.d CoNDiiNsi-lo Milk DivFKCt?, 

Causes and Prevention. — All sweetened cundensed milk nnt 
lield at a Irjw temperature prows darkei- in cilnr with ap;e. Jf 
manufactured pr("iperlv and nrit exposed tei nnfa\'oral>le condi- 
tions, this In'own color appears xer}- c^raduall}' and not until the 
condensed milk is many montlis old. If ex[)oscd to hiL^h tem- 
perature in stora;;x* or transportation, when stowed ag'ainst the 
l>oiler room in the hold of the steamer, or lyin.q' on the shelves 
of the warm grocery store or drug store, etc., it turns brown 
rapidly. Condensed milk in cold storage retains its natural color 
indefinitely. A\'here milk is recondenserl (the condensed milk 
is redissoh'ed either in water or in fresh milk and condensed a 
second time), the product is always darker in color. This brown 
color is due to the oxidizing action of heat on both, the lactoi^e 
and the sucrose, a ])ortion of the sugar caramelizing. Experience 
has shown that the sugar is more sensiti\'e to the oxidizing 
action of the heat of recondensing, than when condensed the 
first time. 

ClIAPTF.R XXII] . 

DEFECTIVE EVAPORATED MILK AND PLAIN 
CONDENSED BULK MILK. 

The following are the chief defects of unsweetened condensed 
milk: curdy, grainy, separated and churned, blo\vn r)r fermented, 
brown, gritty, metallic. 

Curdy, Plain Condensed Milk and Evaporated Milk. 

General Description. — Curd)', unsweetened condensed milk 
is a term used for milk in ^\'hich a part of the casein is precip- 
itated in the form of lumi)s of \arious sizes. The appearance 
of lumps of curd in this ])ro(lnct is a defect that may render the 
goods unsalable. 

Causes and Prevention. — .Lumps are usually due to a poor 
((ualit)' of fresh milk, the use of excessive heat in the sterilizing 
pr^icess and too high a degree of concentration. 

Lumps in Plain Condensed Bulk Milk. — Lumps are prone 
to appear in plain condensed bulk milk, as this class of goods is 
usually made from fresh milk that may be slightly sour, as is the 
case in creameries and in milk idants where the surplus and the 



Unswi-:e:td;nkd Condi'.nskd Milk Di^fects 253 

returned milk is often manufactured intii plain crmdensed bulk- 
milk. This defect can be a^;oided by neutralizinc;' the milk l)efore 
heating, with an alkali (sodium bicarbruiate :"ir lime \\'ater), heat- 
ing less intensel}', or 1jy not carrying the condensing process quite 
so far. If the plain condensed bulk milk ci^mes from the [lan in 
lump}- condition, it can usually fie rcdticed to a smooth body b}- 
passing it through an ice cream freezer at cird.inar}- temperatures. 

Lumps of Curd in Evaporated Milk. — The danger of lump- 
iness, or curdiness in CAaporated milk is greatly augmented b}' 
the fact that, in addition tri the causes named under plain con- 
densed l)ulk milk, tlie sterilizing process must be dealt with. 
The high sterilizing teiuperalure used, tends tci precipitate the 
proteids of milk, and the temperature cannot be reduced fjek'u- 
certain limits ^-ithout impairing the keeping qualit)- of the pr(j- 
duct. ]Most of the evaporated milk, after sterilization, is sub- 
jected to the shaking process in which the coaguhun in the cans 
is reduced to a homogeneous creamy fluid, provided that the curd 
is not too hard. A curd will frirm in the sterilizer in the majorit}- 
of cases. If it is '=oft enough, so that it can lie cnmiileteh^ iM'oken 
up, no harm is done. If it is so hrm that mechanical shaking 
fails to cause it to disappear, then the evajjoratcd milk will reach 
the market in lumpy condition and is dilTicult to sell. 

Effect of Quality of Fresh Milk.— The qualit}- of fresh milk 
is all important in preventing lump)- c\-aporated milk. The milk 
must come from healthy cows in good, nrjrmal pliAsical cfin(liti(:in. 
It must not contain colnstrum milk nur l.>e strijjper milk and it 
must receiA'c the best of care on the farm and reach the factory 
perfectly sweet. Milk that is not of high (pialit>- in e\"ery respect 
should not be rccei\-ed at the factor}-. 

The acidity- iif milk due to acid fermentation, lowers the 
curdling point of the milk, parth- !>}- clianging the reaction and 
parti}- b}' lowering the citric acid c^intent. kli.gh acidity there- 
fore is 'one of the causes of curd formation in CA'aporated milk. 
If abnormal curdling is to lie prCA-ented, one of the first and fun- 
damental essentials is that the milk reach the condenserv in as 
fresh and sweet a condition as possible. 

Effect of Relation of Mineral Constituents of Milk. — More 
recent studies of the heat coagulation of milk, however, bv Som- 



254 



L'NswKi'.'rj'iNUi) C(.)NL)i':NSi';r> Milk Di'j'i^c'i's 



nier and Mart,' and 1)\- RuLjers" slmw tliat tlic litratal)le acidity 
iif fresh milk is not the llId^', and nften nrit tlie realh' imixirtant 
factor, crmtrdlhng tlie cciatj-nlatii in ni niiU-;, Init tliat tlie staljiHty 
of the casein, or its resistance to the ci iac';nl;ilinf( effect of ex- 
posure to heat, depends on the relation of certain ash crmstit- 
uents. 

v^ommer and JIart conclude that maximum stability (if the 
casein demands a proper ])alance of calcium and maL^nesium v\'ith 
the phospjliates and citrates, whdle the sodimu and jxitassium 
chlorides in the concentrations present do not ha\'e an)- marked 
influence on the coagulating" pioint. Thus these in\estiL;Titors state, 
the coas^'ulation of milk on heating" ma_\" he due either to an excess 
or a deficiency of calcium and magnesium. The calcium in the 
milk distributes itself between the ca.-;ein, citrates, and phos- 
phates chiefly. "If the milk is hi^li in citrate and phos])hate 
contents, more calcium is necessar)- in order that the casein 
may retain its optimum calciimi content after ci'impetinc,' \vith 
the citrates and p)hosphates. If the milk is hiqli in calcium, 
there ma\' not be sufficient citrate and ]")hospliate to compete 
with the casein to L.^-er its calcium content to the optimum. 
In such a case the additimi of citrates or phos])hates makes the 
casein more stable by reducing" its calcium content. The magne- 
sium functions ])\ ret)lacing tlie calcium in the citrates and 
phosphates. 

"In most cases the coagulation is due to an excess of calcium 
and magnesiimi. It is possible to balance this t'xcess ■b\- citrates, 
|)liosphates, carfjonates and other salts.' See als(. Chapter XT 
on " vSterilizing," Alojonniei' \'iscosit\' Controller. 

The factors of relation of ash c< 'nsiituents are influenced 
and largely controlled b)' such conditions as breed, jieriod of 
lactation, health and feed of the cows. .\nd this fact in turn 
nia\' be accepted to e.\])l,am, win- there is a vast difference in 
the abilit}' of nulk pi-oduced in different locabties, to withstand 
different degrees ol concentration ;ind sterilization without 
de\'elo]")ing a jiermanent .and objectionable curd. It is a well 



> H. H. Sonimer and E. T{. Hart. Tlie Heat Coagulation oC Milk, Jour. 
Biol. Chemistry, Vol. XL. No. 1, I'.iUi. 

2 L, A. Rogers, Address, Millc Soclion National Canners' A.ssociatlon, 
Cleveland, 0., 1920. 



Uxsw'Ki-iTL'.xKi) CoxDi-;xsi;i) ^Milk Di:fi:cts 255 

known fact, c^talili^lu (1 li\" jiractica] i-x])eni'nce in processing, 
and by analyses cf different brands .if L'\api ^rated niil]<, that in 
some b'nropean cmmtries, milk caji Ijc ci^ndcnsed ti i a much 
higher degree laf ci jncentratii m than in musi sectinns nf this 
ciiuntr}-, \\'ithiiiit becdming permanenth' cunh'. 

Effect of Forewarming or Preheating on Curdling. — As ex- 
plainer! in Cliapiter XI (ni "Sterilizing," under "Factors that 
Decrease \'is(-(isitA- iif I'"\ aju irated Milk." the readiness with 
wdiich milk coagulates in the sterilizei" is dimnushed by lengthen- 
ing the peril id . if ])rclieating in the forewarmer, i ir 1)}' raising the 
tem])erature of preheating, nr Imth, And \ace \'ersa. the shrirter 
the perirjd nf jircheating and tlie Inwer the tenuperature (below 
210 degrees Ix ) ti i which the milk is fi irew'armed, other cnnditions 
being the same, the greater the danger nf curdling in the steril- 
izer. 

It is not unpi-obable that hei-e again the nii idihcation rif the 
balance of the calcium and magnesium with the pluisphates and 
citrates, ma_v lie the hmdamental cause of tliese idiennmena. 
In this case the lunger exposure to thi: fi irewarming heat, or the 
higher temperatui^e ul furewarming. i ir bnth, ma_\- hax'e the eff'ect 
of lowering the suliddc calcium content In' ]irecipitating part of 
it as insolulile calcium pilmsphate. If ci i.agulation is due ti i an 
excess of calcium or magnesium, a> it usuall}" is. then this lower- 
ing of the calciimi cnntent. as the result uf preheating, will mini- 
mize the danger nf coagulation in the sterilizer. 

Effect of Addition of Water on Curdling. — Additiun of ex- 
traneous «-ater ti i the exapcirated milk lessens the intensit}' nt 
coagulation in the sterilizer, 'idiis is a matter jjreity generalh' 
understiHjd b\' the ex])erienced ujieratur, as pointed nut in Chapter 
XI on "Sterilizing" under "I'actnrs which Decrease X'iscusit}' 
and Tendency to Curdle." It is due to the dilutinn of both the 
casein and the seiaim in milk. 

Effect of Concentration. — The ninre ci incentrated the e\-ap- 
orated mdk the greater the danger nf lumijiness. .Ml the con- 
ditions cansnig lumpiness are intensjlied by the degree of con- 
centration.' The manufacturer must, therefnre. stud\- the be- 



1 For detailed discussion of relation of quality of fresh milk to curdlneSB 
of evaporated milk see Chapter A'lII on "Manufacture of Evaporated Milk." 
"Quality of Fresh Milk." 



256 Unswi'IvTivnKd Condivnsed Mii^k Djvi'UCTs 

lia\-irir rif his ])rodiict at different degrees of concentration, and 
Mien decide Imw mucli evaporatinn it i.vill stand without develop- 
ing subsequently a jicrmanent curd in the sterilizer.^ 

It is obx'ious that any excess or deficiency of calcium, or 
any excess of acid ])resent in the uriginal milk, is magnified in 
direct proportion as the concentration increases. Therefore, the 
higher the concentration, the more difficult it is to put the evap- 
orated milk through the stei"ilizing process vithout the formation 
of a permanent curd. 

Effect of Sterilization. — The coagulum is formed in the 
sterilizer. The higher the tem])erature, other conditions being 
the same, the firmer the curd. The lowest temperature that will 
efficiently sterilize the evaporated milk should, therefore, be 
used. .Since the sterilizing temperature to be maintained cannot 
l)e modified belo\v certain limits, it is necessary, Avhen the milk 
is very sensitive to the heat, to lower the degree of concentration. 
In some factories fractional sterilization is resorted to with 
batches of milk that are suspicious. P.y so doing, lower tem- 
peratures can be used effecti\-ely, Init this process calls for much 
more lalior, increases the cost of manufacture and decreases the 
ca]iacity of the factory. 

Effect of Fractional Curdling. — Experience has shown that, 
if the proteids in evaporated milk are partly precipitated by heat 
before the milk reaches the sterilizer, the curd or lumps formed 
in'the sterilizer are less firm and can be shaken out more readih'. 
H is, therefore, advisable to heat the milk in the forewarmers to 
as near the boiling point as possi1)le and to hold it at that tem- 
perature for at least five minutes before it is drawn into the pan. 
The superheating of the e\'aporated milk l:iefore it leaves the pan 
is an additional safeguard against the formation of excessive curd 
in the sterilizer. 

Effect of Homogenizing Evaporated Milk. — Excessive pres- 
sure in the JKjmogenizer tends to so cliange the physical prop- 
erties of the casein as tn render it more sensiti\'e to the steriliz- 
ing process. E\'a])orated milk, hnmogenized under excessive 
pressure almost inx-ariably furms a firm, unshakable curd in the 



1 For detailed disi u.s.'jion see Cliaptur VIII, on "Striking," and Chapter XI, 
on "Sterilizing." 



UnSWKCTIvNKD CoNDIiNSCD MiLK DEFECTS 257 

sterilizer. The h(jmop-eni2ing pressure should be kept dciwn to 
one thousand to fifteen hundred pounds.' 

Effect of Addition of Bicarbonate of Soda. — As shuwii in 
Chapter XI on "Sterilizing" the addition to the ex^aporated milk 
of bicarbonate of soda diminishes the viscrisit^' and tendencA' to 
curdle in most cases. 

This is due to the fact, that in most ca->es. the ci lagulatii'm 
is due to an excess of calciiuu and magnesium, wdiich Idwcr^ tlie 
stability of the casein. The ac'ditidu i if carlionates in the form 
of bicarbonate of sofla reduces the excess of calcium and mag- 
nesium, assists in balancing these mineral C(-instituents. and 
thereby makes the casein nmre -;tal)le. 

Occasionally it happens, hdwexer. that tlie addition rif sodi- 
um bicarbonate increases, instead of decreases, the \-iscositv and 
coagulabilit}" of the e\'a[)iirated milk, and in such cases, the diffi- 
culty increases in direct pro|)ortii"in with the amount of l)icarbon- 
ate added. Tn this case the Aiscosity and coagulabilitA- of the 
e\'aporated milk are inidoubtedly due. not tij an excess of calcium 
as is usually the case, but to a deficienc_\- i>i calcium. Under such 
conditions a soluble calcium or magnesium salt should be added 
in the place of bicarbonate, in order to diminish the viscosity 
and to render the casein mcjre stable. 

Acid Flux in the Cans Causes Lumps. — Similar as in the case 
of the sweetened condensed milk, the presence of acid flux in the 
cans of e\-aporated milk ca.uses lumpinc^s. The acid that reaches 
the interior of the cans causes the milk cnming in contact with 
the scams to curdle. (.)nly acid-free Hux slmuld be used in the 
manufacture and sealing nf the cans. 

Grainy Evaporated Milk. 

General Description. — This term is snmetimes ajiplied to 
lumpv milk, in H'hich case it means the same. ISy grainy milk. 
ho\ve\"er, is generally unrlersti hkI nulk which ccintains a sediment 
of a white granular a])pearance, which is insoluble. 

Causes and Prevention. — This granular sediment is largeh' 
found in the hermetically sealed cans after the sterilizing process. 
It is due to excessi\'e1y high sterilizing temperatures or too long 



1 For detailed discus-sion of tlie effect of liomogenizing on curdiness see 
Chapter IX on "Homogenizijig" and Chapter XXIII on "Separated and Churned 
Evaporated Milk." 



258 Unswretknkd Condensed Milk Defects 

exposure of the milk to the process. It consists largely of the 
mineral matter of milk, rendered insoluble and precipitated b}' 
heat. The use of lower sterilizing temperatures or the shorten- 
ing of the period of sterilization will help to avoid this defect. 

Evaporated milk in the condensation of which the "Continu- 
ous Concentrator" was used, has a tendency to show slight grainy 
condition, though this is barely perceptible. 

Separated and Churned Evaporated Milk. 

General Description. — This is a \ery common defect. A 
portion of the butter fat of the contents of the hermetically 
sealed cans, has separated and appears in the form of lumps of 
cream or of churned butter, c>n top of the e\'aporated milk. A\'hile 
this separated evaporated milk is normal in quality and whole- 
someness, its appearance condemns it. 

Causes and Prevention. — As explained in Chapter IX on 
"Homogenizing," the fundamental cause of separated and 
churned evaporated milk lies in the difference of the specific 
gravity between the butter fat and the rest of the milk constitu- 
ents. The fat globules, being lighter than the serum, tend to 
rise to the surface, forming a layer of thick cream. AVhen this 
separated evaporated milk is subjected to agitation, as is the 
case in transportation, this cream churns into lumps of butter. 
This tendency of the fat to separate in storage and churn in 
transportation., increases A\ith the increase uf the size of the fat 
globules, because the larger the globules, the larger is their cubic 
content in proportion to their surface. This fact is based on the 
well known ph}'sical law, that the surfaces of two spheres arc 
to each other as the squares of their diameters, and the cubic 
contents of two spheres are to each ntlicr as the cubes of their 
diameters. The cubic contents determine the gra\itv force, or 
buoyancV; while the surfaces control the resistance force. There- 
fore, the larger the fat globules the greater is their buo\-anc-\- 
and the weaker is the relative resistance which they must over- 
come in their upward passage. 

Effect of Locality and Season. — Since the predominating 
size of fat globules in milk, varies with breed and period of 
lactation of the cows, the ease with which evaporated milk 



LTnswlvEtened Condensed Milk Defects 259 

separates and the difficulty of (j\-ercnming this defect, difter 
.greatly \\ith locahty and season of A'ear. The fat glolmles in 
milk from tlie Channel Island breeds, a\ er.age twC) tu three times 
as large as those in milk from the Ihilsteins and Ayrshires. 
Therefore, factories located in Ilolstein and Ayrshire territories 
are not troubled nearly as much \\dth fat separation in e\-ap- 
orated milk, as factories in localities where JcrseA'S and Guernseys 
predominate. 

Again, the fat glolniles are largest at the beginning rif the 
period of lactation and decrease in size as the period of lactatinn 
advances. 

In order to e(|ualize the ciuti>ut of e\-a])cirated milk through- 
out the }'car, crmdensing concerns make e\'er}- eftort tn induce 
their patrons to time the IjreediiiL;' r'f their cn\\is in such a way 
that the fresh cows arc distributed thn ui.s^hout the year. The 
result of this practice is, that the milk snpjdy of these factories 
represents at all times a mixture of milk from cows at all stages 
of their peri(Td of lactation. This naturally equalizes the be- 
havior of the finislied ])roduct as far as sej^aration of the fat is 
concerned, facilitating the C(3ntroI of this separation. On the 
other hand, in lijcalities of factories, ne\\dv estaldished, summer 
milk is largel}' produced and the majority of cows freshen in the 
spring. This causes a marked increase of the size of the average 
fat globules in early summer, rendering the manufacture of 
e\-aporated milk, that does not separate its fat, more difficult. 

Effect of Degree of Concentration.-— Other conditions being 
the same, the more concentrated the product, the less the danger 
of fat separation in the finished product. The leason for this 
lies in the fact that «-ith the concentration the A-iscosity and the 
resistance force of the evaporated milk increase, hindering the 
fat globules in their upward passage. This is partly offset by 
the increase in the specific gra\-it}- of the product, but the in- 
crease of the resistance force exerts a stronger influence against 
separation of the fat, than the increase of the gra\-ity force exerts 
in favor of fat separation. 

HoweA-er. as the concentration increases, the evaporated 
milk becomes more sensitive to the sterilizing process and 
beyond certain limits it would be necessary to reduce the tem- 
perature or the length of exposure to heat, or both, in order to 



260 UNSwivicri'.NMi) CoNDKNsrcn Mirj-c Di^fi^cts 

])re\'eiit the more liis^lily cnncentrated milk from l)ecoming per- 
manently cnrd)-. If, in urtlcr to increase the \'isci)sity, the dej^i'ee 
(if concentratii in is carried sc) far that tlie steriHzin.i^" process has 
to he shortened, ndthini;- is gained Imt much may l)e lost. It 
is ob\'ions, thcrefrire, that the degree of coricentration does not 
furnish a |)ractical basis fm^ contrnlling fat se|jaration. 

Effect of the Sterilizing Process. — Prolonged exposure of 
the evaporated milk in the sterilizing heat tenrls to so change the 
physical properties of Ihe albuminoids, as to renrler the product 
more \'isc(jus. W'ithin the limits of the necessary sterilizing heat, 
long exposure to uKjderate heat is more effecti\'e in this respect 
than short exposure to a high degree of heat. Since the greater 
\'iscosit)' tends to keep the fat globules from rising, the use of 
a prolonged sterilizing jjrocess, in which the heat is applied 
slowly, is more effective in pre\'enting fat separation in the 
evaporated milk than a rapid, short jimcess. in \\'hich the tem- 
perature used is very high. 

It should be understood from the discussion in previous 
chapters that, in regulating the i)rocess of sterilization, the pro- 
cessrjr should be gr)^ erned f)}' the condition and behaxior of the 
milk and tliat on the ime hand the flegree and duration of heat 
should alwavs ht sufficien.t to insm'c absolute sterilitv of the 
])roduct, \\hile on the other he mu^t guard against the f(jrmatiiin 
(if an unshakable eiu'd.' 

Effect of Superheating. — The superheating of the milk be- 
fore sterilization and the ';t("ipping of the reel nf the sterilizer 
as explained imder "Sterilizati' m," als(-i tend h< so increase 
the \'isc(isit_\' of the e\-a|)( irated milk as to minimize its tendenc\' 
to separate its fal. liul here again good judgment is recjuired, 
otherwise there is danger of s|((int:ineous thickening of the pr'od- 
ucl after manufacture. 

Turning the Cans in Storage. — l\rany manufactiu'ers, in an 
effort to a\'oid fat sep;iralion, ha\e ado]i1ed the jiraetice of turn- 
ing their goods in st irage at regular inter\als. This operation 
naturally interferes with and retards the rising of the fat to the 
surface. ,is long as the goods remain in the fact(jry. y\fter the}' 
lea\e the factory this control must of necessity cease and if the 



For aetalled discussion S60 Chapter XI on "Sterilizing." 



Uns\vp:i'.ti;.\I':d CondiuxstId ^[ii.k Di{Fj-:cts 



261 



cACijir, rated milk, nwin^; {•> the pnieess i if r.iaiuifaeture and the 
eciiiditiMii r,f the ]iniduet. i- destined tu separate il^ t'at, tlie turn- 
iiig lit the ea.si,-;, wliile at tlie factury, caiiiidt perniaiientK' prexent 
'^eparaliem. Wdiere the Qdrids are cdiisumed immediately after 
the)' lea\-e the faetiji-y, this jn'aetiee ma\' serx'e the juirpuse; hut, 
sinee the lari^e ludk nf e\ aju ii^ated milk maiuifaetui'ed, is exposed 
to ])rciloii^cd storage, its ad\aiita^e is Aer\' limited. 

Effect of Homogenizing. — Under a\-erac;e eonditions eareful 
attention to the preeautions aho\e discussed wall grealK" mini- 
mize and often pre\'(nt fat separation. At hest, howexe)-, much 
of the e\'aiieir;ited milk on the market shows sIl^iis ijf sejiaratirm 
after srxty to ninety days and sonie of it e\en after two weeks, 
leir the lundamental eanse of separation, the ditterenee in ^^ra\'it\" 
hetween the f,at Ljlohules and the re^t of the milk constituents, 
is still present: then aL;ain. nraler less laxajral.ile ciaiditions. ex'en 
the ;d)(n'e precautions may not pro\-e adeipiate to Kcei") tlie fat 
Irrjm se])aratniij;'. 

The intri iiluction oi an\' ayent c:ir process, therefore, ca]iable 
ol permanently remo\in^' this fundamental cause, must proA'c 
a lastini^' henellt tii the manufacturer rif exapoiaated milk. This 
ayen.t has Ijeen foimd in the homoL^enizer. The homo^-enizer 
makes it possible to divide the fat L;lol)ules so tineh-. that their 
Imovancy or L',ra\it\' force is not ,i_;reat enouyh to oxercome the 
resistance of the surrounding" li((uid. The}- are unable to rise to 
the surface, luit remain in h,omo,L;eneous emulsion. 

It is f)uite prohalde that aside from the reduction of the size 
of the fat L;dohules, the efflcienc}' of the homoL;enizer tej iirex'ent. 
fat separatioiii is due ,'il--ai to the ]ihysical change of the casein as 
the result iit homoC'X'uization. The casein Ijeccmies more xisccius. 

Tlie chiel ohjectioii to the use of the homooenizer is its 
effect on the casein of the milk, when subjected to excessixe jires- 
sure. liexTind certain limits of pressure hiimoi^enization so 
affects the casein, that the latter is more prone to cuialle in the 
sterilizer. Htiwexer, experience has amply shown that the maxi- 
mu.m pressure reiptired to ]ire\'ent fat separatiini in the hnished 
product, IS not great eneiueh to seriously atTect the behaxdor of 
the casein during sterilization. Hence, the ]")rri])er regulation of 



262 UNSwivirn'.NKi) OondKnskd Mii.k DrCFKCi'S 

the pressure ami llic iiitellif;eiit use nf llic In niK jL^eiiizer, furnish 
a satisfaclcir)' aiiil i"eHal)le means to ])re\'ent fal se;")aration.' 

Fermented Evaporated Milk. 

General Description. — Fermented exapcjrated milk is evap- 
nraled milk, ^\■hieh after sterilization, has underjjune fermenta- 
tion. The t)'pe of fermentations fnund in this ])riidnct \aries 
w'th Idealit)', season of year and factory conditions. 'J'he con- 
tents (if the cans may haxe soured with curd fnrmatinn, or a 
curd ma_\- ]ia\-e farmed witliout acid (le\-elnpment, ur the fer- 
mentatir-n ma\' be c;aseijus, in A\'hich case the cans ljuh;"e, and 
th.ese ,L;aseons fermentations may lie acci mipanied h}- acid lurma- 
tion or liy putrefacti\ e products. In all cases r,f fermented ndlk 
the product is entirel_v worthless. These defects are usually. 
tlKTiiL^F not a|wa3-s, detected duriuL;- the peril kI of incubation. 

Fermented e\'apoi'ated milk is the result, either of incumjdete 
sterilizatii in. or of leaky cans. The causes of fermented e\'ap- 
orated milk differ A\'ith the specific ty|")e of fermentatii ms ])rci- 
duced ; the\' will be discussed separately and as relatini;- to the 
respective types of fermentations. 

Acid Fermentation, Sour, Curdled, Evaporated Milk. 

General Description. — Upcni o])eniiyL;' the cans the contents 
aie found ti i be ^our and curd}-. 

Causes and Prevention. — 'Jdiis condition is the residt of the 
presence nf acid-producinp; species of mien i-i irL',anisms, usually 
I if the lactic acid tx\>c, \\'hich sour the miUc, and the acid ]iriulnced 
curdles the casein. Since the majririt}' nf Ihe lactic acid bacteria 
are nnt resistcant ti i heat and ;ire destrnyeil at rrlati\-el)' Inw heat, 
this defect is ncit usually caused b}' inc(im]ilete sterilizatii m. The 
lemperatiu'e ijf sterilizatii m, though it nduhl be insnttieient to 
kill spore forms, is hi,L;"h ennugli tn make it impnssible fur lactic 
acid bacteria to jjass the [process alixe. 

The I inly way in which this flefcct can ncciu" is thriiu^h sub- 
sequent ei intamination nf the cimtcnts nf ihc cans with these 
germs, and the unly possible channel, thriini;h which this sub- 
scqrient contaminatii m may occur, is leak\' cans, i.ir leaky seals. 



^ For detail.s on tlie u.se of liomogenizer see Chapter IX on "Homogeniz- 
ing." 



LiNswj'.iiTKNivD Condknskd Milk DEFy-XTS 263 

A careful ex;aniinatii ni (it tlic cans nf sm:.ii-, curdlcrl c\-a|M-iratcd 
milk nsiiall}- shows fault\- cans (ir falllt^■ seals. 

Bitter Curd. 

General Description. — Wlicn the cans are npeiierl the con- 
tents present a solid coai^uhmi, ',;ciicralb." iioticeald} white ]v. 
color and \"er\' bilter to tile taste, similar to the hittcrness f<i 
dandelions, lliere is a separation of jiracticalh' clear wIica-, the 
curd does ncit break doA\-ii readil\' u]"ion shrdvin^ and the acid 
reaction fjf tlie mi.\ture rii curd and \\he\' i^ aliruit -.i,^ to .4(1 per 
cent, A\hich is normal lor cAajiorated milk. 

Causes and Prevention. — Alicr(.ocopic examinations under 
high mac'.aiilication ci\ cr.ltures in sterile mdk show the presence 
of A-er\- small liacilli. The milk foj-nis a lirm coanailnm in h\-e to 
se\'en daws and A\dien i"'\-er one wtx-k old the cu,rd has tlie same 
strong', bittei' ta.ste as that in tlie cans, ddic bitterness increase- 
with aL;'t. 'bhese bacilli gn tw be«t at '0 decrees I*'. dMnex' are 
facultat;\"e aiiaenibes, devek r]iinL;" li(ith, in aerobic and anaerobic 
media, but ]ireler anaerobic cciiidiiii ms. 

In the ca^es under ■ ibser\atii"'n no snores were detected and 
exposure for fifteen minutes to J]2 deijrecs V. destroyed these 
yxrms. The abia\-e find.ino- dd not exclude tlie p(:)ssibility .af s]jore 
lormati(")ii under ci'iiditions \ ery unfa'.C'ralde tri cTowtli and bfe. 

The |iresence cif this species of bitter currl or-anisms sul;- 
;;xxsts inceimplete sterilization rif tlie cwaporated milk. The strik- 
ing,' whiteness of the curd in all cases that lia\e crime to the 
writer's atlention. is further ])roof of the oorrectness of this fle- 
diiction. ft indicates that th.ese cans recei\ed relati\-ely little 
heat ill the sterilizer, otherwise the curd w-oulfl liaA-e a darker 
color. This defect usnall_\ does imt show u[i in all the cans i if 
one and the same tjatch, but iiiih- in a limited iiortion i if eacdi 
batch. This fact sm.;";jests that the distribution rif heat in the 
sterilizer is not uniform, some cans getting less heat than others. 

This defect occurs generalh' m summer, a fact w liich ma\- l)e 
due to one or lioth of the following conditions; 

\\ bile it is well known that there is a ,gronp eif species i.if 
l)acteria, }-east and torula that are capaljle of producing a bitter 
curd, either direct, or through the secretion of casein-curdling 



264 



Unsvvi';i';ti',nivd Coniji-nsi'j) Mii.k DiiiTXTs 



enz}-mes, and while lliese dilTercnt s])ccics uf iiiicr()-(ir_!:.anisms 
conic from a \ai-icty of S(")nrces, the most commim sources are, 
the soil, iiastnre, water and tlie lulder itself. It is a notcvvorth}' 
tact that this defect is mijst commonly found in millv and milk 
prc^iducts when the cows are on pasture. Tt is, therefore, jirobalile 
that, in most cases, this troublesr)me !^"erm is carried into the riiilk 
on the f.arm. 

Attain, in summer, at a time wdien this defect c;"eneral!}' 
iiccurs, tjie effect on the cows rif the summer heat and flies, and 
the tendenc}' towarrl hi.c^ii acid in milk, render the milk mrist 
sensiti\'e to the steriliziuL;- heat. The opei'ator finds it difficult 
to a\'oid the formation of a disastrous curd in the sterilizer. In 
order to t^uard at.':ainst this troiddc he is tempted to cither kow'er 
the temperature, or shorten the duration of the sterilizing' process. 
This tend.s toward,s incomplete sterilizatic>n. A very frecjuent 
result of this incomplete sterilization in the late summer 
months, is the formation of a hitter curd. A\dien the processor 
returns to the proper sterilizing pri.icess, the occurrence of hitter 
curd in the cans disappear.s and the product is normal. 

A further safeguard against 1he recurrence of this troulde 
lies in ])ro\'iding for uniform distribution of heat in the sterilizer. 
If tJie cans lia\-e to be stacked in deep tiers, wdiich is un- 
desirable and should be a\-cii(led, slats shoidd be placed o^'er 
the top rif e\-ery second row of cans. This will make possible 
the free access of steam to^ at least one end of each can. If the 
circulation of steam in the sterilizer is pnor, the nniforni distribu- 
tion of heat can Ijc facilitated by tilling the sterilizer .about one- 
third full of water so that, with e\er)' rc\(ihUion of the framc- 
wor-k, the cans ha\-e to p.ass through this water once. The water 
reaches e\"erv nook in the interior i>\ the sterilizer, distriltuting 
the heat much more uniforndy lh,an the sle.am. I'nevcn distribu- 
tion of the heat m.a\' also be due to .an uuproper conditiim of the 
steam-distributing pijie located in the bottom of the sterilizer. 
Scime ol the ])crforations in this ])ipe ma\' ha\c become too large 
by wear, oi' may lia\'e become clogged with scale or (he cap 
at the end of the jjipe m.ay ha\'e come off. In all of these cases 
the distribution of the heat in the sterilizer is found to be irregular, 
interfering with the uniformity' and dependability of the proccSs 
of steriliz.ation. The |iroccsser shiudd m.ake sure, by daih' in- 



UNswF.i'.Tr'.NF'.D CoNDExsKD Mjlk Drff.cts 265 

si)ectiiin, that the stt--ain-flistriliutiiiQ' pijic is in pruijer o|:ierating 
condition, Tf tliese ]")recautions fail to remedy- tlie trrmhle, then 
tlie entire process is madeqnatc and either more heat, rir loiiQ'er 
exposure tei the same licat is necessar\-. 

Sjiitzer and H]iple' in\"esti,L;ated a case of bitter evaporated 
miU':, in wdiicli the tri"iu])lesome orLjanism a]>pears to ha\e been 
I if a dilterent type tlian was tlie case in tlie hitter exaiji irated 
milk e])ideniics under oh.serwation ])y 1 fmiziker. as descnhjed 
ahiiNc. S])itzer and l'',p]ile f'Hinil the liitterness Ut he due tri the 
presence in tlie e\a|)Mrated milk, of an i ii-^anism that ci irrespi mds 
with Ali^ula's (l''0()) classification nf llacillus panis as described 
b\' Lawrence and Lauliach.- 

Tliis organism is a non-nnitile bacterium, ri)d-^hape, with 
riiunded ends and measuring about .4 b\' 2.0 microns. It is spure- 
beai'ing, the sprircs forming readil\' in d.S ti i 72 hours and ap- 
])eariiig usuall}' near the center of the rrid. The wrganism is 
capsulated and is \er}' resistant to heat. S])itzer and Ejtple 
hnmd it to stir\d\-e a teniperatui^e of 2?t) degrees F. for X minutes, 
l)Ut ^\-as destrci3-ed at the same temperature upun 1(J minute 
exposure. The orgaiiisni dijes iiiit funn gas, it does not swell 
the cans, nor does it coagulate the casein. The contents of the 
cans apipear perfectl\" noiaiial to the e_\"e, the only change noticeable 
is the intenseh' bitter taste. It is an active proteolytic germ 
callable of secreting enzAuues wdiicli are prnte(il\-ticall\' active, 
rapidh' breaking d(jwn the ])ri'teids nf milk into large (piantities 
of peptones and hjwer nitrugenous coiiipnunds of comidex nature. 
The authrirs suggest that the exce^--i\-e peptonizing functinn of 
this organism niav' be the primar\- cause of the bitterness. 

The description of the cultural characteristics and thermal 
death-point cif this (irganisni suggests that the presence of this 
germ in the evaporated milk, and tlie spoilage of the product, 
are not due to a faulty ]irocess of sterilization, liut are the result 
I if conditions in the factory that jierniit this germ to Ir.dge and 
to contaminate the milk. Unsanitar_\- condition of pipes, pumps, 
homogenizer, filling machine, etc.. vxriuld hie the most likeh" 
breeding places and sources of contamination. 



1 Spitzer and Epple, Bitteriies.s in Evaporated Jlilk. Journal of Dalry 
Sclence, Vol. III., 1920. 

2 Lawrence and Laubach. Studies on Aerobic, Spore-bearing, N'on-path- 
ogenic Bacteria, ,Iournal of Bacteriology, Vol. I., p. 193. 



266 ITNswui^Ti'.Ni'n CoNni'.NsEi) Miuk Defects 

Blown Evaporated Milk (Gaseous Fermentation). 

General Description.- Tlic cinK nf tlic cans Ijulge nut ver}- 
Odticcalil y, frc(|ueiUl\' sn iiuicli sn Ih'il llic seams of tlie cans 
burst 0])en. This is due In i^asenus I'ermentatinn causing high 
|)ressure in the cans. The pi'essure is nften srj great that upon 
npening !lie cans, ninst nf tile cnntents arc Mown fjut witl: tre- 
mendous fnrce. Ill s(-inie cases nf 1)ln\\-n e^"aporated milk, the 
contents lia\e <ni acid ndnr, ])leasant and aromatic. In most 
instances, hn\',e\er, tlie\" give niT \-er)' fnul ndijrs and suggesting 
hydrogen suUide, imt uidike aggrax'a.ted cases nt IJniburger 
cheese. 'Idie^e ndnrs are e.x'ceedingh' penetrating and difficult to 
remo\'e from anvtliing t]ie\' cnnie in cniilact with. 

Causes and Prevention. — The liacteria causing gaseous fer- 
mentatiniis in eva])oratcd milk usualh' lielnng to the anaerobic 
group of ljut\'ric acid sjtecies and in mrist cases, though not al- 
A\'ays, the putrefactix-e t)'])es |)re\-ail, such as Bacillus putrificus, 
Plectridium no\-um and Tlectridium fnetidum, especiallv the lat- 
ter, Ijecause nf its cxtranrdinary pnwer of resistance to heat. 
Plectridium fnetidum is an oliligatfiry anaercilje and it al)solutely 
re-fuses to grow under aernbic cnnditiniis. It is an activel}- motile, 
medium-sized nrganism with iLagella and s]>ores. At one end it 
has an Indian clult-likc enlargenient, in wdiich a]ipears the spore. 
The bacillus resembles a kettle-drum stick similar to B. tetani. 
Under strictly anaernbic cniiditinns, and inculjated at 90 degrees 
F., it fermenls milk in fnur da\-s. The milk ilrst curdles, then 
gradually the curd dissoh'es ( digests! cnmpleteh-, lea\"ing a clear 
yelloAV liquid, similar in a])pearance tn butler oil. The fermenta- 
tinii is accnni])anied by the ex'nlutinii n'i a penetrating foul odor. 
I'his or.ganism sur\-i\-es e>:])nsure fnr \5 minutes to 245 degrees 
.v. Its thermal death point lies between 245 and 250 degrees F.^ 

Plectridium foelidum, as well as most of the other species of 
anaerobic, S])ore-bearing lnit}'i-ic acid bacilli and bacteria, is 
present abmidantl_\' in cnlii\aled snil, in licld crops and even on 
the kernels of the grain. Since this type of evaporated milk 
defect is cliaracteristic, es[iecially, nl the product manufactured 
during the late summer .and earl\- fall ninnlhs, it is ver}' probable 
tha.t the dust incident tn the har\esting nf the lield crops, fur- 



Huiiziker, A Study of Gaseous Fernifniation in Evaporated Milk. 



UNs\vi':E'n:.\n{D Co.\'di-:nsi-'.d Mii.k Dki-'i-xts 



267 



nislies the chicl snurce of crintaniinati'iii nf tlie milk, tliruic;li it 
is quite possible tliat ci intaininati' in with these c;'crms nia\- also 
result from the use of nnelcan equipment in the faetor}-. 

In order to axrjid the ceeurrenee of bluwii, feinnented, e\"api"i- 
rated milk, thercfure, it is ne'~cssar\- tii eniplox- the hic;'hest steriliz- 
ing' temperatures, nr the !iingx-;t exqnymnre t;' the sterilizing heat, 
or liotli, consistent with fi-eeilurn "f the milk fr'ini curdiness. F.x- 
perience has shuwn tliat the use 'if the ranges nf temperalni'e aiul 





The result of g'aseoits 
fermentation 



Fig'. 89. Plectridium foetidum, 
a hig'lily resistant species of 
anaerotoic nilcro-organisms, 
causing" "S'well heads" of 
evaporated milk 



time of exposure, gi\'en under Chapter XI mu "Sterilizing," guard 
effectixeh' against tins defect. 

Blown Evaporated Milk Due to Freezing.— If the evai3o- 
rated milk is exposed to storage tem]ieraturcs fielow the freezing 
point of water, the contents ot the cans will freeze. A\diile freez- 
ing, the contents exjiand. sufhcientl\' to ■.■anse the ends of the can-> 
to bulge. Wdien the cans are siibsequently transferred tri warmei' 
temperatures. sCi that their ciantents melt again, the milk contracts 
and the cans resume their normal shape. 

Wdiile the whole.-onieness and fl;n or of ilie j.n'oduct are not 
affected h_\^ the freezing process, the remelted c\aporated milk 
IS usuallv less -.mooth and r,|ten slightl}' grainy, ddus !>, due to 
the fact that, during th.e prricess of fi'eezing, thci'e is a ]iartial 
separation cif the watei'A' prirtion from the caseous material. 1'he 
casein contracts and the watery pcirtirm freezes, A\dien melted, 
the eniulsion is less complete than it was before freezing. The 



268 llNswivi'/n-'.Ni'.ii Conim';nsi':i) jMij.k Diu-'i',cts 

casein remains in its c<intr;icted fnrni and mhs tlie product ol its 
original sriK i(;)tliness. 

Blown Evaporated Milk Due to Chemical Action. — While 
properly processed ewiporated milk is perfecth' sterile, and from 
tJTe liioloqica] ])fjint ol" view, keeps indel'i nitelx', tlie cans ol \ci'_\' 
old e\'aporated milk- nia\' hulge, a^^ the result of the actiini of the 
acid in the mdk nn the containei". I'^wiiiorated milk crjutains 
from .33 to .?() yicr cent acid (calculated as lactic acid). Wdien 
the tin cans are filled with tlie e\'aporated milk, the tinplate is 
bright and untarnished, both, inside and out. After the sterilizing 
process, the inside surface of the cans is dai-k and dull. This is 
caused hy the combined action of acid ,an 1 lie.at, which seems to 
weaken the tinidate. 'I'his ])henomenon is further illustrated b\' 
the fact that A\dierc creameries pasteurize their .^kimmilk- and 
return it to the patrons in the milk cans liot, the milk cans are 
short-li\'ed ; tlle^- soon corrdde and begin to leals, 

The acid in the e\"a]iorated mil!< continues h' act on the tin- 
plate of the can after manufacture and in the case ol \-er_\' old 
e\'aporated milk, the acid ma^■ decompose a considerable part iif 
the iron. This action is accoin]iaiiied b\- the exriluliini of hx'dro- 
gcn gas, wdiich causes the cans to bulge. Idiis action is hastened 
In- continued exposure of the goods to lii,L;h tenpieratures (sum- 
mer heat). This fact \\'as ex|)erimeutall_\- demonstrated,' also, 
by scratcliing the bc)ttom of tin cans on the inside with a file, 
then filling the cans with a .4 per cent solution of lactic acid and 
acetic acid, res|)ecti\el\-. .\fter sealing, the cans were sterilized 
in the autocku'e, si i as to a\-r)id au}- ]iossibilit\' df bacterial actiini. 
After cooling, these sterilized cans were incub;ited for some time 
at 90 degrees F. The cans containing the dilute acid licgan to 
swell, wdiile the check cins, containing distilled water only, 
remained normal. 

Blown Evaporated Milk Due to Change in Altitude. — (Jans 
cjf evaporated milk when Idled in lactories located at a low 
altitude (near the sea lc\el ) ina_\ bulge wln.ni transferred to a high 
ahitude. The danger from this sonn-r is iuteiisiried. if the e\ap- 
orated milk liap|jens to be cohl at the time of lilling, and when the 



1 Hunzikcr and AV'righl, Indiana iVKi"i''iiUural TDxperiniont Slatioa. Re- 
sults not published. 



UNswiiETENKD Condensed Miek Defects 269 

temperature to which the cans are exposed at the hii;h altitude 
is high. 

This t}'pe of swelled cans ol)\-i(iuslv has nothing to do with 
the quality of the contents, nor is it the result of fermentation or 
chemical changes. It is caused hy the fact that the pressure in 
a can scaled at tlie sea level is somewhat greater than the atmos- 
pheric jjressure surrounding the can \\-hcn transferred to a high 
altitude. If, at the same time, the milk ])acked at the sea level 
goes into the can at a low temperature and the atmospheric 
temperature at the high altitude, to which the sealed cans are 
shipped, happens to Ix- hi.gh. the difference in pressure between 
the interior and exterior of the can is further increased, flue to 
the expansion of ilie milk and of the air in the can. The com- 
bination of these factors is sufficient to cause the ends of the can 
to bulge, making it erroneoush- a])|iear that the package cr)ntains 
fermented g;'oods. 

This has actually ha|)p)eneii in the case i.if one factor\- filling 
a Go\ernment "war cr)ntract, the wdiole shipment of e\"aporatefl 
milk fjeing rejected l)y the (".o\-ernment, because of the fudged 
cans. 

Occurrences of this type can be pre\Tnted by filling cans, 
intended for markets in high altitudes, with the e\'a])orated milk 
wdiile warm. 

Brown Evaporated Milk. 

General Description. — It is the aim cif the processor to so 
go\-ern the sterilizing process as to gi^e the evaporated milk a 
rich, \'ellow cream^• color. Frequenth", this colc>r limit is over- 
stepped to the extent of imparting to the e\-a]Xirated milk a brown 
color, suggesting coffee with milk in it. In this crinditiijn e\-ap- 
orated milk fails to appeal to the consumer. 

Causes and Prevention.— The dark cc)lor in e\aporated milk 
is due to the oxidizing action of excessi\-e heat on the milk sugar, 
causing the milk sugar to caramelize. This can be a\'oided b)' 
reducing the sterilizing temperature, or shortening the sterilizing 
process, or both. The storing of e\-aporated milk at high temper- 
atures (summer heat) also tends to deepen its cok^r with age. 



270 Unsweetened Condensed Miek Defects 

Gritty Plain Condensed Bulk Milk. 

General Description. — Grittiness in tlic unsweetened periods 
appears nsually only in the plain condensed bulk milk. It is a 
defect which renders the product undesirable for ice crear 



a 

^.. ,^ _.^ ,,.,,, -. - . -^m 

makini 



Causes and Prevention. — The cliief cause of this defect is 
too great concentration. Plain condensed bulk milk which is not 
condensed over 3.5 parts of fresh milk to 1 part of condensed milk 
does not become gritty. When the concentration exceeds 4:1, 
the milk sugar begins tu crystallize out, making the product 
gritty. Milk sugar requires about six times its weight r)f water 
for complete solution in cold water. \A'hen condensed at the 
ratio of 4:1 or over, the plain condensed bulk milk contains con- 
siderably less than five parts, by weight, of water to one part 
of milk sugar. This high concentration, together with the [prac- 
tice of storing this product at refrigerating temperatures in order 
to preserve it, is responsible for the grittiness. This trouble can, 
therefore, easily be prevented by not condensing to (|uite as high 
a degree of concentraticm. 

Metallic Evaporated Milk and Plain Condensed Bulk Milk. 

General Description. — Both, e\'a[)orated and plain condensed 
bulk milk may show a metallic and inickery flavor, though this 
defect is rather rare. 

Causes and Prevention. — 1_Mie metallic flavor ma)' be due 
to the same cause as metallic sweetened condensed milk, i. e., an 
unsanitary condition of the \acunm pan, in which case its recur- 
rence can be readily avoided by thoroughly cleaning all parts of 
the pan including the dome and the goose neck, and rinsing down 
the whole j^an thoroughly with clean water each morning before 
operations begin. 

Unsweetened crjndensed milk made l.i_\- the use of the "Con- 
tinuous Concentrator" may have a metallic flavor when the 
scrapers in this machine are improperly adjusted, causing them 
to cut into the copper walls and thereli) incorporating metallic 
copper in the product. This source of inetallic fla\'or cati be 
removed l)y pro])er adjustment of the revolving spider and its 
essential parts. 



Adulterations of Condknsed Milk 271 

Evaporated milk ma}- also show a metallic fla^■or as the result 
f'i chemical action of the acid in the milk on the can. This occurs 
usually only upon prolonoed storage. W'ry old e\-aporated milk 
is very prone to hnrc a metallic tla^-or frrim this source and 
particularly when stored at a rather high temperature. This can 
best be avoided bv endeavoring to move the goods sufficiently 
rapidly to limit the age of the milk to a reasonable period of time 
and by avoiding liigh storage temperatures. 

Cans, in the manufacture and sealing of which an acid llux 
is used, are prone to gi\-e the contents a puckery, metallic llax'or, 
due to the zinc chlr>ride and h\"drochloric acid present. This can 
be avoided by using cans only in the manufacture rjf which a 
non-acid flux, such as gasoline-resin flux, is used, and bv using 
a non-acid flux for sealing the filled cans. 

Chapter XXT\'. 
ADULTERATIONS OF CONDENSED MILK. 

It is the sense of the Federal Pure Food Act that the addition 
to condensed milk of any substance except sucrose, and the 
abstraction of an}- substance from milk except water, is an 
adulteration. 

Skimming. — Condensed millc made frdm partly or wholly 
skimmed milk must lie labjcled and sold as condensed skimmed 
milk in order to comply "\\-ith the Pure Food regulations, llow- 
e\'er, it is possible for cnndenseries receiving fresh milk, rich 
in butter fat, to skim a part of that milk and ha\'e tlieir i^roduct 
still conform with the food standards. 

Skimmed sweetened condensed milk can -eadily be detected 
by its whitish color, while condensed whole milk has normally 
a rich yellow color. When diluted, to the consistency of ordi- 
nar^■ milk, skimmed condensed milk, lioth the sweetened and the 
unsweetened, foams ^-ery profuseh* when shaken, while diluted 
condensed wd^ole milk behaves similar to ordinary- whole milk.' 

Addition of Artificial Fats. — In order to lower the cost of 
manufacture, attempts ha^•e occasionally been made to skim the 



1 For chemical tests of butter fat in condensed milk see Chapters XXXI 
and XXXII. 



272 Aikiltkkations of Condrnsf.d Mti,k 

fresh milk and snlistitute tlie alistractcfl fat 1)y artificial fats of 
animal or \'ci;X'ta1)lc r)ri!_;"in. 

Uccent improxemcnts in tlie metliofl (jf manufacture have 
made it pussihlc td manufactiu'c e\'a|)iirated milk, made from 
skim milk In which fnrciL;!! fats, especialh' ^■e,L;'etal)lc nils, such 
as ciiciianut nil, ha\e heen added. This milk has e\ery appear- 
ance I if, and will ci unmercialh- keep as w(dl as genuine e\apnrated 
milk, .\ representatix'e of this imitation e\a|ji i|-ate<] milk is the 
"llehe" product. 'I'his product consists <if skim milk tn wdiich 
iiave heen athled ye.^etaldc fats ti i replace the butter fat. The 
mixture is licimoyx'iiized in order to fiirm a complete emulsion, 
then it is evaporated, filled in cans and sterilized in a similar 
manner as the genuine evaporated milk. 

The Federal law requires that the composition and ingredi- 
ents of these imitation products ap|)ear pLainly on the laljel of the 
package. 

ft should be clearly understood liy the manufacturer, the 
dealer and the consumer that this imitation milk is inferior to 
the genuine evaporated milk, in the fact that it lacks the im- 
portant growth-promoting and curati\'e ]iro])erties which are 
inherent in whole milk. If sold on its o\\"n merits, and in accord- 
ance witli the Federal law, there can Ije no logical oljjection to 
tlie imitation product, but if ofifered to the consumer as the 
g'enuine article, the manufacture and sale of imitation exaporated 
milk is a heinous crime against humanity. 

Experiments conducted at Cdiio State Uni\-ersitv, by Mr. 
j. h. Hutchison, instructor in the Department of Agricultural 
Chemistry under the direction of Professor < ). ]<j-f. Chief of 
IJcpartment of ].)airy Ilusliandry and ]3r, J. F. Lipman, T'riifessor 
of yXgricultural Chemistry, demonstrated that "ITebe" milk, when 
fed to young wldte rats, resulted in malnutrition accompanied 
by stunted growth, scire eyes and death of some of the experi- 
mental rats, in a siniilai" manner as did other rations in wdiich 
the fat soluble \ itamines were lacking. 

ddie \'f)luine of "filled" e\-aporated milk- manufactured in this 
country is assuming large |)roporlions and is growing annually 
as shown below : 



AduLTI'.RATIONS of CoNDIiNSliU iMlLK 



273 



Annual • Output of Imitation Evaporated Milk, Made from 

Wholly or Partly Skimmed Milk to Which Foreign Fats 

had been Added.' 



Tear 


Case Goods 
Pounds 


Bulk Goods 
Pounds 


Total 
Pounds 


1016 


12,000 

l.s!504 

41,033,S55 

02,202,221 


14,1,^,712 

17,4X7,00,4 

7,501,1X2 

2,74X,120 


14,140,71 ' 


1017 

lolS 

10l'» 


17, 5 05, 5 OX 
4X,( ,25,037 
o5, 01 0,341 







Mdthcrs \\4i(i Ijin- f\ ;i]:i, -ratctl milk fur feedin-" infants and 
children should be caiitiinnjd ti i Mbser\-e carcftdly whethei' nr iiMt 
they recei\-e the i;-entiine article. Imitation e\Tipi .rated milk is 
net a babv food. I'.abies and ^rMwini;" children need biitterfat 
for their best dexeh ,|..ment. If canned milk is used ftir infant 
feeding', it sh...idd be made fi'nm whole milk mi]}'. (See alsci 
Chapter XX on "\'itamine I 'n .j.erties (.f Condensed Milk." I 

Addition of Commercial Glucose, — Cummercial ,L;luci.,se be- 
longs to a ,L;"r(Hip cif starch iio'ducts in \\4iicli dextr("ise is the 
leading;" d .nstituent. It is niantifactnred by the actnn dl dilute 
acids in starch and starch}' matter, ^r . lecasi' .nail}' \V(Hjd}' hh.re. 
In this CdunlrA- it is almost wh',11} made frdni maize starch. 

Starch _L;liiciise cii.-curs in c.aiimerce in sc\-eral f'lriirs, \"ai'\'inL; 
from the condition of juire anlndr'ius dextrose, thrnUL^ii inferiur 
kinds of solid suL^ar, ti , the cinidition nf a thick s}'ru])}" li(|uid, 
ci.loriess and transparent, resembling' nn. lasses in ci insistenc}' 
and gh'cerine in appearance: it cnntaiiis a lar^e jiroportimi i.f 
dextrin. In connection with the manufacture of ccnidensed milk 
the term "g'lnc! ,sc" refers h< this thick, S}ru])}' liipiid. It is added 
to the condensed milk with ;l A'iew of substilutiiii;' a portir.n of 
the sucrose and thus redticine;' the cost i if maiiufacture. It has 
also been suggested that the i.resence ui Cdmmercial L;Iuci'se in 
cijndensed milk prcAcnts the precipitation of sugar cr}'stals, E-x- 
periments ha\"e shoA\ai, howe\er, that condensed milk containing 
\-arying amounts of glucrjse, will becume saiidv just as readilv 
as normal condensed milk. 

That glucose cannot be used as a sid.stitute fi.r sucrose, is 



' The Market Reporter, U, S. Bureau of Markets, Vol. I. No. LS, 1920. 



274 ADUI/rivRATIONS OF CONDRNSED MiLK 

obvious from the fact that its presence defeats the ^•cry object 
for \\'hich sucrose is added. Instead of ser\-ing as a preservative, 
as is the case with the best refined, g-ranulated cane suo;ar, glucose 
acts as a most effective fermentative. It lias been explained that 
the presence in sucrose of traces of invert sugar, or levulose and 
glucose, causes condensed milk to ferment. Glucose belongs to 
the monosaccharides. Its chemical formula, like that of levulose, 
is CgHj^O,;, it oxidizes readily and under the influence of yeast 
and other micro-organisms it ferments, yielding mainly alcohol 
and carbon dioxide. Its presence in condensed milk, therefore, 
is prone to start fermentation, and the manufacturer who uses 
it with a \iew of lessening the cost of manufacture of condensed 
milk is, indeed, [>racticing poor economy. There is no adultera- 
tion of sweetened cijndensed milk that will produce such in- 
evitable disaster as the addition to it of glucose. Aside from this 
fact, the law prohibits the addition of anything except sucrose. 

Addition of Bi-Carbonate of Soda, Ammonium Hydroxide, 
Lime Oxide and Lime Hydrate and Other Alkali. — These alkalies 
and alkaline earths are frequently added to evaporated milk, for 
the purpose of neutrali.zing excess nf acid, or balancing the ash 
constituents, in order to diminish the \iscosit}' and tendency to 
curdle, to facilitate the sterilizing process, and to prevent the 
milk from curdling when exposed to heat. If used in reasonable 
quantities, they interfere in no \\'ay with the quality and health- 
fulness of the product, and may in exceptional cases prevent 
great loss. If used in excess, the milk will foam very badly in 
the vacuum pan, which renders the process of condensing a diffi- 
cult one and the finished product has a bitter flavor. Under 
ordinary conditions, their use is entirely unnecessary and simply 
means additional labor and expense. The abo^•e agents and also 
viscogen, are sometimes used with the \ie-\\- of thickening sweet- 
ened condensed milk and increasing the outimt. Kxi)erimental 
results,' howe\'er, showcfl that these agents cannot be used in 
large enough (|uantities to ])roducc the alxn-e results without 
materially lowering the fpiality of the product. 

Addition of Cream of Tartar. — Cream of tartar is used ex- 
tensi\'ely in the manufacture of candies and caramels. Its purpose 



^ Hunzlker, experiment.^ not published. 



AdULTKKATIONS of CoNDIiNSED MiLK 275 

is to make the sugar in tlie>e products precipitate in the form of 
very fine and soft crystals. Coiidenseries, which ha\'e been con- 
tinually troubled with siiyar crystallization and sugar sediment, 
have tried to overcome this defect by adiling cream of tartar to 
the sweetened milk in the \acuum pan. Cream of tartar is an 
acid salt (acid potassium tartrate, I\H.C_,TI,0,,; ), and it is this 
acid which in the manufacture of candy causes the fine and soft 
grain of the sugar. It is ol)\-ious that if enough cream of tartar 
were added to condensed milk to produce the desired effect on 
the sugar, the acid present would curdle the milk. Its use is of 
no value to the manufacturer of condensed milk. 

Addition of Starch. — 'J'he past}- ami thick coiisistenc\- of 
sweetened ccjndensed milk frequently suggests to the public that 
it contains starch. 'Phis is erroneiius, for it is doubtful if con- 
densed milk is e\er adulterated \\'ith starch. There would be 
nothing gained by sn doing, and the presence of starch in con- 
densed milk could be readily detected witli iodine. Iodine gi\es 
the starch cells a deep blue culor. 



PART VI. 
MANUFACTURE OF MILK POWDER 

ClFAPTKR XX\^ 

DEFINITION. 

^Iilk powder, (lr\- milk, piil\-erized milk, dehydrated milk, 
desiccated milk, milk flc'iir, i,^ made fmm cow's wlnjle milk, or 
]iartl}' iir wdinlly skimmed milk, nr from whole milk that has been 
cr.riched hv additinnal liritterfat, tci which sti.^ar, or alkalies, or 
lioth ma}', (ir ma^' not have been added, and which has been 
cwiporated (n drxness either nndcr atmospheric jiressure, or 
in A'aciio. I'nw ders nia<le from cream containinf^- 18 per cent 
bntterfat (ir more, <;re called cream po\\-ders. 

KINDS. 

1'hc milk- |)o\\-ders on the market vary chiedy in their solu- 
bilitA" and fat ci intent. 'J'he bmlk of the milk powders is produced 
from \\di(ilh' or parth' skimmed milk. Most of the milk powders 
of the early da}'s of this indiistr)- contained added cane sugar 
and alkalies. The pnrpcme of the addition of alkalies was to 
lend ,i;-reater so!nbilit\- to the priiteids. 

The process of manufacture, howe\er, has been improved 
til the extent to A\here the scilubilitA' nf the proteids can now 
be preser\ed withoul the admixture nf alkalies, ^fost of the 
milk p(iwdei> put nn the market in this countr\' are free from 
admixture nf an\' substances foreign ti i nurmal milk. 

HISTORY AND DEVELOPMENT OF INDUSTRY. 

The (iri^;!!! and histnrx uf the milk ])o\>.der industry- are very 
closel}' rclale(! and intimateh' connecfed with those cif the con- 
densed nn'll< industry. The fnndanieulal ]nir])i"ise nf the t\\'0 
products is mie and I he s.ame, i. e., ti i preser\-e milk as nearly 
as possible in its natural eimditinn, and tn reduce its bulk to the 
minimum, so as ti i m.akc pnssible its eciuinmical transportation 
til all |iarts of the world. 



MaNUFACTURI; OF MiLK POWDF^R 



277 



The fliftcrence lietween milk iM^iwdcr and crinden^ed milk 
is maiiiK" rmc nf dcL;rcc nf (-Miicentratinii. It i^ imt surprising;', 
thcreftirc, that the iii\-ciitii ins nf [irneesses cif mamifacture nf the 
t\\ I ' jM-nducts date hack tci ahemt tlie same period, the mirldle rif 
last cciittiry, and in ni'ist eases the inxenteirs r,\ the rine priidnrt 
had alsri in mind and t;a\'e due con^ideratiein tr) the finisihilitie'^ 
nf the other. 

The fn'st ci immercialk; usable ]irocess was inAcnterl \>v 
('ii'imwade wliri stcui'ed a jialent freim the ririti^h ( ii"i\ernment 
in 1S5.^. His jjmcess cnnsi'^tedi lii'ieflx' of fir^^t adding' carlionatc 
(it srida ()r ])(itash t" the fresh mdk, then ewajn iratiuL;" in ripen 
jacketed pans and with ciiii>lan,t aL;atatiiin, until a diiup;li-like 
sidistance was nhtained: then addiuL'; cane sup'ar; the mixture 
was then pressed hetween i'idlei'< intri rihlion^. further dried 
and then pid\-erized. The alkali, m the form ' if carlmnate nf 
M ida I ir jiiita.^li. \\"a,■^ addled in nrder tii render tlie casein nifire 
-dlulile, and the purpn^e nf the admixture nf the -uijar AA"a^ to 
prnduee L;ranulalinn nf the dnup'h tn^warrl the end (:if the prncess 
facdit.atin:,; the renin\al nf mni-tui"e dnriuL;' tlie later stat'es nf the 
di-\anL; i.)rnce-.s. ddie ex'ajmratinn in npen i.ian< was later super- 
seded he tile ii<e nf the \acuuni ]jan. The '"irimwade jinice^s n| 
manufacturiiiL'' milk pnwder was in practice Inr snme }'ears. 

Since the intrnductinn nf the Crimwaile iirocess. se\"eral 
mndillcatiniis tlierenf haxe keen patented, and mimernus new 
processes tor desiccating' milk, that imnh'e principles entireh' 
difl'erent from the ("irimwade prncess. haxc keen in\'ented, ha\'e 
found n'ide cnnimercial api'dicatinn and lia\'e practically super- 
seded the use of the earlier inx'entions. 

The I'lerfection nf |)o:ice-ses suitahile fnr the cnnimercial 
manufacture nf rlried milk is of relati\'i:d}' recent origin and date- 
hack largeh- tn the closiiiL;' ^'cars nf the nineteenth centur}' and 
the first decade nf the twentieth ceiitrv. Up to that time the 
annual output rif milk powder was crimpai'atixel}' small. Cut 
within the last scnre rif years rapid prngress has keen made and 
the wni'ld war has lent this industi'N' additiniial impetus Toda\' 
the annual [irnductinn is a^sumiii- kirge iirn]irirl icius, especialh' 
that rif pnwdered skim milk, thnugh crm-iderahle (|uantit)es of 
powdered whrde milk, pnwdered cream and pnwdered buttei'milk 
are also manufactured, as shriwn kelnw. 



278 



Manui-'acturi-; oi' Milk Powdivr 



Annual Production of Skim Milk Powder, Whole Milk Powder 
and Cream Powder in the United States.' 



Kind of Product 


Pounds by Years 


1918 


1919 


Skim milk powder 


25,432,007 

4,164,3,34 

654,360 


,33,076,131 


\Vhole milk powder 

Cream po\\'der 


8,660,785 
592,070 







Accordiii!^' to Potts,- tlie number of firms manufacturing;" 
p(jwdered milk products in the I'nitcd States is as fnllnws: 

Skim milk powder 47 

Whole milk powder 15 

Cream powder 3 

Description of the Principal Processes of Manufacture. 

The prrjcesses of desiccating' milk, which l;a\-e ];ni\-eu C'ln- 
mercially successful and have found -v\'ide a]i])licatii ni, ma^• l)c 
con\'eniently grouped into three fundamental citepriries, accord- 
ing to the predominating princi]ile upon \\Jiich tncv are hased. 
These are : 

1. Dough-drying processes. 

2. Film-drying processes. 

3. Spray-drying processes. 

For detailed discussion of the more outstanding principles 
covered in some of the patents of these processes the rcafler is 
referred to the following brief descriptirm and illustrations. 

1. Dough-drying Processes. 

To this group kirgely belong the earliei' and cruder ]iro- 
cesses. The milk is condensed in an\' maimer, either \)V heating 
in open pans under atmospheric pressure and usuallv with the 
help of mechanical agitation ; or in the vacuum pan with or with- 
out mechanical agitation; or in o|)en \ats by lilowing heated 
air through the milk, tri a high degree of ciincentration and to 
a dough-like consistenc}-. The concenlr;ited product is then 



1 The Market Reporter, U. S. Bureau of Markets, Vol. I., No. 14, 1920, 
'Potts. Data furnished by correspondence. 1920. 



Manufacture ok Milk Powder 



279 



spread on trays or other similar containers, and dried to a hard 
substance in \acuum chani1)ers or in r.ther vaults or drying ap- 
])aratus, pro\-idcd with heating de\'ices fir currents of hot air. 
The dried iiroduct is suljsequently ground tci a fine powder. 
Examples of this type of milk-drying processes are the AVimmer 
process, the Campbell process and others. 

, The Wimmer Process. — The milk 

is Ijoiled in a \'acuum pan similar to 
that used in the manufacture of con- 
densed milk. The vacuum pan has a 
deep steam jacket for heating, but in 
the place of the usual coils, the pan is 
equipped with a mechanical stirrer. 
The milk is condensed at a relatively 
](iw temperature and the stirrer re- 
\-ol\-es until the water content of the 
milk is reduced to about 30 per cent 
and the milk has beccime porous and 
crumblv, tlunigh it still forms a com- 
])act mass. The drying is then com- 
pleted in the open air and without addi- 
tional heating. The product is then 
ground to a powder. This is the pro- 
rig-. 90. THe wimmer milk ^^.^^ invented bv Ole Bull Wimmer of 
powder macmne 

Copenhagen, Denmark. 

The Campbell Process. — This process was invented, pat- 
ented and impro\-ed by J- H. Campbell of New York City, U. S. 
patent Nos. 668,139 and 668,161, February 19, 1901 ; U. S. patent 
No. 718,191, January 13, 1903; U. S. patent No. 762,277, June 
14, 1904; and by J. H. and H. C. Campbell, U. S. patent No. 
668,162, FelM-uar)- 19, 1901 ; and by C. H. and P. T. Campbell, 
C. S. patent No. 771,609, October 4, 1904. 

The Campbell process consists essentially of concentrating 
milk to a high degree of concentration by blowing heated air 
through it in an open \at. The milk is reduced to a ^•ery thick 
consistenc)', resembling a batter. The concentrated milk is then 
remo\'ed from the e\"aporating tank, is reduced mechanically to 
small units by means of a pugging or shredding machine, or 




280 



ManuI'ACTuuH oi? Mu.k Powdi^r 



i"ither"wise. This siilxlJN'ided pi-odiict is tlieii ])laced on shelves 
(ir trays and (h'ied in a chandjcr heated tu a temperature lielow 
the eoagulatin;,;" ])iiint of tlie allnimen. 




Fig-. 91. The Campbell milk drier 



I. A concentraUng vessel, a outlet, b vah-e. c hot watei- jacket, c^ hot 
water pipe, c- discharge of Jacket, B air pipe, e connecting hose, f stand pipe, 
g air-distributing disc, t air chamber. — II. E pug mill, 1 cylinder, ,i hopper, 
k chute, 1 horizontal shaft, m blades for stirring, m' projections for scraping 
blade.s. F Vermicelli-machine, n hopper, o cylindrical chamber, p piston, q 
spiral screw, q' worm-wheel, o' small holes, r^ endless traveling apron, s tray 
with perforated bottom. — III. G drier, t body of drier, H blower, t' flue, u 
opening to insert trays, u' opening for removing trays, vv endless chains with 
projections for supporting trays, w coil heater, w' pipe circulating hot water. 

In the proeesses nf the d(iut;'h-(h-yiii,y" |)rinciple o\ desiccatitm. 
the dried product is reduced to a marketalde ])(iwder liv ^rindini; 
it and then boltiii"" or or siftiii"' it. 



2. Film-Drying Processes. 

'To this gToup belnnc;" the iiunienius processes in wdiich the 
milk, w'itli or without pre\'i(ius cmicentration, is dried on the 
surface rjf one or more steam-heated. re\dl\'inq' drums. The 
milk is either picked up bv the re\i ihint;' drums, (jr it is spraved 
onto these drums, forming" a thin I'dni \\'liich dries ra|)idl\'. The 
film of dried milk sri formed is atomaticalh- remo\'ed \vith each 
re\'olution of the drum liy means of a mechanical scraper. In 
some of tile jjrocesses of the film-drving tvpe the dr^•ing■ cyl- 
inders operate in the open, under atmospheric i)ressiire, in others 



ManufacturK of IMii^k Powder 



281 



the flr\-inL;" (innns are inca.sed in a \acuuni eliaiii1)er and the 
(h-_\inL'; is aeconi])lishe(l under reduced jjressure. Snnie nf the 
IJ. S. patents nl the hhn-dr\'inc;' ]")rocess that ha\-e found wide 
eomniereial ap]ihcatirjn are descri1)ed below. 

The Just Process. — This jimcess a]iiieai-s t^i he the llrst 'if 
its t\]ie tliat found wade api)lieati'm in tlie desiccatinc;" rif milk. 
It was im-ented and patented li}- Jnhn A. Just rif S}'racupe. Xew 
\hirk, I'. S. oatent Xr.. 712, ,^4.-. X.ivend.er 4, l')02. 




Fig. 92. The Just milk drier 



The essential e(|uiiiment inxuhed in the Just preieess con- 
sists (if twii horizuntal steam-heated re\-i ih ui.l;- metal c}dinders. 
These c\-Hnders are installed .sutiiciently cluse to each other so 
that there is contact at their [jeriphery. A milk destrdnuin;,;" tank 
(7) with adjustable dischart^e (8 and 'i) in the center o\-er and 
bettt'een the two cylinders. Scrapers cir kmAes (II) ^\hich re- 
niON'e the flried tilm of milk frnm tlic c\dinde)>: and receptacles 
(12) \\'hich recei\-e the tini.-.hed ])o\\dei-. 



282 



Manufacture of Milk Powdfr 



The patent claims of the Just process cmer the treatment 
nf the milk with calcic chloride ( Ca ( ) -|- Ca CU ), or with the 
double salt of sodium and calcium citrate, to reduce the acidity 
of the milk, and with alkaline hypi ichli irite fnr the nurfjose of 
preser\'inf; the fatty acids in the finished jjroduct, the heatino 
and boilinc,'' of the milk Ijv bringing- it in cuntact with a heating 
surface of a temperature abo^e 212 degrees V. and helnw 270 
degrees F., allowing the thus treated and heated milk to Unw 
in regulated (piantities on the surface of the steam healed re- 
\olving' metal cylinders, where it is dried in the fi n-ni nf n film 
and from which it is removed by mechanical scrapers. The 
temperature of the heating surface on the cylinders is In exceed 
212 deg-rees F. and to be below 270 degrees F. 

IMie high temperature to which the milk is heated nb\-i(iusly 
reduces the solubility of the finished po\\'der. The [nirjx'ise nt 
neutralizing the acidit}' of the milk, before drying, is t<:i mini- 
mize the solubility-destroying' action of the high heat. 

The Hatmaker Process. — This is similar to the Just process. 
James ]-;. ITatmaker of London, England, ptn'cliased the Just 




Tig. 93. The Jnst-Hatmaker milk drier 

process for operati<.)n in luirope arul later secin-ed a patent of 
his own, which rej^resents a modification of the original Just 
process, and which is known as the Just-Hatmaker process, 



AEanuFacture of 1\[ii<k PowdUr 



283 



The Gathmann Process. — This process and equiinnent was 
in\-ented and patented Ia- I.nuis GathnTann nf \\'asiiin<:;t<'in, 
D. C, L'. S. patent Xo. ,S34,31(\ (lctol)er 30, l'>(Xi. 

In iliis iinicess, similar as in the Jtist pmcess, the milk is 
dried in the idrm i.n' a him on a rc\'i ih-ine. steam-heated drum 
under atmospheric pressure. In this case, howCA-er. i"nd}' one 
drum is used, the drum (Al is cone-shaije instead of cylindrical 
and its surface is spiralh' L;i'ii(")\-ed r)r corruLjated (a) and the 
;uljacent -surface against which the cime revoh'cs is also similarly 
ci 'rrui;"ate(l hut the sjural L'rrio\-es ( 1)' I runniuLf in the opp(jsite 




Fig. 94. The Grathmann milk drier 

du'ection from those on the cone, as is cimimou in gTindinti'- 
mills. Hence \\dien the cone re\'(d\-es the dryinc: milk is kneaded 
and ground between the two surfaces and is gradually carried 
or pushed bA' the corrugated surface of the re\'olving- cone to 
the smaller, or discharge end of the machine. 

The adjacent corrugated surface against which the surface 
of the cone grinds, and which incases the lower half of the surface 
of the cone, is steam jacketed (b-), so that the milk is between 
two heated surfaces. 

A hopper (D) regulates and feeds the flow of the milk to 
the cone at its larger end and a brush ( (?j ) located near the 
smaller end of the cone remoA'es such parts oi the dried milk 



284 



Manui"ac'i'i;ki', ni' I\Itj,k I'owoKu 



as ni:i\- adliurr In tlu- l' riiidiiiL; surface. r.allle Imards or dasli 
l)nartls arc pruxidcd tn i'ccci\c sncli nf tlic niid< as ma}' s])lasli 
tr( iin the CI jnc. 

ddic iiatciit claim cii\eis the ih'yin.L; 'if tlie mih< hy feeding 
It to a Cdiitiiun nisl\- nidxiiiL;", heated surface, wliere it is permitted 
t(> f(jrui a ciimparati\'el>' tldn hi_\ei-, heating- it tci c\a])orate tlie 
water, and simultanci )usl\' sulijectiiiL;" it ti i a kneadiui;, wliicli 
^radualh' changes to a L^riudini;" actinii, as tlie milk solidihes, 
and fnrms a powder. 

'idle temperature uf the heatiuL; surface is rec cjiiuiendcd lo 
lie that iif Ijoiliiii:- A\-:iter, hut ma\- he Itetweeii 212 decrees 1'. and 
270 de,L;-rees F. The milk enters the hii])f)er witlmut preheatiiiL;' 
and without dtlier treatment. 

The Passburo; Process. — This lu-ncess was in\"ented and 




Fig". 95. The PasslJiirg: milk drier 



]iatente(l h\' I'jnil l'asshui"n" nf I'.erhn, (lermany, U. S. ])atent 
Ko. 72t),742, April 2S, l')0,i. This film dr\-er operates under 
reduced ]n-essure. It consists nf an outer casing" (A) in which 
re\C)l\'es mie steam heated, metal drum (T), [in autnmatic milk 



Manufacture of ;Milk Powj>fk 



285 



supply i'ei;iilatiiig' feed ( li ) which l-;ee|)^ the milk in the \acuuni - 
ca^in-- at a constant le\-eh an ONci-llnw- aperture ( I ) that re-uhite-- 
the thickness df tlie him, a x'acunm fmnif), a scrajier iS) tri 
remrix'c the iilm rif rlricd milk frMm the rcNCiKim:;- drnm and an 
evacuated recei\'er (111 fur tlie dried sulistance. 

ddie nullv- is drawn into the drnm easinc;' '<'■' \acunm cliamlier 
hy tlie irircc i.l the wacunm in tins chandler. l'.\" the prii|ier 
adjustment nf the feerl \-ah'e anrl the i i\e]-h( iw \-al\e. the milk 
rises icj a :^i\-en le\-el and stays at that le\'el while ■ q-K-rali' in is 
in prrj^ress. 'idle re\"i ihini;" steam-heated dnmi sliL;htl\' 
dips into the milk in the A^aciuini chandier and picks t^i, a fdni 
of milk AAhich dries under reduced ]")ressurc while the drum 
makes nne rcA^i ilution. ddie dried tilrn is reniri\-ed Iw the auto- 
matic scraper and the hnished dried ndlk is discharged into the 
receiA'cr, while the moisture-laden air and wapeirs escaj'C through 
a Condenser located cintside of the di'\ ing apparatus. 

The Ekenberg Process. — Tliis is alsri a film drier o|)ernlinL; 
in A'acuo. This process was iuA-ented by Martin Ek'enfjcrg of 
Stockholm, Sweden, in the ^-ear ISOo and is co\ercd !)}■ a numljer 
of United vStates patents, some of the earlier of which are patent 
Xo. 7('<4.'>95, 190-f, and Xo. ;s3,f)00, ^Farch 21, 190,^. The patents 
cOA'ering this pi'eicess are ri-\\med ly\' the Ekenljcrg Compaii}- eif 
Cortland, X. Y., A\dio are operating nimier(;ius milk dr^dng fac- 
tories in the States rif X'ew ^'ork and ^fichigan. 

The Ekenljcrg niilk drier is called exsiccator, ft consist^ 
111 a re\-oh-ing, steam heatedi nickel drim), inclosi-d in a \acuuni 
chamher. The ends of the drum form hell-sliajied howls, 
dished outwai'd. ddie ilnun is er|ui]i])ed with knixcs or scrapers, 
wdiich remioe the film of dried milk that gathers on tlie drum. 
Attached to the \-acuum chamher there is a snKiller chand)er 
wdiich ser\-es to receiA"e the dried milk as it is scraped from the 
drum. This is sepai'ated frrim the large \acuum chamher by a 
scries ejf air locks, sci that the materia! ma\" fie remo\ cd without 
breaking the x'acuum in the lai'ge chandler. 

The milk, as it enters the \acuum chand.ier, is S]:)ra\'ed into 
the concaA'c ends r>f the drunu In this manner it is fore-con- 
densed. It is then withdi'awn fmni the wacuuni chamber Iw a 
pump, and returned again, this time being spra^-ed upon the 



286 



Manui'acturK of Milk PowdKS 



periphery of tlie dnini. The milk remains on tlie (hnini rmly lonf^ 
enough f(ir it tn nial<e three-quarters nf a rcx'ohition. 

After the dried milk is remii\ed fruni the exsiccator, it is 
placed in a special drying; chamber at a temperature of 90 degrees 
P. where it remains Imic;' en()u,c;"h for the milk sugar to crystallize. 
This is usually accomplished in about an houi". After this it is 
ground and sifted in a similar manner as is the case in the miUing 




Tig. 96. The Ekenbergf exsiccator 

Courtesy of Ekenberff Co. 

of wheat llour. It is then ready for the market, which it reaches 
packed in either tins, boxes, or barrels. 

The fact that the milk is ex'aporated under reduced pressure 
makes it [)ossible to accomplish the drying at a relati\elv low 
temperature, although the him of drying milk is naturally ex- 
posed for a \ery brief time to the direct heat of the drum, and 
which ob\'iously varies with the steam pressure in the drum. 
The manufacturers claim that the drying of the milk takes place 



Manufacture of Milk Powder 



287 



at a temperature nf aljout 100 de.i^rees F. and that the milk at 
no time reaches temperatures higher than 120 degrees F. 

The Covers Process. — This prucess and equipment was 
indented and patented by F'rancis X. Goxers, of ( )\vegn, Xew 
York, U. S. patent No. 939,405, November 9, 1900. 

Tn the Go\-ers patent the milk is dried on twn re\-("ih-in,c. 
hollow cylinders (5) located at such prr.ximity to each nthcr 



S9 




ao 



Fljr. 97. The Govers milk drier 



that there is practical contact at the [)eripherv nt the two z\\- 
inders, in a similar manner as is the case with the lust process. 
These re\'oh-ing- c}dinders, howe\-er, are incldsed and operated 
in an outer casing which serves as a \-acuum chamljer (2 I, \\hich 
connects with a \acuum pump through pipe [2~ ) . There is a milk 
supply tank (1) with regulating vahe (4). feeding the milk tu 
the vacuum chamber through pipe (3). Plates (lOi which bear 
against the opposite ends of the c}dinders ( .^ i form with the 
revolving cylinders a receptacle (13) to receiA-e and retain a 



288 Manufacture; oi' Mii.k Powder 

Miiali (|uantit\' nf tlie milk tu lie desiccated. The cylinders are 
cliari;"ed witli hut water lhrnu;.^]i jiipes (If)). Scrapers (21) re- 
1111 )\e the dried milk frcim the c\diiiders, [iiid a rntatinr;- \'alve 
arrann-enicnt (2.S and 2')) is prriA'ided tn eatcli the dried milk as 
it is scra]icd f n nn the c^diiiders and tn carr}' it from the vacuum 
chaniher withnut hreakint;- the \'acuum. 

In the ii|ieration cif this machine it is aimed to maintain a 
partial \acuum, sufficient to cause the milk tci 1)oiI at a tem- 
perature I if ahout 1.^7 decrees F. Throuiili the re\-ol\-in£,'- metal 
cylinders passes a continuous flow of Imt water at a temperature 
somewhat hit;"lier than 157 degrees F. Init bekiw 212 degrees F., 
so that tlie milk is iie\'er exposed to 212 degrees V. in^ir ri\-er. 

In the small receptacle of milk at (13) to wdiicli the milk 
is cnntinualh" sup]:)lied from the outside, and as rapidly as it 
e^'aporatcs. the milk is heated, to aliout 137 degrees F. \>y the 
re\'o]\-ing c^dillders. It is partlv condensed and a thin film of 
tliis condensed milk coats the surface of the c^dinders wdierc it 
dries, the dried film is remo\'ed from the cylinders by the scrapers 
and discharged to the outside of the ap])aratus through the \'anes 
rif the four-winged A'ah'es (28), located near the bottom on both 
sides of the vacuum chamber. 

The Buflovak Process. — The principle of drying milk and 
other liquids on a steam- or hot water-heated revohdng drum 
has been ]iut to extensi\'e application through the acti\'ities of 
the Buft'alo Fi^iundrv cK: Machine Co., Rufifalo, N. ^'. This com- 
pany has, during the last decade, im-eiited. constructed and 
perfected the "^'.uflo^•ak" \-acuum drum drier. Patents were 
granted their engineer, Mv. (). S. Slee|)er, In- the United States 
OiN-cniment in l'"'l], l')13. 1'"'14, 1015 and I'tp.. All these patents 
were .assigned to the i'>uft"'alo Foundry M- Machine Co. 

Tliese patents ]iertain to the drum drier as used for wdiole 
mdk, skim milk, Inittermilk and milk jiroducts in general. The^' 
are ajiplicable to otlier jiroducts as well as to milk, but for milk 
they are made specially accessible for cleaning and for sanitary 
control. 

The r>ullo\'ak drier ci insists of a casing in wdiich re\'ol\'es 
a steam-heated, polished drum. The milk is fed to the surface 
or peripher}' of tins drum 1)_\' a pan located beneath tlie drum 
;iiid placed lighth' against the drum. The pan has an overflow 



Manufacture of Milk Powder 



289 



alonq- one side fcir the autuniatic renio\-aI of the surplus milk not 
taken up 1)}- the drnm. To the liritti.im of this casing' is sup])Hed 
a f|uaiitity of milk. This is pinn])ed t' i the siipph- |)an under the 
drum, the oxerHowini;" milk rumiin,!^ hack into the kiwer portion 




X'fk 



Fig". 98. The Buflovak vacuum drum drier 

Courtes\- of Kiitfalo Foundry ^t Mai.hlne *'o. 



of the casing". There is slight pressure in the supfjly pan which 
causes the drum to take u|) a hea\y and cA-en cuating. Xear 
the sup|)h' pan is installed a le\-eling arrangement \\hich Ie\'els 
off and equalizes the la_\'cr i if milk mi the drunu As the drum 



290 Manui^acturE oi-' Mii,k PowdKr 

rc\(jl\L-s and the lavci' uf milk reaches wliat is termed the frnnt 
<if the maehiiie it is ei intiininnsh' reniox-ed in tlie ffirm df a dry 
fdm l)y a statiiinar\' scraper-. ;\t this pdint the macliine is pro- 
vided with a l)rea.ker' which consists of a shaft with a numher 
of rods projectinj;- through the same, which revolves to break 
up the lilm of dried milk as it lea\es the drum. 'I'his does not 
reduce the lilni to ;i ]io\\(ler, hut causes the material to he suffi- 
cieiith' broken up to allow it to fall into the rcccixcr where it 
can be easily handled for iemo\al. 

'I^he receiver is a larLje cylindrical ])an placed below the 
scraper at the fr(.int of the machine. ( )bser\ation Lflasses are 
placed so that all internal parts may be seen while beini.,'- operated. 
The receiver is e(|nip])ed at erich end with a door of the full wiflth 
of the recei\er, facilitating^ the rapid remo\al of the dried milk. 

Aside from the circulating- pimip for supplying the milk to 
the feed pan, there is a condenser and a dr^■ \acnnni pumii. He- 
fore the vapors reach the condenser, they pass through a dust 
collector. This is water-sealed and ])re\ents the accumulatif>n 
in the \'ai)or pipe of any dust that may escape from the drum 
and pass to the condensei-. 

This drier is operated under a high \ acuum, permitting rapid 
evaporation at a relati\el\' low temi)e!-atnre. The actual drviuL; 
time of the film of milk on the drum is about (< to 7 seconds. 
The o|)eration is continuous and at the conclusion of the da\''s 
run the machine is washed out. If subsefpientl)- closed up and 
evacuated for a few mituites, the entire interior will lie dry. in- 
suring a sanitarv condition of the machine. 

3. Spray-Drying Processes. 

To this .group belong the several processes in which milk is 
desiccated by atomizing it into a fine spray and in an atmosphere 
or current of heated air.- The small particles of tlie tnilk spray sur- 
render their moisture (piickly and dro]i to the bottom of tlie drying 
chamber in the form of flakes of dried milk while the moisture- 
laden air escapes to the exterior, screens or other forms of dust col- 
lectors being provided to recover such parts of dried milk as may 
escape from the drying chamber with the expelled air. The principle 
of desiccating fluid substances by atomizing them into an atmosphere 



AIaXL'FAC'IUKE (Jf AllLK POWDKR 



291 



,of heated air dates back to the inventii'ii i")f Samuel R. Percy in 
1872. 

The Percy Process. --This proce^'- wa-- iii\-ciited and ])ateiued 
by Samuel R. Percy of New York City, U. vS. i)atent No. 125,406, 
April 9, 1872. The jirocess embraces in its claims, a process of 
atomizing and desiccating fluid and solid substances, also any viscid 
substance containing water, by the use of dried, heated or cooled air 
or gas, which forces the substance into atoms ; the atoms are thrown 
forward, and forced into a chamber and dried in consequence of the 
dried or heated air which propels them into the chamber and also, 
owing to the dried and heated state of the chamber into which they 
are thrown. 

The Stauf Process. — The Stauf pruce^-- represents the first 
commercialh- successful application of the desiccation of milk by 




Fig. 99. 



The Staiif milk drier 



the spray-drying principle invented by Percy. The Stauf process 
was patented by Robert Stauf of Posen, Germany, U. S. patent No. 
666,711, January 29, 1901. 

The patent claims are as follows ; "The process of obtaining 



292 JManufacturk of Milk PoWdku 

the solid constituents of liquids, such as blood, milk and the like, in 
the form of powder, said jirocess consisting in converting the liquid 
into a fine spray, bringing such spray or atomized liquid into a reg- 
ulated current of heated air, so that the liquid constituents are com- 
pletely vaporized, conveying the dry powder into a suitable collect- 
ing space away from the air current, and discharging the air and 
vapor separately from the dry powder." 

The Stauf patent shows a vertical drying chamber (e) into 
which the liquid (milk) to be desiccated is atomized through jets 
or nozzles (b) under pressure, into a fine spray. A current of 
heated air is admitted at the bottom of the drying chamber (f) run- 
ning in the same direction as, and mixing with, the spray of milk, 
and evaporating the watery constituents of the spray. The steam 
and dried particles are carried upward by the heated air, retaining 
the atoms momentarily in the current of hot air and causing them 
to surrender substantially all the remaining moisture in the form of 
vapor, and the product is prevented by the cooling effect of such 
evaporation from undergoing chemical change. The vapors and 
dried atoms are guided by a cone (g) extending downward from the 
top into the drying chamber, into collecting chambers (h) where the 
desiccated milk or dry powder gathers in hoppers (i) away from 
the vaporizing current. The moisture-laden air or gas is separated 
from the dry powder and escajies through the sides of the collecting 
chamber, which consist of mill gauze, woolen fabric or like pervious 
material. 

The McLachlan Process. — This process was patented b}' 
John C. McLachlan of Chicago, III. U. S. patent No. 806,747, De- 
cember 5, 1905. This process is a modification of the Stauf process. 

Mcl^achlan uses a tall vertical drying chamber (B) surrounded 
on its sides by a jacket or casing (A), containing steam heating coils 
(Ci) with intake, and nulkt of steam; a circular, ])erf(irated pipe 
(M) is installed near the top of the chamber for the purpose of dis- 
charging into the chamber heated air, an atomizing jet (O'') enters 
through the side of the drying chamber near the top, an air pump 
(O) forcing heated air into the atomizing nozzle (<-)'), a slide door 
(D) at the bottom of the drying chamber for the discharge of the 
dried powder through opening (E), and a perforated covering (K) 
over the top of the drying chamber for the escape of the moisture- 
laden air. 



ArAxi'FAC'iTRi-: (iF Mii.K Powi)i:r 



293 



In tlii^ a])|)aratus the s]ira\- (jf llie milk enters into the upper 
[)art (i\ the dryint; chaniljer and is j.crmitted to drop through an 
atniiis|ihere of lieati'd air. As tlie atrmis of dr^dng milk descend, 
they surrender more and mure of their moisture and at a certain point 
toward the buttom the\' ha\-e discharged substantially all their mois- 



su ] 




FigT- 100. The McLachlan milk drier 

ture and are deposited in the form of a dr)- powder in the bottom 
of the dr)'ing chamber, from wdiere they are discharged by a slide 
door, [n the meantime the vapors pass freeh' up and out of the 
upper or of)en end of the chamber. 

This [irocess differs from the Stauf process essentially only in 
the fact that the milk descends through an atmosphere of heated air 
and that the dr\'ing chamber and the collecting chamber are one and 



294 ManuI'ActurK oe Milk I'owuer 

the same, while in the Stauf patent the milk spray ascends and is 
carried into separate collecting chamhers. 

In a later design, U. S. patent No. 1,038,773, September 17, 
1912, McLachlan causes the heated air to Ije forced into the drying 
chamber throngh a rotating discharge head located in the center of 
the drying chamber. 'I'he rotating discharge head directs the air 
currents radially outward toward a dcflecling ring. 

The milk is blown into the drying chamber through multiple 
supply nozzles or atomizers. These supply nozzles enter through the 
periphery of the deflecting ring. They discharge in a horizontal 
plane and incline to the radius m such a manner as tn cause maxi- 
nnim c(jmmingling of the finely divided particles of the milk with the 
heated air. The dried powder, deposits in the bottom of the drying 
chamber, a belt conve)'or discharges it into a screw conveyor pocket, 
whence it is removed to any suitable storage container. 

The moisture-laden air leaves the drying chamber through 
drums near the bottom and top of the drying chamber. These dis- 
charge drums are efpiipped with suitable arrangement to recover 
such parts of the powder as are dejjosited on their surfaces. 

The Merrell-Merrell-Gere Process. — This process is similar 
to the Stauf process except that the patent covering the ]\Ierrell- 
Alerrell-Oere process specifically refers to the desiccation of pre- 
viously condensed milk, while the v^tauf ])atent makes no specific ref- 
erence to the use of condensed milk, althfjugh the term "milk" may 
have been intended to embrace all kinds of milk regardless of the 
degree of concentration ])rior to desiccation. 

'i'he Merrell-vSoulc Co., of Syracuse, N. Y., purchased the 
Stauf [latent in 1905 and two years later L. C. ]\Ierrell, I. S. Rlerrell 
and W. B. Gere, of Syracuse, N. Y., assignors to Merrell-Soule Co. 
patented the [irocess as applied to desiccating condensed milk, U. S. 
])atent No. 860,929, July 23, 1007. Their patent claims read as 
follows ; 

1. "The process nl (ibtaining the solid constituents ol 
liquids and semi-liqnids, in the Icirni ul powder, which process 
consists m concentrating the substance l)\ remo\iug a large 
percentage of the water therefrom, converting the concentrated 
mass into a tine spra\', bringing such spra\' into a current of dr\' 
air or gas haxing an a\idity for moisture so that substantially 
all the remaining li(pii(l constituents are separated therebv. 



Manufacturi{ 01' Milk Powder 



295 



CI )n\-e\iiiL,'" tlic (lr\- powder iiit.i a suitahlt' CdllectiiiL; space i\\^a\ 
from tlie air nr !L!;as cui'rent. and discliars^iiin" tlie air or L;as sepa- 
rateh- irum the dry powder. 

2. "'Idle |)roce.ss of olitainiiiL;" the s<did constituents of hqiiid^ 
and scmi-h(|uids, in the form of ])o\\der. which ])ri!cess consi^t^ 
m concentrating tlie substance \)\ i'enio\'iiiL;" a lar^e ])ercentaL;"« 
id water tlierelrom, conx'ertini;' tlie concentrated ma>s into a 
spra\'. hnni^ini^' such s])ra^■ into a cnia'eut of (\r\ heated air oi 
t^-as liaxdn;^ an a\"idit\' for tlie moisture of the suhstance treated 
retaiiiiui;" the atoms moiiientanh- in -aid current so that suli- 
stantialh' all the rcniaiuiiiL; moi-ture is con\-erted into \apoi 




Pig". 101. The Merrell-Soule milk drier ' 

and the product is pre\eiited ]:\ the coolini;- effect of such e\a[i- 
oration from underijiiint^' chemical clianL;'C, conxawini,'' the diw 
powder into a suitable collecting' S])ace awa\' from the \"api irizinq- 
current, and discharLn'iiL;" the ;iir or ,L;as separateK' froni the diw 
pr)wder." 

The Alerrell-Soule Co. are operating' numerous powflercd 
milk factories, with lieadi|uarters in Syracuse. N. \'. ddiis com- 
pany has sutijected the spray-dr\-im_;- jirocess to much experi- 
mental study ill efforts to perfect the preicess and to impro\-e 
the qualit}' and keepiiiL; properties of the product. 

( )b\iously, during- tlie life of the Stauf patent, which ex- 
pired Januar\- 2'). 1918, no one could make milk powder b}- the 
spra^'-dr^dm,!- iirocess, whether from milk uncondensed. or from 



■ From Plaintil'f's Ret-'Oi-rl in tlif U. S, Iiistrlct Court. :MHrren-Soul6 Co 
vs. Ri'-o Milk Products Co. 



296 



MANUFyVCTURI*. OF MiLK PowdKR 



milk |irc\"ii iiish' cundensed withmit |);n-iiiL;" triluitc tn the (i\\'ncrs 
<il' this patent, the Merrell-Smilc C<i. 

The C. E. Rogers Process. — This pniccss was patented 1)\' 
Charles I'.. Uo-ers (if Detroit. Micli., U. S. patent Xn. 1,-'_Y),001, 
Ma_\- 13, 1''17. and X... l,_'4.i.S7S, ()rtnl,cr 2?,. I'M". 




Tig. 102 and Pig. 103. Rogfel's milk drier 

C'ourtes>' oC i\ E. Kdfier.s 



^ desiccating' cliamV)er, - .sprai' nozzl. s, ' .spiay iiipcs, ' luit air inlet con- 
duit, ^ end of air conduit, "deflector, 'air (lischaia^r eondiiits, "recovery 
screen.s, "pivots, "^ tiar, ^' loose screens l"<-ii' \'iltratin,L;, '-springs, '-'rods con- 
tacting witll '■' I'ains. 

The patent claims e(i\ei" the desiec.itinn In' ihr s])r:i\-dr\-ini; 
process iif llnids inidudiiiL;' cundensed milk. The a])]iai"atiis con- 
sists (if a lai'L;e di'viiiL;' chamhei', the spr;i\' n(i/zles are located 
near the tn]) on all fdui" sides df the chamhei-. The hot air is 



Manufacturi{ of ]\IrLK Powdkr 297 

;uimitlfd iipar tliir iHittiuii in the renler ul" tlic (ir\-mL;- chamber, 
means for lieatint;" tlie air, l)li iwin^;" it intu the (h'\-inL;- chamljcr 
and screens li'cated near the lirittiim at tlie |ieri])her\- nf the 
cliamliei- for rhscharL^ini;' tlie sjiciit air are ])r()\i(le(L 

In this apjjaratus tlie sprayed milk falls frrini near the tup 
')f the dr\'ini.'; chaiiiher thrmi^li an asceiidini;" current nf heated 
air. The milk spra_\- entering; un all -^ides causes an e\en distribu- 
tidii cif the spray i)articles and a cunseqiient e\en de])(isit uf the 
dried milk particles (.n the bdttum uf the drvin-- chamber. The 
pre\d(iusl)- ciiiidcnsed milk is sjirayed intn the dryiiiLj' chand)er 
while heated to a tem|)erature rif 140 degrees 1'., the temperature 
oi the air in the dr}'in!^- chamber rani^es fn mi lS(j ti i 200 ilei^rees 
F. The distance ii\er wdiicli the spra\' falls thr'ait;ii the asceiid- 
iiiti" current i d' heatc-d air Ijeinn" sufficient to pei-mit the removal 
from the milk particles i if substaiUialh- all the reiiiaininL;' 
moisture. 

The Gray Process. — Chester Earl C,r-d\ ni luireka, Calif., 
and Aa.ge Jensen i.f ( )aklaiid. Calif., I'. S. patent No. 1,078,X48, 
No\-ember IS, 1013, Chester Karl Cray, .VssiL^amr ..f ,,nedialf to 
Aa-e Jensen, C. S. patent Nn. 1,107,7X4, .Vu-'ust bS, V)14. and 
Chester Earl Cray, I'. S. patent Xo. \ .157 .'>:•<?. ( )ctu])cr 20, l')],^, 
and C, S. jjatent Xo. 1,200,01,C May 14, T'lS, sulyiected the jios- 
sil)ilities of sprax' di"\'ing' t' > e.\lensi\e stufh' and iiu'eiited anfl 
patented successi\c iiiipn ■\enieiits and new jirinciples relatint.; 
to desiccation of milk and Mther li(piid substances. 

Gra_\- ])ateiit Xo. 1,1()7,7S4 iii\(il\es an apparatus wdth a 
cii'cular desiccating;' chamber .\, lia\diiL;' a cime-shape Inwer sec- 
tion I!, terminatini^' in a dischart^e (j[)eninL;' lor the dried sub- 
stance, and a dischari^-e (ipcniiiL;" C fijr the moisture-laden air. 
The heated air is introducei! into the desiccatint,'" chamber 
peri])herall)- in a taii,L;ential directinn, b}- means of a blower D. 
Between the blnwer and the dryiuL;" chamber there is an inclosed 
heatiii;,;' C(jil (steam coil) M\-er and aniund which the air is blown 
intfi the diwiiyc;' chamber. The tanc^ential entr\- of the heated air 
into the circular chanilier sets u[) a cycb^inic current therein anfl 
this effect is aui^niented by introducint;" tlie air at sex'eral different 
jjoiiits through tangential openings a. The milk to be desiccated 
enters under pressure througl) a spray nozzle H. located in the 



298 



Manui-'acturi'. oi-' Milk Povvdi':k 



center nf the elianiher and is atomized. 'Pile distinctixe features 
I il this ])i'(icess are : 

1. 'I'he heated air enters at the |ieri])hery. fr)rms a cyclonic 
currenl niovinc; tangentially toward the center where the moisture- 
laden air esca]ics at C. 

2. Tlie atiimized niih< enters at tlie center nf the cyclonic 
air current, partakes of the .rotary mo\ement of the air current, 
liut hecause of their (greater specihc c;Ta\it\' the particles of drv- 
iu"' milk influenced ]>\ centrifugal force are caused to tra\'el in 




Fig-. 104. The Gray milk drier 

s])iral lines outwardly throu}.^h the current uf air and are finall}' 
arrested by the confinin.s.;' walls of the chamher down which 
the}' fall to the dischari:;e end at the bottom. 

^. The exhau.stiveness of the remo\'al of moisture from the 
particles of milk is au,Limented b\' the fact that the heated air 
movini^- through the spra)- of milk spirally toward the center, 
where it escapes, has taken up its maximum charge of moisture 
by the time it reaches the center, which is the jioint of its dis- 
charge and it is dryest near the ijeripher)'. The spray of milk 



ManufacturK or' Milk Powder 299 

beinp- dischartrefl into tlic cvcldiiic current at the center, carries 
its maximum moisture content at tliat point, crradualh' surrenders 
it to tlie air, as it m<"i\-es r)ut\\';ard to the periplier\- rif th.e c^-c'onic 
current. The coni])1etion of tlie (h-_\-in,y- is accomplished in tlie 
zones of incomini,;- heated air whiclt carry the least humidity. 
Therefore, as the outwardl}- mri\-ini,;- particles of milk surrender 
more and more of their moisture, the}- ])ass throuc^'h drver zones 
of heated air. This oh)\-iously both accelerates the speed of 
d^^■inL;" and enhances the completeness of the remo\-al of moisture. 

4. Inasmuch as the danii^er of the solul>ilit\--destroyino; effect 
of heat is Q-reatest while the milk is still in the liquid state, and 
this effect is j^ractically completely absent in milk from which 
the l.)idk of moisture has been remo\-e(l, this process has the ad- 
ditional ad\'anta,L;'e of ma.ximum pi'eservation of the s( ilul)ilit\- 
in the finished product. The temperature of the c^'clonic air 
current is lowest \\'hen it reaches the center \\ here the moisture 
content of the milk is i;Teatest. lly the time the i)articles of milk 
come in contact with the hottest air (at the |)eripher}-| their 
moisture content is lowest. 

5. This process tends to facilitate ma.ximum reco\-er_\" of 
the milk powder. The moisture-laden air escapes in the center, 
where the particles of milk are heaxiest, and wdiere their ,L;reater 
specific gra\-ity causes them to partake of the centrifui^al nKition 
mo\-int;' them outward until when completel_\' dried, they strike 
the steeply tapered cr)nfining- walls cif the drying' chamber and 
fall to the bottom of this chamber. 

Gray patent Xo. 1,137,933 in^"ol\■es, in addition to the new 
and advantageous features established under patent Xo. 1,107.784, 
and explained abo\"e, a|)paratus and a method for suppr>rting th.e 
milk nr other substance to be desiccated on and b}" the introduc- 
tion of a solid, sheet-like, or finel}' di\-ided substance. In the 
case of milk, the supporting or absorliing material used ma\' be 
pre\"iousl_\' desiccated millc. 

The desiccating chamber A described in this patent is similar 
to the desiccatin.g chamber shown under patent Xo. 1,107,784, 
and the intake of the heated air B and discharge of the moisture- 
laden air C are unchanged. The intake of the milk and support- 
ing material into the desiccating chamljer is located in the center 



300 



Manui'acturi- of Mii,k Powdp:r 



near the top of tliis cliamlicr. 'I'he mills- and ^n]i]iiirtinL; material 
enter tlinm^li an inlet (hict ]{. through wliieli a shaft !'* extends 




Pig-. 105. The Gray milk drier 



diiwn til a \'aned distributer (■, which is re\i il \(.-d 1>\ ;in\' suitable 
power nieclianisni. The material to be dried enters the duet K 



Manufacture of Milk Powder 301 

at the upper end being- fed thereto b}' a screw con^■eyor H, which 
receives the product from the coating chamber I w'liich is located 
above the drying chamber. The coating chamljer is cone shape. 
At the upper end nf this chamljer there is pro\ide(l a means for 
introchicing the nucleus mass or supporting material, in this case 
the previouslv desiccated milk, and distributing the same in the 
chamber, as well as a means for maintaining in this chamber an 
atmosphere which carries the milk to be desiccated in com- 
minuted form. The nucleus mass ur supi)ortin,g material is fed 
to a rotary distrilniter K by a screw cimveyor M, receiving its 
material from a hopper X. Extending down through a hollow 
shaft r^ is a pipe O terminating in an atomizing nozzle and the 
milk to be desiccated is fiirced through the pipe and nozzle under 
pressure. liv this arrangement the Cdmminuted milk and the 
comminuted supporting material come intu intimate contact 
whereby the particles nf the supporting material become cnated 
with the milk to be desiccated. 

At the br)ttom of the desiccating chamber a grading mechan- 
ism is pro\-ided crmsisting of shaking screens Q and Q^ and a 
hopper I' w'hich sei)arate the desiccated milk into three grades. 
Shaking screen O is (if relatively large mesh. It is designed to 
remo^■e cmly the larger [larticles which pass from this screen to 
a pulverizing apparatus R where they are reduced to a finer 
condition. The material passing through screen Q drops on 
screen Q.\ the mesh (if which is of such size as to permit the 
passa,ge oi only the finer particles, while the intermediate sized 
particles are discharged into receptacle S as the finished product. 
The finer particles pass down onto a shaking flruor Q- and from 
there into a recei\"er L'. wdiich may also recei\'e the pul\-erized 
material from pulverizer R. A con\e}'(ir \' carries the material 
from recei\"er U up into hopper \. this material constituting the 
nucleus mass or supporting material usefl for desiccating the milk. 
There is no drying actiijii in the C("iating chamljer. 

This apparatus and process ma>' be operated continuously 
and after it is once in operation the output is claimed to be e(]ual 
to or greater than would be possible, with an apparatus in which 
the liquid milk itself is sprayed into the current of heated air. 

This process yields a product having particles of appreciable 
size, which facilitates ease and completeness of solution in \\'ater. 



302 



Manufacture of Milk PowdFr 



It is superior in tiiis respect to the line state of di^'ision of the 
prochict of otlier processes, in which state the particles are more 
difficult of mixture and solution, tliouf^h they may be equally 
soluble. 

Gray patent No. l,26r),013 de\iates in principle frf)m No. 
1,1 57, 'A^S, in that the li(|uid to be desiccated is distrilnited on a 
desiccating- supporting; surface, and the dried milk is removed 
from this surface in hnely divided form. The operatiim is made 
crmtinudus bv causing the sprayinj;- (ir depositing- devices to 
tra\el in unison with the de\ices for rcm()\-iiit,'- the dried material, 
but so as to deposit the liquid on the supporting surface after the 
same has lieen cleaned of the dried sidistnncc. 

The d e s i c c ating 
chamber is of large 
size and cone-shape. 
The inclined or taper- 
ing sides A form the 
supporting surface. It 
terminates at its bot- 
tom in a suitable dis- 
charge opening V>. reg- 
ulated by a ^•alve 1). .'\t 
the top in the center 
there is an exit C for 
the moisture-laden air, 
and peripheral inlet 
openings D for' the 
heated air, similar as in 
the apparatus of the 
two pre\-i(-jus patents, 
and so arranged as to 
create in the drying 
chamlicr a c y c 1 o n i c 
action, \\ herebv an}' 
particles hea\-ier than 




rig. 106. The Oray milk drier u„ 

the air are caused to seek the walls of the chamber and be 
deposited thereon. In the center of the upper portion of the 
drying chamber is .i mtary s|-)i-ay nozzle F, arranged to direct 
the milk in a fan-shaped spray against the inclined wall .\. The 



Thf, Si'ray Prockss 303 

milk reaches the spra}- nuzzle under pi-essnre thrdUL;]! pipe G. 
The nozzle rotates by means nf a traveler I -^upiiwrted liv a track 
i and a roller arrangement i'. The traveler extends d(-i\\n throu.^di 
tlie desiccating chamber, with driving attachment I\ and L near 
bottrim. The tra\'eler is proxiderl with a brush marie rif a mass 
of chain links ]\I, depending f|-nm the traveler anrl resting in 
contact with the inner surface of the inclined u-all A. This brush 
insures the remo\-al of the dried material from the surface in 
hnely di\-ided form. 

]f it is desired to control the temperature of the sup|)orting 
surface A during the drying operation, the sui)]5orting wall mav 
be jacketed, thereb}- fr)rming a surrounding chamlier X thrtjugli 
wdiich a circulating medium "i the desired temperature mav be 
passed tn effect the proper ciintrol of the temperature of the 
surface. 

The design and arrangement of the apparatus co\-ered by 
the above patent is such that while the majrir portion r)f the 
surface is constantly exposed to the dr-cing effect of the cvclonic 
current of the heated air, the l)rush and the tra\-eler \\-hich 
propels it, advance around the chamber so as to remo\-e the 
dried milk from each portiiin r.f the surface in succession and the 
sprav nozzle operates in such a manner as to direct the spra\' 
of milk against the surface in the rear c<i the tra\"eler and brush, 
or on that portir)n of the surface frrim which tlie flried milk has 
been removed.^ 

CllAFTKE XX\-]. 

COMMERCIAL MANUFACTURE OF MILK POWDER BY 

THE SPRAY PROCESS. 

Pre-heating of Milk. — It has been demontrated that in order 
to preser\'e maximum solubilitv of the finished product, the fluid 
milk should not be heated al3i.\-e 1,^0 degrees F. 

Accordingly the practice has been generalh- ad<"ipted in 
plants drying milk by spray-dr^-ing to heat the milk to from 
140 tiT 130 degrees F. For this purjxjse similar equijjment is 
used as in the manufacture of cimdensed milk. 

Pre-condensing of Milk. — A\diile. in the early days of the 
use of the spray-drying principle for desiccating milk, the fluid 



1 See also Dick process, page 3.35. 



304 Tim Si'KAY Process 

milk, without |jrecondeiisinf;', was sjirayed, and while tliis pro- 
cedure is entirely feasible, it was srmn fi^mnd that it "was more 
economical to remove a considerable iiortion of the water of the 
fluid milk and to reduce the product to a crincentratirm of abriut 
4;1 or 4.5:1 before spravinw. This is accomplished b}- condens- 
ing the fluid milk by any of the methods for condensing as de- 
scribed under the "Manufacture of Condensed Milk" in this 
volume. In general practice the \acuum pan is used for this 
purpose in most of the milk powder plants. 

Effect of Pre-condensing on Economy of Manufacture. — 
The chief ad\'antage and purpose nf pre-condensing, instead 
of spraying the fluid, or uncondenscd milk, lies in the greater 
economy of operation in the case of pre-condensing. 

The fluid milk crmtains more water than the condensed 
milk ; more water must be removed during the spraying process, 
hence less milk can be desiccated in equipment of the same capa- 
city and in the same space of time than in the case of spraying 
pre-condensed milk. The pre-condensing therefore means greater 
capacity of the available equipment- shorter hours and greater 
economy of operation. 

Again, the fuel requirements are greater in the process of 
desiccating Ijy the spray method than b)- e\'aporation in the 
vacuum pan or the film method. The comparati\e efficiency 
of evaporating i.\'ater l)y means of air and in \acuum, is well 
understood. The heat-transmitting coefficient of air is much 
lower than that rif steam and metal heating surfaces. The 
heat applied in the fr)rm of heated air is less completely utilized 
than the heat aj^plied in the form of steam in cop];)er jackets and 
coils, hence in e\-aporation by heated air there is greater waste 
of heat and fuel. The various factors which enter into the dry- 
ing by means of air and the resulting losses of heat transferred 
are discussed in detail by E. ffauslirand' in his re\ised treatise 
entitled "Urving by Means of ,'\ir and Steam." 

Effect of Pre-condensing on Bulkiness of Spray Milk 
Powder. — (Jther conditions, such as orifice of spra^' nozzle, 
pressure of milk, and temperature to which the milk is preheated 
being the same, the milk pow'der made by spraying fluid or un- 
condenscd milk, is somewdiat more liulky than that made bv 



^ Hausbrand. "Drying by Means of Air and Steam,' 



The Stray Prockss 305 

f)re-criiuk'nsiii£;" the milk" liel'ire s|)i';i\'iiiL;". The spraNiiiL; 'if iiii- 
coiulensed milk ri|i])ears to i)ni(hicc a nmre llak\' pi iwder wliile 
the spraying' of ci indi'iT^ed milk result'- in a ni'ire L;Taiudar 
prnvder. 'I'lie flake ^liape dues not jiaek as chisel}- t'loether as 
the STamdar sha])e. This is dhxinush- an adxantai^e in !'a\-iir (,f 
iire-ci mdensiny'. 

I Iiiwexer, the plu'sical shape and cnnditi'in iit the |)Mwdered 
milk can he controlled to a considerahle exti-nt ]>\ modification 
of the Coarseness iir Imeness of the spra\'. In fact, ]>y such niiidi- 
lication it is possible to make a distincth' L;ranular ])rofluct from 
uncondensed millc, and a decidedl}' llak\- product fmm the pre- 
condensed milk. 

The finer the spra\' the moi-e llak\" the milk powder: the 
coarser the S])ra_\' the more Ljranular the milk imwiler. The fluid 
railk makes a finer spvax- than the condensed milk; therefore the 
more flak^' condition of the |io\\der from the hornier. 

.-Vside from the concentration of the milk to he s|)raved, the 
Imeness or coarseness of the sprav can he regulated \)\ the size 
of the orifice of the sprav noz/des and hv the pressure of tlie 
milk. 'Idle lari:;"er the (^irifice or the lo\\i(_-r the pressure, or both, 
the coarser will be the spra}" and consecpientl}- the mo|-e i^ranular 
the milk powder. Therefore, in order to reduce the flakiness 
and bulkiness of milk powiler made from uncondensed milk, and 
to make this milk powdei" more gi'anular, the orilices of the 
siira'S" nozzles must be relati\'eh' larL;"e or the pressure cif the 
milk must be relatixel}- low, or both. Superheatino- i,f the milk 
(boibni^" it at 212 deL;a'ees f". ) b_\' turnini^- steam direct into it 
also assists in minimizing;- the fluffiness and bulkiness of the re- 
sultiipQ' milk powder Init it dmdnishes the sobd)ilitA- of the 
product. 

Effect of Pre-condensing on Keeping Quality of Spray Milk 
Powder. — Inasmuch as the sjiraA' milk i)owder that is now com- 
merciall)' manufactured does not contain enouLjh miiisture, 
when properly desiccated and pnitected Irom dampness, to 
sustain bacterial action, the keejiinc^- (uialit\- of this |iroduct does 
n(-)t materiall}' depend on bacterial decom])( ;sition or freedom 
therefrom. 

Milk powder does became stale with ai;"e, ]iowe\-er and 
!imch of it gradualh- de\elo]js a tallowy fla\-or and odor. This 



306 T]ii: vSi'RAv Process 

tiuist he attii1)Ute<l tn clu'iiiical cliaiiL^es, (nu' (if the chief of which 
is (ixidatiiin. While there arc numerous ai^ents, which come in 
contact with, or enter into, the composition of milk powder, that 
n^ciY lirint,; aliont, or ma\' inxite oxidation, air is one of the most 
likeh' factors to pla\- an important role. 

Air, as is well known, acts as an oxidizin-^- a.L,'"ent. Since 
there is a noticeahle tendenc\- of the product from uncondensed 
milk to he flakier and bulkier than the product from condensed 
milk, it api)ears that with this increased hulkiness, there may 
he mi'ire air in a ,L;i\'en hulk, \ar\inL;- somewhat with the metlicjd 
of paekini,;". 

Tint ex|)erience has shdwn that there is enough air ccjutained 
both, in a ))ackat;e of milk ])o\vder made from uncondensed milk 
and in a like packat^e of milk pow-der made from condensed 
milk, to cause deterioration, when other conditions, such as 
liL;ht, or tem])erature, or lioth, are fa\-orahle, or wdien there is 
present in tlie product enough moisttire. 

There are no experimental results a\-ailal)le that show any 
difTerence in tlie keepiriL; cpialit}' of the two products and the 
experience of the commercial manufacturer points to the con- 
clusion that the milk |)owder made fmm uncrindensed milk 
keejjs as well as the prodiict made from ]n-e-condensed milk. 

Effect of Pre-condensing on Solubility of the Spray Milk 
Powder. — The llaky and llnffy [jowder of the uncondensed milk 
;;-oes into solution at the start somewhat slower than the more 
ijranular powder made of condensed milk. This is due to the 
fact that the flak\- jiarticles with their relati\ely lari.;e exposed 
surfaces. comiuL; in immediate contact with the water. dissoKe 
and take up water so rapidly, that the)- run together and paste, 
formint;" a coating;' around the rem, lining mass of the |)roduct, 
wdiich renders the penetration of the water mto the mass some- 
what slower at the start. 1 lowr\er. this is no indication that 
the Hakv ])ow<ler is less soluhle th.an the L;"ranul;ir powder, in 
fact the llak)- powder, because ol the lari^e relati\e surfaces of 
its ])articles and, therefore, the ^reatei" area of contact, does 
dissoh'e more r.'ipidK' when it .actualh' comes in contact with 
water. 

h'.xperiments c(indncti'd b\' llunx.iker indicate that the differ- 
ence in speed of solution between the tuo products is \'er_\' slit^ht 



Thf, vSpray Process 307 

and that the total solubilitx- is \L'r\' slii^lith- L;Teatcr in the case 
of the more flaky milk pnwder made fri mi nnci inden>cfl milk. 
In these experiments the ammint nf nn'lk pnwder. the amnnnt 
and temperatnrc of the water and the kind and amrinnt of me- 
chanical agita'tion were exactly alike. .Vt tlie end nf one minute 
from the time the milk powders were ])nt into the water, the 
amount of solids dissiih'ed was practicalh' the same in the case 
of the flaky ])Owder made from uncondensed milk as it ^\as in 
the case <if the f^ranular pr.wder made from ]ire-condensed milk. 
And after tliat the [lercentac^e rif total solids dissoh-ed from the 
powder made from uncondensed milk was sliL;"hth- c'reater than 
the percenta<:;"e of total solids dissoUed at the end of the same 
respecti\'e periods i.if time from the ])owder made from ;ire-con- 
densed milk. 

Here attain it should be understood that uncondensed milk 
ma}- be so atomized and dried • lars^e orilice of spra_\' nozzle and 
low pressure) to increase the size and i^'ranular crmdition of 
the particles eif the resulting' powder sufficient!}', so that for 
all purposes !or wdiich milk po\\-ders are used commercialh" and 
domesticall}' the ease or difficulty of solution is no longer au}- 
factor. 

Effect of Pre-condensing on Recovery of Spray Milk Powder. 

— The finer, lighter and more fiuftA- the milk powder the greater 
is the tendency of a portion of the powder to escape from the 
drying chamber. TTence it is cdn-irius that the iirciduct from un- 
condensed niilk, wdien desiccated in such a manner as to intensif}' 
the flakiness at the expense rif a granular condition (small orifice 
of spray nozzle and high pressure I. will tend to escape from 
the drying chamber more profusel}- than the more gramdar 
powder made frorn pre-condensed niilk. Pre-condensing facil- 
itates maximum recovery. 

It should be borne in mind. h('iwe\'er. that the fineness of 
some of the particles of dried milk- made frr)m either uncon- 
densed or pre-condensed milk, makes necessar}' the use of an 
efficient dust collector. W'ithout ^-uch a dust collector, a portion 
of the finer and lighter particles will he lost in either case. In 
the case of the flakier and finer product cjf i.nicondensed milk, 
the dust collector must lie such as to collect a product of that 



308 Till', Si'RAY Process 

lineiK's-^. in iinlci' ti > l)c cfiicieiit and tn accnmplish maximum 
rcci i\cr\'. 

Tlic percentaLjc of rccoxerx' (if the snlids nf milk in tlie form 
I 'I mills' |ii.w(ler in an\' i^'i\'cn dcsiccatinj^' arrani^'cmcnt then is 
lar^iel}' a matter (if efficienc\' (if the dust ci illectcir, and the effi- 
ciency <if dust Cdllectors must increase as the fineness and flaki- 
ness (if the jirdduct increases. The recdvery mav lie materially 
facilitated, howe\"er, ]')\ such an arrangement ( if the desiccating" 
ap]iaratus, as will cause the particles nf drying;' milk to ti"a\'el 
in a direction o])p(isite to that of the escajjiipL;- air, as indicated 
in the Cra}' jiateuts. 

Heating the Air. — This is done either by the installation 
and rijieration of a furnace, similar in priiKijile to hot air fur- 
naces, or by steam coils installed in a closed, insulated \-ault. 

The hot air fniaiace makes possible the heatiipt;" cif the a:r 
to higher temperatures and it is claimed to be souiewdiat more 
economical from the standjioint of fuel consumption. Its dis- 
ad\-antages are that the tem])eratui-e is somewdiat more difficult 
lo control, it fluctuates rapidly with the condition of the fire. 
There is also more or less danger of impure air, because in the 
case of e\en slight leaks between the lire box and the hot air 
chaml:)er, s(.)ot and aslies tend to ]tv dra\\'n into the heated air 
and are thus Idown into the dr\'ing chandjer where they mix 
with and deposit in the milk powder. 

vSteam coils, enclosed in a vault, liave been found less 
objectionable in this respect. While it is more difficult to attain 
rpiite as high a degree of heat by this method, the heated air 
can l)e maintained more easily at a unilorm temperature and 
there is no danger of iminudties leaking into the air. 

The air is drawn into the furnace or hot air vault from the 
atmospliere. it may be, but usualh' is n(^it, hllered liy admitting it 
through an air liller, located at the intake, into the hot air vault. 
Absorbent cotton or other similar [lervious material may be used 
for this jnirpose. 

The earlier patents also cover an air drying arrangement in- 
stalled before the air reaches the hot air vault. This greatly as- 
sists in c(jntrolling and making uniform the results of the drying 
|irocess from one day to another, neutralizin.g the distin-bing cf- 



Tin; Si'RAY Process 309 

feet rif the uneontroUable fluetuations in the humidit}' of the at- 
niospherie air, as affectccl l:)y weather eonditioiis. However, in 
comniereial o])eration the artiheial drying of the atmospheric air 
is s'cnerally omitted. 

The air ma)- be Ijlown into the desiccating chamber by a 
blower fan, in which case a suction fan is frequently also installed 
to draw the moisture-laden air from the desiccating chamber; or the 
injection of the air int(j the drying chamfier may all be taken care 
of by a strong suction fan located at the air exhaust end of the 
desiccating chamber. It is claimed that the doulde arrangement 
of blowing in and drawing out of the heated air, requiring less 
powerful suction at the exhaust end, minimizes the escape of milk 
]")Owder with the moisture-laden air and thereby facilitates the 
rec(jver_\". The speed of the drying action and the exhaustiveness 
of desiccation ma\- be augmented bv introducing the air in such a 
manner as to ])roduce a c\'clonic air eurrent moving spirallv toward 
the center of the dr^'iug ehamber, where it escapes wdiile the milk 
S]ir:i\- issues irnm the center, is acted on bv the centrifugal force 
and m()\-es tangentialh' toward the peripher)' as shown in the Gray 
patents. 

The temperature of the air as it enters the desiccating cham- 
ber is generalh- held at from 250'' to 300^ F., the temperature of 
the moisture-laden air discharging from the drying chamber ranges 
from 130^ F. to 200^ F. 

Spraying and Desiccating. — Plie dr\ing is accomplished hx 
forcing the milk or condensed milk, in the form of an atomized 
spray, into the current of heated air in such- a manner, that the 
fluid milk jiarticles, or atoms of the milk spra)', remain in suspen- 
sion sufficiently long to cause them ti i surrender substantially all 
of their moisture. The dried particles or flakes of milk arc al- 
lo\yed to deposit at the bottom or sides of the drying chamber or in 
a separate collecting chamljer, from wdiere they are removed for 
sifting and packing through a hopijcr, while the moisture-laden air 
escapes separately to the outside. 

The Desiccating Chamber. — The desiceatmg cliamljers iu 
commercial use vary considerabh' in size and in shape, as ^yell as 
in arrangement of spray nozzles and intake and outlet of heated 
air. 



310 Tiiiv Spray Prockss 

Most of these chambers arc rectangular, measure from about 
12 feet in length, width and height ui)ward to much larger dimen- 
sions. Some are longer than they are wide and others are much 
higher than they are wide and long. yStill others are of the circu- 
lar type, resembling small silos, and some are cone-shape. 

The desiccating chambers are usually completely lined with 
tin plate on the inside, making them air tight or nearly so. In 
order to jM-event waste of heat by radiation through the walls, top 
and bottom, they must be properly insulated. This is generally 
done with asbestos sheeting. 

Spray Nozzles. — The milk enters the desiccating chamber 
through one or more spray nozzles, under a pressure of about 
3,000 pounds. The spray nozzles are generally located in the side 
of the drying chamber in close proximity to the top, so as to give 
the spray particles as far a distance to fall through the heated air 
as the height of the chamber permits. Or the spray nozzle may be 
located in or near the center of the drying chamber, in its upper 
portion, in which case the spray issues outward radially, or is blown 
out of the nozzle tangcntially by giving the spray nozzle a rotary 
motion. 

When more than one spray nozzle is used, the multiple noz- 
zles are either arranged in a straight row along one side, or they 
may be distributed over two or over all four sides of the desic- 
cating chamber. 

Diijerent types of spray nozzles or atomizers are used. In 
some hot air under pressure, or steam, propels and blows the milk 
through the nozzle on a similar principle as the boiler water in- 
jector. In other cases the spray nozzle consists of a heavy black 
iron cajj, about one and one-quarter inch long and with a one-half 
inch threaded bore. This cap is screwed on to the end of the 
milk pipe, or its laterals. In the center of the closed end, the cap 
has a very fine opening with a diameter of from one-half to one 
millimeter (.02 to .04 iricb). A small brass disc, about one-quar- 
ter inch thick and snugly fitting into the iron cap, lays against 
the closed end of the cap and covers the small orifice. This brass 
disc carries two minute spiral grooves at its periphery, through 
which the milk under pressure is forced between disc and cap 



The Stray Process 



311 



and esca]H'S tlir("inc^"li the ^iiiall nrilice in the cap. tMrniini^' a 
fine spray or mist. 

The small orifice through which the milk spray enters the 
desiccating chamber increases in size b)" usage dtie to wear, and 
necessitates the frequent replacing of the old caps or nozzles b)' 
new ones. When in operation, these spra_v nozzles at times be- 
come clogged and must be changed for cleaning. It is necessary, 
therefore, fur the njieratnr ti i super\i<e the process continualh', 
making" sure that all the spray nozzles function properly, so as to 
secure maximum efficiency and speed of desiccation. 

In order to facilitate the changing of spray nozzles while desic- 
cation is in progress, the nozzles are so p.>laced as to connect with 
the milk pi])e on the outside of the desiccating chamber, the nipples 
carrying the s])ra\- nozzles connecting with the milk supply pipe by 
means of Barcd joints (loose joints), can be turned in all directions 
sufficiently to withdraw the nozzles from the desiccating chamber 
independently and at any time during the desiccating operation. 

Spray Pumps. — In ui^der tri maintain a iinifnrm efi^^■ienc^• of 
desiccation and to secure a uniform fineness of spray, it is im- 
[jortant that the pressure of the milk should be uniform. To ac- 
complish this requires a si")ecial t}'pe of pump. The pjumps be^t 




Tig. 107. Higli pressure pump for spraying- milk 

Courtes>' of L'liion Steam Pump Co, 

suited for this purpose are three C}dinder pumps with large, heavy 
valves and with extra deep stuffing boxes that can be packed with 
one-half inch packing rings, and special, heavily bolted glands that 
can be readily adjusted when the pumji is running. 

The triple cylinder arrangement insures a steady pressure 



312 Tl-Ilv vSl'RAY PrOCI'.SS 

and continuous flow llu'out,'!] the spray nozzles and the deep stuf- 
iin,L,' l)iixes enhance the ti.t^htness of the seal. The hardening of 
condensed milk on the plun,L;'ers is prevented hy an open pot water- 
seal which coni])letel\- merges the stuffing Jjoxcs, the water serving 
to both ciiiil and luhncale the jiacking ancl to ]ire\'ent its being hard- 
ened bv abs(jrl.)ing condensed nn'lk. While the ptimjj is in operation 
a small stream of cold water is allowed to run into this water pot 
and to overflow through a stn'table 0]")ening. 

These pressure pumps should also be provided with proper 
relief or overflow valves, so as to avoid the danger of excessive 
liressure and variation in the sj^jray, in case several of the spray 
nozzles should become clogged simultaneously. 

At the finish of the run of milk, a quantity of water should 
be pumiced through these high pressure ])umps and jjipes and it 
is advisable to allow the pumps and pipes to stand full of water 
when the\' are not in use, so as to loosen and remove remnants of 
condensed milk, ])reventing their accumulation in the cylinders and 
avoiding difficulties incident to plugging and clogging. 

The pressure used at which the milk is forced through the 
spray nozzles varies from 800 to 3,500 pounds per square inch, 
the itsual range of pressure employed fluctuates between 2,000 and 
3,000 pounds. The nniltij)le nozzles with the fine openings require 
less pressure to secure the same atomizing effect than when fewer 
or one large nozzle is used. 

Hot Air Intake and Discharge. — The heated an- enters the 
drying chamber at points varying with different types of cham- 
bers. Where the spra}' issues forth fi-iim nozzles located all on 
one side, the heated air often is admitted through a slot located 
directly under the spray nuzzles and the air travels in the same 
direction as the spray and mixes with it. 

In desiccating chambei's in which the sj>ra)' nozzles are in- 
stalled on all sides, the healed air ma)- enter near the bottom in 
the center of the desiccating chamber, ])ass up through and mix- 
mg evenly with the spra_\- that issues from .all sides toward the 
center. Or the heated ;iir may enter at the top and pass downward 
with the spra)'. < )r it ma)- enter ,-it the peripher\- at \-arious points 
near the to]), in the form of a cyclonic current moving spirally to- 
ward the center, and escaping in the center through the top of the 
desiccating- chamber. 



Tin', Si'KAv PkocI'.ss 313 

The arrangement of tlie exit nf the incii^ture-laflen, spent air 
also (litTers with different dr\'ing ehanihers. fn many cases, esjje- 
eiail)- where the lieated air and s])rav enter at one side, the exit 
of the moisture-laden air is on one side, in tlhs case i in the side 
opi'iosite that of the intake. In other cases the spent air escapes 
at the top and in stih others near the Ijottrmi of the desiccating 
cliamber. 

Hausbrand' points out that the air ahvaws enters tlie desic- 
cating room liotter than it lea\'es and that the spent air is usually 
more completely moisture-saturated than the inconnng air. The 
densit)- of the spent air therefore is .greater than that of the air 
at the intake. The sjjent air is heavier, ft has, consequently, an 
inclination to jiass downward. Ifaushrand accordingl}- holds, that 
in vertical dr\ing rr)onrs the direction of the currents of air should 
Ijc from top to hiittom, since the mo\-ement is then more uniform 
tlian when the heated air enters beluw .and at once takes the shortest 
path t(j the uppi-r exit, witimnt coming in contact with all the dry- 
ing material. 

It is imjjortant that the drying room lie protected a.gainst 
the entr\- of air from outside. The walls must be free from leaks, 
the peep holes or sight ,t;Tisses, the doors and the shutters in the 
ho])]ier at the bottom, nmst fit tightly. 

'khe outgoing air, in a properlv operating desiccating cham- 
ber, should have a temjjerature considerahl_\" lower than the incom- 
ing air. .\s ]ire\'iousl_\- stated, it usuall}' is, and it is desirable that 
it should be below 200" F,, and ]")referably not above about 130^ F. 
The lowering of the temperature of the heated air in the desiccat- 
ing chamlier is due to the cooling eftecled 1j>' the rapid e\"aporation 
of the moistiu'e from the sj)ra\' of nulk. 'khis cooling effect in 
turn p)rotects the milk solids against changes resulting from contact 
with the hot air, and assists in preserving their original solubility. 

Recovery of Desiccated Milk,-- Because nf tlie extreme fine- 
ness and lightnos (il the milk ])iiwder made \>y the spra\' pi'dcess 
of desiccating milk, a certain portion of the most tlak)- and flttffy 
particles escapes from the desiccating chamber with the outgoing 
air. As previously stated, the proportion of jiowder that thus 
escapes varies greatl)' with the degree of flakiness or granulation 



1 Hauslnarnl, l)r\inK hy iJean.s .->f Air an<.l Steam, ItMjl. 



314 The Spray Prockss 

of the product. But even in the case of (juite granular powders 
a very appreciahle portion leaves tlie desiccating chamber. Again, 
efforts have been made to prevent this esca|)e of milk powder bv 
extending the lenglli of the desiccating chamber, thereby augment- 
ing the distance between the intake and exit of the hot air. This 
arrangement subjects the dried particles over a longer distance to 
the gravity force, their o])|)Ortiniity to drop to and deposit on the 
bottom of the desiccating chamber before being caught in the out- 
going air current is augmented, and the tendency for escape is 
diminished. In iither cases, see Gray patent, the intake and dis- 
charge of the air and the direction of the particles of milk are so 
arranged that the uKjisture-laden air escapes in the center while the 
milk spra\' nidNcs tangcntialh' tuward the peripher\-. thus making 
for minimum escape and maximum reco\'crv of the jiowder. 

At best, howcA'cr, there is need of provisions to recover milk 
powder carried off in the air currents escai)ing from the desiccating 
chamber, and diverse contrivances have been designed and are in use 
in milk powder factories for this purpose. 

These arrangements for the purpose of reclaiming or recover- 
ing the milk powder are known as "dust collectors.'' They are 
similar in principle to those used in flower mills. wSome of these 
dust collectors now in commercial use are guaranteed to accom- 
plish 99.9 per cent recovery of such products as corn starch, wheat 
flour and the like. 

They chiefly consist of vaults or drums or other containers 
into which the suction fan, located at the air exit end of the dry- 
ing chamber, discharges the outgoing air. These vaults are 
equipped with a series of canvas screens or liags on which the par- 
ticles of milk ])(>v\'dcr floating in the outgoing air, are deposited, 
and from which b_\- mechanical shaking nr (itlierwise, the t'scaping 
milk i)0\\(ler is reclaimed and recovered. 

In some factories a part of the rcco\'er\' equipment consists 
of a so-called cyclone. This is usually a cylindrical receptacle 
with cone-shajjed bottom. The air escaping from the drying cham- 
ber is blown into this cyclone with great force and, being thrown 
against its walls, drops at least a portion nf the fine, dust-like milk 
powder it contains. 



CV.'MPOSITKJX AND PrOI'K KTIKS OF AIlI.K 1 'oWI il'.KS 313 

Bolting. — The priwdfrc-d niilk re-^ultiiit;" fr^ini the ^f>i'ay dry- 
ing process of desiccation requires no grinding. It is ver)" fiour\- 
in its |")hysical nial<c up, and after sifting it is ready to be packed. 

Packing of Milk Powder. — Tlu- dried mi1k is put ijn the 
market m packages of various types, such as fibre containers, tin 
cans and barrels. The sizes \'ary from 8 ounce packages to 200 
pound barrels. Of tlie small size jiackages the 10 pound can with 
friction top [jredominates. The barrels vary some in net weight 
with the process of manufacture used, the granular product of 
the dough-drying and iilm-drying processes being heavier than the 
flaky jjroduct of the spra3--dr^■ing process. 

The bulk of milk i)Owder reaches the market in barrels : these 
are jjaper lined, similar as sugar Ijarrels. 

ClI.M'TKR XXA'II. 

COMPOSITION AND PROPERTIES OF 
MILK POWDERS. 

Chemical Composition of Milk Powders. — Tlie ciiemical 
composition of milk powders \'aries jirincipally with the percent- 
age composition of the original milk from which the powder i5 
made, and to some extent with the jjrocess of desiccating. 

The jjercentage composition of the fluid milk is controlled 
primarih- l)y bjcality and seasim (if year, as determined b\- breed, 
period of lactation and feed of the cows. For these reasons milk 
powders made Ijy the same process, but in different localities and 
at different seasons of the }'ear, often show very considerable 
variations in their percentage composition. 

Effect of Atmospheric Conditions. The atmrispheric C()n- 
dition, esfjecially \\-ith reference to humidity of the air, has a 
further, frefpienth' quite material effect on the chemical composi- 
tion of the powder from the standpoint of dryness or moisture 
content. Experience has amply demonstrated that when there is 
a high degree of humidity in the atmosphere, the resulting milk 
powder shows a higher per cent moisture than when made on a 
clear, drv day. 



316 Composition anmi rKoi'ivKTiivS oi' Mii,k Tt'owdUrs 

Effect of Process of Manufacture.- 'flic inHucnce nf the 
process of manufacture on the coni|iosition (if the milk powder 
refers primaril\- tii modihcations of the milk prior to desiccation, 
allliDU^h the method n\ desiccatitin itself also exerts a limited 
effect. 

'Idle greater the percentage of hutterfat to which the original 
milk has been standardized or modirted, the lower must necessa- 
ril)- be the percentage of solids not fat, and this same fact is true 
also of the finished powder. Hence the milk powders ma\' vary 
from sa}' one per cent of fat and possibl)- over 'JS per cent of 
solids not fat in the case of skim milk powder, to over 70 per cent 
of fat and less than 30 per cent of solids not fat in the ease of 
cream powder. AA'h(.ile milk ])owders generally contain from about 
26 to 29 per cent fat. 

The degree of dr^'iiess, or per cent of moisture, aside from 
atmospheric conditions is largely governed by the process of desic- 
cation. Generally speaking, milk powders manufactured Ijy the 
s])ra)'-drying process contain less moisture than those made by the 
film-drying and dough-drying processes. 

The spray-drying process, at its present state of perfection, 
makes |)(issible the removal of all but a very small percentage of 
moisture. Spra)' ])Owders containing as low as one jier cent 
moisture are quite possible ; in fact, the moisture content of these 
powders, as found in conuuerce, ranges from about .5 jier cent to 
3.5 ])er cent, averaging about 1.5 to 2.5 per cent. 

The powders resulting from the filiu-drying processes generally 
contain from about 3 to 6 jjcr cent moisture. 

Some milk powders, es|)eciall\' certain brands of foreign man- 
ufacture, and jiarticularl)- those of the dough-dr\'ing jjrocess, also 
contain added sucrose. 



COMPOSITIO.N ,\XI) i-'ROriiRTIlvS OF AllLK POWDI-RS 



3i; 



Chemical Composition of Milk Powders. 



Analyses Made or 


Water 


Butter- 


Protein Milk 


A.h 


Cane 


Reported by 


% 


fat 

% 


% Sugar 

' % 


vc 


Sugar 
% 


Whole milk powders: 






1 






Riclimoiid' .... 


0.39 
4.02 
4.74 
3.02 
1.40 


27. y? 

27. ')H 
2'Klh 
2C,.7? 
2'). 20 


27.4X' 31.42 
24. 5' » ' 34.10 
20.00 ' 32.24 
32.0('> 31.00 
20. ')2 3(i.4X 


0.00 
0.24 
?.(>3 
5.67 
0.00 




Richmond' 


1.25 


Richmond' 




C. Huyo'e- 




l.arsen & WJiite" 




r)takar Laxa^ 


4,07 


25.00 


24.84 ! ?,?.7? 


20 


3,13^ 


Alerrell-Soule Cn/' 


1.50 


28.20 


2f).f,7 ! 37.><i< 


?./ ? 




Part skim milk 












powders: 






i 






Richmond' 


5.15 
5.01 
S.30 
5.00 


19.90 
15,20 
13.00 
15.12 


31.10 1 34.' )0 
3X.3'' 34.07 
30.57 4X.X5 
33.30 ' 3').70 


7.11 
o.(-,7 
7.28 
0.')0 




C. IIuv^'C' . 




C. HuYe;e- 




Larsen ct "White'' 




Otakar Laxa* 


5.46 


21.00 


25 (7) ' 40.' '3 


5.74 


1.10" 


Otakar La.xa' 


4.X0 


17.13 


2<).XX 40.72 


0.84 


5.08" 


Otakar Laxa* 


5.x 5 


15.72 


30. '05 : 40.07 


n.of, 


1 .40" 


Alerrell-Soule Co.= . . . . 


2.12 


14.20 


32.20 ' 44.41 


7.01 




Skim milk powders : 






1 


1 




Richmond' 


7.40 
7.00 


2.?5 
1 .00 
1 .00 


3.-' .45 45. (■)<.) 
37.2H 4('..30 
37.00 ' 47.00 


7.X',) 
8.00 ' 
8.00 ' 


2.80 


C. Hu^■o'e- 




Lar.?en X: White' 




Otakar Laxa^ 


7.15 


1.57 


33.2') 1 47.23 


8.03 ' 




StockiiiL'-''' . . 


2.40 
3.30 


1.35 
1.25 


37.70 : 4';.<:M 
'33.'n 50.88 


8.21 
7.X7 




Mojonnier FSriis. Co.". . 




Mojonnier E!ros. Co.". . 


1.72 


1.15 


35.01 52.24 


8.03 




Mojonnier Bro.^. Co."'. . 


1.00 


1.'J7 


34,75 51.')2 


8.24 




Cream powders ; 












Alerrell-Soule Co.' .... 


.xo 


50.40 


l').lo ■ 25.45 


4.16 




Merrell-Soule Co."' .... 


.00 


05.15 


13.42 ' 17.80 


2.'d ' 




Merrell-Soule Co.'' . . . ., 


.50 


71.15 


11.12 1 14.74 


2.43 





^Riclimoiid, I>airy Chemistry, 1911. 

= C. Huyge. La Poudre du lait. Revue geiiHrak- du hiit. A' ol 3. Xo, 14. 
1904. Also Leach Food Analyses. 

'^Larsen & AMiite, Dairy Technology-, 1!0.3. 

* Otakar Laxa. Berichte der laktologischen Anstalt d^-r k, k, bohmischen 
technischen Hochschule in Prag, Vol. VIII., 1917. 

» Merrell-Soule Co. Descriptive Bulletin Concerning Jlerrell-Soule Pow- 
dered Milk. 1918; also Stocking-. Manual of Milk Products. 1919. 

" Mojonnier Eros. Co. Analysis by reciucst of author. 1919. 

a Hydrocarbons in ash. 



3l8 COMPOSI'I'ION AND PkOPKR'I'IKS O]- iMlLK PoWDRRS 

Solubility of Milk Powders. — If milk pnwders are to take 
the place of fresh milk or condensed milk on the table of the con- 
sumer, and for most of the industrial uses to wliich they are being 
put, they must be readily soluble. One of the greatest obstacles 
in the progress of the milk powder industry has been that the 
dried milk of most of the ]irocesses failed to be readily and com- 
pletely soluble. I{arlier processes prescribed the admixture to 
the milk of alkalies in order to preserve the solubility of the pro- 
teids, which otherwise \\ere rendered insoluble by the high heat 
uf the respective j)r()cesses. It is obvious that a dried milk, the 
solubility of which can be retained only by the admixture of al- 
kalies, is a poor substitute for milk, and the very principle of add- 
ing chemicals to a food jiroduct like milk, is contrary to our ideal 
of successful manufacture of high cpiality of product. 

The term "Solubilit)" is here used in the broader sense of 
the word. Milk is not a true solution. It is part solution and 
part emulsion. "Sfilubility'' here implies a powder, in which those 
constituents which are in complete solution in normal fluid milk, 
have retained their original solubility, such as the sugar of milk, 
and in which those constituents which are present in normal fluid 
milk in the form of an emulsion, as is the case with the casein, 
fat and part of the ash, have retained their original emulsifying 
power. In short, the term "solubility," as used in this discussion, 
means those attributes of the milk jwwder that enable the pow- 
der, when mixed with water, to again form a solution and emulsion 
of a character, ])h)'sically and mechanically, similar to that of nor- 
mal fluid milk. 

The solubility of milk powders varies principally with the 
ipiality of the fluid milk and with the process of manufacture. 

By (.jualit)' of milk, as here referred to, is meant chiefly the 
acidity. The combin.ition of the heat of desiccation and of high 
acidity, tends to rob the pmtein ,-md ash constituents of the re- 
sulting ])Owdcr of their natural solubility. The higher the de- 
gree of acid in the fluid milk, the lower will be the solubility of 
the powder. The fresher and sweeter the milk at the time of desic- 
cation, the more soluble will be the powder, other factors being the 
same. 

For this reason many milk powder factories are endeavoring 



Composition and Propertiks of Milk Powdrrs 319 

to receive their fluid milk twice daih', and some are using alkaline 
neutralizers in order to reduce the acidity of the milk before desic- 
cation. 

One fundamental reason why even sli,C(ht increases in acidit}- 
do very markedly reduce the solubility of the finished powder, lies 
in the fact that the high degree of concentration necessarily mul- 
tiplies the percentage of acid, and with it the solubility-destroying 
effect of the heat of desiccation. 

The process of manufacture controls the solubility of the milk 
powder chiefly by tlie degree of heat to which the milk is exposed 
and by the manner in which the heat is applied. 

In the film process of drying, for instance, the milk is exposed 
to the heated cylinder charged with steam under pressure, and con- 
secpiently it is subjected to temperatures far exceeding that of the 
boiling point of water. This high heat docs materially reduce the 
solubility of the resulting powder, though this unfavorable effect 
may be minimized to some extent by having the cvlinders operate 
in a vacuum chamber under reduced pressure. 

In the case of the spray-drying process, the milk is not exposed 
to a steam-heated metal surface. The fact that the air entering the 
spray-drying chamber may have, and usually does have, a tempera- 
ture of from 275 degrees F. to over 300 degrees F., appears to not 
materially affect the solubility of the resulting powder. 

In the spra}--drying process the evaporation of the moisture in 
the atomized spray is so rapid that it brings about a marked cooling 
effect, and it is believed that the milk solids are kept in a relatively 
cool condition until they have surrendered substantially all of their 
moisture. 

This [)rotection of the milk against the solubilit\'-destroying 
action of heat appears to Ije especially insured bv the process of 
the Gray patent, in which the coolest strata of the heated air only 
come in contact with the incoming moisture-laden milk, and by the 
time the milk particles enter the zone of the hot incoming air they 
have surrendered the bulk of their moisture. 

That a marked cooling effect does take place in the drying 
chamber is further borne out b)' the fact that the moisture-laden air 
escaping from the drying chamber has a temperature very much 
lower than the entering air. The outgoing air of a properly operated 



320 CoMI'oslTI()^ and 1'koi'i-;ktji;.s oi' Mij:,k Powders 

spray-drying chamber usually has a temperature of from ISO to 
abriut 180 degrees F. 

In the spray-drying process i( is customary to heat the fluid 
nnlk or the condensed nnlk to not to exceed 150 degrees F., and it 
appears that when this is done the milk solids are not exposed to 
temperatures materially higher than 150 degrees F. until they have 
given off their moisture; in fact, it is possible that at least during 
the early stages of desiccation they are actually cooled by their 
rapid surrender of moisture. 

Experimental study has demonstrated that, when a certain de- 
gree of concentration has been exceeded, exposure to high heat de- 
stroys the solul)ility of the ]irotein constituents of the milk. This 
is a matter fif common knowledge to the operator of the sterilizer 
in the manufacture nf evaporated milk. In the sjiray-drying process 
the change from high concentration of the milk in the liquid state, to 
complete dryness, is so instantaneous that no damage is done and 
when once drv, ex|)osure to heat docs no further harm. 

The solubility of the powder resulting from the spray-drying 
prficess may be materially |-educed, liiiwe\-er, if the fluid milk, 
prior to desiccation, is heated to temperatures considerably in ex- 
cess of 150 degrees F. 

The powders of the properly opierated spray-drying j)rocess are 
practically completely soluble in cold water. The powders of the 
film-drying process require hot water for their solution and even in 
hot water they fall short slightly, but unmistakably, of complete 
solution. 

The relative solubility of spray- and film-dried powders is 
shown in the following table : 



Composition and Propkrtiks of Milk Powders 



321 



Solubility of Milk Powders of Film-Drying Process, and 
of Spray-Drying Process. 



Process of Desiccation 



In Cold Water 
78.5° F. 



Per Cent 

In 
Solution 



Percent 

of 

Powder 

Dissolved 



In Hot Water 
210° F. 

r ~ ^ (Percent 
Per Cent | q( 



Solution 



Powder 
Dissolved 



Total Srilids 



Film-process powders: 

Skim milk powder 

Cream powder 

Spray-process powders : 

Skim milk powder fmilk heated 
to 150 de,c:rees F. befrire 
desiccation) 

Skim milk powder (milk heated 
to 210 degrees F. before 
desiccation) 



3.94 I 60.61 
3.46 I 61.13 



5.61 I 90.12 



4.42 



"8.00 



4.53 ! 80.03 



5.76 1 101.76 



5.09 I 88.16 5.33 | 94. i; 



Prr)tein 



Film-process powders : 

Skim milk powder 


.41 
.49 

^.00 




.65 
1.62 

1.97 
1.74 




Cream powder 




Spray-process powders: 

Skim milk powder (milk heated 
to 150 degrees F. before 
desiccation) 




Skim milk powder fmilk heated 
to 210 degrees F. before 
desiccation) 


1 
1.47 1 













The solubility tests, the results of which are recorded in the 
foregoing table, were made as follows : 

Two samples of film-process powders and two samples of spray- 
process powders were used. T\\elve grams of each powder was 
added to 200 cc. of water at a temperature of 78.5 degrees F. The 
four samples were placed into a mechanical shaker and shaken for 
ten minutes. 

After shaking, 100 cc. of each lot was poured through a paper 
filter and the filtrate analyzed for percentage of total solids. 

The remaining 100 cc. of each lot was heated to the boiling 



322 Composition and Properties of Milk Powders 

point and held there for five minutes. The water lost by evapora- 
tion was replaced. The hot solutions were then filtered and analyzed 
for total solids. 

The results of the above tests show that the spray-process 
powder when made from milk that was not heated above 150 de- 
grees F. before desiccation, had the power of returning into an 
emulsion in cold water that would filter in a similar manner and 
would pass through the filter with a similar degree of completeness 
as ordinary milk. The powder was substantially completely soluble. 

When made frum milk that had been heated to the boiling point, 
the spray-process powder lost slightly over 10 per cent of its solu- 
bility. About one-half of this loss was recovered upon heating the 
water and powder mixture to the boiling point. 

The film-process powder in cold water went into a filterable 
emulsion to the extent of from 60 to 70 per cent of the powder 
added, and in hot water to the extent of from 78 to 80 per cent of 
the powder added. 

The very marked difference in solubility of the powders from 
the two processes could be readily observed also without chemical 
analysis. When the solutions of the film-process powders were 
allowed to remain at rest in test tubes there would always gather 
a very considerable deposit of solid matter in the bottom. This was 
the case in both hot and cold water, but the deposit was very con- 
siderably more voluminous in the cold mixture than in the hot 
mixture. 

In the case of the spray-process powders no such deposit of 
solid matter could be detected, neither in the hot nor in the cold 
mixtures. 

It is further interesting to note that the percentage of protein 
found in the filtrates from all the powders with the exception of 
the hot solution from the film-process cream powder, followed very 
closely the [)ercentage of total solids in the same filtrates. This 
suggests \-ery obviously that the degree to which the solubilit}-, or 
better the power of the milk powder to return to the character of 
the original milk, is impaired by the process of desiccation, is largely 
controlled by and depends on the extent to which the process of 
desiccation changes the physical properties of the protein of milk. 

Miscibility and Readiness of Solution of Milk Powders. — 
The rapidity and readiness with which milk powders go into so- 



Composition and I-'koi'ICrtiks oi- AIitK Powders 



323 



called solution is a factor which does not always depend on their 
actual solubility. 

Other conditions being the same, it is ubvious that the tiner the 
particles of the powder the more rapidly will it dissolve. This fact 
is based on the well-known physical law that the smaller a body the 
larger is its surface in proportion to its cubic contents. The sur- 
faces of two spheres are to each other as the squares of their diame- 
ters and the cubic contents nf two spheres are to each other as the 
cubes of their diameters. This is clearly demonstrated in the fol- 
lowing example : 

One sphere has a diameter of 2 inches and the other sphere has 
a diameter of 4 inches. The surfaces and the cubic contents of 
these spheres are as follows : 




Pig-. 108. 




Sphere with 
4-inch dia. 
4 X 4= 16 

4 V 4 X 4 = 64 



Sphere with 

2-inch dia. 

Surfaces = 2x2 = 4 

Cubic contents ;= 2 X 2 X 2 = 8 

The surface of the sjihere with the 4-inch diameter is four 

times as large as the surface of the sphere with the 2-inch diameter. 

But the cubic content of the sjjhere with the 4-inch diameter is 

eight times as great as the cubic C(jntent of the sphere with the 2-inch 

diameter. 

And again, the cube and circular shape of a body has a smaller 
surface than the oblong and flake shape body. 

The greater the area or surface of a body with a given cubic 
content, the more surface is exposed to the solvent and the more 
rapidly will it dissolve. Therefore, the finer and more flaky the 
particles of milk powder, the more readily and more rapidly will 
they dissolve. 

The spray-process powders usually are finer and more flaky 



324 CoMPOsrrioN and Properties oe Mii^k Powders 

than the fihii-process powders, hence the former should go in solu- 
tion more rapidly than the latter. 

The above facts concerning the relation of fineness and flakiness 
of milk powder to ease and speed of solution prevail to a certain 
point. When that point is exceeded mechanical handicaps enter 
into the results that tend to retard solution, at least in the beginning. 
In the case of excessively fine and flaky milk powders, the exposed 
surfaces are so great and the particles so small that when the powder 
is placed into water, the rapid solution of the powder that comes 
into immediate contact with the water causes the powder to run 
together and paste, forming a pasty coating around the remainder 
of the powder. This coating hinders and retards the penetration of 
the powder by the water and thereby renders complete solution 
slower, at least at the start. 

This difficulty is generally not experienced with the film-process 
powders, which are of a granular nature. It can be largely avoided 
in the case of the spray -process powders by so adjusting the orifice 
of the spray nozzles and the pressure of the milk, as to increase the 
coarseness of the spray. The coarser the spray the less flaky and 
the more granular the powder. High pressure and small orifice in 
spray nozzles produce a very fine spray and a flaky powder. Low 
pressure and large orifice in spray nozzles produce a less fine spray 
and a more granular powder. 

The concentration of the milk at the time of spraying also in- 
fluences the coarseness or fineness of the spraj' to a considerable 
extent. Other conditions being the same, the higher the concentra- 
tion of the milk at the time of spraying the coarser the spray and 
the less flaky and the more granular the resulting milk powder. 
When the milk is sprayed before previously condensing it, a finer 
and flakier powder is produced than when the milk is first con- 
densed at the ratio of about 4:1, and the condensed milk is sprayed, 
always assuming, however, that other conditions, such as orifice of 
spray nozzle and pressiu'c of milk be the same. It is possible, even 
by spraying the fluid, nncondensed milk, to produce a jiowder that 
is distinclb' granular, by the proper adjustment of the above factors. 

The miscibility of the dried milk with water depends, aside 
from its solubility, readiness of solution and character of the protein, 
on the physical condition of its butter fat. If the process employed 
is such as to destroy the globular form of the fat globules, it is 



Co.MiTisniox AXD pROPi'.kTiKs 01-' AIii^K Powders 325 

iin]iossiljlt; to reduce tlie dried milk to a honiooeneous fluid, similar 
to normal fresh milk. The fat in such milk will rise to the surface 
quickly, similar to the fat in a mixture of oil and water. 

Keeping Quality of Milk Powders. 

Moisture Content. — ( )ne nf the fundamental reasons for 
which milk is reduced to a dry powder lies in the efforts of the 
manufacturer to preserve it. 

Bacteria and other micro-organisms require moisture to grow, 
thri\'c and accomplish their work of decomposing the substances in 
which and on which they Ii^'e. In the absence of moisture bacterial 
action ceases. 

In properly desiccated milk pow'ders, such as are now manu- 
factured and placed u])(in the market, the percentage of moisture 
has been reduced to a point that precludes the possibility of bac- 
terial decomposition. If these desiccated milk powders are packed 
and stored in such a manner as to protect them against dampness, 
the)' may reasonahl}- be exjjected to keep indefmitely insofar as 
their keeping (jualitA- depends on freedom from bacterial action. 
Milk pjowders with excessive moisture content and milk powders 
that are exposed to dampness, on the other hand, are prone to be- 
come lumi)',-, mold)" and to de\'elop di\'erse undesirable fla^'ors. 

Air, Light and Heat; Relation to Stale Flavor, Tallowy and 
Rancid Flavor. — hi spite i-f the f.aet that the Iciw moisture con- 
tent renders milk powders practically immune to bacterial action, 
the)' are subject to deterioration \\'ith age when certain other con- 
ditions, such as air, light and heat are fa\'orable, or when metals and 
metallic salts are present, or both, and experience has ampl)' denr- 
onstrated that praeticall)- all milk powders made from the usual 
q'ualit)' (if milk under the present methods of manufacture and 
packing, and usual conditions incident to stora.ge, develop a dis- 
agreeable stale fla\'iir, winch often degenerates into a tallow\' or so- 
called rancid ilavcjr with age. 

Exact data showing the fundamental changes which these pow- 
ders undergo are not available, but the findings of .Rogers, Hunziker 
and others,^ as the result of extensive experimental studies of the 
keeping qualit)- of butter strong!)' suggest, that these changes are 
of chemical rather than of biological nature and that oxidation of 



' Hunziker. The Butter Industry, 191:0. 



326 CoMPOSlTlOiN AND PROPERTTRS ()[•* AJjI,K POWUKRS 

one or more of the constituents of these products plays an important 
role. Success in the manufacture of milk powders of superior 
keeping quality, therefore, demands also the protection of the prod- 
uct ag;ainst ajjencies that invite oxidation. ' 

Exclusion of Air. — The nxidizint.,' ])(i\ver of air is well known. 
Milk powder exposed to atmospheric air will not keep. It soon de- 
velops a stale flavor, and if it contains a considerahle percentage of 
butterfat it becomes tallowy. 

For this reason milk powder should be, and usually is, packed 
in such a manner as to exclude the outside air as much as possible. 
The powder [jacked in bulk is sealed in barrels lined with heavy 
paper. vSmaller packages consist of tin cans, or fibre cans with tin 
ends and friction caps. 

Unfortunately the body of the milk jjowder itself is not en- 
tirely free from air, so that unless packed under vacuum there al- 
w'a_\'s is some air in the package. \\'hile protection against free ex- 
posure to outside air, by proper pjacking, greatly minimizes the de- 
teriorating action, and does distinctly enhance the keeping quality 
of the powder, the air present in the sealed package is sufficient to 
cause slow deterioration when other conditions, such as heat or 
metallic salts, or both, are present. The packing of milk powder in 
vacuo would vmdoubtedl)- assist in preserving the milk powder. 

Exclusion of Light. — ^The ra\-s of light intensif\' the oxitliz- 
ing action of the air. It is, therefore, important that milk powder 
be kejit in the dark. This is automatically accomplished by sealing 
it in the usual commercial packages. If the powder nuist be held 
in the factory for a considerable number of hours before packing, 
it should be kept in covered containers. Remnant barrels, or other 
broken packages in the home or in industrial establishments using 
milk powder should be kept tightly co^-ered. 

Effect of Heat. — Meat, similar as light, intensifies the 
oxidizing acti<jn of air and of other oxidizers and catalizers. Milk 
powder kept at relatively high temperatures becomes stale and de- 
\'eloiJS other defects quicker than milk powder kept in the cold. 

Metals and Metallic Salts. — C'ertain met.'ils .and their allovs 



' The .siMisitiveiie.s.s of most of the spra.N' jirocess niUk powders toward 
oxidizing iigerits is augmented b.\- tlie fact tlie atomizing pi-oee.ss under high 
pressure cau.ses a subdivision of the fat globules, depriving the fat of at 
least a portion of the protective gelatinous layer which surrounds each orig- 
inal fat globule, thereby exposing the fat more directly to the destructive 
oxidizing agents. 



Composition and Pkopijrtiks of Milk Powders ill 

and salts are most active (jxidizers. 'Phis is especial!}' the case of 
copper and its alloys, such as brass and German silver ; also the salts 
of copper. Iron, -while not inert from the standpoint of oxidation, 
is much less active and its salts exert but a slight oxidizing action. 
Tin and nickel have no oxidizing action. 

On the l)asis of these facts it is nut impn iliahle, tliat the 
hf)ldin,g, heating anfl condensing nf milk in cupjier container'^, 
and the use nf cupper drimis in fdm-dr\ing and nf liras^ nuzzles 
in spray-drj'ing, are factors ci intril)ut< ir\' ti > the fleterioration of 
the resulting milk pnwdcrs. 

Cnntinuiins, or flash heaters thr(iugh wkich the milk passes 
rapidly and to the metal surfaces of which it is exprjsed for a 
very short time only, are a negligible factor in this respect. 
Even if these surfaces are of untinned co]-)per, there is luit \'ery 
remote danger fif damage to the product. 

bSut not so with containers in which the milk is held for 
hours, or in which it is condensed prior to desiccation. Here 
the time and conditions of exposure are sufficient to^ in\-ite 
chemical action of the acid and lactose of the milk on the copper 
siu'face of the container. If the holding tanks are of copper. 
the_v should be hea\'il\' tinned; <ir in their jdace glass enameled 
tanks should be used. 

The copper \acuuni pan is another menace to keeping 
qualit^•. Salts of copfjer are especially likel}' to form on the 
inner surface of the dome which is exfjosed to the sprav and to 
the -^'olatile acids C)f the boiling milk, .\fter each day's work 
the dome, as well as all the other |iarts of the interior of the 
pan, should be scrupulonsh- cleaned to pre\ent an\' accuinulation 
of copper salts, which would otherwise Ijecome a part of the 
next batch and of the milk po\\der made therefrom. 

In the manufacture of whole milk ])owder, particularly, due 
to the action of the coj)per of the \acuuni pan on the bntterfat, 
the tendency to cause damage to the finished [jrodnct, is great. 
It is ad\-isable to skim the whole milk, condense the skim milk 
only and add the cream after condensing, in order to minimize 
this danger. 

Sandblasted iron pi])es are |)relerable to so called sanitary 
pi]")es, unless the inside copper surface of the sanitar^' pifies is 
properh' tinned and the tin coating is reasonabh' permanent. 



328 Composition and Proim'.r'i'iivS oi- Mii,k Powdt-.rs 

T'l wliat cxti-iit tlic brass iiozzlfs jci i|Kir<lizc the keeping' 
cpialit}' iif lilt' ])(i\\'(lcr is difficult ti i saw l'>ni it is well Icnri^vii 
that tlicy snlliT ci nisidevahle wear as the result nf tlie sprayiiii;', 
and this means that the atnniized sitrav carries olT particles riF 
brass wdiicli later ln'come a part of the I'mished powder. 

The metal drums used in tlie h!iii-dr\an;; process are n'cn- 
eralh' c(.)iistriicted, of metal other than cupper. Many are rif 
hjcjhly polished steel and some are nickel plated. The desiccat- 
in,;:;' eipiipment used in this process is therefure mat expr)siipc;" the 
product to cojiper and Clipper salts, thereby lar;;el\- a\-riirlinc;- the 
possibilit}- iif injuring- the kec|")iiiy rpialit)- rif the resnltiiiL'' milk 
powder thn^iipcjii this channel. 

Insects in Milk Pov/der. — Milk pii\\-der ma\-, and under cer- 
tain conditions does, become infested with insect life, sncli as 
maggots, weevil, etc. This infection may take place in the fac- 
tory itself, but more often it is the result of contamination after it 
leaves the factory. 

Such contamination is generalh- due to a faulty ]iackagc. 
Whenever the seal is lirdken the danger of insect iuA'asion is 
\-erv great. Manufacturers ha\'e found also that packages sent 
to the tropics are especialh' prone to succumb to this nuisance, 
the pre\'cntiou of which necessitated the packing o\ the pnwder 
destined frir the tr(ij)ics. in hermeticalh' sealed cans. 

Lumpy Milk Powder. — As pre\'ii nisi}- stated, milk ]i(iwder 
exposed t''< dampness in\'arial)lv beciimes luni]i\-, and e\'eii when 
exposed to atmospheric air of niij-mal liumidit\' it will gradiialh" 
fr)rm lum|)s, owing t(i the highly hygn iscnpic properties of the 
milk pnwder. In nrder tn i")re\"ent luini>iness. the pi"i\\'der must 
be stored in a dry ]ilace and packed in a manner to pnitect it 
against direct contact \\itli atiiKisphenc ;iir. 

.'\t best milk pnwder has an inherenl tendcnc} tn "lump up." 
This is especiall}' true nf ft'dky pDwders. The more granular 
px'i-w'ders yield less readih' to this defect. 

In order ti i minimize the teiidencx' toward himpmess, the 
milk powder shuuld be allnweil tn (.-(1111, alter desiccation and 
before sifting and packing. If sifted and ])acke(l while still 
warm, the snft conditinn nf the fat causes the particles tn lump 
together after sifting. If sifted and pack'cd after the milk pnwder 
has surrendered its heat, the fat has had an n])pnrtiinit}' tn 



Cost of Manufacture 329 

solidify and hardni and after sifting" the parinde^ remain separate 
and i^rannlar and rlo ncit s( i readil\- stick ti ii^etliei' in tlie fnrni 
lal Innips. 

COST OF MANUFACTURE, 

The appi'oxiniate cii^.t nf nianufactnre of wlinle milk powder 
and slcim milk pnwder is indicated kckiw: 

Cost of Whole Milk Powder. 

lUO U.S. wh.ik- milk S3.350 

Barrels and Imers per 100 Iks. milk 100 

Labor ].ier 100 11. s. milk 103 

Fuel fconden^inq' and dr\'ini;0 per K'O lbs. milk.. O.'^I'' 

( Txerbead per 1(.K3 lbs. milk 074 

Interest, insurance, etc., f.er 100 11.^. milk 050 

Total cost per 100 11)^. milk S3, 850 

I'utal cost per jjoinid of whole milk ])i"jwder, 
calculated on basis ol 12,5 pounds of ])'i\\'der 
made frr.m 100 piunKN of Avlnile .iiilk, wdien 
price eif whole mdk is ,"-"3.3,^ S0.30S5 

Cost of Skim Milk Powder. 

KX) lbs. skim milk SI. 13 

Ba.ri'cls and liners (Xi8 

k^uel ( ci:.ndensin,y and dr^■]nL;■| pi-r K'O lbs. .skim 

milk 080 

Labor per 100 lbs. skim milk 193 

(J\-crhead per 100 lbs. .skim milk 074 

Interest, insurance, etc., per 10(1 lb',, ^kim milk',. .040 

Teital cost per 100 ll)s. skim mdk SI. 504 

Total cost per pound "f skim milk powder, 
calculated on basis of 8.,"i pounds powder made 
f r. im 100 pounds skim milk, when price of skim 
milk is $1.13 SO. 1875 

MARKETS. 

The uses of milk powder are very diversified. Whole milk 
powder is widely advertised for infant food and for general family 



330 Drikd Buttkrmilk and Dried WiuCy 

use. Considerable quantilies are used 1>\ market niill< dealers for 
"recuiistitutiuy" milk for market milk puriiuses, especially at times 
of shortage of the fluid milk supplw Large (juaiitities of whole milk 
powder ai"e ahsi^-hed also 1)\ chocolate factories ill the maiuifacture 
of milk chocolate, the hutterfat lieing one of the essential com- 
jjoneiits on which the milk clKicolate dejiends for its superior 
smootlmess and fla\or. 

Skim nnlk powder is used in the consumer's kitchen, in baker- 
ies and contectiouers' establishments, in the m.anufacture of ice 
cream, fermented milk be\'erag"es, and starters used for cream ripen- 
ing where milk and skim milk are not availal)le : in the pre|)aration 
of baking ])owders, of pure cultures of lactic acid bacteria, of drugs, 
choice toilet soajis, etc. In l{ureipean countries the chocolate fac- 
tories purchase vast (|uantities of skim milk powder in the manu- 
facture of milk chocolate and allied products, and nitmufacturers of 
diverse jirepared food products, such as cereals, soups, noodles, and 
vegetables, furnish additional markets for this Aahiable dairy 
product. 

CllAfTi:K X.Will. 

DRIED BUTTERMILK AND DRIED WHEY. 

These by-products of the creamer)- and cheese factory can be 
redticed to a powder in a similar way and by the saiue processes 
and luachinery as are used in the manufacture of dried milk and 
dried skim milk. 

Dried buttermilk makes a splendid chicken feed, botli for egg 
])roduction and for fattening chickens, and it is used also to make 
up a ])art of the ration for feeding hogs and )-oung stock. It is best 
diluted to about the original bullermilk (one part powder in ten 
jiarts water) ;md mixed with the grain feed ijilo a mush. 

lyike fresh buttermilk, so is dried buttermilk a wholesome, nu- 
tritious and easih' digested food and recommends itself especially to 
persons with weak digestion. When properly made, buttermilk 
powder keeps indehnitely and may, therefore, be available for im- 
mediate use at all times. 

The following analyses show the com]xisition of buttermilk 
powder and of the fresh liutlermilk from which it was made: 



Dkii'.d Bi:TTi;K.\ni,K and Drii:ii \\'in;'i' 331 

Composition of Buttermilk Powder. 

I'Vc-sh Inmermilk Buueniiilk jjowder 

Huttcrfat 1 .17 jjc-r cent 1 1.70 jier cent 

I'i'fjtcid~ 3.00 jjcr cent 30.24 [;cr cent 

LactO'-e 2.07 per cent 33.50 per cent 

Ash .83 jjcr cent 8.25 per cent 

.\cidit\- .00 per cent 6.00 per cent 

Water 91.63 per cent 4.32 per cent 

Total 100.22 per cent 102.01 per cent 

' 'I he hiittertiiilk of which the composition i< ^hown in tlie above 
table wav made at the plant of tlie l-liiffalf) l''oundr_\- and .Machine 
Com|jan\', Buffalo, X. ^',. under the Mip(_-r\'i^ion of the writer. The 
machine used wa^ of the B.iiflo\'ak t\]je. TIk.- buttermilk was fur- 
nished b}' Schlosser Bros., of B'rankf'jrt, Indiana. Thi«; batch of 
bntternn'lk bajijiened to be abnormalh- bitjb in biitterfat : theref(jre 
the larye biitterfat content of tlie Imislied jtroduct. .\boiit thirt\' 
pounds of steam pressure were us(_'d in tlie drying; drum, the tem- 
perature in the \'acuuni diamber was 12.^ degrees F. and the vacuum 
t went\'-fi\e to twent\-six inches of the- mercury column. 

This buttermilk ])Owder had a nice, clean, acid taste, it \\'as 
much relished b\' all who sani]4ed it and, when fed to chickens for 
fattening, produced satisfactory .gains in weight. 

The annual jjroduction of buttermilk' in the United States was 
4,341,157 pounds in 1918 and 5,278,827 ],ounds in I'n'K 

The chief (jbstacle to e.xtensi\-e production of buttermilk jjow- 
der lies in the fact that tlie manufacturing cost iiu'ohed in reducing 
buttermilk to dr\-ncss is \'erv high in proportion to the market \-aluc 
of the finished product, when used for Iiog and chicken feeding. 

Buttermilk ])Owder can be manufactured by any uf the jjrocesses 
describecl under the manufacture of milk jiowder. However the 
spray process is nrjt a-, well suited for the desiccation of Ijuttermilk 
as is the film, or roller process. 

In the sjjra)' process there is a considerable tendency for the 
milk to clog the spray nozzles, .\gain, the cost of manufacture b\- 
the spray process is greater than that b\' the film process. .\s 
stated under the manufacture of milk jjowder, heat in the fonn of 

' Hunziki-l-. Iniliiiua .\ k |-icnltu lal IC.xl'c.'linM-ii t .Sl.ition. Twc-iit v-.si .\t h An- 

niKil Report, no:;. 



332 iMAi/ri'Li Mii.K 

heated air, is iml a-^ ecdiKnuiealK and as ellicieiilU- uhlized as heat 
111 the form of sleaiii applied in sleanie<l-lieal;'d metal drums. 

\\'hile, as previously shown, the s]ira\-dr\ int;" |ii-i'eess is the only 
prrieess of desieeating nnlk, ihat preserx'es the original solubilit\' ot 
(he milk, this ad\aiitage is lost in the ease of InUlerniilk. 'I'he aeid 
in the hiitlermilk has ehaiiged (he easein from ils line emulsion, 
sueh as it repre.^ents in normal milk', lo a eoiiditiem whieh renders 
the partieles of easein, or eurd, ineapable of permaneiith' remulsi- 
f}'ing. TIk' eurd in eommereial Imltermilk docs not sla)' in emul- 
sion, but settles to the botlom. llenee nothing is gained li\' dr\'iiig 
the Inulermilk b\' the more expensi\e proeess of spra_\--drying. 'I'he 
him proeess, whieh is the more eeonomieal, is iherefore better 
adapted fur the manufaelure of hnltermilk' ]'o\\'der than the spra\- 
drying process. 

It is advisable lo ]ireeoiidense the Initlermilk, before dt'sieeat- 
iug, at the ratio of about 2:1. 

One gallon of buttermilk' \at'l(ls about ./I pounds of l)uttermilk 
jxiwder, or the manufaelure of one pound of ])Owder retpiires 
about 1,3'' gallons of buttermilk. The eosi of manufaeture is t'Sti- 
mated at about 2 eents ]ier pound of buttermilk powder or aliout 
1.44 cents per gallon of buUermilk. 

Whey powder is manufaetm-ed in a similar m.anner. Its eliief 
\-alue lies in its usefulness in the diet of infants and invalids, with 
wdioni the eonsumption of easein produees digesti\'e disturbanees. 
Since fresh whe\' is often not obtainable, the whe^' powder, the good 
keeping quality of whieh permits of keeping il on hand, furnishes 
an admirable substitute, ^^'hcn made from sour whc\', it otters 
mail}' advantages in cooking and baking and should be especiallv 
well suited for sueh dishes as pan cakes, ete. 

MALTED MILK.' 

Definition. The pr(HlMet Kiinwn as m.alled milk i'^ that re- 
sulting from Ihe eomliinal ii ni of whole milk' with the extraet of 
malted liarkw and wheat Hour, and ihe mixlure is redueed to a dr\' 
form by dcsieealion in vacuo. 

History of Malted Milk Industry. -The in'oees-- nf the manu- 
faelure of mailed milk was invenled Iw Air. AA'illiam Ilorliclv", of 



' Tnrcii-m.il imi (tn 1 trfini I inn, llislor\' ;in(l rrncr.s.s nf I\r;i niH'iu'Uire, rocoh'ed 
tlirouKli llii' fnin-tcKV or irnrlick'a Mailed Milk Co., Uaoin(\ Wis., tifai-i'li S. 
l',11S. 



Maltf.d Milk 



333 



Racine, Wis., in the year of 1883. 'i'he product was first placed on 
the market under llie name of "Malted Milk," given it by its in- 
ventor, in 1887, 

Prior to the advent of Horlick's malted milk Mr. Horlick was 
making "Horlick's Food.'" It was through suggestions of members 
of the medical ]jrofesbion, who complained that it was almost im- 
possible to obtain first class, pure, clean, wholesome, whole milk, that 
Mr. Horlick took ujj the idea of malted milk. In consultation with 
Dr. R. C. Hindley, then Professor of Chemistry at the Racine Col- 
lege, who later became Chief Clieiiu'st and .Superintendent for Mr. 
Horlick, the manufacture of malted milk was subjected to consider- 
able experimenting by its inventor before the product reached the 
market in its |>erfected form. 

The ciin\'enience, nutri- 
ti\-e \aliie and fligestibilit}" 
rif this product recommended 
themsches to aiul \\'ere aj)- 
preciated by the medical 
professiijn, and its relishing 
properties- ap]jealed t'l the 
public. The iiuln^trA- gre\\' 
ra|jidl)- and is t'''da}" assum- 
ing large [trriportions. 

Manufacture of Malted 
Milk. — A mash 1=- prepared 
b}- mixing wheat flour with 
barley malt i',i good diastatic 
qualit%'. This ma=h is raised 
to the proper temperature 
for a sufficient length of time 
tri insure the complete con- 
\-ersion cif the insoluble 
-tarch into the sr.luble malt 
'-ngars dextrin and maltose. 
Thi'^ conx'ersion is closely 
akin t''i starch digestion in 
the human s}'stem, hence the 
resulting liquid is essentiall}' a predigested product, claimed to 
be of much \-alue as a special forid for infant^- and in^-alids. 




rig-. 109. Vacuum pan for malted milk 

Coui'tesy of Arthur Harris & Co. 



334 Malted jNIilk 

This extract is cuniljined with wholt- iiiill< and reduced to a dry 
powder in a vacuiini at such a low temperature as will thoroughly 
pasteurize the malted milk and yet ])res.er\-e its digestibility. 

Keeping Quality of Malted Milk. — Malted milk is the <>n\y 
milk pijwder made from whole milk that will keep indefinitely in 
any climate. Those who have subjected the manufactiu-e of malted 
nulk to most intensive studv hold, that the keeping quality of malted 
milk is due ti;i the fact that the fat globules are very finel_\- di^-ided 
and are surrounded b\' a coating" or envelope of gluten, sugars and 
salts, which protects the fat against the deteriorating action of the 
air. 

In dried whole nulk the volume of fat is too great and the piro- 
portion of other solids too limited, to cause the fat globules to be 
properlv coated, the air therefore has more or less access to the fat, 
causing such changes as are prone to lead to the development of a 
tallowy flavor and rancidity. 

The use of wheat flour, while originally a survival of "The 
Horlick's Food," from which malted milk was de^•eloped, ma}' also 
be res|)onsible, in part at least, for the keeping quality of malted 
milk. Its large amount of gluten may assist in yielding an etTective 
coating for the protection of the fat globules. Experiments made 
with flour of other cereals gave results that did not warrant their 
use in the place of wheat flour. 

Again, it has been experimentally found that malted milks made 
b\- mere mechanical mixing of the required ingredients, also become 
stale and rancid rapidh", and that the onl}' product that has perma- 
nent keeping qualit\' is that in the manufacture of which scientific 
use is made of the action of enzymes and other ferments, etc. 

Uses of Malted Milk. — :\Ialted milk is a I.mkI ..f acknowl- 
edged high degree of food value and of sn]ierior digestibility. Being 
a whole milk food, it also contains the indispensable growth-promot- 
ing and curati\'e pro]ierties contained in whole milk. 

Ii is ])laccd on the market both in ]iowder and in tablet form. 
Its high digestibility, nutritive value and health-protective properties 
render it most valuable as a wholesome food for infants and in- 
valids, and its compactness and keeping qualit\' facilitate its trans- 
portation to and use in all parts of the ,globe. Malted milk, there- 
fore, is of special merit for use in countries and territories which are 



Malti-;d Mh,k 335 

barred b}' their g-efjgra|ihical location and climate from the profitable 
husbandr_\- of the dair_\- cow, and where the limitations of transpor- 
tation render the a\-ailabilit\- of fiuid milk difficult or im])Ossiljle. 

The annual outptil rif malted milk in the L'nited States was 15.- 
654,243 pounds in 1918, and 17,4''5,887 pound- m l'U9. 

Federal Standards for Milk Powder, Skim Milk Powder and 
Malted Milk.'— The fiillnwin- standards of dried milk prtiduct- 
were adopted by the United States Department of Agriculture 
March 16, 1917, and became effective March 31, 1917, as per Food 
Inspection Decision 170: 

"Dried Milk is tlie product resulting from the remowil of water 
from milk, and contains, all tolerances being allowed fijr, not less 
than twent)'-six jjer cent (26'; ) of milk fat, and not more than five 
'per cent (S'} ) of moisture. 

Dkikd Skimmetj Milk is the product resulting from the re- 
moval of water from skimmed milk and contains, all tolerances being 
aliowefl for, not more than five per cent (5', i nf moisture. 

Maltf.ii Milk is the jjroduct made Ijy combining whole milk 
with the liquid separated from a mash oi ground barley malt and 
wheat flour, with or without the addition of sodium chlorid. sodium 
bicarbonate and potassium bicarbonate in such a manner as to secure 
the full enzMiiic action of the malt extract, and by removing water. 
The resulting jiroduct contains not less than se\'en and one-half per 
cent (7.5'',{ ) of fjutter fat and not more than three and one-half per 
cent (3.5';'(- ) of moisture." 

Dick Process.- — .^. 'M. Dick imx-ntcd and patented a sp)ray- 
drying apparatus t'i>r milk. I'. S. jjateiit Xm. 1.2')8.470. 1''19. 
similar t'l the McLachlan ])atent Xcc 8(J9.747. In the r)ick dryer 
the milk enters 1)\' gra\-it}' and is s])ra}ed and distrilnited b\- a 
re\"ol\nng disc arrangement. I 'art nf the heated air enters at 
the top and |)art at the Ijottmn nf the desiccating chamber., 'idie 
air entering at the Vnjttom is hotter than that entering at the top. 

1 United States Department of Agriculture, Food Inspection Decision 170. 
March 31, 1917. 

^ Tills process came to the autlior's attention too late for detailed dis- 
cussion in this volume. 



PART VII. 

STANDARDIZATION, TESTS AND ANALYSES 

OF MILK, CONDENSED MILK AND 

MILK POWDER 

CiiAi-n-K XXIX. 
STANDARDIZATION. 

Prior to the enactment of the F*ederal Food and Drugs Act, 
which became effective January 1, I'-'O? . the milk condensing 
factories made no special effort to ])lace on the market a product 
of any definite and specilic composition. The milk was con- 
densed, either as whole niilk, no matter what the original com- 
position of the fluid milk was, without modification, or it was 
parti}' skimmed or wliolh' skimmed, befiire condensing. If any 
effort towards modification of the composition was made, such 
effort was practically wholly confined to the regulation of the 
fat content of the finished product and even in such cases wide 
fluctuations were quite frequent. 

With the enforcement of the Federal Food and Drugs Act, 
the milk condenseries found themselves called upon to manu- 
facture a product that would com])ly with the Federal standards 
established and ^^'hich prescribed the minimum per cent of fat 
and milk solids permissible in condensed milk. 

It became necessary therefore to guard against the produc- 
tion of condensed milk, the per cent fat and milk solids of ^A'hich 
fell below the specified standard. And later, with the rapid 
development of the condensed milk industn,'. competition 
gradually compelled the indi^•idual concerns to ncit only a\'oid 
the manufacture of an illegal jiroduct by causing its \'aluable 
components to fall short of the percentage recpiired bv the 
standard, but tn so modify the composition as to not have the 
finished product materially exceed the rcfpiired standard, in 
order to keep down the cost of luannfacturc. Furthermore, in 
the case of bulk condensed milk, \vhich goes to confectioners and 



S'l AN'DARDIZEI) CoNDI-.XSF.D MiLK 



337 



ice cream niarmfacturci's, the 1iu_\-er 'ii'teii -pecifie- m lii^ 'irder 
the desired comjjcisitifJii of tlic ]n-'ifhict, necessitating;' ttaiidarrliza- 
tifiii to meet these ^fiecial demand^. 

These lactors and c(niditiMiis irie\italil}' led to tlie adoptic'n 
of the practice ol earefnll\- ^tandardizniL;" condensed milk for fat 
and milk suluN. The detail- "f method- n-cd fi ir -tandardiznif; 
vary considerahl\- with difTereiit nianufacttirers. The principle 
U[)Cin which standardization is ha-ed. ho\\e\er. i^ oheiiiu^lN' \"er\' 
much tlie same under all condition-, and variations in details 
affect the results largeh' onl\' with reference to the degree of 
accuracA". 

Some manufacturers standardize the lluid milk before con- 
densing, Cithers prefer to standardize after e\ ap' iratioii only, 
while still others standardize hoth, tin- lluid milk and then again 
the finished product just prifjr to canning. Each of the three 
methods is practical and the dunldc metliod of -taaidardizing 
before and after condensation is olndously the most exact. In 
the case of sweetened condeii-ed milk standardization before 
condensation is jireferalde inasmuch as the admixture to the 
finished product of w^ater, ^]<\m milk or cream is not ad\-isable 
from the standpoint of keejnng rpi.alit}-, tiidess these [uaiducts 
have been pre\dciusly properly pasteurized. Fn the case of 
evaporated milk, which is much thinner, more mi-eible and whicli 
is subsefjuently sterilized, these ofjjections are largeh' remcned. 

The m.ateriaK generalK- used fc'r standarflizing are skim 
milk, condensed skim milk, cream, butter and water. Water is 
used only to lower the per cent total solids, or tlie degree of 
concentration, and is of ser\ice only after condensation of the 
milk. 

The calculations employed f<"ir -tandardizaticiii are identical 
for rdl forms of eondensefl milk and milk powder, both sweetened 
and unsweetened. The addition of cane sugar to the lluid milk 
does not alter the ratio of fat to milk solids, since the added 
sugar merel}' disfdaces a portion of the water in the finished 
product. 

'I'he per cent total S(jlids in the condensed milk is controlled 
primaril}- by the de,grce of concentration as determined by the 
Beaume hydrometer or by ,gra\-im,ctric analysis and it mav be 



33S Standardized Condensed Milk 

further mdclificd In' tlir addition (if water ti > the finished product 
in case condensation has passed bey(jnd the desired point. 

Aside from this, the fundamental effort of standardization 
is conhned to secnrinL;' the desired proportion of l)utter fat to 
milk sohds not fat. When this is accomplished all that is neces- 
sar}' to insure the reiiuired composition is to subject the product 
to the nccessar\- degree of concentration. 

Standardizing the Fluid Milk. — In ortler to properly stand- 
ardize the fluid milk it is necessary to know the recjuired per 
cent fat and solids not fat in the finished product and the per cent 
fat and solids not fat in the milk to he standardized and then 
to calculate the ])ro])ortii m of fat and solids not fat needed in 
the fluid milk. This calculation is most con\-eniently made by 
allei;ation. This then shows the amount of fat or solids not 
fat, as the case may be, that must be added to secure the desired 
proportion of these inoredients and from this the amount of 
cream, or butter, or skim milk that must l)e used for standard- 
izing' can be readily determined. 

Example 1. 

The standard for e\aporated milk is 7.S per cent fat and 
25.5 per cent total solids, or (25.5 — 7.8) =^ \~ .7 per cent solids 
not fat. 

Amount fluid milk in batch, ~,rX10 ])ounds. 

Fat in fluid milk, 3.3 per cent. 

Solids not fat in milk, ').0 per cent. 

Fat wanted in c\aporated milk. 7.S per cent. 

7 Sohds not fat wanted in e\a])orate(l milk. 17.7 per cejEt.. 

\\niat per cent fat should fluid milk cemtain" 

r I ' - 

/ How much cream, testimj ^,i tier cent fat, must lie added? 

' { . , . . 

7rns\\'er : s. n. f. in c. m. : s. ii. f. in r. m. -=- f. in c. m. : \ ; 
=: X 'o f- rec|uired in r. m. 

s. n. f. ^= si ilids 111 it fat. 
f. = fat. 

cm. ^ condensetl milk, 
r. m. = raw or fluid milk. 
17.7 -. 'jI - 7.8 : V ; X = 3.<)()6' , fat. 

The raw milk must contain 'M^Ki^' , fat. 



r, 



Sta.\dakijizi:u Coi\iji-;nsi;d Milk 



339 



How much 25^7 cream is rcriujre'l tf rai^c the ])cr cent fat 
in the 7,000 pdunds of milk te^tmc;- ^.'-i' , fat tn 3.0r/,' , - 

.^.3 r ^ n 21.04 



//, 




21.70 



luirmph 25', cream must lie arlded hi tlie raw milk si i that 
each 21.7 puunds (if ^taiidardizcrl milk cintains .C>C< pcnrnds rif 
added cream and 21.04 ])iainds nf the urii^-inal milk. Meiice 
21.7 : .66 = 7fX)0 : /' ; y = 213. lbs. of cream. 

Total hatch, 7000 ])ounds. 

I?''", cream. 21.^ pounds, 

3.3'; milk, (>7X7 p(junds. 

Example 2. 

.\mount of lluid nu'Jk m hatch. 7.li')0 pounds. 

h"at in fluid milk, 4.,"' ])er cent. 

Solids not fat iu fluid milk. S..^ jjer cent. 

h'at wanted in e\"a))orated ruilk. 7.X jier cent. 

Solifls not fat wanted in e\-aporated nulk. 17.7 per cent. 

How much fat sh'iuld lluid nullc contain.' Mow much skim 
milk must be added? 

.Answer: 17.7 : 8.3 = 7.S = X ; >' = 3.~?' . . The (Tud milk 
must contain 3.7?'", fat. 

Ho\\" much skim milk mu>t Ije arldcd to lower the per cent 
fat in the fluid milk to 3.75'", ? 



4.5 



.0 




.■>./? 



.75 
4.50 



Enough skim milk must be added to the fluid milk so that 
each 4.5 pounds <"if standardized milk contain^ .7? ponnd,-^ of 



340 



Standardizi':d Condrnskd Milk 



added skim milk and 3.75 pdiinds of (irigdnal milk. Hence 
4.50 : .7? -=. 7000 : X ; ■■•; = 1167 pounds of skim milk. 

Total liatch, 7000 pounds. 

Skim milk, 1167 pounds. 



4.5 'T. milk, 5833 pounds. 

Standardization of Finished Product. — In a similar manner 
standardizatirm may Ije accomplished after condensation. In 
this case the [)roportiiin of solids is. best increased or tlie propor- 
tion of fat reduced b)' the addition of ccnidensed skim milk in 
the place of ordinar}- skim milk, while the projjortion of fat is 
increased by the addition of cream as explained under Stand- 
ardization of Fluid Milk. 

If it is desired to low'er the total scdids in the finished 
]"irodnct, without affecting the proportion of solids not fat to 
fat, the nccessar}- amount of water required is determined a- 
f.41o\\-s: 

Example 3. 

E\'aporated milk in batch, 3000 ])ounfls. 
Total solids in evaporated milk, 27.%, 
Total solids desired, 25,5S"i . 
Ho\\- much \\-ater must be added.'' 
Answer : 

7^ ^ 



0, 




1.5 



Tri each 2.-', 5 pounds c\"aporated milk must be added 1.5 
pounrls water. Hence 25.5 : 1.5 — : 3000 : X I X = 176.5 pounds 
III water. 

()ri!^in.al batch ex'aporated milk, 3000 pounds. • 
W atei' added, 176.5 pounds. 

Standardized e\a[ioratcd milk-, .^176.5 jiounds. 

The rcsidts nf st.-mdardization in which cream is used to 
alter the proportinn (4 fat to solids not fat, arc not absolutely 
matliematicalh" accurate, tiecausc of the fact that the per cent 



SlAN'DARDIZKU CoNDIiNStD AIlLK 341 

rif s'lhds 111 it fat ill tlif ci'eam is si iiiie\\"hat li'wer tliaii in milk. 
This causes a slight shortage of solids not fat in the standard- 
ized ]irndiict. This error is so slight, howeA'er. that it maA" 1)C 
eiin^idered within the limits of the experimental error and f'^r 
all jjractical purposes this method of standardization may be 
accepted as relialde and accurate. 

Standardization of Sugar (Sucrose) in Sweetened Condensed 
Milk. — Tliis i- most rcaihh" acci ini])lislied li}- standardizing 
the proportion of sugar to the per cent total solids in the fresh 
milk. 

If it is desired to secure a sweetened condensed milk, the milk 
solirls of which mereh' comph- with the Federal standard of 28 per 
cent, it is ik-sirable and necessar}-, from the standpoint of keeping 
qualit}'. tfi add eneiugh sugar ( sucrose ) so as to have the finished 
jiroduci contain at least 44 per cent sucrose. 

Example 4. 

Amount ijf fluid milk in hatch, 15,000 priunds. 

Fluid milk contains 12 ]ier cent total solids. 

How" much sugar must lie added m ijrder to insure the 5\\'eet- 
cned condensed milk to contain 44 per cent sucrose, when the milk 
has Ijeeii condensed sufticienth- to contain 38, per cent milk solids"^ 

Answer: 28 j 44 = 12 :':/ : y = 18.87. 

To everv 100 ]"iounds of fluid must be added 18.87 pounds 
sucrose. 

To 15,000 pounds fluid milk must be added 

18,87 > 15.000 

=r: -bSU.r pounds sucrose, 

100 

If it is desired to produce a sweetened condensed of heav}- 
bodv and containing a high per cent of milk solids, as for instance, 
o2 per cent milk solids, the per cent sugar contained in the finished 
product ma_\' be considerabh" reduced. Such sweetened condensed 
milk mav contain. sa\" 40 per cent sucrose. 

Example 5. 

Amount of fluid milk in batch is 15,000 pounds. 

Fluid milk contains 12 per cent total solids. 

How much sugar must be added to insure the sweetened con- 



-l42 CUK.MICAI, TllSTS AXI) AnaI,\SI'.S 

rleiised milk to cuntain 40 ])cr cent sucrose when the milk has been 
condensed suf¥icientl\- to contain 32 jier cent milk solids? 

Answer: 32 : 40 = 12 : ^ : = 15. 

To e\-ery KX) pounds of fluid milk must be added 15 pounds 
of sugar. 

To 15.00() |)0unds fluid milk must be added 

15 \ 15.000 ,,_^ , . 

=: _2."'0 pounds (jt sucrose. 

100 

Cu.M'Tju-; XXX. 

CHEMICAL TESTS AND ANALYSES OF MILK, SWEET- 
ENED CONDENSED MILK, EVAPORATED MILK 
AND MILK POWDERS. 

In assembliuL;' these metlmds lA analyses, preference has 
been i.;i\-en the "( )ffieial and rro\isi(inal Alethnds nf Analysis," 
published hx the American Ass(iciatiMn nf ( )fficial A^iricultural 
Chemists.' The official methods ha\'e been mndihed and supple- 
mented b}- iither methods in nmnerous cases \\diere\er, in the 
judo-ment df tlie ^^^■iter and others, such nic idificatii nis and sub- 
stitutions are bettei' adajited f("ir anahsis of these s]iecial prod- 
ucts. A special eii'nrt has further been made to include in this 
chapter modifications and abbreviations of tests and analyses, 
adapted for the use of the factor}" operator, whose kno\\dedt;'e. 
skill, facilities and ti'nie are too limited to enable him to success- 
full}- follow the directions of the official methods, or to execute 
delicate and rlifficult chemical anahses. 

For practical factory tests of fresh milk on the receivmg 
platform, detertuinini;- its fitness for condensin;^. the reader is 
referred to Chapter III, "Inspection of Milk at the Condenser\-." 

MILK. 
Specific Gravity. 

Aerometric Method by Means of the Quevenne Lactometer. 

--L'se an accurate (Jne\enne lactometer with thermometer at- 
tachment and a lactometer c}lin(ler about ten inches hiijii and 



' LTnited .StatL-.s J teparlnn-iU ol" .Vgiuultnie, Bui-eau of t 'liemistr\', Bulletin 
No. 107. 1912. Also Journal of tlie As.-sn. of C^ffloial Ari'. e~"heiiiists Vol II. 
No. 3. Nov. 15, 1916. 



Chemicai, Tests and Analyses 343 

nne and iiiK--half inclic-^ wide. ImU tlu- c\dinder witli milk at a 

temperature l)et\\'eeii 33 and (>5 de^^rees !■'. Insert tlie lactumeter 

and when it has found Us eijuilibrium, note the point on the scale 

at the surface nf the mill<. Tlie correct teniperatiu'c is dO de,q"rees 

I". For e\"er}- flei^rce Ivdirenheit al)ii\e 'lO add nue-tenth pohit 

to the ohser\ed reachuL:,', and for e\"er\- de;4Tee Fahrenheit lielnw 

'')0 deduct iine-tentli point fi'i im the oh^erxed rearhn;,;-. This rule 

holds giidd I ml}' when the ranf;e nf temperature i^ within the 

limits of ."1,"^ decrees and (>? deg'rees I". 

The s|)ecific gra\dt)- is calculated 1)\- addini,;" 1 .OrjO ti i the 

lactometer reading;' and di\idino- the sum by 1 ,000. I'.xample : 

Lactometer reading is 31 at (>3 degrees F. Corrected reading is 

31.5; 

.r ■ ■ 31.3 -^ IfKX) ,^,,_ 

specihc CJ"ra\it\' is ^ — ■ = 1.031.-^. 

' -^ - 1000 

Gravimetric Determination. — Thi^ consists nf the filling of 
a perfectly dry picnometer or other graduated flask of known meas- 
ure with milk at the standard temperattn'c (60 degrees F., or 15.5 
degrees C.) and weighing the flask and contents. The weight of 
the flask is then deducted from the weight of the flask plus con- 
tents and the difl:'erence is divided b}- (he weight of an ec|ual volume 
of water at standard temperature. The result is the specific gravity 
of the milk. 

The \\''estphal balance method furnishes another accurate means 
of determining the specific gravity. Both the gravimetric method 
and the W'estphal balance method, wdiile accurate when operated 
b\' the skillful chemist, re(|uire considerable time. Experimental 
comparisons have demonstrated that for all practical purposes the 
Qtievenne h)'drometer, when accurately graduated, )'ields correct 
results, and the simplicity and rapidity of its operation render its 
use in the determination of the specific gravity of milk highly ad- 
vantageous and satisfactory. 

Total Solids. 

By Means of the Babcock Formula. — I^or rapid and reason- 
ably accurate work the total solids of milk may be determined b)' 
the use of the Babcock formula, which is as follows : 

Total solids =-^ -. 1.2 . f. 
4 



344 Chemical Tests and analyses 

L = Que\'enne hicdinirter reading", 
f = per cent of fat. 
Example: Lactometer reading" is ."'2: per cent fat i.s 4. 

Total solids ^ ^J^ ].2 \ 4 = 1_'.S per cent. 

Gravimetric Method. --" I I eat from three to live grams of 
nnlk at the ten"iperalnre oi lioiling" water initil it ceases to lose 
weight, using a tared flat dish of not less than 5 c.c. diameter. If 
desired, from fifteen to twent\' g"ran"is of ptire, dry sand n"iay be 
pre\'ii 'usl)" placed in the dish. Cool in a desiccator and weigh rapid- 
1}' to avoid alisori)tiiin of liNgroscopic moisture.'' 

Ash. 

"Weigh about twent)' grams of milk in a weighed dish, add 
6 c.c. of nitric acid, evaporate to dr)"ness and ignite at a tempera- 
ture just below redness until the ash is free from carbon.'' 

Total Nitrogen. 

Place about five grams of milk in a Kjcldahl digestion flask 
and proceed, without evaporation, as described under "Gunning 
Method" for the detern"iination of nitrogen. Multiply the percent- 
age of nitrogen by 6.38 to obtain nitrogen compounds. 

Gunning Method. 
Apparatus. 

(a) Kjeldahl flasks for both digestion and distillation. — 
These are flasks having a total capacit)' of about 550 c.c, made of 
hard, moderately thick and well-annealed glass. When used for 
distillation the flasks are fitted with rubber stoppers and bulb tubes, 
as given tuider distillatioi"! flasks. 

(b) Kjeldahl digestion flasks. — 'J^hese are pear-shape, round- 
bottomed flasks, n"iade of hard, moderately thick, well-annealed 
glass, l"ia\-ing a total capacity of about 250 c.c. The^' are 22 cm. 
long and have a maxinunn diameter of 6 cm., tapering gradually to 
a long neck, which is 2 c.iti. in diameter at the narrowest part and 
flared a little at the edge. 

(c) Distillation flasks. -Imu" distillatii in a llask of ordinary 
shape, of about 550 c.c. capacity may be used. It is fitted with a 



Che.micai, Tksts and ANAL^■sEs 345 

nihljer slojijier and with a Inilb tube aljove to prevent the [lossibility 
eif sodium liydrale being carried OA'cr meclianically durinc,' distilla- 
tion. The bulbs may be about 3 cm. in diameter, the tubes being 
of the same diameter as the condenser anrl cut off obliqueh' at the 
lower end, which is fastened to the condenser b\' a rubber tube.'' 

Preparation of Reagents. 

"(a) Potassium sulphate. Tlii^ reagent ^liiiukl lii- yuilxer- 
ized before using. 

(b) Sulphuric acid.-- The -uli'huric ai'id -^hin.ild ha\e a 
specific gravity of 1.84. It should be C. P., containing no nitrates 
nrir annnonium syilphate. 

(c) Sulphuric acid. — .V-IO -ripui, m. 

(d) Standard alkali solution. --The strength 'if thi^ ^oluti^m 
relative to the acid must be accurateh' determined, N-10 solution. 

(e) Metallic mercury or mercuric oxid.--lf mercuric oxid i- 
used it should be prepared in the wet wa_\', but not from mercuric 
nitrate. 

(f) Granulated zmc or pumice stone. — ("ine (jf these reagents 
is added to the contents of the distillation flasks, when found nec- 
essary, in order to prevent bumping. 

(g) Potassium sulphid solution. — A solution of fiirtv grams 
of commercial polassiinn sul|)hid in one liter of water. 

(h) Sodium hydroxid solution. — .\ saturated scilutinn of so- 
dium h_\droxid free from nitrates. 

(i) Indicator. -,\ siilntinn nf cichineal is prejiarcd Ijy digest- 
ing and frequently agitating three grams of pulverized cochineal in 
a mixture of 50 c.c. of strong alcohol and 200 c.c. of distilled water 
for a dav or two at ordinarv tem|)eratures. The filtered solution is 
eniplo\"ed as indicator.'' 

Determination. 

Place the substance to fje analyzed in a digestion flask, employ- 
ing from 0.7 to 3.5 grams, according to its proportion of nitrogen. 
Add 10 grams of powdered potassium sulphate and from 15 to 25 
c.c. fordina.ril)- about 20 c.c.) of sulphuric acid. Conduct the di- 
gestion by starting with a temperature below boiling point and 



346 CiiKiMiCAi, Ti'srs and Anaiasi{s 

increasing; ihc luat t;ra(hiall\ until frolhini;- ceases. Digest for a 
time after the mixture is colnrless, or ncarh' sii, (ir until oxidation 
is complete. On not add either jiotassium |)ermanp;anate or 
potassium siUphid. DiUite, neutralize, distil and titrate with stand- 
ard alkali. In neutralizint;. it is con\enieiU to add a few drops 
of |)henolphthalein indicator, h\- ^\■hich mie can tell, when the acid 
IS com]ileteh' neutralized, remeniherini,' that the ])ink color, which 
indicates an alkaline reaction, is destro\'ed h\' a considerahle excess 
of stron,s^ fixed alkali. 

Casein and Albumin. 

"(a) Casein. — The deterniinatinn slmuld he made when the 
milk is fresh, or iiearl\- so. ^^'hen it is not ])racticable to make this 
determination within twent\-four hoiu's, add one part of formal- 
delnde to twent\-tive hundred parts of milk and keep in a cool 
place. Place about 10 grams of milk in a beaker with about 90 c.c. 
of water at 40 degrees to 42 degrees C, and atld at once 1..^ c.c. of 
a 10 ])er cent acetic acid solution, v^tir with a glass rod and let 
stand from three to five minutes longer. Then decant ur tiller, wash 
two or three times with cold water by decantation and transfer pre- 
cipitate conipleteh' to filter. Wash once or twice on filter. The 
filtrate sliould he clear, or nearl\- so. If it he not clear when it first 
runs throu,gh, it can generall\- be made so l)y two or three repeated 
filtrations, after which the washing of the precipitate can be com- 
pleted. Determine nitrogen in the washed |)reci]iitate and filter h\ 
the (umning method. To calculate the e(|uivalent amount of casern 
from the nitrogen multiph' h\' t),38. 

In working with milk which has been kept with preservatives, 
the acetic acid should be added in small proportions, a few drops 
at a time, with stirring, and the addition continued until the licjuid 
abo\'e the precipitate Ih'Couk's clear or \er\' nearl\- so. 

(b) Albumin. — b'.xaclK neulrali/e with caustic alkali the fil- 
trate obtained in the preceding operation (a), add 0.3 c.c. of a 10 
per cent solution of acetic acid and heat the li(|uid to the tempera- 
ture of boiling water until the albumin is com])letely iireciiiitatcd, 
collect the precifiitate on a filler, wash and determine the nitrogen 
therein. Nitrogen imdtiplit'<l b\' fi.3S ecpials .albumin." or 



Cni'.AiiCAL Tksts axd .\xal\se.> 347 

Tf) the tillraie nf the casein deteriiiiiiation add 0,3 c.c. uf lU per 
cent acetic acid, boil until the allnimin \r. cuinpleleh- precijtitated and 
proceed as directed in previous parai^raph. 

In the place of the above methods the per cent of albumin may 
be determined by subtracting" the per cent of casein from the per 
cent of total nitrogen. 

Milk Sugar (Lactose). 

Optical Method. 

Preparation of Reagents. 

"(a) Acid mercuric nitrate. — hissuKe mercur\- in d'.uble it^ 
weii^ht (jf nitric acid. S]X--cific grcavit\' 1.42. and dilute with an equal 
viilume of water. One culiic ceiuimeter of this reagent is sufficient 
for the iptaiitities ni nnik mentioned below. Larger i|uanlities ma\' 
be used witlmut attectiiiL; the results f)f polarization. 

(b) Mercuric iodid with acetic acid. — Mi-x 3,i.J gram- "i ]>''>- 
tassium iodid. lo.s grams of mercuric chlorid, 2(J c.c. of glacial 
acetic acid and 040 c.c. of water." 

Determine the specihc gravitx' of the milk b_\" means of a deli- 
cate h}-fIrometer, or. if preferred, a ])ycnonieter. The quantit}' of 
sample to be taken fur the determination \-aries with the specific 
gra\'it\- and is to be measured at the same temperature at which the 
specihc gra\-it}' is taken. The volume to be measured is indicated 
in the following tafde, which is based upon twice the iKjrmal weight 
of lactose (32.'' grams jier K)0 metric c.c. I tur the \ eiitzke sugar 
scalc- 

Place the i]uantit\' of milk indicated in the table in a flask 
grafluated at 102.6 c.c, add 1 c.c. of the acid mercuric nitrate solu- 
tion or 30 c.c. of the mercuric iodid s(.ilution (an excess of these re- 
agents does no harm), hll t(j the mark, shake, filter through a drv 
filter and jKilarize. It is not necessar\" to heat before polarizing. If 
a 200 ni.m tube is used, divide the polariscope reading by 2{ or, if a 
400 m.m. tube is Used. b\' 4) to ofitain the per cent of lactose in the 
sample. 



348 



CiiHAdCAi, Tksts .\ni) .\^^^l,^•sl,:^ 



Volume of Milk Corresponding to a Lactose Double Normal 

Weight. 



Specific Gravity 
of Milli 


Volume of Mill< 

for .a Lactose 

Double Normal 

Weiglit Ventzke 

Scale 


Siieciflc Gravity 
of Mill< 


Volume of Milk 

for a Lactose 

Double Normal 

Weight Ventzke 

Scale 




C. C. 




c. c. 


1.024 


(i4.25 


1.031 


(■i3.X() 


1.025 


( .4.20 


1.032 


(<i.7r- 


1.026 


(.4.15 


1.033 


(.3.70 


1 .027 


(>4.05 


1 .034 


(i3.(>5 


1.028 


(:.4.00 






1.02O 


63.^)5 


1.035 


(>^.?'? 


1 .030 


63.00 


1.03(1 


(j3.50 



4 



Low's Volumetric Method Modified. 
Preparation of Reagents. 

"(a) Copper sulphate solution. — nissuht- .U.(j3'' ^ram 
CuSO^ .5HX) in water and dilute to 500 c.c. 

(b) Alkaline tartrate solution. — Dis.sol\'e 173 i;ranis nf Ivo- 
chelle salts and 50 grams of sodium h^'droxid in water ancl dilute 
to 500 c.c. 

(c) Mixed solution. — -Mix equal \iilumes nf SMlutinns (al and 
I 1) ) ininiediatel)' before use. 

(d) Standardization of the thiosulphate solution. — Trepare a 
solution of sodium thiosulphate, dissolving 24.t>5'' grams of pure 
crystals lo 1,000 c.c. Weigh 6.36 grams copjier foil. Dissolve by 
wanning in minimum amount of nitric acid and water reipiired. 
looil to expel the red fumes, add IdO c.c. strong bromine water and 
boil until the Ijromine is thoronghl)' expielled. i\.enio\'e from the 
heat and add a slight excess of strong ammoninm h)'droxid : 223 c.c. 
is about the right amount. Again boil until the excess of amnioni;ii 
is exjielled, as slmwii by a change of color of the li(|uid, and partial 
jjrecipilation. Now add a slight excess of strong acetic acid ( 100 
to 130 c.c. of 80 per cent acid) and l)oil for a minute. Cool to 
room temperature and dilute to 1,000 c.c. Titrate a known amount 
( 10 lo 13 c.c.) of the copper solution, to which 10 c.c. of a 23 per 
cent solution of pure potassium iodid has been added, with the 



ChE-mical Tests and Analyses 349 

ihiosulphate sokiiion until tlie brown tinge lias become weak', then 
arid sufficient starch liquor to produce a marked blue coloration. 
Continue the tnration cautiously until the color due to free iodin 
has entirel)- \-anished. The bhie coloi- change; toward the end to 
a faint lilac. If at this point the thiosul]iliate Ije added drop b_\' drop 
and a little time be allowed for complete reaction after each addition, 
there is no diftictilty in determining the end point within a single 
drop. One cubic centimeter of the ihiosulphate solution will be 
tound to corres]jrjnd to .006,36 grams of copper.'' 

Determination of Copper. 

"After washing the precipitated cuproir^ oxid, co\'er the goocli 
with a watch gia.^,b and dissolve the oxid Ij)' means of 5 c.c. of warm 
nitric acid ( 1 ;1 ) poured tmder the watch glass with a pipette. Catch 
tlie filtrate in a flask of 2.50 c.c. capacity, wash watch glass and 
gooch free of copper : 50 c.c. of water will be sufficient. Boil to 
expel red fumes, add 5 c.c. of bromine water, boil off the broitiine 
and proceed exactl}' as in standardizing the thio^ulphate." 

Determination of Lactose. 

I'lace 50 c.c. of the mixed copper reagent in a beaker and heat 
to the boiling point. \\ bile boiling briskly add 100 c.c. of the lactose 
solution containing not more than 0..300 grams of lactose and boil 
for six minutes. Filter immediatel}' tlirough asbestos and wash. 
6.)btaiii the weight of lactose e(|uivalent tn the weight of co]jper 
f(.)Und from the following table : 



330 



Cni:MlCAL 'I^'ISTS AND AlNAUVSKS 



'Table for the Determination of Lactose (Soxhlet-Wein). 



Mini- i 


MllU- Mllli- 1 


Mnii- 


Milli- 


Milli- 


Milli- 


Milli- 


Milli- 


Milli- 


gram^ 


grams 


grams 


grams 


grams 


grams 


grams 


grams 


grams 


grams 


ol 


o< 


of 


ol 


0{ 


of 


of 


of 


of 


of 


copper 


lactose 


copper 


tacf084 


copper 


lactose 


copper 


lactose 


copper 


lactose 


1*1 


71.6 


160 


116.4 


220 


161.9 


280 


208,3 


340 


255. 7 


101 


72,4 


161 


117. 1 


221 
222 


162,7 


281 


209.1 


341 


266,6 


102 


73.1 


162 


117.9 


163,4 


282 


209,9 


342 


257.4 


103 


73.8 


163 


118.fi 


223 


164,2 


283 


210.7 


343 


2sa.2 


104 


74.6 


164 


119.4 


224 


164.9 


284 


211.5 


344 


259.0 


105 


75.3 


165 


120.2 


225 


165.7 


285 


212.3 


345 


259.8 


lOB 


76.1 


166 


120.9 


226 


166.4 


280 


213.1 


346 


260.6 


107 


76. S 


167 


121.7 


227 


167.2 


287 


213.9 


347 


■251.4 


lOS 


77.6 


168 


122.4 


228 


167.9 


288 


214.7 


348 


262.3 


loa 


78.3 


169 


123.2 


229 


168.6 


289 


215.6 


349 


263.1 


110 


79.0 


170 


123.9 


230 


169.4 


290 


216.3 


360 


253.9 


111 


79. S 


171 


124.7 


■231 


170.1 


291 


217.1 


3,51 


264.7 


112 


80.5 


172 


125.5 


232 


170,9 


292 


217.9 


352 


265.5 


113 


81.3 


173 


126.2 


2.33 


171,6 


293 


218.7 


353 


263.3 


lU 


S2.0 


174 


127.0 


234 


172,4 


294 


219.6 


354 


267.2 


115 


82-. 7 


175 


127.8 


285 


173,1 


295 


220.3 


3,55 


268.0 


1 lo- 


83.5 


176 


128.5 


236 


173,9 


290 


221.1 


356 


268.8 


ll? 


84.2 


177 


129.3 


237 


174.6 


297 


221.9 


36f 


259.6 


118 


85.0 


178 


l;i0.1 


238 


175.4 


298 


222.7 


3-j8 


270.4 


119 


83.7 


179 


130.8 


239 


176.2 


299 


2-23.5 


359 


271,2 


120 


86.4 


180 


131.6 


240 


176.9 


30O 


224.4 


330 


272.1 


121 


87.2 


181 


l:?2 . 4 


241 


177.7 


.301 


225.2 


361 


272.9 


122 


87.9 


182 


i:».l 


242 


178.5 


302 


225.9 


362 


273.7 


123 


88.7 


183 


133.9 


243 


179.3 


303 


226.7 


363 


274.5 


124 


89.4 


184 


131.7 


244 


180.1 


304 


227.5 


364 


275 3 


125 


90.1 


185 


135.4 


245 


180.8 


306 


228.3 


365 


276.2 


126 


90.9 


186 


136.2 


246 


181.6 


306 


229.1 


366 


277.1 


127 


91.8 


187 


137.0 


247 


182.4 


307 


229.8 


367 


277,9 


128 


92.4 


188 


137.7 


248 


183,2 


308 


230.6 


368 


278,8 


129 


93.1 


189 


138.5 


249 


184.0 


309 


231.4 


369 


279.6 


130 


93.8 


190 


139.3 


250 


184,8 


310 


2.e.2 


370 


289.6 


131 


B4.6 


191 


J40.0 


251 


185,6 


311 


232.9 


371 


281.4 


132 


96.3 


192 


140.8 


S52 


166,3 


312 


233.7 


372 


282.2 


133 


96.1 


193 


141.6 


a>3 


187.1 


313 


234.5 


378 


■283,1 


134 


96.9 


194 


142.3 


254 


187.9 


314 


235,3 


374 


283.9 


135 


97.6 


19.5 


143.1 


2'55 


183.7 


315 


236 1 


375 


■284.8 


136 


98.3 


196 


143.9 


266 


189.4 


316 


236,8 


376 


285,7 


137 


M.l 


107 


144.6 


2,57 


190.2 


317 


2:^7,6 


377 


•286,5 


138 


99.8 


198 


145.4 


268 


191.0 


318 


238.4 


378 


287.4 


139 


100.5 


199 


146.2 


259 


191.8 


319 


239.2 


379 


288.2 


140 


101.3 


200 


146.9 


260 


192.5 


320 


240.0 


380 


289.1 


141 


102.0 


201 


147.7 


261 


193.3 


3-21 


24:>.7 


381 


2S9.9 


142 


102.8 


202 


148.5 


262 


194.1 


322 


241.6 


.382 


290.8 


143 


103.5 


203 


149.2 


263 


194.9 


323 


242.3 


383 


•291.7 


144 


1W.3 


201 


I'lO.O 


261 


195.7 


324 


243.1 


■.m 


282. 6 


145 


105.1 


205 


150.7 


265 


196.4 


326 


243.9 


385 


293.4 


146 


105.8 


206 


151.5 


266 


197.2 


326 


244.6 


386 


294.2 


147 


106.0 


207 


152.2 


267 


198.0 


327 


245.4 


387 


295.1 


148 


107.3 


208 


1.53. 


268 


l:l8.8 


.328 


246.2 


388 


2J6.0 


149 


108.1 


209 


1,5,;. 7 


269 


1!)<J,5 


329 


247,0 


889 


2,16.8 


150 


108.8 


210 


1.54.5 


270 


2110,3 


3:10 


247,7 


3',X) 


2ff.7 


151 


1(».6 


211 


155.2 


271 


201,1 


331 


248 , 5 


391 


•298.5 


152 


110.3 


212 


1.5fi.O 


272 


201.9 


3;!2 


249,2 


.392 


29;1.4 


153 


111.1 


213 


1,56,7 


273 


202.7 


3.33 


250.0 


393 


300.3 


154 


111.9 


2W 


1,57,5 


274 


2iVi,5 


334 


■250.8 


394 


311.1 


155 


112.6 


215 


1,58,2 


275 


21M,3 


335 


2,51.6 


395 


302.0 


156 


113.4 


21« 


1,59,11 


276 


205,1 


336 


252.5 


396 


302.8 


167 


114.1 


217 


159,7 


277 


205.9 


337 


253.3 


397 


398.7 


158 


114.9 


218 


160, 1 


278 


206.7 


3:i8 


•261.1 


:iS8 


304.6 


159 


115. C 


219 


101,2 


279 


207.5 


339 


2.51,9 


399 


305.4 














1 




400 


306.3 



Chk.mical Tes'i^ a.\d Analyses 



351 



Butter Fat. 

The Babcock Test. 

Standard Glassware." 

lal Standard milk te-t Ij^ttle-.. L;"i"aduated t' < ^ per cent and 
with suh-divi^ii in^ i,f .1 ];(.-r cent. 

(bi Standard pijiette L;Tadiiatc'd t' > \7.i'i c.c. 

(CI .\cid measure L.'raduated ti i 17.,^ c.c. 

(d) CentrifuLj-L--l'.abc'ick tester. 

(e) Water bath i' 'V reading;' at 1,^0 t^ > 140 dc--ree> V. 

(f) Calipers fur nica^uriiiL;' fat Cihimn. 

(g) Sulphuric acid. ^])ecilic graxit}' 1 .S2 t<' l.'^.V 

Determination. 

I'ipette ]/.() c.c. ^f the pruperh- ini.xcd sample ' n milk iutf 
the milk test Imttle. .\dd 17.5 c.c. of acirl and ^hake until all the 
cui"d ih CI impk'tel)' diss(,]\'ed, 
Ruth milk and acid ^Iniuld ha\'e 
a temperature 'if ,^,^ f • 7<l de- 
grec^ y. If milk and acid are 
too wanu. set tile sample but- 
tles anil the acid jar into a 
tnaiLih iir tub nf water at .^.^ ti i 
70 degrees F. fur thirty minutes 
before testing. The te^t bottles 
ciantaining the mi.\ture of mdk 
and acid are then whirled, in 
the hJabcock tester for ri\-e 
minutes at about one thousand 
re\'olutions per minute, in the 
case of a tester with a tweh'e- 
inch diameter w heel. Fill the ^.^^ i^,, Babcock tester 

test bottles to the bottom of Oourt.-.^.v of i 'reamery Packag-e irfg. 
, 1 -il 1 4. » ^n (.'ijinpaiiy 

the neck with hot water. the 

water shrjuld be soft, preferably rain water or distilled water. 
Tf hard tap water i-- used it should be boiled to jirecipitate the 
carbonates, citherwise the test ma)' be difficult to read, owing to 
the presence of bubbles rif gas on top of the fat column. I\e\'oh-e 




1914. 



1 Hunziker, Indiana Agricultural Experiment .Station. Circul 



ars 41 and 42, 



.^52 ClIliMICAL Tl'.STS AND AnaLYSKS 

a,L;ain ;it full s|iccil fiir twn nuniiU-^, fill tlic te~t Imttlcs ti > near 
the ti'p iif the L;va(Iiiatii Ml witli hut water. Whirl in the centrihicc 
Uir line minute. Neiw -^et the li'st Imttles in the water l)ath at 
l.V"! decrees ]\ tnr h\"e minute^. The te.'^t i'^ ui'W rearh' te) he 
read. The fij^ures nu the test Imttles re|n-esent per eent. Tu the 
ease ni the S |>er eent standard milk test buttle the suh~di\'isirins 
rejiresent tentlis per cent. l\ead in mi the he.tti im nf the hnver 
curve to the top of upjicr cur-\'e eif the fat column, including the 
meniscus in the readinq'. 

Gravimetric Method — Paper Coil. 

"Make coils of thick filter ]iai)er, cut iiitu strijis (i.23 h)- fii.o 
e.m., and thorou.qhlA' extract with ether and alcolnil, cir enrrcct 
the \\ei,i;ht of the extract hx a constant (ibtained for the paper. 
I'r'ini a weicihini;" bottle or weiL^hinc;' pijiette. transfer ahi'Ut ? 
Q-rams of milk to the cuil. care beini;" taken to keep the end of 
the coil held in the lingers, dr^-. Dr\' the coil, dr\' end d(T\vn, on 
a piece of ,Qdass at the temi)erature of boiling' \\'ater ; transfer to 
an extraction a|")paratns and extract with absi^ilute ether or pe- 
troleum ether boiliuc;' at about 4.^ degrees C. : dry the extracted 
fat and weigh." 

Roese-Gottlieb Method. 

"Weigh 10-11 grams of the milk into ;i Rohrig tube or sonie 
similar apparatus, add \.2? e.c. of concentrated ammonium h\-- 
droxid (2 c.c. if the sani|Tle is sour) and mix thori mghh-. .\dd 
10 c.c. of 9? ]ier cent alcolvd 1)y xnlume and mix well. Then add 
2? c.c. of washed ether and shake \-igorously for thirty seconds, 
then 2,^ e.c. nf petroleum ether (redistilled slin\l\- at a tempera- 
ture below 00 de.grees C.) and shake again lor thirt\' seconds. 
Let stand twenty minutes, or until the np]ier liipnil is |u-aetically 
clear. i)raw o(f as much as inissible ol the ether-lat -solution 
(usually 0.5-0.8 e.c. will be left) into a weighed flask through a 
small fpn'ek-actitig liller. The ll,'isl< should alwaN's Ite weighed 
with a similar (niu as a ci 'unteipoise. I\e-e\tract the liipiid re- 
maining in the tube, this time with oiiK 1 .^ c.c. I'f each ether, 
shake N'igoroiisl \' thirlv seconds with each and allow t<i settle. 
Draw off the clear solntimi throu,L;h the sm.all filter intn the same 
fl.'isk as before .and wash the ti]) i>f spi^dt, the funnel and (he 
filter with a few e.c. of a mixture nf the two ethers in equal parts. 



ChKiMical Ti'STs and Analyses 353 

For absolutely exact results the re-extraction must be repeated. 
This third extraction }'ields usuall}' ncit mnrv than ah'jut 1 mp,^ 
of fat (about 0.02 per cent on a 4 gram charge) if the previous 
ether-fat solutions ha\-e lieen drawn oft closelv. E\-aporate the 
ethers slowly on a steam bath, then dry the fat in a boiling water 
'iven to constant weic^'ht. 

Confirm the ]nirit}- of the fat 1)\- di'-S'":l\"inu' in a little ]ie- 
troleum ether. Should a risiduc remain. remo\"e tlie fat cfim- 
pletely with ]")etri ileum ether, flr\' the residue, wei^ii and deduct 
the \\-eight. Finalh- correct thi^ weitiht by a filank determina- 
tiou on the rea,£(ents used." 

SWEETENED CONDENSED MILK. 
Preparation of Sample. 

Pour the contents of the can into a bowl or on a glass plate. 
Scrape out the can thoroughly, remo\-ing all the sugar sediment 
from the top anrl Ijott^'m oif the can. .Mix thuri iuglil}- wdth |)cstle 
or spatula until a lionn )geni lu^ emulsion is secured. This i^ 
important, as it is e.xceedingK difticidt ti i -.ecurc a re]iresentati\"e 
sample other\\-ise. 

If it is desired t<> use a 4(J per cent s(dution as directed in 
the determination of the indi\'idual inL;redients, weigii accurately 
40 grams of the properly mixed contents nf the can into a 100 c.c. 
graduated flask. Add 00 c.c. nf '.\ atei'. The sweetened cm- 
densed milk mixes soniewdiat difficultl\- with the water. Complete 
solution is facilitated by addnig the water in --exeral install- 
ments, shaking after each additiiui initil cimdensed milk sedi- 
ment adheres no longer in the liMttum and side^ uf the llask 

Spec fie Gravity. 

Aerometric Method by Means of Beaume Hydrometer. 

Apparatus. 

Beaume Hydrometer.-- I '^e a >|jeciall\- constructed lieaume 
hydrometer with mercur}- bulb, and a scale of 30 to 37 degrees B., 
graduated to tenths degrees. Length over all, twelve inches : 
length of spindle, six inches ; length of empty bulb, four and 



354 CiiUMiCAi, Ti-;sTs and Analyses 

I 'iic-(|uarter inclies; width of empty bulb, thirteen-sixteenths of 
one inch. 

Hydrometer Jar. — Use a £;las.s or tin cyHnder with su!)stantial 
base, minium leni^th twcKe inches, minimum width one and a 
half melies. 

Determination. 

l^se the original undiluted condensed milk. The Beaume hy- 
drometer is graduated to read correctly at 60 degrees F. (15.5 de- 
grees C). At this temperature the sweetened condensed milk is 
too viscous for rapid and accurate work. Warm the condensed 
milk to 100 degrees F. or above and correct the Beaume reading 
by adding to the observed reading .025 points for every degree 
Fahrenheit above 60. At a temperature of 100 degrees F. or above, 
the reading can be made in fifteen minutes or less, after the hydro- 
meter is inserted in the milk. 

The specific gra\itv is determined bv the use of the following 

formula : 

^-, .^ . 144.3 

hpecinc Lrra^•ltv = 

144.3— B 

B := Beaume reading at 60 degrees F. 

Example: ( )bserved Beaume reading at 120 is 31.6. 

Corrected reading =31.6^ |( 120 — 60) V .025] =33.1. 

144.3 

Si)eci(ic t;"ra^'itv = =n 1.2077. 

144.3 — 33.1 

The following, table shows the specific gra^'ity of sweetened 
condensed milk when the Beaume reading is known. 



Chemical Tests and Analvses 



355 



Beaum6 



Specific 
Gravity 



Eeaum^ 



Specific 
Gravity 



Speciflo 
Gravity 






1.000 


16.5 


1130 


29.7 


1.260 


0.7 


1.005 


17.1 


1.135 


30.2 


1265 


1.4 


1.010 


1.77 


1.140 


30.6 


1.270 


2.1 


1.015 


18.3 


1.145 


31.1 


1.275 


2.7 


1.020 


18.8 


1.150 


31.5 


1.280 


3.4 


1.025 


19.3 


1.155 


32.0 


1.285 


4.1 


1.030 


19.8 


1.160 


32.4 


1.290 


4.7 


1.035 


20.3 


1.165 


32.8 


1.295 


5.4 


1.040 


20.9 


1.170 


33.3 


1.300 


6.0 


• 1.045 


21.4 


1.175 


33.7 


1.305 


6.7 


1.050 


22.0 


1.180 


34.2 


1.310 


7.4 


1.055 


'22.5 . 


1.185 


34.6 


1.315 


8.0 


1.060 


23.0 


1.190 


35.0 


1.320 


8.7 


i.om 


23.5 


1.195 


35.4 


1.325 


9.4 


1.070 


24.0 


1.200 


35.8 


1.330 


10.0 


1.075 


24.5 


1,205 


36.2 


1.335 


10.6 


1.080 


25.0 


1.210 


36.6 


1.340 


11.2 


1.085 


25.5 


1.215 


37.0 


1.345 


11.9 


1.090 


26.0 


1.220 


37.4 


1.350 


12.4 


1.095 


26.4 


1.225 


37.8 


1.355 


13.0 


1.100 


26.9 


1.230 


.38.2 


1.360 


13.6 


1.105 


27.4 


1.235 


38.6 


1.355 


14.2 


1.110 


27.9 


1.240 


.39.0 


1.370 


14.9 


1.115 


28.4 


1.245 


39.4 


1..375 


15.4 


1.120 


28.8 


1.250 


39.8 


1.380 


16.0 


1.125 


29.3 


1.255 


40.1 


1.3 85 



Gravimetric Determination, 
Dilute a measured portion of a 40 per cent solutiim with an 
equal \-olutne of water, use 5 c.c. rif the diluted mixture, cor- 
responding to 1 gram nf the condensed milk and proceed as 
directed under "?vlilk.'' 

Total Solids. 
Dilute a measured portion of a 40 ])er cent solution with an 
equal \-olume of water, measure 3 c.c. of the diluted mixture, 
corresponding to 1 gram of the condensed milk into an e\-ap- 
orating dish containing 15 to 20 grams of pure dry sand and 
proceed as directed under "Milk." 

Ash. 
Ignite the total solids at very low redness, cool, and weigh. 
See "Milk." 

Proteids, 
Determine nitrog-en in 5 c,c, of the 40 per cent solution 



356 CiiKiricAL Tests and Analyses 



according to tlie Gunning method, see ''Milk,'' and multiply the re- 
sults by 6.38. 

Lactose. 

Dilute h\e grams of a 40 per cent solution to about 40 c.c. 
and add .6 c.c. of Fehling's copper solution. Nearly neutralize 
with sodium hydroxide, make up to 100 c.c. filter through dr)- 
filter and determine lactose in an ahtpiot as directed undei- 
"Milk — Determination of Lactose.'' 

Fat. 
Modified Babcock Test. 

Weigh eighteen grams, or measure 16.1 c.c. of the 40 per 
cent solution into a standard Babcock milk test bottle. -Vdd 
4 c.c. of commercial sulphuric acid, specific gravity 1.82 to 1.83. 
Shake immediately until acid is tlniroughly mixed with the milk. 
W'hirl in Babcock tester for six minutes at full speed. The 
centrifuge must run smoothly. Stop the tester gradually and 
remove tlie bottles carefully so as not to lireak the layer of float- 
ing curd. Decant the clear wdiey Ijy slowly inclining the bottle. 
Now add two-thirds of a 17.6 c.c. pipette full of water. After 
thoroughly shaking to emulsify the curd and to wash it free 
of sucrose, add 4 c.c. sulphuric acid, shake, whirl and decant as 
before. Then add one 17.6 c.c. |)i])ette full of water, 17.5 c.c. 
of sulphuric acid and complete the Babcock test in the usual 
\vay as directed under "Milk." }ifultiply the reading by 2.5. 

This method yields \'ery satisfactor}- results «-itb s\\'eetened 
condensed milk containing not less than 4 to 5 per cent fat. 
With condensed milk of a Inwer fat content the decanting of the 
clear whey is difficult, since the curd in the partly skimmed 
[jroduct is too heavy to float in the form of a firm cheese. 

The Roese-Gottlieb Method. 

As jjracticed in the Dairy Lain irate iry. Bureau of Chemistry, 
Department of Agriculture. 

"Weigh out 4 to 5 grams of the homogeneous sample of 
condensed milk into a Riihrig tube (Zeit. L'nters. Nahr. u. Ge- 
nussm., 1905, 'J:531) or some similar apparatus and dilute with 
water in the tube to about 10.5 c.c. — or, if preferred, weigh into 



Cii i:.\i M.Aj, TiChTs AXi) Analyses 



357 



tlie tube 1') tM 11 -ram- m|' n 40 ]ilt i;em -ulutiMii n\ the -ub-tance 
— ad'l I'l i.e. of roiirciUratf d aiiimoninni liyilroxul ( _' r.c. if tlie 
-.anijjje l>c -nuri and mix thriroui^lilN' with tlie milk. Adrl 10 c.c. 
'if ')? ],(■]- cent aleolinl and mix well. Tlien add 2? r.c. <<i v.-a'^hed 
etli_\d etiier and .sliake nil;' in ,iisl \" for half a miiinte, then add 2? 
c.c. nf ]jetr' ileum ether (redistilled -lnwly at a temi/erature helcw 
'I'l deL;"ree^ C. ]>reli rahl \" i and '■hake ayam Inr half a minnie. 
Let stand 20 miiuites nr until the ujiiiei' liquid i- ]n-actically clear 
and it^ cwn lower lc\el cnnstant. I)ra\\' olT nf tlie etlier -r.lutiiin 
as much as possihle — usualh- 0..^ to O.H c.c. will he left — into a 
weig-hcfl flask tlirou,t;h a diminuti\e i|uick actin,^' iilier, of selected 
paper. The tkask- ^hoidil alu'ays he weiiihed with a -imilar ore 
as counterpoise. 

"Re-extract the li'piid remaining;" in the tuhe, this tiuK with 
oril\- 1 .s c.c. of each ether, -halcmy" \i,s;orou^h' half a minute witli 
eacli, a.nd allow to settle. 

"Draw off tile clear solution throncdi the small filter into 
the same lla-^k as liefore and wash the ti)) of the ~j)i;;'ot. tlie funnel 
and the fdter witli a few c.c. of a mixture of the two ethers in 
e<pial ];arts ( pre\-iousl\- mixed and free from de])osited water). 

" I'or perfecth' exact results the re-extraction must he re- 
])eated. Thi'^ exti action yields u.-ually not more than akon.t a 
milligram of fat, if the |n-e\dous ether-fat-^, dutions lia\e keen 
drawn off closeh' — an amount a\■era^■inL;■ akont .0_' ]ier cent ■ 'ii 
a -l-L;ram cliar,L;"e. 

" I'.\ apoi-ate the ether slowl\- iju a steam hath, then dr\' the 
fat in a. hoihii',;' water o\en until lo^s nl wei,i4ht ceases. 

"l'ro\e the jniritN- of the fat he dissok.in^- in a little Jje- 
tiaileum ether. Should a re-idue remain, wash the fat i 'Ut com- 
pletely with ])etia ileum ether, dry the resifiue, weiL^h, .and deilucl 
tfie wei.^dil. ('I'liis sliould not olteii he neiessarw) 

"k'inall}- deduct the \\eiL;ln ohtained k\' klauk determination 
on the chemicals u.-ed. 

"I'.y this method practically aksolute re-.uU-, can la ol'- 
taiiietl." 

Sucrose. 

iJeterminc \>\ dilTerence, deductiiiL; llie milk si .lids (a^li 
]j1us pruteids plus lactose plus fat) from the total solids, ur 



358 Ciiii-MiCAL Ti-;sTs and Analyses 

in\-ei"t the sucmse, deteriiune, the total iiu'ert sut^ar, deduct friini 
this the hictijse calculated as imert su^ar and calculate the 
difterence as sucrose. 

Milk Solids. 
Deduct the per cent sucrose from the per cent total solids. 
Tlie diiierence represents the ]'>er cent milk solids. 

EVAPORATED MILK. 
Preparation of Sample. 

Shake the can of e\ap)orated milk \'it;"orously before opening. 
If, upon (jpenitiL;' the can, separated cream or small lumps of 
butter are f'.nuid to adhere to the seams and around the junction 
of the ends and the bind}-, set the can in a water bath at 130 
deijrees F. for ten minutes or until all fat is com|detel}' dissoh'ed. 
Then pour tlie entire contents into a ])eaker and prmr back and 
forth several times until a homotjeneous mixture is secured. If 
it is known before opiening' the can that the contents are sep- 
arated, submerge the whcde can in a water bath at 130 degrees 
F. for ten minutes, then shake, open and proceed as above. 

If it is desired to use a 40 per cent solution, as directed 
under the determinatii.in of the iudi\-idual ingredients, weigh 
accurate!}' 40 grams of the prdperlv mixed contents of the can 
into a 100 c.c. graduated llask. Add (>0 c.c. water and mix thor- 
eiughh' b_y shaking or stirring. 

Specific Gravity. 

Aerometric Method. 

Apparatus. 

Beaume hydrometer. — L'se a special Ik-aume Indrometer 
with a scale ranging from h\'e to tweh'e points, graduated to 
tenths degrees and mercur^•-weightcd. Length oxer all ele\'en 
inches, length nf spindle six inches, length of em|)t\- bulb iouv 
inches and width of em])tx- bulb se\en-eighths inch. 

Hydrometer jar. — L'se a glass or tin cylinder with substantial 
base. Minimum lieight ten inches ami minimum width one and 
a half inches. 

Determination. 

The lieanme hydrometer is graduated to read correcth' at 
t>0 degrees F. (1,^.5 degrees C). F"or e\ery degree Fahrenheit 



Chivmical Ti'.sts and Analyses 359 

abo^•e fiO arid .0313 points t<'' tlie iihiLT\-eii readme:. Fi'i' e\"ery 

dej^ree Fahrenlicit lielnw f/i. rlcdiict .0.^1.^ pMint^ fr':im tlie ob- 

.';er\'ed reading. 

The s]")erific graxitN" i^ determined 1)\' tlie n^e 'if tlie fi iHi iwing 

formula : 

14,-. 3 

Speciiic L;ra\-it\" = ;v-^ rr 

14.-. ,-1 — I! 

P) =: C'irreetefi lieaimie reading. 

F.xample: lleaume rearling at •'"'O degi'ee~ V . i- T.''^^. 

Cnrreeted reading = 7.S 4- | i ."^O — 00 i ■ f}^]^] = S.43. 

143 3 

Si>ecihc L;Ta\-itA' =: ^= 1.001,-. 

145.5 _S.43 

F.qnally gnnd results ma\" lie "litained 1)\' dilntmc;' the e\;ip- 
eirated milk with an eipial weight iif water. Then take the <jue- 
\-enne lactometei- reading at M.) rlr^aees h'. .Multi]ily the reading' 
by 2. add K)f«. and divide by 1000. 

Gravimetric Determination. 

Dilute the e\"a])eirated milk with fnur times it- weieht of 
water anrl proceed as rlirected tmder "Milk." 

Total Solids. 

By Means of Specific Gravity and Babccck Formula, 

Determine tlie specihc gra\at\- a- almxe directed. Multipl}' 
bv lOCO and -ubstract 1000, Then u-e the foil, , win- formuki, : 

F ^^ The figure deri\'ed fn im the s|)ecihc gra\-it_\' b_\- abei\-e 
calculations. 

f = per cent fat. 

Ftxample : E\-apiirated milk tests 7.X pci' cent fat and has a 
specific gra\'ity of 1,0013, 

L = (1,0013 X IClOO) — K,00 = ol,3. 

Total solids ^ ''-^ + k-' / 7R := 24,74 per cent. 

For rapid determination of the total solids of ewaporated 
milk the factory operator is referred to the following tables from 
which the per cent total solids may be read at a glance when the 
Beaume reading at 00 degrees F. and the per cent fat are known. 



360 



CiiK'iMiCAi:, Tksts and Analysk 



•ts 



Per Cent Solids of Evaporated Milk. 

The I'.caimu' Dc-rees at ()0 Dt-recs F. are Indicated m the 

ITni-iziintal Line at the Tii]i. Tlie I'er Cent of Fat is Slmwn 

in the Vertical Cnltimn at tlic Fcft. 







Beaume 


readin 


g at 60 degrees Fahrenhei 


t 






8.0 


8.1 


8.2 


8.3 


8.4 


8.5 


8.6 


8.7 


8.8 


8.9 


FAT 






















PER 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


CENT 


per 


per 


per 


per 


per 


per 


per 


per 


per 


per 


cent. 


cent. 


cent. 


cent. 


cent 


cent. 


cent. 


cent. 


cent. 


ceot. 


6.0 


21.75 


21.94 


22.13 


22.32 


22.52 


22.71 


22.90 


23.10 


23.29 


23.49 


6.2 


21.99 


22.18 


22.37 


22.56 


22.76 


22.95 


2:3.14 


23.34 


23.53 


23.73 


6.4 


22 23 


22 42 


22.61 


22.80 


23.00 


23.19 


23.38 


23 58 


23.77 


23.97 


6.6 


2147 


22!66 


22.85 


23.04 


23.24 


23.43 


23.62 


23.82 


24,01 


24.21 


6.8 


22.71 


22.90 


23.09 


23.28 


23.48 


23.67 


23,86 


24.06 


24.25 


24 45 


7.0 


22.95 


23.14 


23.33 


23.52 


23.72 


23.91 


24.10 


24.30 


24.49 


24.69 


7.2 


23.19 


23.38 


23.57 


23.76 


23.96 


24.15 


24.34 


24.54 


24.73 


24.93 


7.4 


23.43 


23.62 


23.81 


24.00 


24.20 


24.39 


24.58 


24.78 


24.97 


25.17 


7.6 


23.67 


23.86 


24.05 


24.24 


24.44 


24.63 


24.82 


25.02 


25.21 


25.41 


7.8 


23.91 


24.10 


24.29 


24.48 


24.68 


24.87 


25.06 


25.26 


25.45 


25.65 


8.0 


24.15 


24.34 


24.53 


24 72 


24.92 


25 11 


25.30 


25.50 


25.69 


25.89 


8.2 


24.39 


24.58 


24.77 


24.96 


25.16 


25.35 


25.54 


25.74 


25.93 


26.13 


8.4 


24.63 


24.82 


25.01 


25.20 


25.40 


25,59 


25.78 


25.98 


26.17 


26,37 


8.6 


24.87 


25.06 


25.35 


25.44 


25.64 


25.83 


26.02 


26.22 


26.41 


26.61 


8.8 


25.11 


25.30 


25.49 


25.68 


25.88 


2fi.07 


26.26 


26.46 


26.65 


26.85 


9.0 


25.35 


25.54 


25.73 


25.92 


2612 


26.31 


26.50 


26.70 


26.89 


27.09 


9.2 


25.59 


25.78 


25.97 


20.16 


26.36 


26.55 


26.74 


26.94 


27.13 


27..38 


9.4 


25.83 


26.02 


26.21 


26.40 


26.60 


26.79 


26.98 


27.18 


27.37 


27.57 


9.6 


26.07 


26.26 


26.45 


26.64 


26.84 


27.03 


27.22 


27.42 


27.61 


27.81 


9,8 


26.31 


26.50 


26.69 


26.88 


27 98 


27.27 


27 46 


27.66 


27.85 


28.05 


10.0 


26.55 


26.74 


26.93 


27.12 


27,32 


27.51 


27.70 


27.90 


28.09 


28.29 


10.2 


26.79 


26.98 


27.17 


27.36 


27.5(i 


27.75 


27,94 


28.14 


28.33 


28.53 


10.4 


27.03 


27.22 


27.41 


27.60 


27.80 


27.99 


28.18 


28 38 


28.57 


28.77 


10.6 


27.27 


27.46 


27.65 


27.84 


28.04 


28 23 


28 42 


28.62 


28.81 


29.01 


10.8 


27 51 


27 70 


27.89 


28.08 


28.28 


28.47 


28.66 


28,86 


29.05 


29.25 


11.0 


27 75 


27.94 


28.13 


28 32 


28.52 


28.71 


28.90 


29.10 


29.29 


29.49 


11.2 


27.99 


28.18 


28.37 


28.56 


28.76 


28.95 


29.14 


29.34 


29.-53 


29.73 


11.4 


28.23 


28 42 


28.61 


28. no 


29.00 


29.19 


29.38 


29.5S 


29.77 


29.97 


11.6 


28.47 


28.66 


28.85 


29.04 


29.24 


29.43 


29.62 


29.82 


30.01 


30.21 


11.8 


28.71 
1 


28.90 


29.09 


29.28 


29.48 


29.67 


29.86 


30.06 


30.25 


30.45 



Chemical Tests and Analyses 



361 



Per Cent Solids of Evaporated Milk (Continued). 

The I'.eaunic ])et;rec^ at (<() I )e,L;rcC'; V. ai'i; Imlicated in the 

Horizontal Line at the 'I'oj). 'Hie l^'er Cent nf Fat is Shfjwii 

in the ^'ertical Column at the Left. 







B 


eaume 


reading at 60 degrees Fahrenheit 






9.0 


9.1 


9.2 


9.3 


9,4 


9.5 


9.6 


9,7 


9.8 


9.9 


FAT 






















PER 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


CENT 


per 


per 


per 


per 


per 


per 


per 


per 


per 


per 




cent 


cent. 


cent. 


cent 


cent. 


cent. 


cent . 


cent. 


cent 


cent 


6.0 


23.68 


23,88 


24.08 


24.27 


24.47 


24.66 


24,86 


25,06 


2^' 26 


25,45 


6.2 


23.92 


24,12 


24.32 


24.51 


24.71 


24.90 


25.10 


25,30 


25..:o 


25,69 


6.4 


24.16 


24,36 


24.56 


24.75 


24.95 


25,14 


25,34 


25.51 


25.74 


25,93 


6.6 


24.40 


24,60 


24.80 


24.99 


25.19 


2,5..38 


25. .58 


25,78 


25,98 


26.17 


6.8 


24.64 


24.84 


25.04 


25.23 


25.43 


25.62 


25,82 


26.112 


26,22 


26.41 


7.0 


24.88 


25.08 


25.28 


25.47 


25,67 


25.86 


26.06 


26.26 


26,46 


26.65 


7.2 


25.12 


25.32 


25..52 


2.5.71 


25.91 


26.10 


26.30 


26,.50 


26.70 


26.89 


7.4 


25.36 


25,56 


25,76 


25,95 


26.15 


26.34 


26,54 


26.74 


26.94 


27.13 


7.6 


25.60 


25,80 


26.00 


26.19 


26.39 


26,.58 


26.78 


26.98 


27.18 


27.37 


7.8 


25.84 


2(;.04 


26.24 


26.43 


26.63 


26.82 


27.02 


27 22 


27.42 


27.61 


8.0 


26.08 


26,28 


26,48 


26.07 


26.87 


27,06 


27.26 


27.46 


27,66 


27.85 


8.2 


26.32 


26,52 


26.72 


26.91 


27.11 


27,30 


27.50 


27.70 


27.90 


28.09 


8.4 


26.56 


26.76 


26.96 


27.15 


27.35 


27.. 54 


27,74 


27.94 


28.14 


28,33 


8.6 


26.80 


27.00 


27.20 


27.39 


27.59 


27,78 


27,98 


2818 


28..38 


28,57 


8.8 


27.04 


27.24 


27.44 


27 63 


27,83 


28.02 


28.22 


28 42 


28.62 


28.81 


9.0 


27.28 


27.48 


27,68 


27,87 


28.07 


28.26 


28.46 


28.66 


28.86 


29.05 


9.2 


27.52 


27.72 


27,92 


28,11 


28,31 


28..50 


28.70 


28.90 


29.10 


29.29 


9.4 


27.76 


27.96 


28.16 


28,35 


28,55 


28.74 


28.94 


29,14 


29.34 


29.53 


9.6 


28.00 


28.20 


28.40 


28.59 


28.79 


28.98 


29.18 


29.38 


29,5S 


29.77 


9.8 


28.24 


28.44 


28.64 


28.83 


29,03 


29 '''2 


29.42 


29.62 


29.82 


30,01 


10.0 


28.48 


28.68 


28.88 


29.07 


29,27 


29.46 


29.66 


29,86 


30.06 


30.25 


10.2 


28.72 


28.92 


29,12 


29.31 


29,51 


29.70 


29.9(1 


.30.10 


30.30 


30.49 


10.4 


28.96 


29.16 


29,36 


29.55 


29,75 


29.94 


30,14 


.30..34 


30..54 


30.73 


10.6 


29.20 


29.40 


29,60 


29.79 


29,99 


30.18 


30,3:! 


.30 58 


30.78 


30.97 


10.8 


29.44 


29.64 


29.84 


30.03 


.30.23 


.30.42 


30,62 


30.82 


31,02 


31.21 


11.0 


29.68 


29,88 


30.08 


30.27 


30,47 


.30,66 


.30,86 


31.00 


31.26 


31.45 


11.2 


29.92 


30,12 


30,32 


30,51 


.30,71 


30,90 


31,10 


31.30 


.31,50 


31.69 


11,4 


30.16 


30.36 


30,56 


30,75 


30,95 


31.14 


3134 


31,54 


31,74 


31.93 


11.6 


30,40 


30.60 


30.80 


30,99 


31.19 


31. .38 


3158 


31.78 


31.98 


32.17 


11.8 


30.64 


.30.84 


31.04 


31,23 


31.43 


31,62 


31,82 


32.02 


32 22 


32 41 



362 



Ci-ii'.MiCAi, Tiis'i's AND Analyses 



Per Cent Solids of Evaporated Milk (Continued). 

The Beaunif DeLjrees at <)0 Deg-rees F. are Indicated in the 

Horizi/uital Line at the 'I'lip. Tlie I'er Cent C)t' Fat is Shown 

m the WTtica! C'ulinnii at the Left. 







Beaume 


reading at 60 degrees Fahrenheit 








10.0 


10.1 


10.2 


10.3 


10.4 


10.5 


10.6 


10.7 


10.8 


10.9 


FAT 






















PER 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


Solids 


CENT 


per 


per 


per 


per 


per 


per 


per 


per 


per 


per 




cent. 


eent. 


cent. 


cent. 


cent. 


cent. 


cent. 


cent. 


cent. 


cent. 


6.0 


25.65 


25.85 


26.05 


26.25 


26.45 


26.65 


26.85 


27.05 


27.25 


27.45 


6.2 


25.89 


26.09 


26.29 


26.49 


26.69 


26.89 


27.09 


27.29 


27.49 


27.69 


6.4 


26.13 


26.33 


26.53 


26.73 


26.93 


27.13 


27.33 


27.53 


27.73 


27.93 


6.6 


26.37 


26.57 


26.77 


26.97 


27.17 


27.37 


27.57 


27.77 


27.97 


28.17 


6.8 


26.61 


26.81 


27.01 


27.21 


27.41 


27.61 


27.81 


28.01 


28.21 


28.41 


7.0 


26.85 


27.05 


27.25 


27.45 


27.65 


27.85 


28.05 


28.25 


28.45 


28.65 


7.2 


27.09 


27.29 


27.49 


27.69 


27.89 


28.09 


28.29 


28.49 


28.69 


28.89 


7.4 


27.33 


27.53 


27.73 


27.93 


28.13 


28..33 


28.53 


28.73 


28.93 


29.13 


7.6 


27.57 


27.77 


27.97 


28.17 


28.37 


28.57 


28.77 


28.97 


29.17 


29.37 


7.8 


27.81 


28.01 


28.21 


28.41 


28.61 


28.81 


29.01 


29.21 


29.41 


29.61 


8.0 


28.05 


28.25 


28.45 


28.65 


28.85 


29.05 


29.25 


29.45 


29.65 


29.85 


8.2 


28.29 


28.49 


28.69 


28.89 


29.09 


29.29 


29.49 


29.69 


29.89- 


30.09 


8.4 


28.53 


28.73 


28.93 


29.13 


29.33 


29.53 


29.73 


29.93 


30.13 


30.33 


8.6 


28.77 


28.97 


29.17 


29.37 


29.57 


29.77 


29.97 


30.17 


30.37 


30.57 


8.8 


29.01 


29.21 


29.41 


29.61 


29.81 


30.01 


30.21 


30.41 


30.61 


30.81 


9.0 


29.25 


29.45 


29.65 


29.85 


,30.05 


80^6 


30.45 


30.65 


30.85 


31.05 


9.2 


29.49 


29.69 


29.89 


30.09 


30.29 


80,49 


30.69 


30.89 


31.09 


31.29 


9.4 


29.73 


29.93 


30.13 


30.33 


30.53 


80.73 


.30.93 


31.13 


31.33 


31.53 


9.6 


29.97 


30.17 


30.37 


30.57 


30.77 


80.97 


31.17 


.31.37 


31.57 


31.77 


9.8 


80.21 


30.41 


30.61 


30.81 


31.01 


31.21 


31.41 


31.61 


31.81 


32.01 


10.0 


30.45 


30.65 


30.85 


31.05 


31.25 


81.45 


31.65 


31.85 


32.05 


32.25 


10.2 


30,69 


.30.89 


31.09 


31.29 


31.49 


81.69 


31.89 


32.09 


32.29 


32.49 


10.4 


30.93 


31.13 


31.33 


31.53 


31.73 


81.93 


32.13 


32.33 


32.53 


32.73 


10.6 


31.17 


31.37 


31. .57 


31.77 


31.97 


32.17 


32.37 


32.57 


32.77 


32.97 


10.8 


31.41 


.31.61 


31.81 


32.01 


32.21 


32.41 


32.61 


32.81 


33.01 


33.21 


11.0 


31.65 


31.85 


32.05 


32.25 


32,45 


32.65 


32.85 


33.05 


33.25 


.33.45 


11.2 


31.89 


32.09 


.32.29 


32.49 


32.69 


32.89 


33.09 


33.29 


33.49 


33.69 


11.4 


32.13 


32.33 


32..53 


32.73 


32.93 


33.13 


.33.33 


33.53 


33.73 


33.93 


11.6 


32.37 


32.57 


.32.77 


.32.97 


3.3.17 


33.37 


33.57 


33.77 


33.97 


34.17 


11.8 


32.61 


32.81 


33.01 


33.21 


33.41 


33.61 


33.81 


34.01 


34.21 


34.41 



Chkmical Tests and Analyses 363 

Gravimetric Determination 

Dilute a measured ijortion of a 40 per cent solution with an 
equal volume of water, use 5 c.c. of tlie diluted mixture, correspond- 
ing to 1 gram of the evaporated milk and proceed as directed under 
"Milk." 

Ash. 

Ignite the total solids at very lo\\' redness, cool, weigh, see 
"Milk?" 

Proteids. 

Use 5 c.c. of a 40 per cent solution, deternnne nitrogen accord- 
ing to the Gunning method as directed under ".Milk," and multiply 
result l.)y 6.38. 

Lactose. 

Dilute 10 grams of a 40 per cent solution to ahout 40 c.c. and 
add .6 c.c. of Fehling's copper solution ; nearl)- neutralize wdth 
sodium hydroxide, make up to 100 c.c, illter through dr_\- filter, and 
determine lactose in an aliquot as directed under "}ililk.'' 

Fat. 
The Modified Babcock Method.' 

Carefully weigh 4.5 grams of well-nn'.xed evajjorated milk into 
the 8 per cent test bottle. Add one 17.6 c.c. pipetteful of water. .-\dd 
17.5 c.c. of suljjhuric acid and shake until the curd in the test bottle 
is comjjletely dissolved. Whirl at usual speed (one thousand revo- 
lutions pjer minute) for five minutes. Alix equal portions of water 
and sulphuric acid in glass beaker. For one or two tests, one 
pipetteful of water and one acid measure full of acid are sufficient. 
Fill test bottle to slightl}- below the bottom of tlie neck with the hot 
diluted acid. Whirl for two minutes. If the fat collected at the 
base of the neck is not clear, shake the bottle until all the curdy 
matter is completely dissolved, fill the bottle to about the 8 |ier cent 
mark with hot mater, whirl for one minute and read the test at 135 
degrees F. The fat column must be read from the top of the upper 
meniscus to the bottom of the lower meniscus. Multiph' the reading 
by 4. This gives the correct per cent of fat. 

Instead of weighing 4.5 grams into the test bottle, a 4.3 c.c. 



1 Hunziker and Spltzer, Indiana Agricultural Experiment Station, Bulletin 
No. 134, 1909. 



364 



Chkmical Tests and Analyses 



jiipetle ina\ be used. After emptying the pipette into the bottle it 
should be rinsed twice and the rinsin,i;s discharged into the test 
bottle. 

For making ninnerous tests 'V 
from the same sani]ile it is advis- 
able to dilute the c^'aporated milk 
with equal parts of water, h\ 
weiglit ; then weigh nine grams of ■■_] " " B 
this dilution into the test bottle and 
add one-half pipetteful of water. 



The Roese-Gottlieb Method. 

Proceed as directed under 
"S\\-eetened Condensed Milk." 

MILK POWDER. 

Total Solids. 

\\ eigh 3 grams of the milk 
powder in a dr\ing liotlle or e"\'ap- 
nrating dish and place in drying 
oven at 100 to 105 degrees C. until 
cr)nstant weight is secured. 

Ash, 



Read from A to D 



■D 



pigr. Ill 

Reading- the Babcock test 



Weigh two grams of the milk powder in a weighed jilatinum 
dish and proceed as directed under "Milk." 

Proteids. 

ITse fi^•e grams of the milk jiowder and proceed as directed 
under "Milk." 

Milk Sugar (Lactose). 

Dissolve ten grams of milk powder in 'XI c.c. of water. Warm 
and stir until a satisfactory solution is ctTcctcd and proceed as di- 
rected under "Milk." and multiph- result bv 10. 

Sucrose. 

For the delermmation of sucrnse proceed as direcled under 
"Sweetened Condensed Milk." 



The AIojoNNitR Thst 365 

Fat. 

The Babcock Test Method. — Di^soKe ten c'rams of milk 
powder in 90 c.c. of water. Warm and mix until a comjilcte solu- 
tion is effected. Then proceed as directed under 'T^Iilk,'' and mul- 
tiply the result by 10. 

"Roese-Gottlieb Method. — Wei^h one L;Tam uf the powder 
in a 30 c.c. li]jped beaker. Kub up with 9 c.c. of water and 2 c.c. of 
concentrated ammonium hydroxid, di.t^est on steam bath until the 
casein is well softened and the whole resembles milk. Cool, transfer 
to Rohrig tube or similar apparatus, using 10 c.c. of 95 per cent 
alcohol for rinsing, followed, after shaking contents of tube, by 25 
c.c. of washed ethyl ether. Shake vigorously for one-half minute 
and proceed as in the determination of fat m sweetened condensed 
milk." 

Chapter XXXI. 

THE MOJONNIER TEST FOR FAT AND SOLIDS.' 

The Mojonnier test for fat and solids in milk and milk prrid- 
ucts represents the use of chemical apparatus and mechanical de- 
vices of a high degree of precision, ingeniously invented, scientific- 
ally modified and especially adapted for accurate tests of dairy prod- 
ucts. It offers methods of fat and solids estimations that combine 
the accuracy of official chemical analysis with the rapidity of fac- 
tory tests. It has been introduced in and is successfully used by 
most of the jjrogressive milk-condensing factories in the country, 
and it is admirably filling a long-felt demand for reliable and accu- 
rate methods of testing milk, condensed milks and milk powders 
and for standardizing these products under factory conditions. 

EQUIPMENT. 

Install the tester on a solid foundation in a room protected 
against excessive fluctuations in temperature. 

1. Tester for butter fat. 

2. Tester for total solids. 

3. Fat extraction flasks. 



'■ Directions furnislied tlirougli courtesj- of Mojonnier Bros. Co., Milk 
Engineer.s, Chicago. 



366 



The Mojonnier Test 



4. Eight 3^^-inch aluminum dishes without covers and with 
tall counterpoise which tares the eight dishes, for fat tests. 

5. Eight 3-inch aluminum dishes with covers and short coun- 
terpoise, for solids tests. 

6. Fat oven. Keep temperature at 135*^ C. 

7. Cooling chamber. 

8. Solids oven. Keep temperature at 100° C. 

9. 250° C. thermometer for solids oven. Have mercury bulb 

30 31 25 II 7 10 3 13 6 




23 17 16 29 14 15 19 10. 24' 

Tig. 112. Tlie MoJouBler tester 

Courtesy of Mojonnier Bros. Company 

fit snugly into brass mercury well. Brass mercury well must always 
form good contact with hot plate. 

10. 250° C. thermometer for fat oven. Observe same precau- 
tions as in (9). 

11. Vacuum gauge on main suction line, registers either or 
both ovens. 

12. vSolids plate. Must be level and held at 180° C. 

13. Fat plate. Hold at 135° C. 



The Mojonnier Test 367 

14. Rheostat for fat plate. Lever must make good contact 
with one button, not with two at a time. When right button has been 
found that maintains constant temperature, mark this point on rheo- 
stat rim. When starting tester each day, turn handle on full until 
temperature has risen to within right point, then turn back to previ- 
ously marked button. 

15. Rheostat for fat oven. Observe same precautions as in 
(14). 

16. Rheostat for solids oven. Observe same precautions as 
in (14). 

17. Rheostat for solids plate. Observe same precautions as 
m (14). 

18. Handle for centrifuge. 

19. Snap switches for each hot plate showing temperature and 
time for treating samples at various points. 

20. Power unit, consisting of vacuum pump, water circulating 
pump and motor for same. Keep pump filled to air cock with oil 
furnished with tester. 

21. Automatic burettes and cans holding the water, ammonia, 
alcohol, ethyl ether and petroleum ether, placed in the order in which 
they are used. E*ach division on burettes delivers the proper amount 
of the desired reagent for a single extraction. 

22. Hood, to be placed over fat dishes when evajiorating off 
ether. 

23. Legs, to be fastened to floor with lag screws. 

24. This side need not be fastened to floor. If necessary to 
take out power unit disconnect connections in rear of machine and 
move this part of machine forward. 

25. Chemical balance. Keep level, clean and handle carefully. 
Raise knife edges gradually and with care. Clean balance daily. 
Keep weights clean. When weights show signs of wear, order new 
ones. 

26. Cock, to exhaust vacuum from oven when cock (27) is 
closed. Must be kept closed when vacuum is turned on oven. 

27. Cock, that switches vacuum from main line into vacuum 
oven. Set of cocks at right is for solids oven, set of cocks at left 
is for fat oven. 

28. Hole in top of fat plate holder, conmiunicating with suction 



368 'I'm; AIo.ionnif.r Tkst 

^i 

fan. on ixiwcr unit. Run exhaust pijje on suction fan out (jf window 
and kec]) hood over the (hshes in ordei" to drive all ether fumes 
from room. 

2*^'. Stool, to he screwed tn floor. 

DIRECTIONS FOR OPERATING MOJONNIER TEST. 

Preliminary directinns fnr tests i>f Ixith ["at and Solids. 

(1) Wash solids dishes with warm water and fat dishes 
with gasoline. 1 )r}- ^\ith a tnwei antl place into heated \acuum 
o\-en for Tue minutes \\ith wacuum on. .\t the end of five minutes 
put these dishes into cooler and, with the pinnp still running, 
keep them there for ti\e minutes hefore weighing. [')>> nut turn 
off motor until last dish is weighed out of cooling chamber. 

(2) \A^hile dishes are being heated and cooled, wash 
pipettes with \\-ater, alciilml and ether and dry by a|:)plying 
\'acuum at exhaust cock tipon tester. Always use clean and 
dr)- ]iipettes for each dilterent sample. .\im ti > clean ])ipettes as 
well as all glassware, immediately after using. 

(3) It is ^•ery important to keej) extraction flasks clean. 
Wash these with warm water immediately after extraction is 
finished. Wash with ^\•ashing ]iiiwder and shot wdien necessar}'. 

(4)) After aluminium dishes ha\e been in cooler for at 
least I'lYC minutes, weigh accur.ately tn .0001 gram, using the 
proper counterpoise. Weigh sulids dishes with co\'er on. Fat 
dishes do not ha\-e co\ers. I'^at dishes should be cooled for 
se\'en minutes before being weighed. 

(5) Use weighing pipettes as follows: Fill fi\-e-gram pipette 
uj) to five-gram mark for butter fat, and one-gram pipette 
up to one-gram mark for total solids. If duplicates arc to be run 
fill two ])ipettes from the same sample. :\s pipettes are filled 
place lower end into cleaned and dry rubber tubes which are 
pressed u|)on knobs at ends and center of weighing cross. Either 
fu'c or less samples for butter fat or l\\v or less for total solids 
ma}- be pipetted imt. 

(6) Weigh the cross witli the ])ipettes containing the milk 
on chemical balance acciu'ately to .0001 gram. Run milk from 
pipette into proper tfask. or vvinch dish if makiuL;" solids test, 
d'he piiiettes may be distinguished l)y the number upon each 



Tin; AIojoxNiKR Ti'.si 360 

crciss. Replace pipette and \\eiL;ii aL;ain. 1 Jiti'ereiu'e in \\"<.-iL;lit 
f^'U-es weig'ht I'f ,sam])le. ]\e]jeal until all samples are run int" 
proper tlasks, and intw weii^hed solid, dishes if snJirK are diCter- 
mined al'oiL;" witli the fat. 

I'lir tat in Sweeteneil Cundensed Milk use a lix-c-iirani 
sanijjle. dMie h\e-i^ram jiijiL-ite delners a]'pri iximatel\" Uvt 
LjTams hetv.'een the li\-e-i;rani marls and the hast rif the Imwl ijf 
the pi|)etle. 

S'lnie iijieratiirs ])reter ti i mix J'JO grams nf sweetened cm- 
densed milk with 201) grams (if w^ater, weigliing these carefull\" 
upon a Uar\-ard tri]i scale scnsiti\"e h> A gram. In this ^^■as(; CLire 
must be exercised tn oljtain the exact weight "i li^ith milk and 
water and to stir these th' 'n aighl}' \'.ith glass or metal ri )d hefcre 
taking sanijjle. A tall tumhler. a (nie-pnund Imttle ^i- a Muart 
cup make good containers in which tn make mixture. .\ ten- 
gram sample nf this mixture is used. This is hest weighed out 
by using two five-gram pii^ettes on weighing cross. 

For total solids weigh out }< (.5000) to }i ('.7300) gram of 
this mi.xture. If tlie undiluted milk is uscd take as nearly (.2500i 
gram as possible. 

For regular 8 pier cent ])lain bulk ciuidenscd milk use sjinie 
size sam]des and treat same as e\'aporated milk. For 12 per cent 
superheated condiensed milk mix lUl.l grams milk with 300 j^rams 
water upon Har\ard trip scale. Weigh ten-gram sam])le I'f this 
mixture into flask fur fat and a t\\o-grani sam|jle iiitd solids 
dish frjr Solids. AIulti]d\' jiercentages obtained ]i\ f(.iur fiir cor- 
rect percentages, when a 1 t" 4 rlilution is made. 

FRESH MILK, SKIM MILK, WHEY, BUTTERMILK. 

Butter Fat Determination. 

( 1 ) Use the ten-gram pipettes fur measuring nut ten grams 
of milk into cleaned but not necessaril)' dried .Mojonnier extrac- 
tion flask. I'se rml}' ten-gram pijjcttes furnished with tester 
and do not use 10 e.c. pi])ettes. The pipette is graduated ti) 
deli\"er ten grams of milk after allowing all milk to run out 
and letting it drain fcir fifteen seconds longer, then Idowing 
geiitlv to remoA'e last drop. The pipette must be perfectly clean 
and dr}' before being used. Wash freijuentl)- with sulphuric acid, 
water, alcohol and ether to insure ha\-iiig a clean pipette. 



370 The Mo.tonnier Test 

(2) Make extractions exactly as in test for butler fat in 
condensed milk, excepting- that in second extraction only 15 c.c. 
of each ether need be used. 

(3) Percentage Initter fat is obtained by multipling the 
weight rif the extracted V)iitter fat by 10. 

(4) If an\' of these products ha\e soured badly, double the 
(.(uantity nf ammrmia in the regular extraction and shake until 
all particles are dissolved. 

Total Solids Determination. 

( 1 ) Determine total solids as in evaporated milk, excepting 
that a two-gram sample is weighed out, and no water need be 
added to spread the milk over the bottom of the dish. 

SWEETENED CONDENSED MILK, EVAPORATED MILK 
AND CONDENSED BULK MILK. 

Butter Fat Determination. 

( 1 ) Remo\'e flask from holder and run 4 c.c. water (one 
charge on water burette) into each flask. Be careful not to add 
more. Shake well until all of sample is mixed with water. This 
can be done without inserting cork. 

For Sweetened Condensed Milk, if not diluted with water, 
add 6 c.c. of hot water with a pipette. To get hot water place fat 
dish filled with distilled water upon solids plate. If sweetened 
milk has been previously diluted with water and a ten-gram 
sample has been used, it is not necessary to add water. 

It is ^•ery necessar}- to shake the flasks containing the sweet- 
ened condensed milk \ery thoroughly after the addition of each 
reagent. Sweetened condensed milk re(|uires more shaking 
than any other liquid milk ]iroduct. 

(2) Before replacing flask into holder, add Ijj c.c. c.p. am- 
monia. Shake well so that all of sample is well mixed with 
ammonia. This can be done without inserting cork. 

(3) i'\dd ''.s per cent alcohol up to base of top bulb of ex- 
traction flask. Insert cork, using best qualitv c<irks onlv. Re- 
place flask into flask holder. Shake thoroughly and see that no 
milk adheres to any part of flask undissoh'ed. In case particles 
of milk stick to side of flask, shake thoroughlv until these are 



Thf, Mojonnikr Ti'ST 371 

washed away. It is "f tlie utmost importance to sliakc thor- 
oughly at this point. 

(4) Add 25 c.c. ethyl ether, insert cork and shake vig"orous- 
ly, lengthwise of flask, with liquid in lar,t;e hull) fA fla^^k, and 
small bulb extended upward. Stop shaking at end of fix-e seconds 
until all liquid has run into large bulb and rejieat \-igorous shak- 
ing for four five-second periods. 

(?) Add 25 c.c. petroleum ether and shake in same wa}'. 

(6) Place extraction flasks into centrifuge anrl whirl for 
tiiirty turns at speed uf abr)ut W) \<. 1'. AT. Dfjuble time fr.r 
sweetened condensed milk. 

(7) Place four 3^/,-inch dishes in line on shelf adjoining hot 
plate, keeping them in order in wdiich their weights \\-ere posted 
upon record sheet. Aim to hri\-e numbers iin flasks correspond 
with numlier of dishes. 

(X) Pour ether extraction to di\"iding line into projjer dishc; 
and slide dishes o\'er onto hot i)late, which should be held at a 
tem|)erature of 1,^5 degrees C. as indicated by thermometer in- 
serted in nickel plated mercur\- well. 

i'>) Repeat the extraction, adding first alcohol enough to 
bring line close up to toji of small neck of llask, then 2? c.c. 
ethvl ether, and then 25 c.c. petroleum ether, and shake A-igorou«- 
ly after the addition of each of abo\e three reagents for four 
5-second periods. 

flO) AVhirl in centrifuge for thirty turns, 

fll) Move aluminum dishes Ijack upon shelf adjoining hot 
plate and pour the secc)nd extraction into proper flishes. Xe\-er 
pour extraction intcj hot dish. Remo\e dish from hot plate a^ 
soon as ether is all e\'aporated. 

(12) When all of ether has evaijorated ]j!ace dishes into 
vacuum o\en, which should ha\'e a temperature of 1,^5 degrees 
centigrade. Keep them there for five minutes after the vacuum 
gauge shows at least twent\'-t\\o inches of \acuum. 

(13) Place dishes int(j colder for se\"en minutes, with pump 
outfit running. See that water is running through cooling plates. 

(14) Place counterpoise for dish and the approximate 
weight for fat on right hand balance pan. 



372 The. MojonniEr Test ^ 

(13) Transfer dish to left hand balance pan and weigh 
(|uickly to- 0.10 millio-ram (0.0001 gr.). 

(1(1) AA'eiglit of fat di\-ided li)' weight of sample taken, 
multiplied b}' 100, represents per cent butter fat. 

Total Solids Determination. 

(T ) The temperature of the iK^t plate in tlie s(Tlids vacuum 
ri\-en must lie 100 degrees C. The temperature of the outside 
solids plate must be 170 degrees to 180 degrees C. 

(2) To weighed milk in solids dish add aliout 1 c.c. water 
and distribute mixture eA'enly o\-er l)ottom of dish. For s^\•eet- 
cned condensed milk use hot water. 

(3) Place not more than two dishes at once upon hot plate, 
which must he perfectly IcA'cl. Allow all \'isible moisture to 
c\-aporate. During the CA'aporation turn the dishes around with 
crucible tongs, sIoavIv, so as to produce an eyen boiling o\-er the 
whole bottom surface of the dishes. The dishes must be wratched 
carefully during the eA-aporation. This step should require not 
more than two minutes. The end point is reached when bubbling 
and crackling ceases and sample shows first trace of brown. 
A'igorous boiling without spattering and complete CA-aporation 
are fundamentally essential. 

(4) Place dishes into A-acuum OA'en, A\-hich must be at 100 
degrees C, and turn on the A-acuum. ITeat for ten minutes. Tn 
the case of sweetened condensed milk keep it for t\A-enty minutes 
in \-acuum o\-en. The gauge should register not less than 
tA\'entA'-tAA'o inches of \acuum. If for auA' reason a-ou cannot 
olitain at least tAAcnty-two inches of \acuum then leaA-e dishes 
in OA-en for twice the regular time. 

{?) ]\emo\-e from OAcn and ]ilace into cooler AIIoaa' dishes 
to cool for fiA'e minutes. 

(6) \A''eigh dishes with covers on in the same manner that 
the butler fat dishes were weighed, being careful to weigh 

ipiickly and \'ery exactly. 

(7) A\'eight of dry solids di\-idcd by weight of milk taken, 
multiplied 1)A' 100 represents per cent total solids. 



Thi', M(j_[onnikk Tksi 373 

POWDERED MILK AND MALTED MILK. 

Method of Sampling. 

^li.x the sani])le thijrnuohly, niakinq- sure tliat it is sufficiently 
pul\-erized and representati\'e rif the entire Irit t^ be tested. Trans- 
fer the pid\"erized samfilc pr(im|)th' t<> a sealed jar. ]\[ix liefore 
remo\-ing' portions fnr testing-. 

Butter Fat Determination. 

il) \\'eiL;ii riut rapidl)-. to pre\ent ahsrirptinn fit moisture 
fmni the air. a.hrmt iine v.'rani nf milk po\\-dei- int^ i fnitter boat. 
Tn case of malted milk, weigh out a 0.5 gram sample. 

(2 I ,\dd N.,^ c.c. I if liot water tn llask. Insert cnrk. ITeat 
llask in water Ijath and shake thormighl^- mitil the samide is 
well mi.xed. 

(3) ,\dd 1.."^ c.c. 1 1 me charge l ammonia, and shake thor- 
oui;"hl\-. 

i4i ,\dfl alcohiil lip t'l line on -mad neck r,f flask, fnsert 
cnrk. Re|dace flask intn flask Imlder. Shake flask tlmninghlv 
with ciirk iiisei'tcd. L'^e liesl i"|ualitA' cnrk nnh". 

( .^ i Cnol flask I)}- ninniriC;' cold water o\"ei" l'"iA\-er end cif 
extraction tiask, if flask is very hot. This is not ordinaril}' 
necessary'. 

(6) .Vdd 25 c.c. ethyl ether. Insert cork, shake vigorousl}' 
until all butter is dissdh-ed out iif Imat. Then add 2? c.c. pe- 
troleum ether and repeat operation. 

(7) Centrifuge flasks, turning handle thii'ty turns after cen- 
trifuge has reached a speed of about 600 R. P. 'SI. 

(8) Pour of¥ extractions into proper, weighed 3;'^-inch alum- 
inum dishes. Ixepeat abo\-e extraction, arlding first alcrihol. then 
2? c.c. i")f each ether. Exceptin.g for \-ery accurate \\-ork a third 
extraction is not necessary. 

The second extraction will remo\-e all but .10 to .1,^ per cent 
of the butter fat. For factor\- control work this would be a good 
margin of safet}". 

(9) t^-aporate ofl-' ether at 133 degrees C. on "fat plate," 
and when all of ether is ofi^, dry fat in fat o\-en held at 133 de- 
grees C. for five minutes after the ^■acuum has reached at least 
twent}'-t\\"0 inches. 

(TO) Cool, weigh and calculate jier cent butter fat. 



374 BACTKRioLoc.tCAiv Analysks 

Total Solids Determination. 

(1) Use .3(K)0 i^ram sam|)lc. Add 2 c.t:. distilled \\-ater to 
the sample in this disli. Mix milk imwdcr and \\atcr tlmroncrhh- 
w itli the blnnt rod. 

(2) Continne the determination asnnder e\aporated milk, 
hilt continne heating;' in the ^"acnnnl o\en for t\\•cnt^' minntes. 

Chapter XXXII. 
BACTERIOLOGICAL ANALYSES. 

AVhile it is ob\'ionslv bevond the scope and purpose of this 
volnme to discuss in detail the techniciue of bacteriological 
anal}'ses and microscopic ]irepar;itions of the milk jirodncts de- 
scribed herein, it is deemed ad\-isal)le t<i ofter some suj^^cjestions 
that may serve for guidance of those who are not familiar with 
bacterial fermentations in condensed milk. 

Sampling. — Take samples of all itroducts contained in open 
receptacles, such as fluid milk, plain condensed bulk milk, barreled 
sweetened condensed milk and milk powder, in sterile, cotton 
plug-ged test tubes, or in small sterile glass-sto]-)pcred bottles, 
and keep them in a ci.ii)l place, iireferabh' not abo\-e ,v"^ degrees 
F. until ready to \ise. Keep canned condensed milk sealed in 
the original package until ready to use. If alread)' o]ien, invert 
a petri dish or a beaker over the can to a\-oid contamination 
U-om the air. 

Dilution for Numerical Counts. — Afakc dilutions in 2^0 c.c. 
glass-stoppered flasks. r>efore opening sealed cans, thoroughly 
wipe ofl.' the entire t(.ip \\ith a sterile piece of cheese cloth soaked 
in a saturated sr)liiti(~in of mercuric bichloride or a ,s pe^- cent 
solution of carbolic acid and flame the top of the can. Hpen 
evaporated milk cans bv punching a hole into their top, large 
enough to insert the discharge end of a graduated pipette. Open 
sweetened condensed milk cans with a sterile knife or a sterile 
can opener. 

In the case of fluid milk and evaporated milk, measure with 
a sterile graduated pipette two cubic centimeters oi the product 
and l'^(S cubic centimeters of sterile water into the J?,^0 c,c, flask. 
In the case of pkiin condensed bulk milk, sweetened C(^ndensed 



Bac'iicrioi/jgical Analyses 375 

rnilk aiifl milk pnwder, usc'tarcrl fla'-ks linldiiiL'; aliont 130 cubic 
centimeters, weit^ii intn them twn ,^"rams uf the prrjduct ami add 
enout^ii sterile water at a temperature cif '>^ d.eyrees F. to make 
up 100 cubic centimeters. Use a sterile spcicm cir spatula t" 
transfer the jirriduct to this llask. A vx ide-Tin luth flask is 
preferable. 

'J"he abine repi'eseiits the hrst dilutinn. The flask should be 
carefull}' shaken until a homogeneous mixture is obt-;iined and 
the soluble portions ha\'e been completelv dissol\-ed. 

1^'rom this dilution further dilutions are made in sterile 
water in L;1ass-stop]iered flasks, according;' ti i reipiirements. The 
dilutions shoidd be sufficient to limit the number of colonies on 
the ])lates to about .^O to 100 per jjlate. Whole milk, as it arrives 
at the factory, usually sh..\vs from 100,000 to 1.000.0<")0 bacteria 
per c.c. i{\api irated milk should be iiractically sterile unless the 
can sh'iw's siccus nf fermentatii in in wddidi case the number of 
bacteria jiresent will depend on the age of the sample can; 
dilutinns as hiidi n.s 1:1,000. (JOO are reci^mmended in such cases. 
I'lain condensed bulk milfc ^\■hen fresh contains frcim about 
1,000 to KJO.OOO 1)acteria ])er c.c, when several days old and in 
the absence of refrigeration, its germ content is often much 
greater. Sweetened coiulensed milk a\-erages from about 500 to 
,^00,000 bacteria per c.c. 

Plating. — loir ])!ating the fallowing media are recommended: 

Meflia for 'J'cjtal Counts and also for acidifiers 
4 grams beef extract 
10 grams jjeptone 
30 grams lactose 
4 ,grams sodium chloride 
12 grams thread agar 
1000 c.c. distilled water. 
;\cidity 0.1 per cent. 

For acidifiers add 1 c.c. of sterile litmus solution to each 
plate before pouring the agar. 

Media for Liquefiers 

4 grams Ijeef extract 
10 grams peptone 



o 



376 Bactkrioi^ogical Analyses 

oO grams lactose 

4 o-ranis sodium clilnride 
130 grams gelatin 
1000 CO. distilled water. 
Acidit}- 0.1 per cent. 
-Media for ^' easts and Akilds 
4 grams l^eef extract 
10 grams peptrme 
12 grams agar 
1000 grams whe}' 

Acidit}^ 0.2 |)er cent. 

.-Veld 1 c.c. of sterile one per cent tartaric acid solution t 
each plate before pouring the medium o\er the dilution. 

Incubation. — lncul:)ate agar, litmus agar and ^^hey agar 
plates at o."! degrees C. {'h degrees F.) fur at least three davs 
before making counts. Incubate gelatin plates at 21 degrees C. 
(70 degrees V.) for fovu- tn five days before making cunnts. 

Making Counts. — The colonies on the plates are counted 
most ci in\-enienth' b\- ])laciug the plates o\'er a standard countiny" 
l)late. In the absence of such a plate, place the ])etri dish upsid 
down on a dark surface and draw, with a blue cra)on, radial lines, 
<li\iding the field into segments. For plates cmitaining nut to 
e.Kceed 100 colonies eight to si.xteen segments are sufficient for 
easy diunting. 

Qualitative Determinations. — Numerical counts cm the four 
kinds of media recommended alio\e usually furnish a fair general 
idea of the types of bacteria present. 

For the detection of gas-producing species, nutrient bouillon 
containing three per cent lactose and three per cent sucrose, re- 
specli\'el\', in fermentation tidies, or nutrient agar containing 
three |>er cent lactose and three ])er cent sucrose, respecti\'ely, 
in test tubes, are serviceable. 

Cans of sweetened condensed milk that show gaseous fermen- 
tation (swell heads) are usually due to certain species of yeast, 
which thrive best in media containing sucrose. 

Cans of evaporated milk that show gaseous fermentation 
(swell heads) are usually caused by anaerobic putrefactive bac- 



e 



BaciKrioloi.k'al ANALYsr-:s 377 

teria, of which I'lcctridiiim f'letidiiiii i-- a iivi^t f)'e']iient rcpre- 
sentati\'e, see "lUown E\'aporated Alilk," Cliapter XXIII. This type 
(if micro-i ji-c:;aiiisnis rcfpiires stridlv aiiaei-dhic cultural cnudition^. 
L'uder limited hiln >r;]_t<tv\ facilities the anaernldc coiulitii'ii^ are 
he'-t ])rndueed In- the use (if ri.wj^eu-al)-' irliiii'.'; chemicals, su(di as 
p\ !"( loalh il td which ])(itassium li\ di-o.xifle i^ add'i-d. I'se dr\- 
(■(inimercial p\r' icjalh il and ]i(ita^^ium h}"dr(i:;ide -ticl->. m pfi- 
]i( rtidii (if 1 L^M'am p\T( ii:(alli il ti i .7 L;ram ]>( if assiun^i lix'ili'i .xirle 
dissdhcd in .alxiut 2 c.e. nf water. 

I'lace 50 L;"rams nf p_\ri iii^alli il intc the Imtt'im part >if a larLje 
•-ize desicca.t( ir. Ila\'e the rim uf the 'le-iccatcr and ;he cor- 
respdudint: rim nf the c(i\ei- C(>\"erc(l with a mixtm"e nf half 
]iaraffine and half bee's wax. I'liur inln the i)\n-( ii^alli d in tin- 
desiccator K)f) c.c, of water and then throw in ,v~ e.rnnis of 
pota'-^ium h\'di-o.\ide. Onickl\- insert culture tuhes, rir jilate-, 
and close the desiccator with the C(>\er. turniuL;" the cic.er -o as 
to secure a jierfect seal. .\f)pl\- three permanent scr(w\' (d.amjis. 

.Anaeroldc ;_;x'rms of the t\'])e ol I'lectndium foeti'lum f/row 
hest in freshly sterilized milk. In the case of I'lectndium foeti- 
dnm the milk hrst curdles, then digests, formnpc." a clear yellow 
licpud. The dicj'cstion he^^in^ at the surface and proceeds down- 
ward, ddiese cultures ckwelop a nio-t penetrating" foul odor. 
rcsemhiiuL;- that of sfjoiled e^i^s.' 

The technique and methrjds for rletermining the liacteri- 
olo,L;acal flora with reference to cultural and nior[)ho|o'^acal 
(diaracteristics of infli\idual sjieeies of microhes ])resent, arc 
identical to those tiserl in the liacteriokn^ical stud\- rd milk aiul 
other similar products, anrl which are full}' descrihed in standard 
manuals on hacterioloyv. 



1 For further (details on the teclinique of Anaerobic Cultures .see Hunziker 
Review of Existing Methods for Cultivating Anaerobic Bacteria. .Journal of 
Applied Microser.py and Laboratory Methods. A^ol. Y, Nos. 3, 4, 5, 6, 



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•- ^ St-, 









nJ "i* d 



I ^ c 



c; 0. C 

•a J cj 
^- aj cj 






^ Oj 'I' 0^ 

C p C 



i S 01 c 



o is "i 



380 CoNDIilNSKD j\IlI,K AND IVJlI.K [^OWni'lR 

INDEX 



tnr 168 

I'.uildiiiK and equipment for con- 

denseries 33 

liidk milk 162 

r.uttcrlat 



A Burtovak process 288 

A, ■-i^„t, „, ,,-■ i cic lUidii\ak rapid circulation evapora 

Accidents, prevention ot vb , .. ' ' 

Acknowledgments 14 

Acid tests 50 

Addition of sugar 63 

Adulterations 271 

Advertisements . 384-424 _,^ ,5 , 

Agitation of sweetened [ ,^ ^^7 j^g ISutterfat test 54 

condensed milk I d »t -u -i- 1-- 

..,.,. •• ,,9 Buttermilk, composition 1// 

/\ir ciiscnarse oiw 1 1 ^^ -n j ttr\ 

.. ■ ^ , ^ nn liuttermilk powder 330 

Air intake 312 , ' , ,-,, 

, ,, . ,.^ annual output 331 

Albumin 346 •.• 1-,, 

,,.■. , 00 00 Oi-i composition 331 

Altitude 88, 89, 90 ,- , , , , 

, , . ,^ ' ',,v manutacture 332 

Anacrohic cultures 3// 1, ,, * j j j 

, , o ■ 1-^ 1 J -Kfii ,-> oi liuttons m sweetened condensed 

.\nglo-bwiss Condensed Alilk Lo.... 21 niilk 2^7 ^41 

-Annual production of — p ■ ' ' ' i, "^3 

, ^^ ' ■,, , ,,, L.iivmg milk 43 

Liutterniilk powder 331 p tj i * d n o- 

, J 1 1, -11 lOA bv-rrotlucts Kecoverv Co 2: 

condensed buttermilk 184 

condensed milk 26, 29 Q 

cream powder 278 . , 

malted milk 335 Calcium m milk .253 

milk powder 278 Campbell process 166, 279 

Antineuritic vitammes 215 Cane sugar iin' 1V1 

."-Vntiscorbutic vitamines 216 ,,^"^ ^-"^' ^^\ 

Can testers 135 

Can w ashing 56 

Care of milk in factory 57 

Casein 346 



Antixerophthalmic vitamines 215 

.Arrangement of machinery 41, 42 

Ash. . 203, 208, 344, 355, 363, 364 

Aspergillus repens 238 ,, . ,. , ^„ 

Atmospheric pressure 88, 89 basing machines 189 

C atch-all 82 



B 



Chemical analyses 342 

of e\aporated ' milk 358, 370 

Bacillus paiiis 265 of malted milk 373 

Bacterioligical analyses 374 of milk 342, 369 

Bacteriological media 375 of milk powder 364, 373 

Babcock test 351, 365 of sweetened condensed milk. 353, 370 

Barometric condenser 77 Citrates in milk 253 

Barrels 110 Coils in pan 72, 73, 74 

licet sugar 63, 64 Composition of — 

Beaume hydrometer buttermilk 177 

'''9. 100, 101, 122, 353, 358 buttermilk powder . . : 331 

Beriberi 215 condensed buttermilk 184 

Bicarbonate of soda 147, 156, 157 exaporated milk 205 

Bitter evaporated milk 263 milk powders 315 

Blow-down valve 76 plain condensed milk 208 

Boiling point at different vacua... 86, 87 sweetened condensed milk 200 

Boiling test 51 Cuncenlrated milk 166 

Bolting 315 Concentration, . ratio of 96, 165, 182 

f^orden, Gail 18 Condensed buttermilk 176 

Borden's Condensed Milk Co 21 Condensed milk — 

Borden patent 18 annual production in U. S 26, 28 

Brands of condensed milk 196 in different countries 29 

Brown e\aporated milk 269 cost of manufacture 217 

Brown sweetened condensed milk. . .251 defects 222 



CONDIiNSF.D AIlI^K AXJ) AliLK ['uW'lJiiR 



381 



digestiliility 212 

factories in U. S 28 

histor\- .'ind dc\elopiTient 17 

• liuritv 211 

stanriarcls 210 

\'itaminc properties 215 

Condensers 76-82 

Condensery lloors 33 

Condensing. . ..6S, 119, 163, 173, 179-184 
Continnous concentrators. . .25 167, 171 

Cooling 103, 129, 165. 174 

Cooling in sterilizer 143 

Correction of Beaume 100, 122 

Cost of inannfacture 219, 329 

Cream Production Co 25 

Curdy evaporated milk 253, 259 



Defecti\'e plain condensed milk 252 

lumpy 252 

gritty 270 

Defective evaporated milk 252 

bitter 263 

brown 269 

curdy 253 

fermented 258 

grainy 257 

metallic 271 

separated 258 

Defective sweetened condensed milk. 222 

blown 242 

brown 251 

buttons in 237 

cheesy 231 

fermented 242 

lumpy ' 233 

metallic 251 

putrid 250 

rancid 249 

sandy 223 

settled 228 

thick 231 

Desiccating chamber 309 

Distribution of heat in sterilizer 138 

Dome 75 

Dough-drsing processes 271" 



Drainage in condenseries. 
Dried buttermilk 



35 
, 330 



E 

Ekenljerg process 286 

Equipment for condenseries 39-41 

Evaporated milk 117 

analyses 358 

behavior toward heat 158 

composition 205 

condensing 119 

control 140 



crjoling 129 

cost of manufacture 221 

rilling 132 

heating 118 

homogenizing 124 

incubati'in 162 

scalmg 134 

shaking 159 

^tandards 210 

si.andardizing 123, 339 

sterilizing 136 

\ iscosil}- tests 145 

E.xpansinii tank i^2 

Exjif.rt^ 198, 199 

F 

h'actory sanitation 54 

Fat-soluble \itammes 215 

Fat standard for export 211 

Federal standards 210, 335,378 

Fermentation tests 53 

Fermented c\aporated milk 262 

F'ernienlcd sweetened condensed 

milk 242 

Filling evaporated milk 132 

F'illing machines 110 

Film-drving processes 280 

Fhj.ir plans 35-39 

Flux 115 

Fractir>nal sterilization 144 

G 

<iaseous fermentations 242, 266-268 

Gas generators 115 

Gas supply 115 

''.athmann process 2H3 

liaulin homogenizer 126, 127 

r.ebee seal Ill 

Cdass-liiied tanks 47, 57, 58, 131 

(jIucosc 273 

Go\ers iirocess 287 

Grainy evaporated milk 257 

Gray processes 297, 299, 302 

Grimwade process 277 

C,ritty plain condensed milk 270 

Gunning method 344 

H 

I latniaker process 282 

Ffcating milk 59-62, 118 

Heating the air 308 

Hebe product 216, 272 

Helvetia Milk Condensing Co 22 

I I igh pressure pumps 107 

Holding tanks 130, 131 

Homogenizers 127 

Homogenizing 124, 129 

Hotwells ol 



382 



CoNDKNsiiD Milk and Mii,k Powder 



Imitation e\Hporatcd milk 216 

annual output 273 

Imports 198, 199 

Incubation 162, 376 

Index to advertisers 384 

Inder to contents 380-383 

Insects in milk powder 328 

inspection of cans 187 

Insulation of piping 42 



Jacket in pan 71 

John Wildi Evaporated IVIilk Co.... 24 
just process 281 

K 

Keeping quality of — 

malted milk 334 

milk powder 325-328 



Labeling 187 

Labeling machines 187 

Lactose 202, 208, 347, 356, 363, 364 

Legal standards of dairy products by 

states 378, 379 

Loading the sterilizer 138 

Locations for condenseries 29 

Lumpy milk powder 328 

Lumpy sweetened condensed milk... 

233-236 

M 

McDonald seal Ill 

McLachlan process 292, 294 

Making bacterial counts 376 

-Malted milk 332-335 

Marking cases 190 

Market prices 196 

Markets 184, 194, 195, 329, 334 

.Mercury column 75 

.\lerrell-Merrell-(;ere process 294 

.Metallic e\aporatcd milk 270 

.Metallic sweetened condensed milk.. 251 

Meyenberg, John B 23 

Milk analyses 342 

Milk inspection 49 

Milk powder 276-335 

.Milk powder factories 278 

Milk prices 45 

Milk quality 47, 48 

Milk solids 201, 205, 358 

Milk sugar 202, 208, 347, 363, 364 

Milk supply 30, 43 

Milk trap 82 

Mineral matter 203, 208 



Miscibilitv 320 

.Modified Babcock test 356,363 

.Mojonnier evaporated milk control.. 145 
.Mojonnicr test for fat and solids. .. .365 

N 

Xailing machines 189 

Xestle-Cham Condensed Milk Co... 21 
New York Condensed Milk Co... 20, 21 
.N itrogen determination 343 



operation of pan 94 

P 

Packing 183, 189, 315 

for export 191 

Passburg process 284 

Percy process 291 

Phosphates in milk 253 

Pilot sterilizer 142, 143 

Plain condensed bulk milk. 162-165, 208 

Plating 375 

Plectridium fcetidum 267 

Polyneuritis 215 

Precondensing for drying 303-307 

Preface 7, 8 

Preheating 163, 173, 303 

Progress homogenizer 127 

Proteids .... 145, 202, 207, 354. 363, 364 
Putrid sweetened condensed milk.... 250 

Q 

Quality of milk 117, 163, 253 

Quevenna lactometer 342 

R 

Rancid sweetened condensed milk.. 249 

Rapidity of evaporation 91 

Ratio of concentration 96, 165, 182 

Retardation 152 

Recovery 307, 313 

Rim speed 173 

Rogers process 296 

Roese-Gottlieb method. 352, 356, 364, 365 

Ruff condensing evaporator 174 

Rust spots on labels 188 

s 

Sampling sweetened condensed milk. 102 
.Sandy sweetened condensed milk... 

223_?28 

Sanitary can '.'.'. .110, 111, 112 

Science and practice of evaporation 

in vacuo 85 

Scurvy 216 

Sealing 112, 134 

Sediment test 52 



Condb;n-sed Milk and Milk Powdkr 



383 



Separated evaporated milk 258-261 

Settled sweetened condensed milk.. 

107, 228-230 

Sewatje disposal 32 

Shaking 159 

Shakers 160 

Size of cans in sterilizer 142, 156 

Solder 114 

Soldering devices 113 

Soldering flux 115 

Solder seal Ill 

vSolubility of milk powders 318 

Sour, curdled evaporated milk 262 

Specific gravity 

101, 123, 204, 208, ,342, 353, 358 

Spray-drying processes 290-315 

Spraying milk 309 

Spray nozzles 310 

Spray pumps 311 

Spy glasses 75 

Stamping of cans 186 

Standardizing — 

evaporated milk 123, 336 

fluid milk 339 

sweetened condensed milk. 118, 340, 341 
Standardization of sterilizing pro- 
cess 143 

Starting the pan 94 

Stauf process 291 

Sterilizers 137 

Sterilizing process 136 

Sterilizing sample cans 149 

Stopping reel in sterilizer 141 

Storage' 183-193 

Striking 96, 120, 164 

Sucrose 203, 357, 364 

Sugar 63-67, 203 

Superheating. 120, 141, 163, 225, 232, 261 

Surface condenser 76 

Sweetened condensed milk — 

analyses 353 

composition 200 

cooling 103 

cost of manufacture 220 

defects 222 

drawing off 103 

filling 110 

manufacture 59 

sampling 102 

standard 210 

striking 96 



.9-14 
..139 
, . 193 
. . 140 



Table of contents 

Tell-tale thermometers 

Temperature of storage 

Temperature in sterilizer 

Testing for density 178 

Testing for viscosity 150 

Thermrimetcr for vacuum pan 76 

Thick and cheesv sweetened con- 
densed milk ...." 231-233 

Tin shop equipment 41 

Total solids 

,343, 355, 359, ,364, 370, 372, 374 

Total solids tables 360-362 

Transportation 194 

Transportation facilities 31 



\'acuo, science and practice of evapo- 
ration in 85 

\ acuum breaker 76 

\'acuum gauge 75 

Vacuum pan 68 

\'acnum pump 83-85 

\'a[ior belt 72 

Venthole cans 133 

\'enthole fillers 133 

Ventilation in condenseries 34 

\'iscolizer 128 

V'iscosimeter 151 

\'iscosit_\' correction 152 

X'iscosity, factors influencing. ... 153-155 

Viscosity tests 150 

X'itamine properties 215-216 

w 

Water 201, 205 

Water-soluble vitamines 215 

\\'atcr supply 30 

Wet-vacuum spray condenser 78 

Wimmer process 279 

Wrinkles on labels 188 



Xerophthalmia 



.215 



Yeast 242, 376 



384 CoNKKNSi'.D Milk and Milk PowdKr 



INDEX TO ADVERTISERS 

Page 

American Can Co., New York 385 

Alois Aufrichtig Copper and Sheet Iron Mfg. Co., St. Louis, Mo. 386 

Bausch and Lonilj Optical Co., Rochester, N. Y 386 

Buffalo Foundry and Machine Co., BufFalo, N. Y' 387 

Burt Machine Co., Baltimore, Md 388 

By-Products Recovery Co., Toledo, 389 

.1. G. Cherry Co., Cedar Rapids, la 390 

Colonial Salt Co., Akron, 411 

Creanierj' Package Mfg. Co., Chicago 391 

Cream Production Co., Port Huron, Mich 392 

Davis-Watkins Dairymen's Mfg. Co., Chicago 394, 395, 397 

F. C. Dickerson Co., Chicago 393 

Dry Milk P^ngineering Co., Chicago 398 

Fngineering Co., Fort ^Yayne, Ind 399 

.1. B. Ford Co., Wyandotte, Mich 400 

(ieneral Laboratories, Madison, Wise 401 

Groen Mfg. Co., Chicago 402 

Arthur Harris & Co., Chicago 404, 405 

.Jensen Creamery Machinery Co., Long Lsland City, N. Y 403 

.tohn W. Ladd Co., Detroit, Mich 423 

Lathrop Paulson Co., Chicago 406 

Milk Drying Machinery Co., Chicago 407 

Mojonnier Bros. Co., Chicago 408 

Louis F. Nails, Chicago 409 

Pfaudler Co., Rochester, N. Y 410 

C. E. Rogers, Detroit, Mich 412, 413 

Rice and Adams Corporation, Buffalo, N. Y 411 

E. H. Sargent & Co., Chicago 414 

Schaefer Manufacturing Co., Berlin, Wise 414 

Sharpies Separator Co., West Cliestcr, I^a 415 

I>. Sonneborn Sons, N\nY Y'ork 416 

Spra>' Drying Corporation, New Yoi'k 417 

Sturges and Burn Mfg. Co., Chicago 420 

C. J. Tagliabue Mfg. Co., Brooklyn, N. Y 418 

Taylor Instrument Companies, Rochester, N. Y 419 

Tor.sion Balance Co., New York 420 

Union Steam Pump Co., Battle Creek, Mich 421, 422, 423 



Coxr)F.xsF,i) Milk axij ;\Iilk Powder 385 



CONTAINERS 

for 

Condensed Milk 

Evaporated Milk 

Powdered Milk 




AMERICAN CAN COMPANY 

120 Broadway, New York, N. Y. 

CHICAGO, ILL. PORTLAND SAN FRANCISCO, CAL. 

Monroe Bldg. ORE. MiUs BIdg. 



386 



CoNDliNSI'ln MlI,K AND MlI^K PoWDItR 



Efficiency and Economy 

ARE COMBINED IN THE NATIONALLY KNOWN 
"AUFRICHTIG" VACUUM PAN 

Our Slaiulnrd "()' G"" Pan will condense 10,000 pounds 
of milk in one hour with two coil and 12,000 pounds 
with three coil system. 

Investigate the econoniicallv operated Jacketed Hot 
Wells. 

\Ye manufacture complete equiijment used in Milk 
Condenseries and Dairies. 

Highest grades of materials and best of workmanship 
is put into our equipment. 

Write for specifications and prices. 

Alois Atifrichtig Copper & Sheet Iron Mfg. Co. 
Third and Lombard Streets Saint Louis, Missouri 




Model FFS8 



^auscH [omb 

Microscopes 

Standards of Optical and 
Mechanical Efficiency 

logical work. Has coarse and fine 
focusing atljustments, with adjust- 
ment heads on side of arm; two iris 
diaphragms, three objectives — includ- 
ing oil immersion — in revolving nose- 
piece; two eyepieces and an Abbe con- 
denser in quick-acting screw sub- 
stage. Number of magnifications ob- 
tainable ranges from 50 to ISUO. Con- 
struction is rugged, and hlaclt; crystal 
finish on arm and base unusually 
durable. 

^i'n'li: for calalotj dc^cribinij thi.^ 
and other models. 

Bausch ^ Ipmb Optical (5. 

NEW YORK WASHINGTON SAN FRANCISCO 

CHICAGO ROCHESTER, N. Y. London 

Leading Amcriran Makers 
of flii/h Grade Opliral Products. 



COXDEXSED IMiLK AND }\IlLK PoWDER 387 



Dry Milk Products 

Manufactured in 

''Buflovak'' Apparatus 

Tlie ''Buflovak" \'acuiiiji Drum Dryer is the 
ideal afjijaratus for convertiug rnilk into pow- 
der form. Tile milk is dried without the slight- 
est danu'i-r of overheating or contamination. 
Every part of the interior is accessible, and can 
be easily cleaned — a distinctive feature of the 
"Buflovak" Dr.yer. 

When considered in the light of steam con- 
sumption, drjdng speed, output, quality and 
drying cost, it is the most economical milk 
dryer on the market. Dries skim milk, butter- 
milk, malted milk and other liquids containing 
solids. 

The "Buflovak" Rapid Circulation Evaporator 
is (^specially adapted for evaporating milk and 
other delicate liquids. 

Vacuum Shelf Dryers for drying casein and 
other products in pans or traj'S. 

Catalog showing all types of "Buflovak" Dryers 
and Evaporators will be mailed on request. 

Buffalo Foundry & Machine C2^ 

20 Winchester Avenue 
BUFFALO, N. Y. 

New York Office: I7 battery place 



CoNDKNsKD Milk and Milk Powder 



THIS MACHINE 

Plays an Important Part in 
Milk Canning 

It labels as many cans a day as you require. 

Orders are fdled {)ronipLly and 
Storage facilities never overtaxed. 




THE BURT LABELING MACHINE 

Is used in the small as well as the largest plants because 
there is no other wa\ to label cans so fast, neat and cheap. 

It applies the label with a hot nioisture-ijroof cement 
which sets instantly, thus i)revenling the label from slipping 
while being wrai)])ed around tlie can and ensuring it always 
being applied tight and matched evenly at lap. No paste is 
put on Ihe can, so there's no possibility of the label discolor- 
ing — it always looks as though just i'roni the printer — that 
increases the sales value of goods. 

Let us tell you more about the Burl Labcler — what it does 
and wliN' you should not be with(Hit it. .lust stale size of cans 
used. 



BVRT MACHINE COMPANY 

Labelinf;, Wrapiiing and Casing IXIachines 

BALTIMORE, MD. 



CoxiJicxsico Milk axu AIilk Powdi-.k 



389 



The By - P?'oducts Recovery Co/z/pany 

TOO ( 'liaiiibiM' of Coiiiiiicri.'c ]5iiililin^' T o 1 i- ([ o . <") h i o 



Milk Products Department 

Autoiiiatic ( 'oiii-i'iiti'at(ii"s i'oi- ' " I'jS'Hpoi'atcd " Milk. 

■■Pr(-scrv,Mr- Milk, Dry Milk au.l 

Suiiar f>t' Milk l^'actorii's 

Wluile Milk, Skim Milk, BLillcrniilk and Whc.v liaiiidly and 

Iu'on()micall\' Heduced lo llitrli (loiui-ntratcs Without 

the Aid of ^'acllUlll I'unips, Condenscr-s, Water 

oi' Kxpeit r,abi)i- 




It is More Kcoiioiniail It is Less Complicated 

It is More Simple to Operate 

No Water Requirements Exceptinii for Cooling 

More ihuii 100 .Machines \oiv in Use 

l'"<)r I'artieidars Write 

The By-Products Recovery Co., Toledo, 0. 



390 



CONDlCNSi;]) MlIvK AND MiLK PoWDRR 



THE 

Cherry Condensed Milk Cooler 




Three Special Features 

1. K is eQuipped with the justly famous Cherrv Twin 
Coil. 

2. The coils are of special diameter to assure their being 
entirely submerged at all times, thus preventing the incor- 
poration of air into the product. 

3. It is equipped with a two-speed drive. This drive is a 
clulch pulley through steel cut gears. This equipment pro- 
vides for operating the coil on high speed for evaporated or 
plain condensed and on low speed for sweetened condensed 
milk. This feature is exclusive on this type of cooling vat. 



A Dependable Outfit 



Where contlensed milk is concerned the requirements call 
for a cooling system enabling the operator to maintain the 
desired variation in temperature between the product and the 
cooling medium and to save every minute of time it is pos- 
sible to save in handling the product. The Cherry Condensed 
Milk Cooler is designed to accomiilish this purpose and has 
proven its elliciency in some of the largest plants in the 
country. 

BUTTER MAKING EQUIPMENT 

For the Condenserj needing a complete Butter Making 
Oullit there is the Cherr> Line of Creamery Kquipnient to 
cover every re(]uirement. 

If you are considering the manufacture of butter, let us 
quote you prices on your needs. Ask for our special catalog. 

J. G. CHERRY COMPANY 

CEDAR RAPIDS, IOWA 

St. Paul, Minn. Tama, Iowa Peoria, 111. 



CoxiiF.NsF.i) ]\IiLK AXi) Milk Puwukk 



391 



The WIZARD 

Condensed Milk Cooler 




I u > * 'i' I't nl; 




DESIGNED particularly for the condensed 
milk trade. It is made extra deep. Coll 
is entirely submerged, thus preventing the incor- 
poration of air with the product made. 

Coil has two speeds, composed of shifting cut 
gears so that coil can be run on high speed for 
evaporated or plain condensed and on low speed 
for sugared condensed. 

Built eilher witti legs high enough to pennit a 10 gallon 
can beneath gate valve or on standard height legs as desired. 

It has the patented A\ izard Multiple Fei;d Coil either 
2" or 2V2" diameter as desired; large built-in brine box; and 
the latter can be htted with direct expansion coils when de- 
sired. Made in sizes from 300 to 1000 gallons, equipped 
for motor or belt drive. 

The Creamery Package Mfg. Company 

61-7 W. Kinzie St., Chicago 

Sales Branches EceryLcherc 



3'>2 



CnNKi-'.NsKi) Milk and A[7i,k PowdisK 



Ruff Milk Condensing Evaporator 




1920 MODEL NO. 7 

The Piufl' Milk Condensing Evii|)(ir;it(ir condenses milk at 
145 degrees temperature without use of vacuum, leaving the 
albumin milk solids soluble. 

Will make a superior quality condensed milk of all grades 
sold on the market, such as plain condensed and superheated, 
sugared condensed milk, sugared milk condensed for the 
chocolate trade, unsweetened evaporated, precondensing for 
milk powder, also buttermilk. 

A world beater in connection with your pan to prc-heat 
milk to 21(1 degrees for making sugared and unsweetened 
evaporated, a saving of I.t per cent to 18 per cent moisture, 
which is generalh- added when milk is heated with live steam. 

This evaporator is built of the best ijiaterial, neat in 
appearance, has a large capacity, economical in power and 
steam, and is a mone>-maker to ice cream manufacturers, con- 
denseries and creamei'ies. The saving on water and power to 
pump would soon pa\' for this entire eiiuipment. 

Apph' to 

THE CREAM PRODUCTION CO. 

PORT HURON, MICHIGAN Mfgs. for Unit.d Slales 



B. TRUDEL & CO. 



MONTREAL, QUEBEC 



Mfgs. for Canada 



CnMii;.\si'i) Mii.K A\ii AIii.K I'(iwdi;k 



393 



TheDickersonVent Hole Filler and Sealer 



Baby Machine 
for 6 oz. cans 



Tall Machine 11 Combination Machine 
for Ifi oz. cans || for 16 and 12 oz. 




TALL SIZF. 
Dickcrson Fillers give EFFICIENCY -ACCURACY ECONOMY 

They are THE WORLD'S STANDARD 

The cans have onl.\' a vent hole. Thc\ are filled and sealed 
eijntinuoush- and autoniaticalh on the same luachine. OXE 
MACHINE DOES IT ALL. By using the old style wide-open 
cans, you transfer much of the can maker's grief to vour filler 
room, (let COMPLETED (vent hole) cans and a Dickerson 
filler. Besides heing neater, cleaner and sal'er, vent cans cost 
less. The pi'ocess of filling and sealing is also much cheapei'. 
The government will "get >ou" if >-ou sell short weights. 
You'll not get a "thank you" for a surjjlus. Fill ever>- can to 
correct weight (to the gram) and neither shortage nor sur- 
])lus will ^vorr^• you. 

A gram A can Ayear=$$$S$ 
The F. G. Dickerson Co., 549 W.Washington Blvd., Chicago 



304 



CflNDKNSI-:!) Mfl.K AND MlI.K I'dWIH',!; 




Progress Homogenizer 

Progress Honiogcnizers urc built in four sizes. Number 1 
handles 90 gallons per hour; Number 2, 200 gallons; Nmnber 4, 
100 gallons; Number 8, 800 gallons. l-"aeh maehine is built 
full rated capacity, and it will do the work it is intended for 
at small expense and to excellent advantage. 

This machine (fuickly ytuys its cosi, and oflinies it results 
in a saving equal to many times its cost in a very short time. 
You manufacturers of evaporated milk nuist avoid the waste 
which may be occasioned by "separated" milk. The Progress 
Ifomogenizer so breaks up the fat globules that the cream 
cannot ])ossibly separate. It will not injure the casein. 

Write to our nearest ofTice for full information and prices 
on the size you need. Many plants have several of these 
machines. Tell us about the size of your business so we can 
judge as (o your lequirements. "Tlie Davis-Watkins Line" 
includes everything needed in Ihc manufacture of I)air\' 
Products. Let us (piole \()ii prices and co-operate with \^)u. 

DAVIS-WVTKINS n.\IR\T^IEN'S MTO.CO. 

ADDRESS NCAREST SALES OFFICE 



NORT hi CH ICAGO, ILL 
J t". R S E Y CITY, N 
KANSAS CITY 




DENVER, COLO 

SAN FRANCISCO, CAL 



CoxiiKNsKi) Milk wn Mii.k I'owdi-r 



3^3 




Progress Circular Milk Can Washer 

L<;ver\- vhIvc; is accessible and easily Hushed. Eacli can and 
cover is drained, washed, rinsed, sterilized and dried inside and out- 
side; all in a few minutes, too, and with a reasonable amount of 
steam and power. Tou can't beat it for efficient, economical results. 

You save on the keeping qualities of your milk by reducing- the 
bacteria count to the minimum. You save milk-can money because 
none of the tin is scraped off, and they don't rust so badly. You 
save labor expense in your plant. The Progress can washer will do 
all these things for j'ou. Figure out what this service is worth to 
you. 

Davis WvTKiNS Dair\7ien's Mfg.Co. 



ADDRESS NEAREST SALES OFFICE 



■JORTH CH ICAGO, ILL 

JERSEY CITY. N . J 

KANSAS CITY, 




VER, COLO 

ATJ FRAflClSCO. GAL 



,i< H-, 



CiiNDi'Nsi'.n Mir.K .wn AFir.K Phwdi'.k 




"Davis Pasteurization" 

Tins IS ail I't'Heii'iit line nf our iiiachiiiei'v which will 
prnpci-ly pasti^urizc lai'i^c quantities of milk at low operat- 
iiiji' fost. With this cquipinciit yoii are insui'ed a natural 
raw taste, the big' Davis cream line and a low bacteria 
count. Tlii'sc arc the tlii'er big' things so essential to the 
lirrptT Imilding of any milk business. 

"I)a\'is Pasteurization" maehinery is automatic in 
eiieratidii, easily cleaned, n-qnires little power expense 
<ind oeenpies small floor space. It needs praefically no 
attcnti(!n while ujierating. The milk is all inclosed so 
there is no loss from evaporation and no chance of con- 
taminatidii. The right temperatures are applied in the 
right way. 

This ('((uipiiicnt \\'ill sol\-e your pasteurization prolilem 
III the simjilest \\ay, insure you against competition and 
cut your cost of handling to a minimum. Write our near- 
est oflice for comjilete information. Tell iis how much 
milk yon handle dail>'. l>et our experts help yon with 
your |irolilems. Such action on your part obligates yon 
in no wa\'. and it ma\' licl]i \dn moi-e than xttw think. Do 
it \()AV." 

Davis -WvTKiNs Dair\i^u]ns Mfg.Co. 



ADDRESS NEAREST SALES OFFICE 



NORTH CHICAGO. ILL 
J tRSEY CITY, N J 

KANSAS CITY, MO. 




DENVER. COLO 

SAN FRANCISCO, CAL. 



Coxi)i';xsi-;iJ Milk ani> AIii.k I'owdi'.r 



397 




A Reliable Butter Maker 

Once a Dislu'ow Owjic)-, alwHVs a I)isl)r()\\- ISoostiT. 
P.iitto-inakiM's t'vci-ywlicrc i)i-oclaiiu the siipcnoritx- of tlic 
l)isl)]'()W. I)uilt s1)-oiij;- ami stiii'ily, it will stand up wt'li 
iiiidiT lica\'y Idads. Idle (jiialily is tlici'c. It is like a 
pui'cdti'cd animal, woilliy of its nami' at all timrs. 

Kor large eapacity and eontinuons work you need tbc 
Nninhcr JM<i'ht Heavy Duty or tlio Nundjcr Kight Giant. 
The Giant barj'rl is a littli' larger in diameter; tlie cast- 
ings and (diai)i are a little heavier. I'.otli bari'ids are (dght 
feet long on tlie inside. 

i{ \ ()U are inleiesled in knowin.t; the detailed iiiformatiiin 
of Ihis wonderfidlN' edieieiit, cojuhined churn and worker, 
write for '"I'he Di.sbrow (jhurn Book." It is free and there is 
no obligation. "Idicrc ai'c smaller sizes, if the Number Eight 
is too large. The free hook shows j^ictures and gives com- 
plete i]iformation on the l)isbi(]w (;hurn >our business needs. 
Send for it NOW. 

Davis -WvrKiNs Dair\7Iens Mro.Co. 



ADDRESS r-JEAREST SALFS OFFICE 



■■JORTH CHICAGO, ILL. 
JERSEY CITY, N.J. 

KANSAS CITY. MO 




■V^S CoN'lil'NSi:!! Mll.K AND MiLK I'OWDI'K 



DRY BUTTERMILK 



OR 



BUTTERMILK POWDER 

is in constantly increasing demand 
at a price that means 

BIG PROFITS 

to the wide-awake creameryman 
equipped to manufacture same. 

Dry Milk Engineering Co. 

is building and installing successful 

Buttermilk Drying Plants 

in Dairy sections everywhere that are 
simple, efficient and economical to 
maintain and operate, require but 
little space and power and insure 

MORE REAL PROFIT 

than any other method of 
Buttermilk disposal. 

Full details and suggestions by our Dry Milk Experts and 
Engineers are yours for the asking. 



DRY MILK ENGINEERING CO. 

139 N. CLARK ST., CHICAGO 



CONIJICNSF.D MjLK ANLi ]\IlLK P(J\\ DKK 



W 




l UNIFQRM sterilization; 

is secured b}' using the Fort AVayne Sterilizer. Built in 
various sizes, from a small Pilot up to a l-i4-case machine, 
it will handle all sizes o-f standard cans without change of 
equipmeut. Let us tell you aljout the recent improve- 
ments incorporated in this sterilizer, and why it is used 
l)y all the leading niauufaeturers of evaporated milk. 

We also build straight line and rocker arm shakers of im- 
proved design, steel trays and tanks, as well as special 
machinery. Our new plant with modern equipment en- 
ables us to give good service at a reasonable price. 

Tell us your requirements and let us show you what we 
can do. 

THE ENGINEERING COMPANY 

1600 WINTER STREET FORT WAYNE, INDIANA 



400 



CoN'i)i-:xsKD AIiLK ANi.) Milk Powokr 



Neither Is of Reeent Origin 



Tile enmlpiised milk iind milk powder industry is 
not new. }'et little lias hccn written on thi' subject to 
eidijiliteii the manufacturer ou its many complexities. 
Xi-vertheless, it has always been the opiuion of those 
eiipaiied in milk and milk product production that sani- 
tary (deanliness must prevail. Due to the jx'rsistent 
(lemainl f(U- eleanliuess, aud assisted b>' the never fail- 
inj^' sei'vice rendered by 




the milk and milk powder industry has reached a very 
hifi'li developnu'ut. 

This cleaner not only appeals to the producer of 
milk and milk products because it establishes the nuist 
sanitary and cleanly conditions, but also because it does 
this so umeh more easily, quickly, economically and 
]irotitably than other cleaners. 



C.iivl.- 




Your supply house will till your 

order o]i our nuwey baidc 

puarautec. 

It (.'leans Clean. 



in every pockaRe. 



The J. B. Ford Co., SoU Mfrs.. Wyandotte, Mich. 




CONDExNSKD AIlLK AND MlLK PoWDEK 401 



WHAT 



THREE FUNDAMENTAL PRINCIPLES 

The different uses for BK are Itased on three funda- 
mental principles. When these ai'e understood it gives 
an appreciation of BK and a knowledge that enahh-s man- 
ufacturers and handlers of dairy products to apply it in 
many wa\'s to li^'htcn lahoi' aiK.l i>r(iduce purer products. 

These principles are: 

1. Ilifjh baftcriacidal power 

2. Solvent Aetion 

3. Harmlessness ^ 

+ 

The bacteria-destroying ])ow('i' of BK is higli. so that 
it kills the l)acteria on coming in contact with tliem. 

The solvent action of BK on albumins — inilk casein, 
etc., softens the accumulations on coils, heaters, pasteur- 
izers, pipes, etc., making the cleaning operation easier. 
Whci'e till' metal parts of equipment are not already 
coatetl with casein the application of BK before the daily 
run prevents a milk film from adhering and also dissolves 
any thin albuminous film that might be there. This sol- 
vent action also exposes the bacteria to pi'ompt (h-struo 
tion. 

These two functions of BK insure a high degree of 
sterilization and cleansing — also great economy of labor. 

BK is a harmless hypochlorite such as iised by the 
most experienced medical men in and on the human body 
— adopted by the great surgeons of the allied armies 
after trying over 150 different articles for protection of 
health and foods of the armies. 

The amount of BK needed to make an effective steril- 
izing solution is very small and the amount of BK left on 
the equipment after using is infinitesimal and negligible. 
Authoritative Experiment Station bulletins prove this 
point conclusively in their tests on chemical sterilizing. 

BK is easy to use everywhere for purifying, deodoriz- 
ing and disinfecting. BK has stood the test of time — it 
has made good. Those who learn its helpfulness become 
constant users. 

GENERAL LABORATORIES 

19 S. DICKINSON ST. MADISON, WIS. 



402 



Condensed Milk and Milk Powder 



GROEN 

Vertical Condenser 
Copper Vacuum Pans 



Built in 

3, 4, 5, 6 and 7 ft. 

Sizes. 




Large Coil 

Inlets and Outlets 

for 

Exhaust Steam. 



Write for Blueprint 

Specifications 

and Prices. 



Deliveries made as 
promised. 



Manufacturers of Copper Vacuum Pans, Hotwells. 

Steam Jacketed Kettles and Special 

Coppersmith Work. 



GROEN MFG. CO., mc 

Coppersmiths 

4529-37 Armitage Ave. Chicago, U. S. A. 



ComjExskd AJilk and ?\Iii.k I'owdkk 



403 



Jensen Vertical Coolers 





"'r"^M>»ig 



"?SV 



iCI 





SPECIALLY BUILT FOR 

COOLING 

CONDLNSED AND EVAPORATED niiLK 

ELIMINATE CRYSTALLIZATION. 

Furnish (Correct Amount of Agitation to Produce a Smooth 

Product. F^liminate Air and Gases Thru Rotation of 

Double Helical Coil During Cooling Process. 

PREVENT CONTAMINATION 

as all Packing and Stuffing Boxes are Outside anrl .\bove the 

Machine. 

ASK FOR CATALOG No. 20 A. 

Jensen Creamery Machinery Company 

Long Island City, N. V. Oakland, California 

Southern Digtribulor: 
BLANKE MFG. & SUPPLY CO.. ST. LOUIS. MO. 



404 



Con'1)i;nsi-:ii AIilk and jMilk Powdi'R 




HARRIS COPPER VACUUM PAN 

FOR MILK CONDENSINC3 

AWARDED GOLD MEDAL 
PANAMA-PACIFIC INTERNATIONAL EXPOSITION 




^' r '\ 









> - //ni«8iiR\, i\ 






Arthur Harris &c Co. 

Pioneer Constructors of 
MILK CONDENSING APPARATUS 



2 1 2-2 1 S CURTIS STREET 



CHICAGO. ILLINOIS 



Coxi)i;xsi;d Milk axu Milk I^jwui-r 405 



Harris Copper Vacuum Pans 

==^:^=^z=zr=:=^^ and z===^:=^^:^^:^:^^ 

Milk Condensing Machinery 

Have been our Specialty for over 
30 years. Over this period vvre have 
continuously produced High 
Grade Apparatus which has given 
most gratifying results both in 
production and service. Large 
capacity Harris Copper Vacuum 
Pans in service today total in the 
hundreds. 

We Solicit Your Inquiries for 

VACUUM FANS STKiilLlZKHS 

FOHKWARMHRS SHAKEHS 

VACUUM PUMPS LABULIXC. MACIIIXKS 

COOLIXC, MACHIXUS HUBBRR PACKED COCKS 

PIP1-: COOLERS SAMPLERS 

RECEIVIXG TAXKS SUPERHEATER RULBS 

STORAGE TAXKS COOEEXC, COILS 

EILLIXC MACHLXES WHICH SCALE TAXKS 
PEEl'HOF.E (;LASSES, ETC. 

Arthur Harris & Go. 

E slabl i s h e d 1 S 8 'i 

212-218 Curtis St. Chicago, Illinois 



406 



C()niii-:nskd Milk anh Milk Powdlr 



The Lathr op- Paulson Company has Perfected 



Can Washer of Super-Success. 
Bigger and?Better Results. 



a N e w Type 
No Waste, Less Work, 



This New li-P Entirely Auto- 
matic Machine has Capacity 
lip to 700 Cans and Covers per 
hour. Practical and efficient 
in every way. Embodies all 
the features of our former 
machines with double their 
eificiency, at less cost. 




V. 



I'ATEXT!^ 



.\u^'. -M, I'.HIT, 

Aus. 211, 1!III7. 

Sept. M, liliin. 

Tel). 22, lillll, 

Dec, 4, r,II7 



,S(;l 



,131 

,133 Apr 



.404 Aug 
SOS Ma 



Apr. 
Sept. 



4. mill. 
9,-1019, 



Ui.S 
192, 



.s, 191S, 
IC, 191S, 
20, 1907, 
3, 190S, 
lo. 1910, 
CANADIAN PATENTS 

585 Nov, 11,1919 193,880 

C48 Sept, 9, 1919 192,647 



. 934 
.1,17: 
.1,249.129 Feb. 



1.2o2.453 Ncn 

1.2i;2.679 Uee 

864.132 Feb 

S,S0.713 Dei 

949,121 



Nov, 
Nov, 



1 II 
1 PI" 
191S 
1 IS 



ruber U, S. and Foreign Patents Pending 

NOTABLE IMPROVED FEATURES: 






1 4 b*^ 

1 -.44 nt 

1 -T'^ syb 

1 -s* ^.4 



193. SS5 
194.208 



Does not require e\'en one man 
to operate. 

Machines are END FED. most 
convenient for disposal of can 
by milk dumper. 

Iiriven by motor or steam tur- 
bine of less than one and one- 
half horse power. 

Dess than one-quarter horse 
power consumed in automatic 
machine drive. 

Water consumption cut seventy- 
five per cent. 

Drying- capacity DOUBLED. Fan 
delivering ISOO cubic feet of 
dry, sterile, super-heated air 
per minute. 

WARM SODA SOLTTTION WASH 
— under pressure of 80 to 100 
pounds. 

('DEAR SCADDTNG WATER 
WA SH i m m ed ia t el y f ollowi npr 

The Lathrop-Paulson Company 
Specialists and Solicit Your 



under pressure of 80 to 100 
povinds. 

STEAM STERILIZATION under 
complete control, any amount 
you desire. 

Operating at the rate of 700 cans 
and covers per hour. HACH 
and EVERY CAN receives 
THREE (o nVE minutes of 
bacteria-destroying' steriliza- 
tion. 

Insures Clean, Dry, Sterile re- 
ceptacles for the conveyance 
of product from ' producer to 
manufacturer nt lowest pos- 
sible cost. 

Macliines ha\e the unique fea- 
ture of handling cans as fast 
or as slow as desired, depend- 
ing solely on the speed they 
are fed to machine, and cannot 
lie crowded beyond capacity. 

are Milk Can Washing Machine 
Inquiries and Requirements 



THE LATHROP-PAULSON COMPANY 

2459 West 48th Street, Chicago, Illinois 



CfixDExsED Milk and AJii.k f'owijj;R 407 

Milk and Egg 
Drying Machinery 



WE iiave over one hundred plants 
in successful operation using 
our spray process in United States 
and Foreign Countries. 

We supply and install complete 
Milk or Egg drying plants of any re- 
quired capacity, guaranteeing the 
highest efQciency at the lowest cost, 
and that our finished products are 
freely soluble. 

We build a tray albumen Egg 
Drier, which produces a crystal or 
flake product. Also a Buttermilk 
Drier, other than the spray process. 
Price and particulars on application. 

Write for Calalogue 



Milk Drying Machinery Company 

Designers, Manufacturers and Builders of Milk and Egg Drying Machin- 
ery. Patented in U. S. and Foreign Countries. Established in 1903. 

t38 North Clark Street, Chicago, Ilhnois 

SultL- 1017-lS City Hall Square BuildiuK 



408 



CoNuiCNsKi) jMilk and Milk I'owdivr 




Mojonnier Milk Tester for Butter Fat and Total Solids 



imlviili'd Ainil ;i. lilK 



Standard Equipment 

in ;ill iii)-t(>-ii:ite ice crcnm, ciindc'iisi'd and (.■\':ip()r;itc(l milk 
phints ;in(l the lari^cr frc'sh milk jjlanls includes the 

TTlQior|Vnl(W> Tester 

II is used 1)>' a lai-t>e majcirily (if the maiud'aclLU'ers of eva])0- 
rated milk, and with it the\' standardize their product to 
within a few hundredths of 1 per cent of an\' standard de- 
sired upon hoth butlei' fat and total solids. 

OTHER MOJONNIER PRODUCTS: 
iVlojonnier Ice Cream Overrun Tester. 
Mojonnier Culture Controller. 
Mojonnier Evaporated Milk Controller. 
Mojonnier Evaporated Milk Can Polisher. 
Mojonnier Evaporated Milk Can Opener. 
Mojonnier Composite Sample Bottles. 
Mojonnier Steam Pressure Copper Kettles. 

Kxlorl.sivo lino of »4(-ieiiI ilii- ]1|t[>ilril I lis iin<l Ijihoriilikry supplies tor chcniiral 
iiiid luu-IorinUiKiciil control of milk proiliu'ts 

Further inlorrjtalion chcci uHy furnisl^ed on any oj (Ac (it?oi'c ptojucls. 

MILK ENGINEERS 
7,!<l WRST JACKSON BIAO., CtllCACO 

Kastern Ofhcv 2(10 Tlftli Avemii;, New York, N. Y. 

Southern Offife 4*>.M Mar^iarottii Avenue. St. Louis, Mo. 

Western Office 2l>T) McAllister Street, San Francisco, Calif. 



C(lMiHXs|-:i.) ,\[llj< AMJ ?\]lI,K I'OWIjKR 



409 



Are You Getting the Highest 
Efficiency From Your 
Testing Room . 



NAFIS 



m 



SCIENTIFIC 
GLASSWARE 



WILL HELP YOU TOWARDS 
THAT GOAL BECAUSE OF ITS 



Accuracy and 
Quality. 





afis 

Testing 

Gi 



L. 





r 






f 


-g '^ 




i 





Nafis 

Automatic 
Acid Bottle 



assware 



is the result of years of experi- 
ence and scientific study. It is 
made to conform witli tlie specifi- 
cations of the United States Bu- 
rt^au of Standards as well as thosi.' 
of the different states, 
^fi-st Bottles are made in cither 
tlie regular or the Circled Gradua- 
tion stA'le. 

Send in a trial order and judg:-- 
for yrnirself. 

If v'our dealer cannot supply you 
with Nafis Glassware, write for 
niir illustrated catalo,s"ue and list 
id" our distril.iutors. 

Louis F. Nafis, Inc. 

Manufacturers of Scientific Glassware for 
Testing Milk and Its Products 

542-548 Washington Boulevard 
CHICAGO, U. S. A. 



410 



C\iNL)F.NsiiD Milk and Milk Powder 



PFAUDLER 

GLASS LINED STEEL 
CONDENSED MILK EQUIPMENT 



This Tank is used in Condciiserit's ami 
Bottled Milk Plants to reduce tlie teni- 
IK'rature of incoming milk. It is Jacketed 
i'or brine circulation, may be ec|uipped 
with either Air or Mechanical Agitating 
Device, and the Milk Inlets are provided 
with spreading devices which spread the 
milk in a thin film over the brine-chilled 
lank wall, reducing it at once to a low 
temperature. Sizes, caijacities and prices 
on request. 





Pfautlltr Glass Llnid Steel 
Milk Storage Tank 



and side agitator. 



Pfaudler Glass Lined Steel 
Jacketed Forewarmer 



PF A U D L E R 
F ore warm - 
ers are made in 
the single-shell 
t\pe or with jacket 
as illustrated. With the latter the major 
])art of the preheating operation may 
be carried out without the introduction 
of steam and finished by the injection of 
live steam with the regular type of 
steam header. It may be had with or 
without the copper cover illustrated. 
Sizes, caijacities and prices on request. 



This Milk Truck Tank is divided 
through the center by a parti- 
tion head which is open at the top 
and bottom and acts as a baffle to 
minimize churning of the contents. 
The interior, including both sides of 
the partition head, is lined with 
Pfaudler Glass Enamel, which ex- 
tends to the outer edges of the man- 
hole flanges and to the end of the 

outlets located at the underside of 

the tank. 

Write for Dairy Equipmenl Bulletin 

THE PFAUDLER COMPANY 




Pfaudler Glass Lined Steel 
Truck Tank 



NEW YOUK 



ROCHESTER, N. Y. 

CHICAGO ST. LOUIS 



SAN FRANCISCO 



Co\iii-:nsi'',i) ^Iii.k Ai\i> ]\Iji,k Powder 



411 



How To Prevent Streaks and 
Mottles in Butter 

Prof. liunzikcr assci'ts th:it s^ti'criks iind HKitth's in Imttor 
are caused by : 

(1) Inroinplelc fusion of Halt utid water in butter. 

12) Fauit> Mechanical condition of the butter >vorkerK. 

13) Overloading of the machine. 

Not one of these causes Init what may be oviM-come by any 
buttermaker who takes pride in liis product. AA^ith Colo- 
nial Salt the buttei'inaker will iieA-pi- be trouliled with in- 
complete fusion. The other two eanses are mcehanieal 
and can be easily remedied. Flake salt dissolves quicker 
than cube salt of the same size <;Taiii. Colonial Salt is the 
onlj^ all flaked Butter Salt on the market. It will produce 
over-run. color, flavoi- and body. Try it in your next 
batch of butter. thk salt that mklts likk snow 

FLAKKS ANI> DISSOLVES LIKE MIS! 

THE COLONIAL SALT CO. 

AKRON, OHIO 
=BOSTON ^=^= ATL.4NTA =^= BUFFA LO 



CHICAGO= 



R & A Hydraulic Can Washer, Sterilizer and 
Drier for Clean, Dry Sterile Cans 



Fig. 610 
wo-tank machine 

shouang 
powerful blower 
md hot air drier 




RICE & ADAMS, Inc. 



166-182 CHANDLER STREET 
BUFFALO 



412 



CoNlilCNSi:!) AIlI^K AND MlLK I'OWDUR 



STERILIZERS 

In All Standard Capacities 



^^^!mm.\y.:^- 




STERILIZER 
LOADING END 



Equal Heat Distribution 

RAPID LOADING 
AND UNLOADING 



Our Shakers are also good 



a E. ROGERS 



8731 Witt Street 



Detroit, Michigan 



C0Mil{.\>KI> MlI^K AND AllI.K I'liWIll': 



413 



HIGH TYPE COPPER 




SA VE 

Fuel, Water 
Milk. Labor 



Largest 
(Rapacities 

Utilizing either 
Live or Exhaust 
Steam 



-Manufacturod 
complete by 



C. E. ROGERS 



8731 Witt Street 



Detroit, Michigan 



414 



Com)Knsi;l) Milk and Milk Powdlr 



SARGENT'S ELECTRIC DRYING OVEN 



( CATIOXTl-:!) 




.\i;iy Im' set lui- any tt'inperji- 
lui-e t'yn]n 711^ <\ to ^7^l\° r. 
:i iifl will main tain tliat teni- 
|iri-at iiii^ indpfln it <=■]>■. Al- 
most a necessity in Milk 
] 'loduct Laboratoi"i*^s where 
tlie maintenance of the low- 
est usalile tf-mperature is 
inipfial i \'e- 

T'rice ('onii.ile!.'^ witli six-t'oi">i 
cord, iilug" and tliemiometer, 
^:i.'.nii. Wound toi- 1 1 "- ni 
l'jn-vr,]i rurr^'nt , 



fr ral.ihn/H..^ juru'shrd 
'ip'ut applii-ation. 



E. H. SARGENT & CO. 

Manufacturers, Importers, Dealers in Chemicals and Chemical 
Apparatus of High Grade only. 



155-165 East Superior Street 



CHI C ACO 



Scliaefer 
Manvifacturing Company 



BERLIN. WISCONSIN 



Manufacturers of 

(Condensed and Evaporated 

Milk Machinery 



Sterilizers 

Shakers 

Test Sterilizers 

Fillers 



Automatic 

IVIaehinery 
Can Conveyors 
Testers 



Can Coolers and 
Speeial INIaehiiiery 

for Special 

Purposes 



Co.\i)i{.\si{ii Milk a.\i> Mij.k PnwDKk 



415 



Make Your Own Cream 

'"PHE Sharpies Emulsilici- enables >ou 
-*- to make e^■ery da> . the exact amount 
oH ereani needed. No shorta;i<\ No 
suri)his. With iHitter. skim milk |»o\\der 
and water you make your own eream in 
jjroper quantities at I he projx'r time 
with this machine..' 




Emulsifier 




— emulsitif's lliree times as llioroiighly 
as any otliiT ciiiulsifier — 

— clai'Kics ttic product. Ttir, cust 
of oil and repairs is guaranteed not 
to exceed $2.00 a year. Sliarples 
is llje most rrorwmical. 

Wrile lo neuresl office for catalog 
describing the Sharpies Emulsi- 
fier anil conlaining ttsers' lellers. 

THE 

SHARPLES SEPARATOR 

COMPANY 

West Chester, Fa. 



BRANCHES: 

Cliicago San P'ranciscu 



roruntu 



-H("> l'n.\'iii-:Nsi-:ii Milk and AIii.k i'ii\\'i)i:K 



Cemcoat 

White Siinitarv iVashable Interior Coatinii 

('(■iiK'oiM 1^ a Mu;\\'-«iiiti' (Mating' apiilicil like paiiil. 
It is i^'lossy and mirriir-likt^ and iiicrcasi's the li^lit li\' vc- 
Ht'ctiiiy it tViiin f\f\-y aiii:'lt'. Paint mi the li^i'lit in Vdiii- 
( 'oikK'Hsi'I'v — CeiiKMiat your «'alls. The Bustoii ISio-clu'in- 
ii-al Labdi'atiiry al'tcr an t^\liausti\-(' test tiiids that Crin- 
ciiaf attVirds iin liTouiid for accinmilation of bai'tci-ia ami 
fiin^i. llrat and eold dors not att'oot t'cnu'oat — it is 
w atiT-proof. 

lAPIDOilTH 

■H TRADE-MARK BH 

Dust-proofs and wear-proofs concrete 
floors by chemical action 

Lactic acid in milk causes deterioration of concrete 
11oors. Pi'e\-ent tliese conditions by tiuslnng on Lapidolitli. 
tile liquid liardener. 

A cheinical cornhiiiation is effected tliroiifi'li the action 
of Ijapidolitli on tile cement, inakine- the tloor g-ranite-like 
and iion-alisorl)inp. 

Many dairies and condeiiseries Iwn'c thoroiigldy tested 
ljapid(dllli lor a iiiiiiilier of years, ^\'e -will refer yon to 
these satislied users and semi saiuiiles and t'oiiiplcfe in- 
I'oriiiation. 

L. Soniieljorii Sons, Inc. 

264 Pearl Street NEW YORK 



dept. so 



CONDKN'SI'.li AIjLK AXIi AllI.K I'nWlil.K 



Are you going to make 

MILK POWDER P 

// you (ire, your logical choice of 
drying equipmeiil is that of the 

SPRAY DRYING CORPORATION 

WHY? 

BECAUSE all the milk pdwclcr is recovncd within tlii" 

spiay chainbcr, and not in a succfssion of 

secondary equipment. 
BECAUSE no milk powder escapes with the outgoing air, 

a common faull with spray dryers. 
BECAUSE it eliminates any need I'or c<.)llecting the powder 

by means of cyclone dust separators and great. 

rambling, unsanitary baffle chambers. 
BECAUSE of the low fuel power and labor cost. 
BECAUSE of the automatic discharge of jxiwder direcLly 

into the bai-rels without conveying machinery 

or hand sho\'eling. 
BECAUSE the space occujtied is only a fraction of that of 

other spi-ay systems. 
BECAUSE no high prt\ssure pump is recjuired for spraying 

the milk, steam pressure furnishing the ft)rce 

with which the milk is sprayed. 
BECAUSE we install these dryers at your plant complete 

in every detail, and set in operation and relieve 

you of any concern in the matti.'r. 
BECAUSE the powder is freely soluble in cold water. 
BECAUSE there is no royalty to pay. 

We build these dryers to operate either ivitlt 

fluid milk or eoudensed milk. lu asking 

us for estimates please tell us /loic 

tnueh milk you trisli to dry. 

Spray Drying Corporation 

50 VESEY STREET NEW YOKK CITY 



418 



CllNI>i:N'SI-.n AfrLK AND MlIJv PlIWDKK 



-r ^ /'~\ y T can reduce manufacturing costs 
J^ V_y \_J and improve your product with 
TAG-ROESCH Time-Temperature Controllers — 

Because: 

Perlcct sterilization of fvery Ijatch 
ni milk bcTonies :i dai\y and 
iialiiral occurrence with pi-acti- 
call\' no labor or attention; 

Regardless of a skilled labor 

shortage, the qnalit\ and the 
i|iianlit>' of production are safe- 
guarded forever, because an in- 
experienced workman, after 3U 
minutes of instruction, can efli- 
cienth' handle a number of steril- 
izers; 

A rich creamy appearance and 

unifornd> heavy consistenc> of 
the linished product are de- 
veloped — despite the fact that the 
condition, ijroperties, and con- 
centration of the milk are lixed — 
because the time and temperature 
CNclcs are adhered to rigidh'; 

A satisfactory product is assured- 




-seven da\ s m tile week 



ind ,32 weeks in the > ear — in exact accordance with the 
pre-delerniined specilications, because the vital factors of 
time and temperature arc no longer a "hit or miss" propo- 
sition; 



No separation of the milk when 
storage, because the milk alwa\ s 
or viscositj'; 

Hard, unshakable curds are avoided, also dark 
formation, due to the fact that excessive time an( 
perature exposures arc eliminated; 

Considerable labor and steam are conserved, which 
ings often are sullicient to more than pay for the 
trollcrs in one >"ear; 

TAG-ROESCH Time-Temperature Controllers can be profit- 
abl\' employed in an> milk c<Hnlenser>' because this device 
can be furnished to handle automatically, an,\ combination 
of lime and temperatuT'e — no matter how unusual or com- 
plicated Ihc slerilizing process may be. 



subse([uentl> placed in 
obtains snfiicient bod\ 



color 
tem- 

sav- 
con- 



m 



IIABUE 



MFG.CO. 

TEMPERATURE ENGINEERS 
18-88 Tliirly-Tliird Si. BrooWyn.N.Y. 



Write for Catalog H-460 

and include details of your 

sterilizing requirements. 



CoNDKxsKii .Milk axu Milk J'nWLLR 



41'' 




I NDICATIiWG-RECOR DING-CONTROLLING 



cover every need in temperature equipment of 
condensed milk and milk powder plants. The 
executive who needs temperature instruments 
will find in the list of Tycos products just what 
he requires for each especial application. 




ANGLE STEM 
THERMOMETER 




RECORDINC3 
THERMOMETER 



Inslriimenls for eMr\ 
Tcniperatiire 'Need 

Angle and Straight Stem Ther- 
mometers 

Engraved Stem Thermometers 

Paper Scale Dairy Thermometers 

Dial Thermometers 

Recording and IndexThermometers 

Temperature and Pressure Regu- 
lators 

Recording Pressure and Vacuum 
Gauges 

Hydrometers 

Bi-Retord Recordinsr 
Thernioinetfr 



Tycos instruments are made for every 
purpose in the Milk Industry from the 
time milk enters the hot well until it is 
ready to be removed from the condenser 
or vacuum pan. 

It will be a privilese for us to send 
carefully prepared literature, giv- 
ing valuable information. .Simply 
ask for it. No obligation. 




SINGLE DUTY 
THERMOMETER 



TAYLOR INSTRUMENT COMPANIES 

ROCHESTER, >. Y. 

There is a Tycos and Taylor Thermometer for Every Purpose 



4 Jo 



COXDI'IXSI'II .ATlLK AND MlI.K PdWDI'.K 



Why the Leading 

Condensed Milk Makers 

Choose Sturges Cans 

— bocaiisc thry arc acouratc^ — absoliit'-lv true In tiicasiiro. 
Sanitary — rasy to clean anci keep clean, i^iiilt (>\tra sti'onj; 
I" withstand k)ny' service. _ _^ 



s 



titr^es 




"^^^ 



are liiiill of the highest grade of 
steel |)late. carefully tinned. S:-ams '^^•^.^' 
solderiHl sinijoth as a china bowl, no '^ 
places for milk to lodge and som'. 
\\rit(> for catalog No. 111. 

STURGES & BURN MFG. CO. 

"Leaders Since 1865" 

CHICAGO, - ILLINOIS 




Torsion Balance Creamery Scales 



lU^^pHffWJR*:'.- 



iM 



The Torsion Balance Co. 



!\o Knifo-Edf:os — No Friction 
No Wear 
SENSITH E and VCCl K.V IK 

Tares and balances in «>ne *>peralit>n. 

No loose part.s to shift. Work- 
ing parts practicnlh' in one 
piece. 

Torsion Balance bollle Cream 
Test Scale, Style 15(10, u.scd 
l)\' collection stations, cream- 
eries, etc., on accoimt of its 
extreme accurac>'. 

Yonr ])rolits ileiuMiil <in \our 
tests as nuich as anything 
else. i)robably more so 

Christian Becker 
Analytical Balances 



llraul OfTi<e: 92 Hoii.le Slre.l 

Ni;\V ^OKK, ^. Y. 
Faelorv: M7-1.';.'! F,if.lilli Sireel 

.JKUSKY CITY, N. .1. 



! 'M West Luke Si reel 

1 <;iii<:At;o, ill. 

1 W California Street 

V SAN FRANCISCO, CAL. 



COMIKXSI'.I) AIlI,K -\.\1) AIlI.K T'OWHER 



421 



GONDENSERY and 
Powder Plant Pumps 







^■^J^iiJ 



\\ ot ^ acuiini 
Pumps for cx- 
liaiistiiiu' Milk 
J'ans iiianiif'uc- 
tiircd ill all ic- 
(|iiii('(l sizf'S and 

sl,^i(>s. 



SPEC 1 Al_ 

HIGH 
PRESS L RE 

PUMPS 

FOR 

Cooliii;,' 

Swoeteiii'd Con 

donsed Milk 

OR 

Sprayint; iiitu 
Drving Cabinet: 




Bull.lins un.l l)<lail !.ir.)riiialii..i AlMa>» Aiinliil.le 

UNION STEAM PUMP CO. 

BATTLE. CREEK. AIICH. 



422 



CoNDiCNSED Milk and Milk Powder 



COMPLETE 

Pumping Equipment 

FOR 

Condensed Milk and Milk Powder Plants 

STEAM, BELT OR MOTOR DRIVEN FOR 
ANY SERVICE, CAPACITY OR PRESSURE 

WELL PUiMPS 

TANK PUMPS Spray Pumps 

BOILER PUMPS 
BRINE PUiMPS 

VACUUM PUMPS 
FILTER PUMPS 

Viscolizers milk pumps 

COOLING PUIMPS 

AU listed and described in Bjdletin i\o. 57 




THE FACTORY BEHIND THE GOODS 



UNION STEAiM PUMP GO. 

BATTLE CREEK, MICH. 



Condensed AIilk and IMilk Pow- 



der 



423 



cr^o 



The Highest Development in tlie Art of 
Treating Evaporated Milklito Pre- 
vent the Separation of Butter 
Fat without disturbing the 
Natural Emulsion of 
Casein and Albumin 




NO. a, VISCOLIZER— BOO-GALLON CAPACITY 



Specially Constructed for Condenseries 
Designed as High Pressure Pumps Should be 

BUILT— PATENTED— GUARANTEED BY 

Union Steam Pump Co., Battle Creek, Mich. 



SALES AND SERVICE BY 

John W. Ladd Co., Detroit — Cleveland 

Cherry-Bassett Co., Baltimore — Philadelphia 



424 



Comii:nski. A[ii,k and Milk TowdKr 



THE BUTTER 
INDUSTRY 



BY O. F. H U N Z I K E R 





7 I 2 pages and over 
loo illustrations. 

The information 
contained in this 
hfiok is new and not 
g e n e r a 1 1 \' k n o \s- n 
even anionic tlie 
inf)st progressi\'e 
creameries and milk 
products factories. 



PUBLISHED BY THE AUTHOR. 



PRICE $5.75