New York State College of Agriculture At Cornell University Ithaca, N.Y. Library Cornell Universit Principles and practice of butter-making Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924002938243 WORKS OF PROF. C. LARSEN PUBLISHED BY JOHN WILEY & SONS, Inc. Exercises in Farm Dairying. By C. Larsen, M.S.A. The Loose Leaf Labo- ratory Manual of The Wiley Technical Series, J.M. Jameson, Editor. An Elementary Man- ual for Agricultural High Schools and Colleges; a Practical Guide for Farmers and Dairymen. 4to, paper, $1.00 net. By McKAY AND LARSEN Principles and Practice of Butter-making. A Treatise on the Chemical and Physical Prop- erties of Milk and its Components; the Hand- ling of Milk and Cream, and the Manufac- ture of Butter Therefrom. By G. L. McKay, Secretary, American Association of Creamery Butter Manufacturers, formerly Professor of Dairying in the Iowa State College, Ames, Ia., and C. Larsen, M.S.A. Third Edition, Largely Rewritten. xiv + 405 pages, 6 by 9. 133 figures. Cloth, $3.00 net. By LARSEN AND WHITE Dairy Technology. A Treatise on the City Milk Supply, Milk as a Food, Ice Cream Making, By-Products of the Creamcry and Cheesery, Fermented Milks, Condensed and Evaporated Milks, Milk Pow- der, Renovated Butter, and Oleomargerine. By C. Larsen, M.S.A., and Wm.White, B.S. xiii+ 298 pages. 5} by 8. 46 figures. Cloth, $2.00net. PRINCIPLES AND PRACTICE OF BUTTER-MAKING BY G. L. McKAY, Dr.5Sc. Secretary, American Association of Creamery Butler Manufacturers, formerly Professor of Dairying in the Iowa State College, Ames, Ia. AND C. LARSEN, M.5.A. Professor of Dairy Husbandary, So, Dak., State College, Brookings, S. D.; formerly Associate Professor, Iowa State College, Ames, Ia. THIRD EDITION, LARGELY REWRITTEN TOTAL ISSUE, SEVENTEEN THOUSAND NEW YORK JOHN WILEY & SONS, Inc. Lonpon: CHAPMAN & HALL, Limitep 1922 Copyright, 1906, 1908, 1922, BY G. L. McKAY anv C. LARSEN PRESS OF BRAUNWOPTH & CO, BOOK MANUFACTURERS. BROOKLYN, N. Y. PREFACE TO THIRD EDITION THE science of dairying is constantly broadening. The methods and art of manufacturing the best quality of butter have gradually changed in conformity with the scientific prin- ciples involved, and no one should now undertake to manufac- ture butter until he has made a careful study of the principles governing the best methods of manufacture The authors admit that, in our present state of knowledge and experimental progress, it is in some instances difficult to distinguish well-established facts from those not universally confirmed; hence, it has been their object to give only informa- tion supported by the preponderance of experimental evidence. The first and second editions of this book have been received by the dairy schools and the practical creamerymen ™ a manner indicating that the work has met with general approval. The third edition has been carefully revised, and additional chapters have been added. The new chapters are: first, Defects Found in Butter—Some of the Causes and their Prevention; second, Neutralization of Cream; third, Milk and its Products as Foods— High Value of Milk Fat; fourth, Cold Storage and Butter for Storage Purposes; fifth, New Tests, including Accurate Method of Determining Per Cent of Fat in Buttermilk, Skim-milk and Ice Cream. The authors’ endeavor has been to bring the book strictly up to date, and to include the latest and most approved methods in dairying. The authors believe that the subject of dairying should no longer be treated as a whole, and for this reason have treated special branches of the subject. In this volume they have en- deavored to give such scientific information as relates to the manufacture of butter. in lv PREFACE The scientific knowledge embodied in the present book has been acquired from time to time, through work done by various investigators at different Experiment Stations and by leading scientists of the Federal Dairy Division. It may be added that the statistics and tables given in this work have been quoted from noted, reliable authorities. The authors are indebted to the following companies and individuals for the use of electrotypes: Cherry Brothers, Cedar Rapids, Iowa; Waterloo Cream Separator Company and Iowa Separator Company, Waterloo, Iowa; Vermont Farm Machine Company, Bellows Falls, Vermont; Burrell & Company, Little Falls, New York; Empire Cream Separator Company and Jensen Creamery Machinery Company, Bloomfield, New Jersey; Dairy Queen Mfg. Company, Flora, Indiana; Elyria Enameled Products Company, Elyria, Ohio; Rice & Adams, Buffalo, New York; Worcester Salt Company, New York City; Russell & Hastings, Madison, Wisconsin; Louis F. Nafis, Creamery Package Company, Borden & Selleck Company, De Laval Separator Company, Arnold & Company, Diamond Crystal Salt Company and Davis-Watkins Dairymen’s Mfg. Company, Chicago; Kirschbraun & Sons, Omaha, Nebraska; Professor M. Mortenson, Ames, Iowa; and Strawberry Point Creamery, Strawberry Point, Iowa. G. L. McKay. APRIL, 1022. ; C. LARSEN. CONTENTS CHAPTER I History OF BUTTER-MAKING AND COMPOSITION OF MILK. rt. Definition of Milk.. . Composition of Milk. ... 3. Variation of Total Solids... . As, Watersoid foe AA ae 5. Fat in Milkk,....... 6 7 to . Propertics of Fat... . Glycerides of Fat... .. 8. Condiuon of Fat... . 9. Theorsez in Regard to Films Enveloping Fat Globules. . . . 10. Classes of Fats. A. Volatile..... B. Non-volatile. tr. Composition of Butter Fat. 12. Proteids (Albuminoids). . An Caseitivien ascencgens B., Albumen... oc... TRI OUPAt hs tonisae hte nla 14. Ash... Ge Riese Pees 15. Gases of Milk...... ey ose ERs cutee 16. Coloring Matter... Pa Orier: Constituents: of; Mal Kies scence eahausaeies sun unmicadpube iste y Reta decease CHAPTER I Mick SECRETION): a ce%sca entra ares ee . Mammary Gland as a Secretory Organ. . . Internal Structure of Cow’s Udder... . Theories of Milk Secretion. ... . Conditions Affecting Secretion of Milk.. .. . External Appearance of Udder............... . Milk Fever..... Fa RR ree Arahat Ep mT An & Wn vi PROPERTIES OF MILK.. Ts Bi) 4 5s 6 7 8 9. 10. CONTENTS CHAPTER ITI Color... . eran Oey eee ee’ . Flavor.. oae-25 : Re tenuate es . Opacity ie Milk. ae . Chemical Reaction of Milk..... Specific Gravity of Milk. Aetihars? vat iche . Natural Separation of Milk and Creamy paecaka 544 Adhesion of Milk ...... . Viscosity of Milk.. Specific Heat of Milk.. [effect of High Heating: on ny Pinpeities ae Milk.. (1) Destroys nearly all Germs. . . (2) Diminishes Viscosity or Body. . (3) Drives off Gases... eae (4) Imparts a Cooked Aste. 3 : (5) Precipitates Albuminoid andl A \sh Chinstiinents, (6) Destroys Properties of Enzymes. . : (7) Divides the Clusters of Fat Globules. . . (8) Caramelizes the Sugar... 20.5 ..600008 General Remarks.........00cces cu eeee Paated CHAPTER IV MILK AND Its Propucts As F'oops—HiGH VALUE oF MILK-FAT.... 1. Chemical Classification of Milk and Its Products as Foods. 2. Biological Classification of Foods............0....0.0.... TAL RTO LEIS sicde a ster oan eee ore alee B. Ash or Mineral Matter.... : C. Two Unidentified but Essential Food Substances, ee CHAPTER V PERMENTS IN: MAE Re jibe ciel tune dos, syect ewes Bae Ree eee een 1. on ant . Size and Shape of Bacteria. eee . Favorable Conditions for Bacterial Growth... .. PRAT: «3 4c wi ceatn eee Asi sea Reon ey are : deageteahel he A. Classihentiet OL MNZ YIN 6S x. aisik on ahs es ines «atts Assy HOO!) fore aeocssanaie e Sskversala tals B. Temperatures. 20244 naw en Gs Moisture. s..5:.200. . Unfavorable CauchGons for pacts va Cienths: . . Kinds of Germs Found in Milk . . Number of Bacteria in Milk... .. . Sources of Bacteria in Milk........0......0..... eee . Effect of Thunder Storms on Souring Milk.............. CONTENTS vil CHAPTER VI PAGE ABNORMAL MILK. ; eee ere ? te atentvb ety 65 1. Colostrum Milk. : ae oe Pearle oes 65 2. Salty Milk... Pe cats 66 3. Bloody or Red Milk... ; Pair 67 4. Blue Milk........ oi 3 eee ee : 68 5. Yellow Milk.... Sees Rehr Wiest ae , 68 6. Ropy: Milk. «2.05032 ae eran ig Coneerit SRERASE SESE 68 7. Bitter Milky cca cea wae 69 8. Milk from Cows which ee Been i in Milk a Long Period. . val . Milk from Spayed Cows.............. Syn sutan PAG A ree ee £O2, Milketromvolck#C OWS artes ccoeiana Anis Oe end ee cs IRA Ud wets 72 CHAPTER VII VARIATION OF FAT IN MILK AND CREAM... renters late ciate tae Rebaleanmhicore aah 74 PART I VARIATION OF FAT IN MILK aN kee we AeA Gn hae ones 74 1. Individuality of Cows... . 74 2. Breed of Cows. ; ; 75 Time between Milles, bes oi A a 75 4. enee Of Mualkingits won eaeacne ee Rees i 76 5. Fore and After Milk................ BAGG ests 17 Age of Cow..... er : Seth cae 78 Advance im acta vomits + cc paces seeoeaer ne eg 78 8. Teed of Cows.. . es ey tee eee 70 OLE MVATONIM e Mt tender ate oe Ste heuc go Pemaeais Mane meanest Gta 5 80 10. Condition of Cow.......... AS Sa Re oe 80 PART II VARIATION OF FAT IN CREAM........... : 81 1. Cream Screw Adjustment. 3 ; : ' : 82 2. Richness of Milk...... ae 3 F 83 3. Rate of Inflow......... Pedra : ae eee 85 4. Speed of Machine......... Epa aK : : she : . 87 5. Temperature of Milk....... F : .. 88 6. Amount of Water or Skim Milk Used to Flush the Bowl........... 90 CHAPTER VIII are SAMPLING, GRADING AND TESTING MILK AND CREAM........ 92 . Receiving and Grading of Milk and Cream.............. 92 A. Detection of Abnormal Milk and Cream through the Sareee:. i "93 BeUse Of Acid Wests, Aen a cucre eeas s amet Wu eas ha a elome a oe 04 Vill omar An fw DD CoMPosITE SAMPLES....... . Definition... .. . When to Sample . Kind of Preservatives to Add nbwns CREAMERY CALCULATION... ....0.0000005- I. 2. . Care of Composite Samples.............0....... . Composite Sampling without the Use “at Bresery atives. CONTENTS C. Use of Fermentation Tests. . a. Gerber and Wisconsin Curd Tests. ........... D. Grading Milk by Heating. . antes eee i. Use of Babcock Test and Ractoneter See e errr e a. Babcock: Pestiot Milk esa tunkicse sag 23244436 495.5 b. Babcock Test of Creat. Rese ett nr ee c. Does the Babcock Test, as Ordinarily Applied to Gr ream, Give Too High a Reading?. eis weet Gays name or hts d. Babcock Test of Buttermilk: and Scie milk—American Association: Lests2 4. craic esse sa eee con e. American Association Test..................5. : f. Determination of the Per Cent of Fat in Butter... . Fe OI DEBE so cc ce cg ang k RRR RSA SE RR . Necessity of ‘Good Milk... bie cscs cows ; Sampling ot Milks 333400 ne tesd games ys ears wampling lubes sve da aarrsy ea eee ue sy es ; Sampling Churned Milk’. ...45.5 Jsauaies sete srozeti Malin onaa sc aeeinen tee nuns : . Sour and Coagulated Milk................... > ApportioningSkimemilks,.20c.o.c000 3 cs serene not seen ena eeee a a ela Washing Casa wanna s catesoisit ia cae cuam aiealgulie win parmesan aha 4 Arrangement of Composite Samples. ........... Average Samples. i. siiciaik ned ecu CHAPTER X Find Average Per cent of Fat......... Calculation of Overrun..... ; (1) Thoroughness of Seiuvainn. (2) Completeness of Churning.......... (3) General Losses in Creamery.......... (4) Composition of Butter Manufactured . Calculation of Churn Yield... . Wee ins . What Should the Overrun in a Crean ery Be?....... . Calculation of Dividends........ Sieh ere st aaah ee arene hee Rie Créam: Raising Coeticient:. ¢ 5 ic..c caupensns aeirmamewee peers oltatement Lo Pat ronsiv.’ eaeann acts smayaiues otis so cise e snare meariees : . Paying for Fat in Cream as Compared with Paying for Fat in Milk. . CONTENTS 1X CHAPTER XI PAGE Heatinc Mitk Previous TO SKIMMING. 145 1. Reasons for Heating. 145 Advantages of Warming Milk to Tish Temperature Previous to Skimming... . 146 3. How Heated....,.... 5 sr eRerar ata ken Sebel Sea dat vee Nackca peas 147 CHAPTER XII SEPARATION -OP (GC RBAMIG inch soaks er unnetee wie AREA Ge eR 149 1. Gravity Creaming.. . 149 A. Shallow-pan System. . 149 B. Deep-setting System. 150 a. Probable Explanation. 152 C. Water-dilution Cream (Hydraulic) 153 2. Centrifugal Creaming. . 154 A. Advantages.... 155 B. History of Centrifugal Beparaters 155 C. Modern Separators... . : 157 D. Classification of Separators. 158 E. Process of Separation. . 158 F. Conditions Affecting ficene y of Separators 161 a. Manner of Heating Milk 161 b. Condition of the Milk. 163 c. Overfeeding the Separator. 163 GZ oSpeedea acs - : 164 e. Steadiness in Running... . 105 f. Thickness of Cream. . 165 g. Slush in Bowl... .. 165 h, General Remarks... . 166 CHAPTER XIIT Farm SEPARATORS....... St Mase eterna chai ie ram Eee 168 T: Tatcoduction of Farm a Seoaators parker cs FEM Re 168 2. Reasons for Introducing Farm Separators.................... 168 3. Objections to Farm Separators....... ; ; Beer ee 171 4. Thickness of Cream. «0.0. 6200a020084 172 5. Power for Farm Separators.......... 174 6. Care of Cream on the Farm..................... 176 7. Disposition of Cream......... : Re oe eee eee eer 179 Ax Shipping Ob Crean, cyyeuswy panes ou een ew eaes nee aoe wes 180 B. Making Butter on the Farm.. 180 CONTENTS CHAPTER XIV PAGE NEUTRALIZATION—THE ‘“‘ NEUTRALIZATION” OF CREAM............-..00..% 183 1 Neutralization, Prinéiple Of; ..ac¢sc0% Kaceease cP eA ee.s Lbs dole ROG 183 2. Neutralization of Cream for Butter-making....................... 184 3. The Preparation and Use of Lime as a Neutralizer................ 192 4. Pints of Lime Mixture Required to Reduce Acidity to .25 Pet Cent (Table) ses. 2 ge OR Te NR eet edit CEN MUMS oe ene a Nha nL 196 Be Other NentraliZersis« « ocsnswes segues ninntieren anneetee hp TAMA aus BOL 199 CHAPTER XV PASTEURIZATIONN o.s5 no oS ate Sao as Sadana. dre Saakne & BMpee as el 201 Te DehnitiOn a. xeans. carsales ae 201 2. Storch Test for Pasteurization... 201 3. Pasteurization Temperatures... ... sate Bitancha Pelee entitle 2 Seem ma dean 202 4. Good Milk and Cream Important... 204 5. Sanitation Must Accompany Pasteurization. . . 206 On Methods:of Pasteurization cscs na sgecasrcih aig eee edcubu tot aes 208 A. Flash or Tietantanisee Method.. Ayn ee srs 208 B. Vat or Holding Method...... ee ee 208 C. Combined Flash and Holding Method. OA Pad Gaia 7 hak 208 is. HUM CIENCY.Ob) PAStCUnIZerSratis >. Goce eae dona oe eieeeald as seek 210 8. Cost of Pasteurization............ Behttae: ny Eng es atae We ue rantcce 9 212 9. Disadvantages of Pasteurization................... 214 to. Advantages of Pasteurization............0... 000 c cesses 214 CHAPTER XVI CREAM: RIPENING:AND) STARTERS... cause ce qipoeemeasink Reet os eae a 215 Cream Ripening: To: Dehnitions: 4 dadveets ye wee eee Meee onion aces 215 25 ODIECtS: OF IRIPEMING 3.5. sas Goes 4 & aemaanealyl eS 215 3. Ripening Temperature of Cream......... 220 4. Amount of Starter to Add to Cream... . Ane 221 $...Mixing ‘the Starter ‘with: the Creaii.c 5 o.caseesancetgesacaeri gens 221 6. Tests for Acidity........... SR en Se OT Trea a ea 221 Al Wan eS LOS tarsi 59,8 6 dre, ck 08 Skt eyes Gay eek DA Notre utas art tase ats 222 B. Fairington Test.. MIS RDA ORBEA TL BARA 223 7, Degree of Acidity that C ream Should be Ripened te LORS ees 224 STARTERS! 8: Definitions... sceoexyyustesssasssedtsdins eaverecaemnd thmekean « 225 OP ELIS LO Tasers eee na Aten ieee Mere Gh INS mtn aa ee mak eRe a a 226 1o. Classification of Starters...............00000.0220.. 226 11. Preparation of Natural Starters... 2.00.0... 000 ..00.000.000 000000. 226 CONTENTS xl PAGE 12. Commercial Starters or Cultures....................... At 227 13. Preparation of Commercial Starters.................... 230 TH THOCUIAIOD yeaaiin cassaces dcecegwccd 2 Sa Seri ekclieda nase Sc cbasree Pane eet Pe 232 rg... Milk Powder for Starters. 5.445 2 Gane . Analyses of Commercial Butter hebween Thirty and Forty Years Ago. . Standards in Different Countrics............. . Factors that Aid in Moisture Control... . 312 ats 317 318 JUDGING I. 2 CONTENTS CHAPTER XXI Sour Flavor...... : P Faulty Factory Ghadiiens Sle heat . Feed Flavors pe elke mee cia Bio A. To Eradicate Wild Garlic. : Advance in Lactation, Winter ane and Stable cancion: ads i Lallowsy lavoro rekcs ees e ss eee . Metallic Flavors. o.. 4 .s¢caces 2. Fishy Flavor... seas tene Meh ig len senes PAU a earet NG usta aes CHAPTER XXII AND GRADING BUTTER. a: Standard for Judging........ Siete BOG Bins Potten nee epee . Manner of Judging....... ch ete EAE : Pewee s a aeeeacees ay Ai BOdWs ccs agegs eae oe ; : a DE Ee ve B. Flavor.. C. Color . De Salt's aust PMS GV EY,aeaale wos . Classification—Grades nel Sane, A. New York Classifcation.... Sot R AEN pn A cbt Rae eee P: Derects FounD In BUTTER—SoOME OF THE CAUSES AND THEIR PREVENTION » Flat.of Insipid Flavors... cccuuc sani ax ewes otable: lav Orsiossh yeas cae ee ee claw mae . Flavors Acquired by Absorption................... > Cheesy’ Plavorin: sacs. 25.5 eee ee oe » 341 2 342 : Bue . 342 B. Chicago Classification............... ee ene 4. Export Butter), ..4s4+ Bit evstellas Nec aastse ee amned AA alan eer ees CHAPTER XXIII CoLp STORAGE AND BUTTER FOR STORAGE PURPOSES.................... 1. History of Cold Storage............ Brak ASME es 2. Mechanical Refrigeration............ WUAR EN ANAS 8533603. 3. Benehits Ob Cold Storages «acionas acca A eaten pee eetene ees 42! GOStIOLStorag Gat shes un cima ran ten nnd atten hs Anns evaluhtsnt dies cana d 5. Should Cold Storage Butter be Branded?............. fea 6. Butter for Storage............. eee 7. Working and Packing Butter for Baeage Pucsesee: a Www w WwWwnnwnnw www Xlll ied Q ica} Eww NN NN Bw HON f+ i ed ea NR N Wb ive) yk 340 340 341 341 341 342 . 347 359 xiv CONTENTS CHAPTER XXIV PAGL . 362 WDtE Treen saa Alsen ity ea ubemmays tenia Bieele ann avant 362 A Natural Tee Systems ign cause 594 FRR Os Ba Ee EES 305 a: Kind of 1Gé: House: s. 2225.46 int 4 Satin hela etches Eh ees 305 b. Size and Shape of Ice House..............000.0eeee . 368 ex Pilling the: IGe Ouse? 25.4 5 sng ces a napnteece So soiestoe sade eons 372 dc PSOUTCEr OL 1 COte prerchainsinn, valoda iss AA aNGIS ook Sieeotermnsce e Sesto 373 B.- Use-ot Ice in Cooling Cream... < ccs... aidines ofc eset ae wwens 374 a. Directly...... PRLS nS mort orn nape Aas ata awad cn eeaee ye Rody 374 beClnvdinectl ys tvcrmece eh alae SNe eA oe alerts ene a am 374 Ge Mechanical Rebrigeration cacao sdsceaccn + a geese & area euees ene 375 a. Application in Creameries..................... > 395. b. Chemicals Used for Mechanical Refrigeration. . san B70 c. Principles of Producing Cold Artificially....... B76 (1) Compression. .... ere err eee 377 (2) “Condensation. ccc cscs wacom aeons eye, (C3) EXAMS 1ONeo 7 Adoni che ose amr atthe nos 378 d.. Transferring: the Coldes. vsccs4% 26 cand acenns 378 CHAPTER XXV FEcONOMIC OPERATION OF CREAMERY...........000cc ccc eeeueeeeeeeeeees 381 1. Firing the Boiler. .. os lahadahi sen smineeanisennee woaoe 4 381 2° Burning Woodor Coalings «icc adausi es dun geek becuase s Sawin 382 4. Daily Weighing of ‘Coal Used): :2i4220c4 2555 veanamonsenans + eacrex 383 4: eCleaning thes poilerks som casi autivusie: bo thet Aare ohare ce alts 384 5. Priming of Boilers... EY yee eka a: Rausrd bandages ecbetioatiae oresan 384 6. The Injector....... de teostitecig amy onehen ot nateraae ined tis abet ace a 385 Fe OSE Pa Hat Orsay cat wsniNale qevecee ged edpaheli aunts toennttok a eerie ia wmeeaes 8. Belt, Pulley and Speed Calculation.................00000000000., 385 APPENDIX T. Legal Standards for Dairy Products..............0000eee eee. 387 IT. Metric System of Weights and Measures...................... 388 BUTTER-MAKING CHAPTER I HISTORY OF BUTTER-MAKING AND COMPOSITION OF MILK THE art of butter-making in some form dates back to time immemorial. History tells us that butter is one of the oldest, as well as one of the most universal, articles of diet. We are told it was used in some form two thousand years before the birth of Christ. References are made to it in early Biblical and other ancient history. We read, in Genesis, that when Abraham was visited by Angels, who appeared in the form of men, ‘‘ he took butter and milk and the calf which he had dressed and set it before them.” The word “ butter” is mentioned in the Bible seven times. It is known that the Scythians and Greeks used butter in 450 B.c._ A little later there is a record of the Persians making and using it. In the early centuries butter was employed in many ways. The Hindoos offered it as a sacrifice in their worship. The Greeks and Romans did not eat it, but used it as a remedy for injuries to the skin. It was considered by them that the soot of burned butter was good for sore eyes. The Romans also used it as an ointment for the skin and the hair. This practice was common in Macedonia, and it is reported that in many cold regions persons use butter as a bath. In Spain, as late as the seventeenth century, it was found in medicine shops for external application only. In the rural districts in Germany, fresh unsalted butter has been employed as a cooling salve for burns, and has been used to some extent in this country. In early times, butter was not generally used as a food, but 2 BUTTER-MAKING AND COMPOSITION OF MILK when it was this was for the purpose of enriching other foods in cooking. We are told it was stored in a melted condition, and was never eaten when fresh. In the early methods of making butter, churning was brought about by agitation of whole milk. In our own country at the present time, in some of the Southern States, the method of churn- ing whole milk rather than cream is still followed by farmers’ wives. Some difference of opinion exists as to the early methods used for creating agitation sufficiently to gather butter from the milk. Such methods were used as placing the milk in earthen vessels and beating it with the hands until butter formed. Later, wooden stirring sticks were used for the purpose of creating agitation. The Arabs churned their milk by placing it in leather bags and dragging them over the ground by means of a rope attached to a horse’s saddle. Another method used was that of placing the milk in skin bags, fastening them to a tree and swinging them back and forth to bring about agitation. (See cut, Chapter XVII.) As time passed, more complete devices or methods were adopted for churning, such as the dash churn. Following the dash churn came the square box churn—which was used extensively in creameries about twenty years ago—and the table butter worker. Now we have the modern up-to-date combined churn. Setting milk in cold water and permitting the cream to rise lessened the time of churning and brought the manufacture of butter down to a science. The adoption of the centrifugal machine for separating the fat from the milk was one of the greatest advancements in butter-making. (See cut of first centrifugal machine in Chap- ter XII.) The first centrifugal cream separator used in Iowa— possibly the first used in America—was a power separator which Jeppe Slipsgaard brought with him from Denmark in 1882, and which was used in a Danish community near Cedar Falls, in Black Hawk County. It is worthy of note that this machine was so novel to the customs officers in New York that they held it for two months before they could decide as to whether it was constructed of iron or steel. They finally decided that it was of steel construction and fixed the duty at $o3. DEFINITION 3 Marked improvements have been made in the manufacture of butter by the adoption of scientific methods and the use of modern equipments. Changes have been made in the period of lactation. Formerly the cow furnished milk only for her young. Through the efforts of man, by breeding and selecting, the period of lactation has been lengthened until at the present time it extends over a period of ten months. The cow at the present time is recognized as one of the most economical producers of human food, hence, dairying has advanced rapidly in all coun- tries that are adapted for the production of forage plants that are suitable for feeding the cow. The United States at the present time produces five times as much butter as any other country. The late census estimates 863,577,000 pounds of factory butter manufactured in 1920 and 675,000,000 pounds of farm butter. Notwithstanding the number of years that butter, milk and other dairy products have been used for food, it is less than ten years since the physiologists discovered that butter and milk contained certain food elements that are essential for the growth of the young that had escaped investigations made by eminent chemists. This discovery was brought about by feeding experi- ments by such noted physiologists as Dr. F. G. Hopkins of Cam- bridge University, England, and Dr. E. V. McCollum of Johns Hopkins University in this country. The discoveries made by these eminent authorities will no doubt be the means of creating a greater demand for dairy products of all kinds. Definition Normal milk is a liquid secreted in special glands cf all females belonging to the mammalian group. It is composed chiefly of water, proteids, fats, sugar, and minerals. Coloring- matters and gases and some organic acids are found in small quantities. All normal milk from the different classes of animals, such as mare, buffalo, goat, ewe, ass, and cow, has a general resemblance in that it all contains water, fat, proteids, sugar, and ash. But milk from different animals varies in the relative proportions of its constituents. The chemical and physical properties are not alike. When human milk is treated with half its volume of 4 BUTTER-MAKING AND COMPOSITION OF MILK ammonium hydrate and kept at a temperature of 60° C. for about twenty minutes, it assumes an intense red color. Cow’s milk turns faintly yellow if treated in the same way. This test was reported by Unikoff, of St. Petersburg (now Petrograd), at the meeting of the Medical Section, Royal Academy of Med- icine, in Ireland. The various kinds of milk also differ from each other in their behavior towards rennet. Richmond has divided milk into two classes: Class I includes milk from the ewe, buffalo, goat, and cow. When rennet is added to the milk from these animals, the casein coagulates into a firm curd. Class II includes human milk, milk of the ass, and mare. When rennet is added to the milk of these animals, a soft curd or none at all is formed. The latter class seems to include the animals without horns, while the first includes those with horns. As the cow’s milk is used as a food to a greater extent than that of any other animal, it has been subjected to more extended and more careful investigation, and, as a consequence, more definite knowledge has been obtained concerning its composition, properties, and uses. The succeeding discussions have reference to cow’s milk, if not otherwise stated. Composition of Milk.—It is impossible to get accurate figures on the composition of milk, as each of the milk constituents is subject to fluctuation from various conditions, such as individ- uality of cow, breed, season of the year, stage of lactation, milking and environment. The average composition, as determined by 280,000 analyses reported by Richmond is as follows: Wialtertc ee Ate Nass Seta a at aheentane 87.35 ate ope enceate yest asset nase erate 250715 Malk=sutat:: axacky $e eh sate ae Fok 4.70 Prpesde (irae ites 265 paGaas es 3.00 | Albumen, ete.. ...... 45 WINS lig dere ceets enva eae, sakes tect Som Pleas aS The composition of various kinds of milk is given by Konig as follows: VARIATION OF TOTAL SOLIDS 5 No. of Casein « “ “cf Analy- Water Fat and Al- Milles Ash ave on | 4 | sugar Gravity ses bumen : Human 107 | 37.41 | 3.78 2.29 6.21 ult i 70 IMAI 6 a rretrn dn a a sera? Rach 50 90.78 | 1.21 1.99 5.67 35 1.0347 Buffalo 8 Bo ee | acer 5105 4.44 75 1.0350 PSS obs needa antisite ‘i 89.64 | 1.64 2,92 5.90 er I .0345 (OWE eee hw He ea oi 703 87.17 | 3.60 4. ee 4.88 71 1.0316 PAW eiaog Sait eg ee BN 32 80.82 | 6.86 6.52 4.91 6) 1.0341 (GGate tse anir ie tend 28> [CSE aa | avers. Nae sou Poa 76 | 1.0328 MON sh sl Sa ae eee 8 84,04 | 4.55 P23 g.34 I.05 1.038 Bate les to: a: acces pices ease 28 75:44 1 0.57 (TE. 47 3.00 Pais) T ..035§ Eléphant: 0.f44 oceee g 79.30 | 9.10 2. 8t a50 50 1.0373 Hippopotamus....... | I 90.43 | 4.51 4.40 II Cannel, Genco estas artes 3 86.57 3.07 4 5.80 ay 1.042 ho ..: ee are | 3 86.55 | 3.15 3.90 5.60 80 1.034 Variation of Total Solids.—As applied to milk, ‘ Total Solids,” is a term that includes fat. casein, albumen, sugar, and ash; in other words, all the milk constituents except the water. ‘‘ Solids Not Fat” is a term often used, and includes the casein, albumen, sugar, and ash, or all the milk constituents except water and fat. ‘‘ Serum” is a term used to designate all the milk constituents except the fat. The fat is the most val- uable constituent of the total solids. The variation in the total solids of milk during the summer months is shown in the table quoted below from Dr. Van Slyke of Geneva, New York: | | Per Cent | Per Cent of Month aS : aa of Water Total Solids ANY Grek itaare, hone cies Sera ees 87.44 12,56 JUNE 2 nes weectskes eee ont S7Br | T2609 | JO cake 2se bes teeedaae es 87.52 | 12.48 | AUBUSty sti Gy sta ec ones S737 Mi s1e363 | September cii5 Magee eae kee 87 9 3r8 Octobern..asadeecrcene : 86.85 13.45 | Dr. Van Slyke also studied the effect of the lactation period upon the total solids in milk. A herd of fifty cows, calving in 6 BUTTER-MAKING AND COMPOSITION OF MILK different months of the year, was used in the experiment. The per cent of total solids of this herd seems to average a little high all through the ten months. The total solids were found to be 14 per cent during the first month, decreasing to 13.47 per cent during the next two months, then gradually increasing with the advance of the lactation period. In the tenth month the average total solids was 14.83 per cent. Pingree, of Pennsylvania, reports having found normal milk from a cow which contained 17.01 per cent total solids. Sherman! reports a very high average total of the milk solids. He treated the milk from thirteen cows, and found it to contain on an average 18.03 per cent of total solids. K6nig reports a minimum of total solids of 9.31 per cent, a maximum of 19.68 per cent, and an average of 12.83 per cent. The average total solids quoted above from Richmond is 12.65 per cent, which agrees closely with KGnig’s results. The difference in total solids of milk from some of the leading breeds has also been studied by Dr. Van Slyke, and the results are as follows: eed Per Cent | Per Cent of of Water | Total Solids Holstéinesona y Secu geen 88.20 11.80 AYTShire isd soue jenn oe ox 87.25 12.95 SHOGENGEI occ Aacieheaetd s+ 85.70 14.30 EOVOlE po eae be ota omeees 85.50 14.50 Giiern Se ye seins ecco nade ace; 85.10 14.90 SJELSCY cal athe tetera te 84.60 15.40 The maximum and minimum amounts of total solids men- tioned above are abnormal cases. The normal variations of the solids in milk are within comparatively narrow limits. For this reason the minimum standard for total milk solids, in States where dairy laws are in force, is fixed by law. Usually 12 per cent is the minimum. Water.—F rom what has been said above concerning the total milk solids, it will be seen that water constitutes by far the largest 1 Jour. Am. Chem. Soc. WATER 7 portion of milk. It is quite uniform, and in milk from a mixed herd the water seldom falls below 86 per cent and seldom exceeds 88 percent. Variations ranging from a little less than 80 per cent to a trifle over 90 per cent are on record. But such variations must be looked upon as occurring in only a very few special cases. It has often been asserted that cows in the spring of the year, when they are pasturing on new grass, or feeding on other suc- culent foods, yield milk which contains an excess of water. Under such conditions there is a tendency for cows to produce milk with a water content a trifle higher, as has already been shown by the figures quoted from Dr. Van Slyke. As a rule this is much over- estimated. It is even a common occurrence to hear creamery slushy ” butter, in the early spring, is due to the excess of water present in the milk. This particular phase will be discussed further under the heading of “ Fat in Milk.” The following question has often been raised: Is the water in ae operators say that their “ soft ”’ or milk the same, or any more valuable than water obtained from other natural sources? The water in milk, so far as known, is transuded from the blood-vessels in the udder into the milk glands. It is so perfectly mixed with the other milk constituents, and holds the milk solids in such perfect emulsion and solution that it would seemingly be impossible to prepare milk so per- fectly by artificial means. However, a substance is prepared by Jacob C. Van Marken, Neuweid, Germany, which, when added to water, produces a substance similar in appearance to watered skimmed milk. The preparation is named ‘‘ Kalberrahm Vita.” The first name literally means calf-cream. It has a syrupy consistency, and in appearance resembles light-brownish molasses. It is sold in tin cans, and recommended highly for calf feeding when mixed with skimmed milk. When mixed with water, it is recommended highly for hog-feeding. Water distilled from milk has the same appearance as ordi- nary distilled water. It is clear and colorless. The chemical reaction when phenolphthalein is used as an indicator is neutral, as is that of ordinary distilled water, even when distilled from milk in which acid has developed. But there is a considerable 8 BUTTER-MAKING AND COMPOSITION OF MILK difference in the taste and smell. This indicates that some of the volatile substances are distilled over with the water. The probability is that these flavoring substances are so closely asso- ciated with water in milk that they are inseparable, and that the only place where this water can be prepared so as to assume these qualities is in the cow’s udder. The conclusion would then be that the water in normal cow’s milk cannot be distilled and replaced by natural water without the loss of the normal good flavor of the product. FAT IN MILK This is by far the most important constituent of milk, espe- cially to creamery operators. It exists in the milk in suspension, in the form of globules so small as to be invisible to the naked eye. Fat globules, at ordinary living-room temperature, are present in milk in a liquid form. Cooling the milk to a very low tempera- ture (about 50° F.) hardens them. When the globules are caused to unite, as in churning, they also solidify. The size of the fat-globules is very minute, and varies con- siderably, according to breeds, individual cows, and the stage in the lactation period. The globules in the milk from the same cow also vary a great deal. Lloyd found fat-globules in Jersey milk to be from 8 to 12 micro-millimeters in diameter. Very few were less than 4 micro-millimeters (a micro-millimeter is tooo millimeter, or zso00 Of aninch). The majority of the fat-globules in milk from Shorthorn cows measured from 6 to 8 micro- millimeters in diameter. According to Fleischmann, the size of fat-globules varies between 1.6 micro-millimeters and 10 micro- millimeters in diameter. A Danish investigator maintains that the diameter of fat-globules is between .0063 and .ooor4 milli- meter, and that 1 cubic centimeter of milk contains from 2.6 to 11.7 million globules. He also asserts that a reflection of the light renders it very difficult to get the proper size of the fat- globules, as the light tends to make the globules appear larger than they are in reality. It has been maintained by some that the larger fat-globules contain fats which are different from those contained in the FAT IN smaller globules. 3ut this is by MILK i) some investigators considered to be a matter of conjecture. Most authorities now believe a. Skim milk. Vise) hee Os neu Om aOnee Hoe ° oe 0 ° . oO . : x ee ee wae oO; ° ne 6° : onrass Dek RETR OP vs 00° ° ae ° ° y Pd oO . 90 2. °° : peer Sayer eS eve =e ‘ Oe eo ° is) ° os? ° : ° bs °, ° Oo ae _ Sener SO. re) - Joo 9° ae Oued io Ors a05 LOS 4% be a geen, ° O° o ae on 6 © o Oc a 9 Q ees re rong Eeeye) OS O°o Oey 2 OOD a ae. ° 0°00% 59 0 ofe0 O ee sepa on Oe 2 oF 2962 00 08 0% °o | Agere Cm om ‘Oc SPOS One 2° ap BO ee > LOPO O °° 028D30 ¢. Cream, - HEU d, Colostrum. C) 2 0 On00 9 20. Fic. 1.—Microscopical appearance of different times. (U.S. that there is no difference in the kinds of globules, even though some experiments ! 1 Gembloux, Belgium, Creamery Jour., Farmers’ Bul. milk. kinds of No. Magnified 300 12.) fat of the different-sized show that fat composed Vol. I. London, No. 8, 10 BUTTER-MAKING AND COMPOSITION OF MILK of larger globules has a finer flavor, and a iittle more oily appear- ance. From what has been said, it will be secn that the minute- ness of the fat-globules is almost inconceivable. They were first discovered in 1697 by A. von Leeuwenhoek. The minute state of division, or the form of emulsion in which they exist in milk, renders it easy to digest when consumed as a food. Properties of Fat.—The specific gravity of pure butter-fat at 15° C. is .93002. The refractive index of butter-fat at 22° C. is on an average 1.459. The melting-point of pure butter-fat, as now determined, varies between 32° and 37° C. (go° F. and 99° F.) When pure butter-fat is rapidly cooled, it solidifies into one solid mass; but if allowed to cool gradually, part of it solidifies, and part of it remains a liquid longer than other parts. This seems to indicate that some fats with a high melting-point sepa- rate out from the fats with a Jow melting-point. This behavior of pure butter-fat is not well understood, as it contradicts the now accepted theory that the different fats are in chemical com- bination with each other, rather than a mechanical mixture of different glycerides of fat. Glycerides of Fat.—By this term we understand that the fatty acid radicals are in chemical combination with the glycerol (glycerine) radical, thus: Fatty acid radicals. Glycerol radical. | CaH7Oz (Butyric) C3H5 4 CisH3302 (Oleic) CisH3502 (Stearic) The chemical formula for glycerine is: Hydroxyl groups. Glycerol radical. | OH C3Hs OH | on The difference and similarity of these two formulas are easily observed, and the reason why the term “* Glyceride of Fat ” has been applied to such a compound is evident. CONDITION OF FAT 11 Condition of Fat—— Whether the fats in milk exist in chemical combination, or whether they exist as glvceride of butyrin, stearin, olein, etc., in the form of a mechanical mixture, is a question in dispute. If they exist in the latter form, the composi- tion of the different fats must be as follows: 3utyrin. Olein. Stearin. | CaH7O> | CisH3202 CisH 302 C3H; ¢ CyH7Oo2 C3Hs 41 CisH3302 CzF C,sH3;02.etc. (a0: Borers Cte and the total fat made up of a mechanical mixture of these and the remainder of the fats in butter-fat. Richmond and other authors believe that fat probably exists in milk chemically, as first mentioned and illustrated; because, if the fat were a mixture of glycerine tributyrate with other glycerides of fat, butyrin or glycerol tributyrate could be dis- solved out by the use of alcohol. But this is not the case. More- over, if butyrin existed separately in milk, it would be possible to distill it off under reduced pressure. This cannot be done. Theory in Regard to Films Enveloping Fat-globules.—The extreme minuteness of the fat-globules in milk renders it almost impossible to determine by direct microscopical observation whether there is a membrane around each globule or not. Fleisch- mann and Lloyd assert that, so far as they were able to detect, there is no real membrane surrounding each globule. The theory generally accepted in the past was that the film surrounding the fat-globules was simply due to surface tension, or to the fact that the molecules of the fat have a greater attrac- tion for themselves than they have for the molecules of the serum in which they are held in suspension. In support of this two arguments are advanced. (t) The natural milk-fat may be removed from milk and artificial fat substituted in its place. The resultant milk has characteristics similar to milk containing normal fat, that is, the emulsion which milk forms with the artificial fat is apparently like that formed with the natural fat. (2) If there were a special albuminous membrane around 12 BUTTER-MAKING AND COMPOSITION OF MILK each fat-globule, cream should contain a higher percentage of albuminoids than milk. This, Richmond maintains, is not so. Dr. Storch concludes from extensive researches that there is a gelatinous membrane enveloping the fat-globules. His conclu- sions are based mainly upon the first three reasons given below. The other facts mentioned also support his conclusions: (1) When milk has been stained with ammoniacal picro- carmine, and the cream washed with water until it is free from milk-sugar, a stained layer is present around each globule. (2) He has succeeded in isolating this gelatinous substance from cream and butter. Owing to its existence in these two substances, he assumes that it is also present in milk. (3) When ether is added to milk, the fat-globules dissolve with difficulty, unless some alkali is added to the milk first. (4) Bichamp maintains that when ether is added to milk the fat-globules are enlarged due to the ether passing through the supposed membrane by the process of osmosis. He considers this fact sufficient to prove that there is a membrane encircling sach globule. (5) Butter containing 85 to 86 per cent fat is asserted by Richmond to have the same consistency as cream containing about 72 per cent fat at the same temperature. The solidity of butter is due to the close proximity of the fat-globules. Now, if cream with less fat has the same consistency as butter, the prox- imity of the fat-globules must be equal to that of the butter; this would indicate that there is a membrane and that this mem- brane increases the size of the fat-globules. (6) The fact that cream separated by centrifugal force is more easily churned than cream of the same richness separated by gravity methods, would also be explained if the fat-globules in milk had such a membrane surrounding them. This membrane, or what is believed to be a membrane, Storch has isolated and analyzed. He finds it to consist of 94 per cent of water and 6 per cent of proteid. The reasons deduced by Storch are strong; and the behavior of cream and butter renders it probable that there is such a membrane enveloping each globule of fat. CLASSES OF FATS 3 CLASSES. OF FATS There are two great classes or groups of fats present in the butter, namely: (1) Volatile and Soluble, (2) Non-volatile and Insoluble. It was previously stated that little is known concerning the way in which the fatty acids are combined with glycerine in the milk; but, for the sake of convenience, the fats will be referred to as if they existed as separate glycerides of fat. The terms ‘ Volatile’ amd ‘‘ Non-volatile ” are applied to the glycerides of fat, or to the fats as they exist in butter. Strictly spealiing, this is not proper, as they do not assume the volatile characteristics until the glycerine separates from the fatty acids; it is only then that the latter become volatile. Volatile Fats.—The first group, or the volatile fats, include butyrin, caproin, caprylin, caprin, and laurin. Butyrin is the one present in the largest proportion. Laurin and caprin are partially non-volatile. Butyrin is the most important fat belonging to the volatile group. It is the most important quan- titatively and also qualitatively. So far as is known, butyrin is the least stable of any of the butter-fats. Under normal con- ditions, so long as the fatty acid remains in combination with the glycerol, it is neither volatile nor soluble in water; but as soon as separation takes place, due to the action of micro-organisms, or to the effect of ight and air, it becomes volatile, and escapes in the form of gas. It is also claimed that these volatile fats have the special properties of absorbing odors and gases to a greater extent than any of the other fats. This absorption takes place when fat comes into contact with the undesirable taints. For this reason it is essential that milk, cream or butter be kept away from any foreign, undesirable odors. These taints may also be imparted to the fat before the milk is drawn. If the cow is fed on unde- sirable food, such as turnips, onions, garlic, etc., the milk from the cow assumes undesirable characteristic flavors which can easily be recognized in the finished product. On the other hand, such 14 BUTTER-MAKING AND COMPOSITION OF MILK foods as well-cured clover hay and bran seem to impart desirable flavors to milk and butter. The presence of these volatile fats in butter is quite uniform, and is a distinguishing feature of pure butter-fat. The detection of adulteration of butter with foreign fats is based chiefly upon the presence of these volatile fats. The characteristic desirable flavor of butter is also believed to be due to the presence of the volatile fats. The volatile fats vary but slightly during the dif- ferent seasons of the year. They are present in the greatest proportion during the spring and early summer months, when cows are fed on grass, and also during the early stage of the period of lactation. They decrease gradually as the lactation period advances. Volatile fats comprise about 8 per cent of the total fats in milk. Non-volatile Fats.—This group constitutes about 92 per cent of the total fats in butter. Chemists now agree that palmitin, stearin, olein, and myristin are the most important ones to be considered, as will be seen from the table quoted from Richmond. These non-volatile fats are of special importance, as the relative amount of each of these fats largely causes the variation in the hardness and softness of the butter and butter-fat. The melting-point of these different fats varies according to the dif- ferent investigators: olein is a liquid at ordinary temperatures and melts at about 41° F.; stearin, on the other hand, has a melting- point of about 150° F.; palmitin also has a high melting-point, namely, about 142° F.; myristin melts at about 129° F. Olein has been found to be present in the greatest propor- tion during the spring, when cows are fed on grass. When cows are fed on normal dry food, as in the winter time, it is present in a much less degree. This, together with the small increase of volatile fats, is the cause of the softer butter so frequent in the spring. The hardness of the butter in the fall or winter is due chiefly to the presence of a slightly increased amount of the fats, with a high melting-point, as mentioned above. From what has been said above, one is led to believe that, by melting a sample of butter which contains these different COMPOSITION OF BUTTER-FAT 15 fats, the fats with a low melting-point would melt first, and leave the remainder in an unmelted condition. Such is not the case. Butter-fat in this respect behaves a good deal like different metals with different fusing-points. When they are melted and mixed together, cooled and then remelted they assume a common melting-point. Butter-fat behaves in the same way. It melts at a temperature of gr” to 96° F. As the body temperature of cows (about ro1° F.) is above this temperature, the fat globules are present in the milk in liquid form when it is first drawn. A peculiarity about these fat- globules in milk is that the milk and fat may be cooled below the melting-point of the fat of butter without the fat-globules in milk being solidified. It requires a temperature of between 60° and 78° F. before the fat-globules in milk begin to solidify. When these small fat-globules are caused to unite, as during the churning process, they solidify at a higher temperature. This behavior of the fat in milk evidently must be due to a relative change in the position of the molecules of fat during the process of cooling and warming. No definite explanations, so far as is known, have been given for this condition of the fat. The non-volatile fats found in butter-fat are practically the same as those found in other animal fats. Composition of Butter-fat.—In his ‘‘ Dairy Chemistry,” Richmond gives the following composition of butter-fat, repre- senting the mean results obtained by different observers: Per Cent (Buenas: Potten race Bates { § per cent volatile. . . CADTOUIS 3 cease awe tse N OO | Caprylin. . SE eee ‘os Has aonstcs Caprin. . ea qs 1.9 Laurin: ;.; r4 : Myristin. . 20.2 | 92 per cent non-volatile. eee Palmitin. . 25-7 Sean Mais gnesinty arahers 1.8 Olein. . ee BS Richmond also gives the percentage of glycerine and fatty acids in each of the different fats, as follows: 16 BUTTER-MAKING AND COMPOSITION OF MILK Butyrin.. 3.8500 yielding 3.43% fatty acids and 1.17% glycerine Caproin.. . 3.60 yielding 3.25 fatty acids and .86 glycerine Caprylin.. 3 255 yielding = .51 fatty acids and .10 — glycerine Caprin....... 1.0 yielding 1.77. fatty acids and .31 — glycerine Laurin... . Fan yielding 6.94 fatty acids and 1.07 glycerine Myristin.. . 20.2 yielding 10.14 fatty acids and 2.53 glycerine Palmitin..... OCT yielding 24.48 fatty acids and 2.91 glycerine Stearin:, <5 5 .<5 1.8 yielding 1.72 fatty acids and .19 glycerine Oléine.3.a.c4ccbee 35 yielding 33.60 fatty acids and 3.39 _ glycerine 100 94.84 12.53 PROTEIDS (ALBUMINOIDS) The proteids of milk are present partly in solution and partly in suspension. They are present in a very complex chemical form. Some of the chemists reckon as many as eight different albuminoids or proteids in milk. Duclaux claims that there are only two kinds of albuminoids, the coagulable and non- coagulable casein. He has, by the use of a fine filter, been able to separate the fat and the coagulable from the rest of the serum. The amount of coagulable casein is claimed to vary considerably, and seems to depend upon the amount of lime phosphate present. The filtrate which Duclaux obtained from filtering the milk was clear and colorless, which proves that the removal of the casein was quite complete. In order to remove casein from milk, a special filter (Chamberland) is employed. Owing to this fact, we may consider the casein to be present in suspension or semi- solution. Noted chemists, such as Babcock, Van Slyke, Duclaux, Storch, Hammarsten, Ritthausen, and Richmond, disagree upon the number of albuminoid substances found in milk, and upon the chemical behavior of each. For all practical purposes it is safe to mention two, namely, (1) casein, and (2) albumen. Those two substances, as all agree, are present in milk, and constitute practically all the albuminoids in milk. But after these two have been separated from milk a slight precipitation can be obtained by treating the filtrate with alcohol. This has been called albumose and also lactoglobulin. From this resultant filtrate a very small amount of material containing nitrogen can again be separated. Dr. Babcock CASEIN 17 has obtained a substance from milk called fibrin. These latter substances, however, are present in minute portions, and are believed by some of the best scientists to be the same as the albumen. Their presence in the filtrate is due to incomplete precipitation of the albumen in the first place. Casein.—Casein is by far the most important of all of the albuminoids. It is the substance which forms the curd in cheese- making. In fresh milk, as is now understood, it is in chemical combination with lime salts. It is on this account that fresh milk shows the amphoteric reaction, which will be explained under the © Properties of Milk.” The coagulation of casein by the addition of rennet or dilute acids is thought to be due to this union between the casein and lime. Fleischmann refers to this as the “ caseous matter’ of milk. The viscosity of normal milk is believed to be due in a large measure to this condition of casein in milk. It causes the casein to be present in a colloidal condi- tion. When milk coagulates by natural or by artificial means, the union between the casein and lime phosphate is largely broken. Casein and albumen differ in composition, in that the casein contains phsophorus and less sulphur than does albumen. Fleischmann maintains that a substance called nuclein is asso- ciated with casein, and is not found in albumen. Casein is precipitated by the use of rennet and dilute acids, and coagulates spontaneously, due to the acid formed in the milk. The precipitates formed by the use of different precipitating agents are not alike. The curd coagulated by rennet contains more fat and calcium phosphate than the curd which is precip- itated by dilute acid or by the spontaneous souring of the milk. Ii milk stands at air temperature for any length of time after milk- ing, the caseous matter (or the nitrogenous matter combined with lime) tends to separate. The caseous matter of milk is not com- pletely precipitated by heat, although heat partially destroys the union between the casein and lime. This largely destroys the action of rennet. Instead of getting a smooth solid coagulum, a more flaky precipitate is obtained. For this reason milk for cheese-making should not be heated to a high temperature. By 18 BUTTER-MAKING AND COMPOSITION OF MILK heating milk in a glass flask to a high temperature, and letting it stand for a time, it will be found that a mineral precipitate has settled to the bottom. This precipitate is believed to be a lime phosphate, which, previous to heating, was combined with the casein of the milk. By adding calcium chloride (CaClz) to milk which has been heated, its normal condition towards the action of rennet is again restored. Albumen.—lIf the casein is removed from the milk by pre- cipitation, and then filtered off, the filtrate will contain a sub- stance which will precipitate when boiled. This is albumen, and is similar in character to albumen from the white of an egg. It differs from casein in that it is not precipitated by rennet or acids, but precipitates on heating. It does not contain any phosphates, but contains a comparatively large amount of sulphur. As the albumen is soluble in rennet and dilute acids, it can readily be seen that it is retained in the whey obtained in cheese- making. When albumen is present in small quantities, as it is in normal milk, heating does not completely precipitate it, unless the casein or curd is first removed. If, on the other hand, albumen is present in excess, as is the case in colostrum, the major portion of the albumen is precipitated when heat is applied with- out first removing the casein. Sugar.— Milk-sugar occurs in milk to the extent of about 5 per cent. It varies very little in quantity, seldom falling below 33 per cent and seldom rising above 54 per cent. It occurs in solution, and is not found elsewhere in nature. Milk-sugar is the most unstable component of milk; its decomposition is brought about quickly and easily by the action of micro-organisms. If these could be entirely excluded from the milk, it would keep for an almost indefinite length of time. As it is impossible under practical conditions to entirely exclude organisms from the milk, the only way to retard and prevent the growth of germs and thereby prevent the changing of the sugar into other products, is to cool the milk to a low temperature (so° F.), or to heat the milk to a sufficiently high temperature (180° F.) to destroy most of the germs. According to Van Slyke ASH 19 and Hart, the decomposition of the caseous matter produces free casein. When about .5 per cent acid has developed in the milk, the free casein combines with the acid and forms casein lactate. The chemical composition of milk-sugar is C12H2201;+H20. Were a perfect decomposition of milk-sugar into lactic acid to take place, the following equation would represent the change: (Milk-sugar) (Lactic acid) Ci2H21012 =4C3H6O3. Such an ideal change, however, never takes place. In sucha case, one gram of milk-sugar should produce one gram of lactic acid. In a number of experiments carried on by one of the authors of ‘‘ The Analysis of Cream during Different Ripening Stages,” the highest amount of acid produced from one gram of milk-sugar was .8 of a gram. This indicates that there are always accompanying by-products produced, besides lactic acid, when milk-sugar is being decomposed in cream or milk. The sourness of milk is due to this change. The by-products which accompany the production of lactic acid are many and various. The most important ones are gases of different kinds, such as carbonic acid gas (COz); marsh gas (CH4); hydrogen (H); and nitrogen (N.) Small amounts of alcohol, formic, acetic, and succinic acids are said to be normal accompanying by-products also. These by-products may also partially result from the breaking down of some of the other milk components. As milk-sugar is in perfect solution, it follows the water of milk, and in cheese-making nearly all of it passes into the whey. Commercially and chemically it is prepared from whey. It is a white. not very sweet powder, and is used for medicinal purposes to dilute pure, powerful drugs. It is also used exten- sively in the preparation of modified milk. Ash.—The ash of milk is present in very small quantities, and when viewed from such a standpoint it may first seem to be of small importance. On account of the effect of the mineral con- 1 Thesis, I.S. C., Ames, Ia. 20 BUTTER-MAKING AND COMPOSITION OF MILK stituents upon the properties of milk, it is one of the most impor- tant components of the milk. It exists partly in solution, and partly in suspension. Babcock maintains that about one-third of the usual ash constituents are in suspension, and that they consist chiefly of lime phosphate. All of the minerals in milk consist chiefly of potash, lime, soda, magnesia, and iron, combined with phosphoric, hydro- chloric, sulphuric, and carbonic acid. Calcium phosphate constitutes about one-half of all the ash constituents. They are named above, in order, according to the extent to which they occur in milk. Gases of Milk.—These do not normally exist in milk to such an extent as to enable chemists to determine them quantita- tively, but they are of great importance, owing to the effect they have upon the quality of the milk, viewed in the commercial sense. Gases in milk may be divided into two classes according to their origin; namely, (1) those imparted to milk before milking and (2) those which are later formed and absorbed in milk. (1) When freshly drawn, milk has a characteristic odor, which seems to be normal to all fresh milk. The gases which cause this odor are very volatile, and by cooling and stirring the milk can, to a large extent, be eliminated. The amount and kind of taints existing in milk, immediately after it has been drawn, largely depend upon the food which the cow has been fed. Turnips, onions, and garlic, when fed to cows a short time before milking, cause undesirable gases or taints to exist in the milk. Good hay, bran, and good grass produce milk of superior quality, containing no odors excepting those which are natural to all milk when first drawn. The milk yielded by cows pasturing in the Alps of Switzer- land is said by tourists to possess a peculiar, not undesirable, spicy odor and flavor. It is maintained by the native people in Switzerland that the peculiar flavor of the Emmenthaler cheese cannot be developed anywhere else in the world. This flavor they believe to be due to the kind of vegetation the cows feed upon. in the Alpine pastures. In Denmark, the poor people GASES OF MILK 21 who do not own much land, graze their cows along the roads where weeds of different kinds grow. Milk from such cows has a peculiar characteristic odor or taint. In this country it is a common occurrence to find that milk delivered by patrons who keep their cows on timber-land pastures has a peculiar weedy odor. Especially is this true in the fall or late summer. If such milk is heated to 160° to 180° F., and stirred occasionally, some of these taints pass off. The addition of a small amount of saltpeter will improve the flavor of milk where such foods as turnip and sugar-bect tops are fed. This remedy is often applied to milk in Canadian cheese factories, during the fall of the year when turnip tops are fed, and also in Germany during the period of the feeding of sugar-bect tops. Yoo much emphasis cannot be placed upon the food that the cows receive. While it is true that much of the desirable aroma and flavor in butter is due to bacterial growth, the kind of food fed to cows is not without significance. It is a well-known fact that districts such as Normandy and Denmark, which have become famous for their high quality of dairy products, have the best of pasture and winter feeds. Besides the kind of food, some physiological disturbances of the cow may cause abnormal taints in milk. (2) Gases or taints which are formed in the milk or absorbed by it are due to fermentation and absorption respectively. The former cause will be considered in a separate chapter, and the latter cause needs little explanation. It is a well-known fact that milk and most of its products have the special property of absorbing odors which may be present in their surroundings. For this reason, milk, as well as other dairy products, should at all times be kept in clean utensils and pure surroundings. Taints appearing in milk immediately after milking are due to absorption within the cow. Taints that develop on standing are due to bacterial growth in the milk, or to absorption from impure surroundings. In the prevention and removal of taints from milk the first step is to remove the cause, and the second to eliminate as many of these taints as possible by a process of aeration or pasteurization. 22 BUTTER-MAKING AND COMPOSITION OF MILK Coloring-matter—It is not known of what the coloring- matter in milk consists. A substance named lactochrome has been found in milk. So far as known, this coloring-substance is closely associated with the fat called palmitin. The amount of coloring-matter varies during the different seasons of the year. It also varies according to the different breeds. During the spring of the year, when cows are first put on grass, the color of of the butter-fat is always higher than it is during the latter por- tion of the summer. During the winter, the fat in milk is quite pale. By feeding the cows some succulent feed in the winter, such as silage, carrots, and beets, the color of the butter-fat is rendered much higher. From this it would seem that the change in the color of the fat with the different seasons, and with the food given, is closely associated with chlorophyl, the coloring-matter of grass. Other Constituents of Milk.—It is said that constituents such as citric acid, urea, nuclein, lecithin, and galactase are present. Babcock maintains that he has discovered a sub- stance named fibrin. This seems to be similar to the nuclein mentioned by Fleischmann, if not the same. But as these substances are present to a very small extent, citric acid, urea, and fibrin being present to the extent of .12, .007, and .coo2 per cent respectively (Fleischmann and Babcock), they are of little importance. CHAPTER II MILK SECRETION The Mammary Gland as a Secretory Organ.—The mammary gland of females belonging to the order of mammalia secretes a fluid known as milk. This substance is strictly a secretory product. There are two kinds of glands present in the animal body, viz., the excretory and the secretory. Generally speaking, an excretory gland is one which receives or absorbs the waste matter of the body, and causes it to be carried off without causing any marked change to take place in the substance excreted. A secretory gland is one in which the raw material is obtained from the blood and then manufactured into a special different product within the gland itself. As an example of a secretory gland, the milk-gland of the cow’s udder is an apt illustration. The glands in the mouth secreting saliva, and those in the walls of the stomach secreting the digestive fluids, are also secretory glands. Internal Structure of Cow’s Udder.—The cow’s udder is composed of two separate glands, the right and left halves. These two glands are distinctly separated from each other by a fibrous tissue running longitudinally. This fibrous partition extends along the abdomen in front, and back to a point between the thighs of the cow. It also serves to hold the cow’s udder in place. There is no connection at all between the right and left glands, and consequently milk cannot be drawn from the left side over to the right, and vice versa. Each of these right and left halves is again divided into two parts, thus making the cow’s udder appear to be divided into quarters. The cow’s udder may then be said to consist of two glands, one on each side, and four “ quarters,” two to a gland. The division between the two quarters of a gland is not complete; 23 24 MILK SECRIETION that is, there is enough connection between the two to allow a portion of the milk to be drawn from the rear quarter through the front teat on the same side, and vice versa. The milk-glands proper are located near the abdomen and extend a trifle downwards into the udder. The remainder of the Itc. 2.—Schematic figure showing cross-section of cow’s udder; and also enlargement of epithelial cells in alveoli when cow is giving milk (1). Each alveolus is surrounded with a membrane called tunica propria. Cell nuclei not shown. When cow is in milk they are also enlarged. When not the epithelial cells are Hat and the nuclei small and spindle shaped (2). udder is filled with ducts, fibrous and connective tissue, muscle, nerves, and blood-vessels, the whole udder assuming a sort of spongy and open condition. The teat is simply a cylindrical-shaped body, with a hollow tube extending down through the center of it. At the bottom INTERNAL STRUCTURE OF COW’S UDDER 25 of this opening, or at the end of the teat, there is a sphincter muscle, which in some cases is drawn up very tight, while in other instances it is so loose that it will not prevent the milk from escaping. In case the muscle is so tight that the milk can be drawn only with difficulty, it may be relaxed a trifle by inserting a small, smooth wooden plug. This will usually dilate the open- ing sufhciently. so that the milk may be drawn with comparative case. In some instances this muscle is so tight that it is necessary to relax it by the use of a sharp knife. This, however, should be done with surgical skill; otherwise the whole muscle is likely to be so injured as to cause the milk to leak away at all times. The upper part of this canal in the teat connects with what is called the milk-reservoir. The size of this reservoir varies in different cows. The average capacity of this milk-cistern is about one pint. The opening from this reservoir into the teat is also guarded with a muscle. Over this muscle the cow has little control; over the muscle at the lower end of the teat she has no control whatever. Opening into the sides and top of this reservoir are a large number of tubes, which are called milk-ducts. These milk-ducts extend from the reservoir up into the milk-gland. They radiate in all directions, divide and subdivide, so as to form a very large number of small tubes. These milk-ducts are surrounded with fibrous muscular tissuc, nerves, and blood-vessels. They are all guarded by a special muscle at the junction with the main milk- ducts, from which they radiate. These muscles are so inti- mately connected with the nerves and muscular system of the cow that she is able to open and close them at will. There are very few cows that are not able to hold up their milk during nervous and exciting periods. It is a common occurrence for a milker to get only a small part of the milk from a cow; this small amount is the portion which is present in the teat and milk- reservoir. Some cows are able to hold up this milk also, but the majority of cows cannot perfectly control the muscle which guards the entrance to the teat. The milk which is present in the milk-ducts and which has to pass through these junctions referred to above can be held up by most cows at will. 26 MILK SECRETION All of the small milk-ducts end in small sac-like bodies, each of which is called a gland-lobule or ultimate follicle. The gland- lobules enclose numerous individual microscopical bodies called alveoli or acini; these are the organs which possess the proper secretory functions. Their outer covering is a membrane called the tunica propria; within this there is an intermediate layer of cell-tissue, and an inside layer composed of cells, which are named the epithelial cells. These epithelial cells within the alveoli are supplied with blood from the cow’s system. During lactation they assume a different form, swelling and extending into the cavity of the alveoli when the cow is yielding milk abundantly, and when she is not in milk the alveoli are flat. A certain number of alveoli are tributary to one particular duct leading from the gland-lobule into still larger milk-ducts. Each aggregation of gland-lobules, tributary to one milk- cistern, constitutes a lobe, and may be likened to a side branch of a bunch of grapes. Each separate grape may represent a gland-lobule. The seeds within the grape, if we imagine each seed to be hollowed out and lined with small column-like bodies, may be likened to the alveoli. These column-like bodies would then represent the epithelial cells. The stem leading from each individual grape may represent the small duct which carries the milk on to the larger ducts. The main stems of the bunch may represent the larger ducts that enter into the milk-reservoir. The air which everywhere fills the openings or interstices of the various parts of the bunch of grapes may be likened to the fibrous fatty tissue between the alveoli and the lobules of the gland. Theories of Milk Secretion.—Although the theories of milk secretion have been studied considerably, many things in this connection are not well understood. Previous to the year 1840 it was thought that the only function of the milk-gland was to filter the milk as it transuded from the blood. It was supposed that the quality and quantity of milk depended entirely upon the food. The theory has also been advanced that the major portion of the milk constituents is a decomposition of the product of the lymph bodies of the blood. It was believed that the lymph bodies were a source of nourishment to the fetus. THEORIES OF MILK SECRETION 27 and that the calf received its nourishment from the same source after it was born as it did previous to birth. It was supposed that after the birth of the calf the opening on the uterus through which the food was supplied was closed, and that a new opening was formed in the milk-gland. These two theories have now been practically overthrown. It has been demonstrated that the major portion of the milk is formed within the milk-gland. The fat, casein, milk-sugar, and part of the albumen are supposed to be formed in the udder. This conclusion is substantiated by the fact that these substances do not appear in the blood, at least not to such an extent as to warrant the assumption that they are not manufactured in the cow’s udder. The total amount of fat in the blood of the cow would not equal the fat in the milk from one milking. By some it is maintained that the substances in milk which are found in solution may be transuded directly from the blood. Here again milk-sugar is found to be in perfect solution in the milk. But this substance can be found nowhere in nature besides in milk. Itis not present in the blood of the animal; consequently it must be manufactured within the gland itself. The water of milk, and the ash constituents which are in solu- tion, are probably transuded directly from the blood. No attempts have been made to determine definitely how casein and albumen are formed within the gland. According to the theory which has been advanced, the fat is formed by the breaking down of the epithelial cells. When the breaking-down process is completed, the transformed cells appear at the opening of the alveoli in the form of distinct fat-globules. This is supposed to be the origin and formation of fat-globules in milk; so it may be said that so far as known the fat is the result of a breaking down of degenerated epithelial cells. Dr. Bitting asserts that the formation of milk solids in the cow’s udder is probably due to a metabolic process rather than to a degenerative. Collier found that a cow giving a normal amount of milk would secrete about 136,000,000 fat-globules per second. He also suggests that a cow secretes about 5 pounds of milk solids per day. As a cow’s udder weighs only about 23 28 MILK SECRETION pounds, the whole udder would have to be renewed twice daily. This is not consistent with our pres nt knowledge of tissue building. The chief incentive to milk secretion is maternity. As soon as the young mammal is born the blood which went to the uterus to supply the calf is turned toward the udder instead. Fic. 3.—A schematic figure showing the course of the artery leading to the mammary gland and the veins returning to the heart. The light-colored lines represent arteries and the dark-colored lines the veins. (From Bitting, Twelfth An. Report, Indiana.) As soon as this current of blood begins to flow, all of the blood- vessels and capillaries in the cow’s udder swell. This causes the minute blood-vessels or capillaries which form a network in the walls of the alveoli to swell, and their swelling stimulates the epithelial cells to activity. Conditions Affecting Secretion of Milk.—There are a great many conditions which affect the milking capacity of a cow. These conditions may be conveniently grouped into two classes CONDITIONS AFFECTING SECRETION OF MILK 29 according to their causes: (1) conditions which are controlled largely by man, and (2) conditions which are inherent in the cow. t. Some of the chief conditions which reduce the secretion of milk and are largely controlled by man are: improper care and treatment of the cow, lack of proper food, incomplete and and improper milking, irregularity, and long periods between milkings. Pregnancy, nervousness, or excitement of any kind affects the proper working of the milk-glands considerably. These latter causes. however, are not always controlled by man. 2. Without denying the influence of those conditions men- tioned above, the conditions which chiefly affect the milk- secreting capacity are inherent. It does not matter how much good care and food a cow receives, if she does not possess these inherent necessary qualities. As was mentioned before, the milk-secreting capacity depends upon the number of gland- lobules, the amount of blood which is supplied to these secretory parts, and the capacity of the cow to digest and assimilate food, and possibly upon a stimulating body fluid not yet well under- stood. The number of gland-lobules is believed to increase until the cow is about seven years old. The milk-secreting glands are present only in a rudimentary form, until the cow has had her first calf, or is well advanced in the first stage of pregnancy. The gland-lobules then increase in number up to the age of about seven. The relative number of lobules in the cow’s udder can only be approximately ascertained. The size of the udder in some measure indicates this. A cow with a large flexible udder is usually a good milker, due to the fact that a large udder usually contains a large number of gland-lobules. The amount of blood which is turned through the cow’s udder to supply the milk-secreting cells may be approximately ascer- tained by the size of the blood vessels. The blood from the heart enters the udder near the region of the hips. It then passes down through the udder, along the abdomen just beneath the skin, until it reaches a point about midway between the flank and the girth. At this place it penetrates the abdominal wall and enters the thorax. The place at which the blood penctrates the abdom- 30 MILK SECRETION inal wall may be felt with the finger. It is supposed that the size of this hole is in some measure indicative of the milk-produc- ing capacity of the cow. This opening in the abdominal wall is called the milk-hole or milk-fountain. Large irregular veins are considered a much better indication of good milking properties than small straight veins. The formation of gland-lobules is entirely inherent in the cow. The only way that these may be increased is through selection and breeding. The amount of blood which passes through the cow’s udder is also largely inherent, although this may in a small measure be affected by the amount and quality of food given to the cow. It should at all times be remembered that a cow is not a mere receptacle into which so much food can be introduced, and from which so much milk can be drawn. After giving due credit for the influence of all other conditions, we must still recognize that the inherent conditions affecting the secretion of milk are the most important. External Appearance of the Udder.—A cow’s udder should be well and symmetrically formed. It should be square and wide, and extend well along the abdomen of the cow, and back up between the thighs. When the udder is empty it should be soft and flexible. The teats should be medium large, be placed well apart, and point downwards. There should be little or no depression in the udder between the teats; that is, each quarter should not appear distinct and separate when viewed from the exterior. The cow’s udder should be covered with fine, soft, downy hair. A light golden yellow is said to be indicative of a good quality of milk. A firm, fleshy udder is undesirable. In the first place, it is not indicative of good milking qualities, and, secondly, such an udder is predisposed to inflammatory diseases. Milk-fever.— This is a common disease in fresh cows. It is due to a congested condition of the cow’s udder. The decompo- sition products of the colostrum milk in the udder are absorbed by the blood, and produce the characteristic symptoms of milk-fever. Dr. Peters, of the Nebraska Experiment Station, says that a good MILK-FEVER 31 and simple remedy for a diseased udder is to pump it full of air. This can be accomplished with an ordinary bicycle pump. After some air has been pumped in, the cow’s udder should be worked or massaged with the hand so as to cause the air to pass through the quarter. He claims that the udder can thus be restored to its normal condition very quickly, thereby preventing and even curing milk-fever. In case the udder is caked very badly, apply a hot poultice. Small five- or ten-pound bags filled with bran and kept hot will prove very satisfactory. A compress consisting simply of a piece of heavy cloth is also used. It should be put on so that it lifts up the entire udder, and tied over the back of the cow. Straw should be put underneath it on the back so that the cord will not injure the animal. CHAPTER II PROPERTIES OF MILK Color.—The coloring matter of milk is associated with the fat. According to extensive investigations, made -by Eckles and Palmer at the Missouri Station, this color is due to carolin, so called because it is the coloring matter of the carrot. It is found in green plants and is closely associated with the chlorophyl, which hides its presence. It is not manufactured by the animal. Animals which produce milk rich in fat, in the form of large fat- globules, possess the ability to utilize this coloring matter to a greater degree than do animals which produce milk having a lower fat content and smaller fat-globules. This explains the downward gradation of the color of the fat in the milk as we pass from the Guernsey and Jersey to the Shorthorn, Ayrshire and Holstein breeds. Flavor.—Milk has a sweet flavor, and a faint odor. Fresh milk has a peculiar taste and odor, which pass off when it is exposed to the air. The flavor is affected by foods and con- ditions of the cow, as mentioned under “’ Abnormal Milk.” Opacity of Milk.—Milk is opaque, except when seen in very thin layers; then it is slightly transparent. The opacity of milk is due to the presence of the fat and nitrogenous matter. When these substances are filtered away on a fine clay filter (the Cham- berland), the filtrate which passes through is clear and trans- parent. It has been maintained that the fat in milk is the chief cause of its opacity, and that the percentage of fat could be determined according to the degree of opacity and transparency of milk with an instrument named pioscope; but it was soon found out that the size of the fat-globules, as well as the number, had considerable influence upon the degree of opacity of milk. For that reason, this method of determining the amount of fat in 32 CHEMICAL REACTION OF MILK wx) Ss) milk was not reliable. The fat-globules themselves are said to be almost transparent, yet the color and opacity of milk is largely due to their presence. This characteristic may perhaps be explained by assuming that the fat-globules in milk deflect the light instead of allowing it to pass through them. After the fat has been removed, the milk still continues to be opaque. When the albuminoid matter has been removed and filtered off the filtrate becomes clear and transparent. Chemical Reaction of Milk.—Milk when fresh shows an amphoteric reaction, which means that it exhibits both an alkaline and an acid reaction when tested with litmus paper. It turns blue litmus paper red, and red litmus paper blue. This peculiar behavior of milk is said to be due to the caseous matter in the milk, which itself has an acid reaction, while the remainder of the serum has a slight alkaline reaction. By testing the reaction of fresh milk with a tenth normal alkali solution, and using phenolphthalein as an indicator, an acid reaction is obtained. After standing, milk soon becomes distinctly acid, due to a change of the milk-sugar into acids, chiefly lactic acid, through the action of micro-organisms. Richmond maintains that the amphoteric reaction of milk has acquired a false importance, as he believes that the neutrality, as measured by the action of litmus paper, is not chemical neutrality. Specific Gravity of Milk.—By specific gravity of milk we mean the weight of the milk as compared to that of an equal volume of water at the same temperature. If a certain volume of water weighs 1000 pounds, an equal volume of milk at the same temperature and under the same conditions will weigh about 1032 pounds. Reducing the figure to a basis of 1, as is always done, the comparison between the two equal volumes of water and milk will be t and 1.032. This Jatter figure represents the average specific gravity of normal milk. It can be readily seen that the correct specific gravity can be obtained only at one given temperature, for, as the tempera- ture of the substance becomes higher, the density of it grows less, and consequently the specific gravity will be less. The tempera- ture at which the lactometers are standardized is 60° F. 34 PROPERTIES OF MILK The specific gravity of milk will also vary according to the relative variation in amounts of the different components. If a sample of milk is rich in solids not fat, as, for instance, skimmed milk, the specific gravity will be high and usually between 1.033 and 1.037. If the sample of milk is rich in fat, as, for instance, in cream, the specific gravity will be less. The specific gravity of milk islessened by the addition of water. Owing to this fact it was first thought that adulteration of milk with water could be detected by testing its specific grav- ity. But this method was soon found to be erroneous, as it is possible to take cream away and add water in such a proportion as not to alter the specific gravity of the sample. A low specific gravity may, however, cause the suspicion that the milk has been adulterated, and the test for water adulteration can be supplemented by testing it for fat. As has been mentioned before, the lactometer reading should be taken at 60° F. If the temperature of the milk is above or below, corrections must be made. The amount of correction which will give approximate results is .1 of a degree added to the lactometer reading for every degree Fahrenheit of tempera- ture above 60° F., and .1 of a degree subtracted from the lactom- eter reading for every degree of temperature below 60° F. The temperature of milk when tested for lactometer reading should never go any lower than 10° below 60°, nor any higher than 10° above 60°. This would leave the range of temperature between so and yo F, In chemical laboratories, the specific gravity of milk is usually determined by the use of a picnometer. In practice there are three instruments in general use for determination of lactometer reading, or specific gravity, viz., Quevenne lactometer, New York Board of Health lactometer and the ordinary hydrometer. The Quevenne lactometer is the one that is used chiefly in creameries. The graduation of each one of them is given in the accompanying diagram. It may be seen from the figures that in order to change the Quevenne lactometer reading into specific gravity, all that is necessary is to add 1000 and divide the sum by 1000. In changing the NATURAL SEPARATION OF CREAM AND MILK 3 or specific gravity into lactometer reading the reverse process will give correct results. The hydrometer gives the specific gravity directly. The Board of Health lactometer has a special graduation. When this lactometer was devised it was thought that 1.029 was the minimum specific gravity of un- ie adulterated milk. The scale on this mel “t | lactometer was made from zero q | to 120, zero marking the point which set a represents the specific gravity of 20 water, namely, 1, while roo is the roe 20] point which is assumed to represent eS the least specific gravity of milk, faeeh| Zemet pl] 1.029. If the specific gravity of a eee C1 certain sample of milk fell to 90, it |. H HoH pee watt ag A indicated that there was Io per cent i q oy of water present. If it fell to 80, 5 aan | Lacan 1,025 4 5 it indicated that there was 20 per os oq cent of water, etc. 0 -| 7 1,030 + q 30 — In order to calculate the total oH | solids, and solids not fat, of milk, cyl Appel) cael it is necessary to know its lactometer | | [ reading, and the percentage of fat | a in it. Knowing these factors, by | the use of the following formula U Z Ss N Qa given by Farrington and Woll, and «g» gpecific Gravity Scale. deduced from Fleischmann’s work, “‘N” New York State. : x : Q” Quevenne. the total solids, and solids not fat, pio 4 Comparative gradua- can be found. tion of lactometer stems. Solids not fat = ¢ lact. reading+.2 times the fat. Total solids =fat+solids not fat. Natural Separation of Milk and Cream.—When milk is allowed to stand quietly for a short time, a layer having a rich- yellow color comes to the surface. This is the cream, and con- tains most of the fat. This separation is due chiefly to the 36 PROPERTIES OF MILK difference in weight, or specific gravity, of the fat-globules and the serum. The force which acts upon the globule of fat is the difference in weight between the fat-globule and the serum which it displaces, minus the resistance with which it meets in its upward passage. This force is great in milk with a high degree of vis- cosity and slighter in milk of a limp and liquid consistency. While the addition of water to milk reduces its viscosity it also lowers its specific gravity. Hence, the so-called ‘“ dilution cream Fic. 5.—Standardized milk. Showing the amount of cream on milk containing the designated per cent of butter-fat. (From Bul. 92, Ill.) separator’ has, generally speaking, little to recommend it. While the skim-milk may give a lower test we must remember that there is a greater quantity of it. Furthermore, it lacks the palatability and feeding value of undiluted skim-milk. But this is a point that need not be Jabored, since the hand separator has all but superseded the different methods of setting milk. In norma] milk, the amount of fat left in the skimmed milk by natural creaming is about .4 per cent. The fat which is left in this skimmed milk is largely composed of very small globules. This is due to the fact that the resistant force on these small globules is equal to or greater than the buoyant force acting upon them. ADHESION OF MILK 37 The completeness of natural skimming is to a certain extent based upon the mathematical law which is stated as follows: “The surfaces of two spheres are to each other as the squares of their diameters, and their cubical contents are to each other as the cubes of their diameters.” The larger the globules are, the greater the surface is, and the greater the resisting force to whicn they are subjected. From the law stated it can be seen that as the size of the globule increases. the cubical content increases more rapidly than the surface. If a fat-globule were split up into smaller ones, there would be more surface exposed to the serum than was the case while the fat was present in one globule. For illustration, suppose two globules of fat to have diameters of 4 and 2 inches respectively. The squares would be 16 inches and 4 inches respectively; their cubes would be 64 inches and 8 inches respectively. It will thus be seen, according to the law quoted above, that the larger globule has a surface only four times as great as that of the smaller one; but the cubical content of the larger globule is eight times that of the smaller one. This illustrates why the large globules rise in cream more quickly than the small ones. In this particular instance the upward force the larger globule is subjected to is eight times greater than that of the smaller one, while the resistant force is only four times as great as that of the small one. Adhesion of Milk—Normal sweet milk adheres to wood, glass, and metals to a greater extent than does water. Whole milk has greater adhesive properties than skimmed milk. A paper moistened with milk or cream makes a label that will stick to any dry object; the same paper moistened with skimmed milk has less adhesive power. The adhesive properties of milk are also due to the condition of the nitrogenous matter. This fact is made use of in painting and whitewashing. Slaked lime, when mixed with buttermilk, or milk of any kind, gives a white- wash which will remain on objects much longer than that made by mixing with water. Viscosity of Milk.—Milk is more viscous than water. The degree of viscosity of fresh milk varies chiefly with the tempera- 38 PROPERTIES OF MILK ture and fat content. So far as understood, the lower the tem- perature, the greater the viscosity. Development of acid, and high temperature lessen the viscosity of milk. Pasteurized milk or cream is less viscous than the same milk or cream unpasteur- ized. This lack of body can again be restored by adding a little viscogen, as recommended by Babcock and Russell. It is not advisable to use it, however, as it does not add materially to the nutritive value of milk, but merely restores the body. The great viscosity of thick cold cream makes it difficult to churn, as most butter-makers have discovered. It adheres to the inside of the churn and simply rotates instead of being agitated. Cream that is cold and thick whips more easily than thin, warm cream, as the viscosity is so great that the air incor- porated cannot escape so easily. In ice-cream making, for the same reason, a greater yield is obtained by using cold, thick cream. Specific Heat of Milk.—The specific heat of milk is less than that of water; that is, it requires less heat to warm a definite amount of milk to a certain temperature than it does to heat the same quantity of water to the same temperature. It also takes less ice to cool the same volume of milk to a certain temperature than it does to cool the same quantity of water to the same tem- perature. The specific heat of milk is, according to Fjord, .o4. The specific heat of cream is about .7._ It varies according to the percentage of fat in the cream. The specific heat of butter is about .4. From these figures it will be seen that it takes less heat to warm milk, cream, and butter, and less cold to cool the same substances, than it does to heat and cool water; but it takes a longer time to heat or to cool milk, cream, and butter; that is, the milk, cream, and butter are not as rapid conductors of heat and cold as is water. The maximum density of milk is not reached, like that of water, at 4° C. but at about .3°C. The boiling-point of milk is a trifle higher and the freezing-point a trifle lower than that of water. Effect of High Heating (180° and above) on Properties of Milk.—The chiet effects of heat upon milk may be summarized in the following headings: EFFECT OF HIGH HEATING ON PROPERTIES OF MILK 39 (1) It destroys nearly all germs present in the milk. (2) It diminishes the viscosity, or body. (3) It drives off gases. (4) It imparts a cooked taste (especially if not heated and cooled properly.) ) (5 uents. It precipitates some of the albuminoids and ash constit- (6) It destroys the properties of enzymes present in milk. (7) It divides or splits up the clusters and fat-globules. (8) It caramelizes some of the sugar. 1. Destroys Nearly all Germs.—Heating milk to a tempera- ture of about 180° F. for ten minutes destroys most of the germs present. This is the temperature used in most creameries for pasteurization. The details concerning the different effects of temperature upon growth of germs properly comes under the heading of bacteriology, and will be referred to more in detail in the chapter on ‘‘ Ferments in Milk.’’ 2. Diminishes the Visc-sity, or Body.—Heating milk or cream diminishes its viscosity; that is, it lessens the body or con- sistency; and in cities where milk or cream is sold directly to consumers, heated milk appears as if it had been adulterated. This diminution in the body is claimed to be due to a breaking up of the clusters, and the fat-globules and the caseous matter. The chemical union of some of the calcium salts and the casein is altered or destroyed. The consistency of milk or cream can be restored by adding a substance named viscogen. Russell and Babcock ! advise this method of overcoming the apparent defect caused by heating. It consists of making a strong solution of cane-sugar and mixing it with freshly slaked lime. This mixture is allowed to stand, and the clear solution coming to the top is the viscogen, which, when drawn off and used in the proportion of one part of viscogen to from 100 to 150 parts of cream, restores its body. This is due to the fact that viscogen causes the fat-globules to cluster together again, and the lime in the viscogen may combine with the 1 Bulletin No. 54, Wisconsin, 1896. 40 PROPERTIES OF MILK nitrogenous constituents in such a way as to aid in the restora- tion of the body of the cream or milk. Nearly all dairy laws forbid the addition of any foreign sub- stances to milk or cream. If viscogen is added, Babcock and Russell suggest tha. it be named visco-milk, visco-cream, etc. When the modification is made, no objection can be raised to its legitimate use. 3. Drives off Gases.—When milk is heated, taints and gases of different kinds pass off to some extent. This is facilitated by San # Fic. 6.—Microscopic appearance of milk, showing natural grouping of the fat- globules, Single group in circle, highly magnified. (From Bul. 64, Wis.) heating and stirring in an open vessel. Many of these gases also escape when milk is aerated and cooled in a pure atmos- phere. 4. Imparts a Cooked Taste.—When milk is heated to 160° F. or above, it assumes a distinctly cooked taste, which makes it disagreeable as a food for many people. On this account, milk for city supply in America is not generally heated above 145° F. In practically all cities where milk is consumed directly, it is subjected to low temperature pasteurization (145° F.) and held at this temperature for twenty to thirty minutes. Under this system the disadvantages of high pasteurization are overcome. For butter-making purposes there are no objections to pas- teurizing cream at a high temperature. The common practice EFFECT OF HIGH HEATING ON PROPERTIES OF MILK 41 in most of our up-to-date creameries to-day is to pasteurize the cream, under the vat or holding system. to 170° F. or above, or, under the flash system, to at least 180° F. The reason why this cooked flavor is found in milk when heated is not well understood. It is supposed to be due to the effect which heat has upon the nitrogeneous constituents and the sugar. 5. Precipitates Albuminoid and Ash Constituents.—When milk is heated, there is a tendency for the soluble salts and a portion of the albuminoids to be thrown down, or changed into an insoluble form. The higher the milk is heated, the greater is this tendency. If a sample of milk in a flask is subjected to intense heat, and then allowed to stand, a fine white sediment will be deposited on the bottom. This is believed to consist of minerals precipitated from the milk. When milk has been heated to about 170° F., and cooled, rennet is unable to precipitate the curd in a normal way. The curd resulting from adding rennet to pasteurized milk is flocculent in nature. It does not assume that smooth and even texture that curd from raw milk has when precipitated with rennet. The behavior of pasteurized milk towards rennet can be ren- dered normal by adding a small quantity of calcium chloride (CaCl). Whether this would affect the quality of cheese mate- rially has not yet been determined definitely. According to G. Fascetti,! if pasteurized milk is used for cheese-making, the cheese ripens more slowly than when made from raw milk. The same investigator also claims that a larger quantity of cheese is obtained per 100 parts of milk when pasteurized milk is used. 6. Destroys Properties of Enzymes.—As was mentioned in the chapter on the composition of milk, there is a substance nor- mal to milk named galactase. This is an enzyme. By heating milk to about 175° F. the properties of the enzyme are destroyed. Owing to this it is easy to determine whether a certain sample of milk has been pasteurized or not. Galactase is present in milk in 1 Exp. Sta. Record, Vol. 15, No. 10, 1904. 42 PROPERTIES OF MILK so small a quantity that it cannot be determined quantitatively, but only qualitatively. A very sensitive and reliable test for determination of the efficiency of pasteurization was invented by Storch a number of years ago. This is fully described in Chapter XV on “ Pasteurization.” 7. Divides the Clusters of Fat-globules.—The fat-globules in normal milk are grouped in minute clusters. When milk is heated, these clusters break up, and each globule exists more or less independently. When heated to an excessively high tem- perature, and exposed to this temperature very long, the fat- globules tend to run together. This can be proved by heating milk in an open vat for about half an hour. A small amount of yellow fat will then be seen floating on the top. 8. Caramelizes the Sugar.—The brownish color which the milk assumes when it is heated excessively is due to a change which the milk-sugar undergoes. Fleischmann claims that the sugar begins to change into a substance known as lacto-caramel at a temperature of 160° F. This change, however, is not pro- nounced enough to be apparent in the color, unless the milk is heated a long time. The higher the temperature is, and the longer the milk is exposed to the heat, the more pronounced is the change. General Remarks.—While all of the above changes have been found by investigators to take place when milk is heated, they can, in a measure, be avoided, if special precautions are taken in the heating and cooling with the special, recently improved forms of apparatus for these purposes. The present common practice of heating milk, for consump- tion as such, to 145° F., and holding at this temperature for twenty to thirty minutes, is accomplished without materially changing its chemical or physical properties, or imparting to it a flavor that is at all objectionable. CHAPTER IV MILK AND ITS PRODUCTS AS FOODS HIGH VALUE OF MILK-FAT THERE are two methods for the classification of foodstuffs for animals and man, and both of these will be briefly considered in this chapter, with special reference to milk and its constituents— particularly milk-fat—as not only valuable but indispensable parts of the dietary. The older method may be spoken of as the chemical method. Tt considers and classifies foods largely in accordance with their content of water, protein, carbohydrates, fats and mineral matter. This, in itself, is quite incomplete, as will be shown later. The newer method, which is known as the biological method, is based upon a study of the properties and values of the different foodstuffs, through feeding them and noting their effect upon growth, health and reproduction. This method, though compara- tively new, has made very rapid strides, and has established the fact that food constituents which come under the same chemical head are by no means either alike or of equal nutritive value. There is neither the hope nor the expectation that the bio- logical will supersede the chemical classification of foods and foodstuffs, in the sense of dispensing with the aid of chemistry. The true, unbiased student of the problems of nutrition recognizes two things; first, that the chemical method has rendered and will continue to render a very large service, and, second, that in itself it is too mechanical and incomplete. In the last analysis, the biological classification of foodstuffs must prevail, but this does not mean that it and chemistry are at variance with each other. Rather it means that there must be a merging of the chemical into the larger or biological method, and that in future a larger, fuller, more intelligent and less 43 44 MILK AND ITS PRODUCTS AS FOODS mechanical use will be made of chemistry as an aid in deter- mining the values of the different foodstuffs and how they may best be combined with each other in the compounding of more economical and complete rations and diets on which animals and man will grow and thrive. At times the biological study of food- stuffs may move in advance of chemistry, as it has already done in discovering the presence in milk-lat of a fat-like or fat-soluble substance, as yet unidentified, which renders this fat altogether superior to other animal and vegetable fats lacking this growth and health-promoting foodstuff. It is the province of chemistry to ascertain, if possible, what this substance is. The same may be said of a water-soluble substance which is not nearly so limited as to its sources, being present in sufficient quantity in cereal grains and most of the mixed diets. CHEMICAL CLASSIFICATION OF MILK AND ITS PRODUCTS AS FOODS From the chemical standpoint, the constituents of the food material consumed by animals and man are classified under the heads of water, combustible matter and ash, mineral matter or salts—all three terms being applied to the last class. The combustible matter includes the carbohydrates (such as starches and sugars), the fats (such as milk-fat, olive oil and other plant oils, and meat-fat), and the proteins (such as the curd of milk, the gluten of wheat and the muscle fiber of lean meat). The carbohydrates and fats are largely burned to supply heat and energy, and are also used for the making of fat in the body and in milk. The proteins are used, in part, for the same purposes as the carbohydrates and fats, but their distinct function, which these latter cannot perform, is that of supplying material for the making of muscle and other body tissue, and the protein of milk. The ash or mineral matter is used for making bone, regulating the heart action and the elasticity of the muscles in general, and preventing acidity of the blood and tissues. Under the older classification of foods we find that milk BIOLOGICAL, CLASSIFICATION: OF FOOD 45 and its products are given a very high place. on account of their high content of the different foodstuffs or constituents, and their high degree of digestibility. A quart of average milk is consid- ered by such high authorities as Sherman of Columbia University to be approximately equal in food value to a pound of steak, or eight or nine eggs. He is here referring chiefly to their heat and energy value and high degree of digestibility. American cheese (a Cheddar cheese) may be regarded. in a very large sense, as a concentrated form of milk, as it contains most of the milk constituents, excepting the sugar. It has about twice the food value of average meat. On this point Sherman says ‘‘ Generally speaking, cheese sells at no higher price than the ordinary cuts of meat. It is a fair general estimate that a given amount of money spent for American cheese will buy about twice as much food value as it would if spent for meat.” Altogether apart from a distinctive and most important function which will be considered later, butter has a very high heat and energy value—a pound being equal to about five quarts of average milk. It is by no means merely a relish, as it has in the past been considered by many. We cannot here afford the space to discuss the food values of the various other milk products, such as cream, ice-crearn and condensed milk. It will suffice to say that cream occupies an intermediate position between milk and butter, combining the features of both. BIOLOGICAL CLASSIFICATION OF FOODS The High Value of Milk and Milk-fat under this Classification The biological study of foods—based upon observations as to the influence of various foodstuffs upon the growth and thrift of animals—has revolutionized our ideas with regard to problems of nutrition, and has established the fact that the biological classification of foods is the true one. In doing so it has shown that milk and milk-fat have values as foods which, a few years ago, were quite unknown, and which as yet have not been deter- mined chemically—or at least have been determined only in part. 46 MILK AND ITS PRODUCTS AS FOODS It was but natural that biological students of the problems of nutrition should give their attention to milk and endeavor to ascertain wherein its different constituents excelled the corre- sponding constituents of other foods. Knowing that the young grow and thrive on a diet composed exclusively of milk, they realized that this food must contain nutritive material of an exceptionally high order. Proteins The proteins of plants differ from those of animals and of each other. Animals do not take the proteins of their foods, whether of plant or animal origin, and use them as such, without any change. In the processes of digestion and assimilation, animals break proteins up into the simpler substances, amino-acids, and from these build up the proteins of the muscle and other tissues of the body. There are eighteen amino-acids that are considered in nutri- tion problems. The protein of wheat (gluten) is able to supply only a limited number of these in sufficient quantity, and some not at all. The proteins of the corn kernel (zein, etc.) are able to supply others, and so on with the proteins of the different foods; but none of these is a complete protein food for the animal body. The chief protein of milk (casein) is, however, an excep- tion, being a very complete and well-balanced protein, which is able to supply the different amino-acids in sufficient quantities and right proportions to build up muscle and other protein tissue of the body. Thus we would say that milk furnishes pro- tein of a quality quite superior to that of almost any other food. This we see exemplified in the fact that the young animal lives, grows and thrives on milk alone. Ash or Mineral Matter In the ash or mineral matter of the food there must be a sufficiency of such elements as sodium, potassium, calcium, magnesium, iron, etc., in the form of inorganic salts. These perform very important functions. Each has its work to do, and they are not interchangeable. BIOLOGICAL CLASSIFICATION OF FOODS 47 In a mixed diet, there is usually, but not always, a sufficiency of the compounds of the different elements mentioned. We quote Sherman upon this point: ‘There must also be main- tained in the body a proper balance between sodium and calcium (the metal of lime). For example, the rhythmical contraction and relaxation of heart muscle, which constitutes the normal beating of the heart, is dependent upon this muscle being bathed by a fluid containing the proper concentration and quantitative proportions of sodium and calcium. Calcium is not always suf- ficiently abundant even when the food is freely chosen; hence the richness of a food in calcium is a factor affecting its value.”! McCollum and Simmonds found as a result of their experiments, “ that the deficiency in mineral elements in wheat and other seeds is limited to three elements, calcium, sodium and chlorine.’’ The ash of milk is present in liberal quantity, is of high qual- ity and well balanced, and is rich in its lime content as a source of calcium. ‘There is more lime in a pint of milk than in a pint of limewater. Two Unidentified but Essential Food Substances—One of These in Milk-fat but not in Ordinary Fats There are, in association with some of the foodstuffs, sub- stances which have not as yet been identified chemically, pos- sibly on account of the minute quantities in which they are present; and yet observation, in feeding experiments, has shown that they are indispensable. If these are absent from their foods, animals will neither grow nor retain vigor. As early as 1906, Hopkins of Cambridge (England) showed conclusively that on an apparently complete food made up of purified proteins, ordinary fats, carbohydrates and salts young rats would not grow, but that when a very small amount of milk was used—enough to make up about 4 per cent of the dry matter of the food—growth became entirely satisfactory. This led him to conclude that there were present in milk unidentified food substances which he termed “ accessory ”’ articles of the diet. 1 Food Products, pp. 19 and 20. * The Newer Knowledge of Nutrition, p. 23. 48 MILK AND ITS PRODUCTS AS FOODS These would be what McCollum terms the “ fat-soluble A,” which is found in milk-fat but not to any appreciable extent in the ordinary fats, and the “ water-soluble B,”” which is more generally distributed in foods, particularly in diets of mixed foods. Bloch, a Danish physician, observed about forty cases of severe eye trouble, accompanied by ulceration, in children near Copenhagen. This would, without doubt, have ended in blind- ness. These children had been receiving skim-milk, instead of whole milk, in their diet, and were practically deprived of milk- fat in their food. When the younger of them were given mother’s milk, and the older either cow’s milk or cod liver oil, they responded and recovered. He attributed the trouble to the lack of fat in their foods; but it will be noted that in all cases the real cause of recovery was the feeding of fats containing the, as yet, unidentified fat-soluble which is present in the fats of milk, the yolk of egg, the liver and other body glands, and the leaves of plants, particularly such plants as alfalfa and the clovers. Mori found fourteen hundred cases of similar eye trouble amongst children in Japan; these responded to the feeding of chicken livers. It has been found both by McCollum and Davis, and by Osborne and Mendel that milk-fat contains a fat-like or fat- soluble substance whose presence or absence in a food, otherwise entirely satisfactory, means the difference between growth and no growth in the young. In addition to this, both these pairs of investigators found that, deprived of such a fat as milk-fat, the young animal would develop a disease of the eyes which would ultimately cause blindness and, if persisted in, would end in death; but that if this fat were restored in time the eyes would become normal again and the young animal would return to its former health and vigor and resume normal growth. It would be unfair to credit any one man, or set of men collaborating with each other, with the discoveries that have been made during the past fifteen or twenty years—and _par- ticularly within more recent years—through the biological study of foods. The list of investigators is rather a formidable one, BIOLOGICAL CLASSIFICATION OF FOODS 49 and, as has already been indicated, includes students of the sub- ject extending from America to Europe and even to far-away Japan. Without doubt the best known of these in America is Dr. E. V. McCollum, whose extensive and most valuable articles appeared in Hoard’s Dairyman and other farm and _ scientific journals, and who has issued a valuable book on the subject, entitled, “* The Newer Knowledge of Nutrition.’ In this book he outlines the investigations conducted by him and his co- workers—Babcock, Hart, Davis, Steinbeck, Humphrey, Parsons, Funk, Kennedy, Simmonds and Pitz —and also familiarizes us with the work of many other investigators. As McCollum intimates, in order to secure reliable and exact data it was necessary to feed purified foodstuffs (purified protein, carbohydrates, fats and mineral salts), and in order to do this and secure sufficient data within a reasonable time it was neces- sary to experiment with small animals. For these reasons, the experiments were conducted mostly with young rats, although like results were also obtained with other animals, including cattle and pigs. Accumulated data, from a variety of sources, show that the results secured are equally applicable to the different animals, including man. In one of the earlier experiments with rats, conducted by McCollum and Davis, they fed a diet composed of purified pro- tein (casein) to the extent of 18 per cent, lactose or milk-sugar 20 per cent (supposed to be pure), about 5 per cent of some fat, together with a salt mixture made up in imitation of the mineral matter of milk, and the balance of starch to make up roo per cent. The results of this experiment were that when the fat used was milk-fat growth could be secured, but that when this was replaced by such fats as lard, olive oil or other vegetable oils, there was no growth. When the fat of yolk of egg was used instead of milk-fat it also induced growth. These experiments established the fact that fats from different sources are by no means equal in dietary value. Following this a more elaborate experiment was planned and carried out by McCollum and Davis. It will be noted that the diet of purified foodstuffs, which proved a satisfactory one, was 50 MILK AND ITS PRODUCTS AS FOODS made up of purified milk constituents. McCollum and Davis next tried the wheat seed or kernel. They reasoned that it con- tained protein, carbohydrates and mineral salts and fats or oil, and that if these were mostly equal in quality to those of milk the only foodstuff that might have to be added would be a growth- promoting fat. They first fed wheat alone and then tried the improvement of it with respect to one dictary factor at a time. The following indicates the different combinations in which wheat was fed, with results secured: (1) Wheat alone... . arent _... No growth, short life. (2) Wheat, plus purided protein. ... ..... No growth, short life. (3) Wheat plus a salt mixture which gave it a mineral content, similar to that of milk Very little growth (4) Wheat plus a growth-promoting fat (milk- fat) _. No growth. (5) Wheat, plus the protein, plus the salt mix- ture. . Bat i _..Good growth for a time, few or no young, short life. (6) Wheat, plus protein, plus a growth-pro- moting fat (milk-fat). No growth, short life. (7) Wheat, plus the salt mixture, plus the growth-promoting fat (milk-fat) Fair growth for a time, few or no young, short life (8) Wheat, plus protein, plus the salt mixture, plus a growth-promoting fat (milk-fat) Good growth, normal number of young, good success in rearing young; life approximately the normal span. This series of experiments again proves the necessity of a growth-promoting fat. But it does more than this; it shows that the proteins and mineral matter from different sources are not of equal value, those of milk being altogether superior in this respect to those of such a food as wheat. Other experiments proved that the seeds of other cereals are, like wheat, quite incomplete in themselves as dicts. In following up this investigation it was found that when polished rice was substituted for wheat, in No. 8 of the series of experiments just outlined, the diet failed utterly to induce growth. This was puzzling. The investigators had been able to induce successful growth through feeding a diet composed of BIOLOGICAL CLASSIFICATION OF FOODS 51 purified protein (casein), milk-sugar (supposedly pure), salts in imitation of the mineral matter of milk, and milk-fat. They could see no reason why the polished rice, supplemented by puri- hed protein, suitable salts and milk-fat should not be a complete food. This was cleared up subsequently by establishing the fact that the milk-sugar used in the former of these two experi- ments, and the germ or chit of the cereal seeds, which had been rubbed off the ricc, contain a water-soluble substance essential for growth, health and vigor. The conclusions finally reached were, first, that amongst the food substances (protein, carbohydrates and ash or mineral matter) coming from different sources there is a marked differ- ence in quality, and that those from milk are of a very high order; and second, that there are two as yet unidentified substances which are indispensable to growth and health, namely, the unknown substance which is present in milk-fat, the fat of yolk of egg and some of the glandular fats, which McCollum and Ken- nedy subsequently designated ‘“ fat-soluble A.” and a second substance soluble in water, which they designated ‘“ water- soluble B.” The absence of the former (fat-soluble A) not only prevents growth, but also causes a serious eye trouble which, if not corrected in time, will end in blindness and death. We have already illustrated this point. The absence of the water- soluble also prevents growth, and causes serious physiological disturbances resulting in a form of paralysis, beri-beri, which is quite prevalent where such foods as polished rice and bolted flour form the main article of dict. But this water-soluble is present in most ordinary food substances, and particularly in a mixed diet, whereas the sources of the fat-soluble are quite limited, the fat of milk, in the form of milk and butter, being the chief of these. In support of what has been said, the utterances of some of our leading physiologists and students of nutrition may be quoted. Dr. H. C. Sherman, Professor of Food Chemistry, Columbia University: ‘“ Especially in the feeding of children should milk be used freely, because of its many advantages as a tissue- 52 MILK AND ITS PRODUCTS AS FOODS building and growth-promoting food. A quart of milk a day for every child is a good rule easy to remember.” United States Food Administration: “ Milk is one of the most important food sources the human race possesses. For the proper nourishment of the child it is absolutely indispensable and its use should be kept up in the diet as long as possible. Not only does it contain all the essential food elements in the most available form for ready digestion, but the recent scientific dis- coveries show it to be especially rich in certain peculiar properties that alone render growth possible. This essential quality makes it also of special value in the sick room. In hospitals it has also been shown that the wounded recover more rapidly when they have milk. “For the purpose of stimulating growth, and especially in children, butter-fat and other constituents of milk have no substitutes.” Dr. E. V. McCollum, Johns Hopkins University: ‘I have come to the conclusion, after carefully analyzing the probable effectiveness of the combinations of foods employed in human nutrition, that the efficiency of a pecple can be predicted with a fair degree of accuracy from a knowledge of the degree to which they consume dairy products. Probably the use of meat and of milk and its products will, in nearly all cases, run more or less nearly parallel, and I venture to assert that it is the milk and butter and cheese, and not the meat which has the good influence in the promotion of the virile qualities of the people. “Milk is worth much more than its energy value or than its protein content would indicate. It is the great factor of safety in making up the deficiencies of the grains which form and must continue to form the principal source of energy in our diet. “Tt seems probable that the only unidentified substance which is physiologically indispensable, which is not sufficiently abundant in the diets employed by the people of the United States and Europe where there are used insufficient amounts of milk, butter, cream, eggs and the leafy vegetables, is the fat- soluble A.” “T wish to again emphasize the fact that there is no way to BIOLOGICAL CLASSIFICATION OF FOODS Or vo supply this dietary factor (fat-soluble A) in the food of children except in the form of milk-fat, and milk is therefore an indis- pensable food for the young.” Attention should be called to one other point. It has been suggested by some that possibly pasteurization of milk or cream destroys the growth-promoting qualities of the ‘ fat-soluble A” in the fat. Osbourne and Mendel found that passing live steam through milk-fat for two hours did not affect it, and McCollum and Davis found that it was not affected by being heated to the boiling-point of water. This should be satisfactory evidence that pasteurization of milk or cream in no way affects the growth- promoting qualities of the miJk-fat. CHAPTER V FERMENTS IN MILK Definition. — The changes which milk undergoes when allowed to stand at a suitable temperature are commonly called fermentations, and the agencies which bring about these changes are called ferments. At one time the ferments were classified under two heads, viz., organized ferments (bacteria, yeasts and molds), and enzymes or unorganized ferments, such as those found in rennet and other fluids in the digestive tracts of animals. This distinction is no longer made, since bacteriologists and physiological chemists have reached the conclusion that the fermentative changes, due to the action of germ life, are caused by enzymes which these micro-organisms produce. However, the enzymes themselves may, from a dairy standpoint, be classi- fied as follows: (1) The pre-existing enzymes of milk, or those which are formed during milk secretion and consequently are in the milk when it is drawn from the cow. The first of these was dis- covered by Babcock and Russell of the Wisconsin Station, in 1889, and was named galactase by the discoverers. It is a tryptic ferment. Since then others, such as catalase and peroxi- dase, have been discovered. It would seem, from investigations made by Russell and Babcock, that the inherent enzymes of milk, which are digesting ferments, are essential to and play an important role in the ripening of the Cheddar type of cheese. They find that it is impossible to produce a typical, normal Cheddar cheese from thoroughly pasteurized milk. According to Storch, the peroxidase has the power of decomposing hydrogen peroxide and setting free “active” oxygen. As this ferment is not destroyed until milk or cream is heated to a high temperature, 54 FAVORABLE CONDITIONS FOR BACTERIAL GROWTH ea it forms the basis for the Storch test for the efficiency of the pa-- teurization of milk or cream for butter-making. This test is described in the chapter on Pasteurization. (2) Enzymes developed through the action of germ life— bacteria, yeasts and molds. These are many and varied, and cause most of the changes that take place in milk and its products, such, for example, as the ordinary souring of milk or cream, and the development of flavor and aroma in cream ripening. (3) Enzymes found in the digestive fluids of animals. All are familiar with the fact that rennet is used in cheese-making. It contains a ferment known as rennin. It is the second class of ferments or enzymes, the class due to the action of germ life (principally bacteria), which is of the great- est Importance in connection with dairying, and with the control of which the dairyman concerns himself most. These ferments are capable of working profound changes, some desirable and some very undesirable. Size and Shape of Bacteria. In size, bacteria are the smallest organisms that exist, so far as known. The size varies consider- ably. Russell! gives the average diameter as sooo0 of an inch. They are so inconceivably small and light that nine hundred billions of them would only weigh z's of an ounce.” Bacteria also vary considerably in shape. They are as a rule classed into three groups: (1) The bacillus or rod-shaped; (2) The coccus or ball-shaped; (3) The spirillum or spiral-shaped (like a corkscrew). Some types of bacteria are classified accord- ing to the way in which they adhere to each other. For instance, when two cocci occur together and form a pair, they are called diplococci; when cocci occur in chains, they are called strepto- cocci; when cocci appear in bunches, they are called staphylo- coccl, etc. FAVORABLE CONDITIONS FOR BACTERIAL GROWTH Food.—Bacteria, like other plants, need food for their exist- ence. The food passes into the bacterial cell in solution, but many organisms use materials not in solution by producing 1 Dairy Bacteriology. 2 Milk, Its Nature and Composition, by Aikman. 56 FERMENTS IN MILK enzymes that dissolve them. Nitrogen, carbon, oxygen, hydro- gen and mineral matter are essentials for bacteria. These sub- stances are furnished in abundance in milk from casein, albumen, milk-sugar, and the mineral salts. Butter-fat in milk is said to be of little value as a food for bacteria. Some organisms, including yeasts and molds, tolerate con- siderable amounts of acid, while others do not. Most bacteria, however, prefer a neutral or slightly alkaline substance. Dark- ness is essential to some bacteria, and is preferred by the majority of the different species. Bright sunlight is a very effective Fic. 7.—a, single bacterium; b, progeny resulting from the growth of a bacterium during 24 hours in milk at 50° I’.; c, progeny of a bacterium during 24 hours growth in milk at 70° I. At 50° F. multiplication was 5-fold. At 70° F. the multiplication was 750-fold. (Bul. 26, Storrs, Conn.) germicide; it is fatal to all species, so far as known. Some germs require air for their growth. These are called aerobic. Others again grow only in the absence of air. These are called anaerobic. Some grow under either or both conditions, and are called facultative. Temperature.—Favorable temperature is essential to bac- terial growth. Temperature is, indeed, the most important means by which the growth and development of bacteria can be controlled. The range of temperature at which bacterial growth is likely to occur may be placed between freezing-point and a little above t10° F. There are, however, exceptions to this i SAVORABLE CONDITIONS FOR BACTERIAL GROWTH . ~~ range. Some few species will grow at as high a temperature as 140° F., and B. bulgaricus will grow very rapidly at 110° F. The growth of bacteria at these extreme temperatures is usually very slight. Even at 50° F. the rate of growth is very slow. According to experiments conducted by Dr. Conn, the multiplication of bacteria at 50° F. was 5-fold, while at 70° F. the multiplication was 750-fold. The following table shows the number of bacteria per cubic centimeter in milk kept at different temperatures.! In so Hrs,| No, of | No. of | I Rs nr In 12 In 50 ee No. at Hate Heus i or at Time Hours be- Hours be- 3 oO $ ours c . - . + Outset | - z : of Curd- | fore Curd- fore Curd- at 50 at 70 at 50 : ae (he e| as a ling at 70° |ling at 50°} ling at 7o ==) | | = a _ 46,000 39,000 | 240,500 11,500,000 | 542,000,000 190 | 50 47,000 44,800 360,000 127,500 | 792,000,000 289 30 | | 36 hours | 50,000 | 35,000 800,000 160,000 2,560,000,000} 172 42 | 42 hours | | | All bacteria do not have the same optimum growing tem- perature. Some species develop most rapidly at one tempcra- ture, while other species prefer a different temperature for the greatest development. It is on this account that certain tem- peratures are employed in ripening starters and cream. Accord- ing to researches by Conn, Bacterium aerogenes develops very rapidly in milk at 95° F. This particular species, producing much gas and an unpleasant flavor, sours milk very rapidly. As a rule, milk which has been held at this high temperature con- tains a preponderance of this undesirable species of bacteria. At 77° F. results are more uncertain; the species of bacteria which will predominate in milk at this temperature depends in large measure upon the number of each kind originally present. According to Conn Streptococcus lacticus has the highest relative growth at about 70° F. This particular species produces no gas, and its presence is desirable in cream for butter-making. Milk 1 Bull, 26 Storr’s Sta., Conn. 58 FERMENTS IN MILK kept at this temperature will, in most cases, providing it has pre- viously been properly treated, develop a pleasant acid taste, will curdle into a smooth uniform coagulum, and will contain a pre- ponderance of the species of germ mentioned above. At as low a temperature as 50° F. acid-producing types of bacteria do not develop very well. But Conn maintains that miscellaneous species of bacteria that produce unfavorable results develop at this temperature. While milk does not easily sour at this temperature, it should be remembered that undesir- able germs are constantly developing. As it is practically impossible to exclude all of the bacteria from milk during milking and the handling of the milk, it is very essential that the multiplication of the germs present be checked, or at least retarded; and this can be done by controlling the temperature of the milk. As low temperature is effective in checking the multiplication of the bacteria, the sooner the milk can be cooled after it is drawn, the better it will be likely to keep. Moisture.—Moisture is one of the essentials for bacterial growth. As milk is composed largely of water, bacteria find in milk a good medium for growth. All the other required food elements are also found in abundance in milk. Damp utensils and rooms are always more conducive to the growth of germs than are utensils and rooms which are thoroughly dried and ventilated. This is well illustrated by a refrigerator. A very damp dark refrigerator is always more conducive to the growth of molds in butter than is a dry refrigerator. Unfavorable Conditions for Bacterial Growth.—The reverse of the favorable conditions mentioned above would be unfavorable to the growth of bacteria. As it is practically impossible to make conditions unfavorable for the growth of bacteria by taking away food, other means must be used. Extremely high tem- peratures destroy bacteria. Low temperatures check their growth, but so far as known do not destroy them. Absence of moisture and presence of direct sunlight are conditions which are not conducive to bacterial growth. Certain chemical substances when added to milk, or to the medium in which the bacteria are present, are very unfavorable to their growth. Some of these UNFAVORABLE CONDITIONS FOR BACTERIAL GROWTH — 59 chemicals entirely destroy all germ life even when added in very small quantities. These are called disinfectants (formaldehyde, corrosive sublimate, etc.).. Other chemicals are more mild in their effect upon germ growth, and merely inhibit or retard the growth of micro-organisms. The chemicals which have this milder effect upon germs are called antiseptics. Boracic and salicylic acids are examples. Practically all disinfectants are I'ic. 8.—Shows a plate exposed in pasture where air must have been very pure and free from germs. (Bul. 87, Nebraska.) violent poisons, and should not be used in any quantity or in any form in milk or dairy products which are intended for human food. The milder preservatives or the antiseptics, are, as a rule, not so poisonous or injurious to human health. In some coun- tries they are allowed to a small extent. For instance, according to reports, the laws of England permit the use of boracic acid in butter to the extent of o.5 of 1 percent. It is, however, safest not to use any of these chemicals, except for preserving samples 60 FERMENTS IN MILK for analytical or similar purposes. As low and high tempera- tures are so effective in producing unfavorable conditions, these should be chiefly employed in controlling the growth of micro- organisms in the dairy industry. Kind of Germs Found in Milk.—The number of species of germs found in milk has not yet been definitely established, due chiefly to the fact that it is in some instances difficult for bacteri- ologists to differentiate one species from another. The descrip- Frc. 9.—Shovws a plate exposed one-half minute under a cow’s udder treated with a 5 per cent solution of carbolic acid. (Bul. 87, Nebraska.) tion of one species of bacteria by two different bacteriologists may vary considerably, as the characteristics of the germs depend so much upon the conditions prevailing throughout the classification process. Over 200 different species have been described. It is possible, however, though all of these types may have different morphological and physiological character- istics as described by different bacteriologists, that some two or more of the 200 types may belong to one species. KIND OF GERMS FOUND IN MILK Gl For this purpose, it is sufficient to classify the bacteria into three groups, viz., (1) those which are harmful to the butter- making industry, (2) those which are beneficial, and (3) those which are indifferent, or produce neither good nor bad results. From the farmer’s or milk-producer’s standpoint, none of these bacteria are desirable. Each milk-producer should make it a point to prevent their entrance and suppress their develop- Fic. 10.—Shows plate exposed one-half minute under cow’s udder treated by merely brushing with the hand; each little spot represents a colony of some kind of bacteria. (Bul. 87, Nebraska.) ment in milk and cream to as great an extent as possible. The creamery operator should endeavor to suppress all of the harmful germs, and foster the development of the desirable ones. The germs which are desirable belong to the acid-producing types, such as Streplococcus lacticus, and the associated flavor and aroma-producing types. such as Sire plococcus citrovorus. The harmful bacteria include those which produce bitter milk. red milk, blue milk, yellow milk, slimy milk, gas, and 62 FERMENTS IN MILK undesirable flavors and aromas. There are a number of species belonging to this group. The pathogenic germs, or disease- producing bacteria, must also be classed with the harmful bac- teria. It is not the intention in this work to give an extended discussion of this subject. For such discussion see special works on Dairy Bacteriology. Number of Bacteria in Milk.—The number of bacteria found in milk varies so much that it is practically impossible to state accurately the average number. The number of germs found varies according to several conditions, such as degree of cleanli- ness of cows, utensils, and milker; degree of purity of the atmos- phere when the cows are milked; the temperature at which the milk is kept and the time it is held. When the milk is being produced under the best practical sanitary conditions, the number of germs need not exceed 10,000 per cubic centimeter. Such results cannot be obtained unless extreme precautions are taken. Milk produced under average farm conditions seldom contains less than 50,000 germs per cubic centimeter shortly after the milking. Milk which is produced under filthy conditions, and which is several hours old, may contain several millions of bac- teria per cubic centimeter. Sources of Bacteria in Milk.—Bacteria are widely distributed in nature. They float in the atmosphere and adhere to particles of dust. Especially is this so in the dusty cow-stable. They are present in all well water to a greater or less extent, and are very abundant in streams and rivers. They are present in the soil to a depth of several feet, the number decreasing with the depth. As these germs are practically present everywhere, the sources of germs in milk may be said to be all around us. The principal sources of germs in milk are, however, unclean dairy utensils, unclean cows, and unclean surroundings. As these germs multiply chiefly by fission, or by one cell dividing into two, it is plain that the number of germs will increase very rapidly under favorable conditions. Under the most favorable condi- tions it requires approximately twenty minutes for this process of fission to take place. Some germs develop small bodies within the cell, called SOURCES OF BACTERIA IN MILK 63 spores. It is not difficult to destroy the sporeless cell by heat, but the spores are very resistant to unfavorable conditions. The spore-bearing bacteria are difficult to kill; boiling for a short time will not destroy them. Hammer is satisfied that they are destroyed by prolonged boiling. Another method is to heat the milk to destroy all the organisms in the vegetative stage, then cool it to a temperature favorable to growth and allow the spores to develop into the vegetative stage, and again apply heat. In this way milk can be rendered entirely sterile. A single heating A B a SS Fic, 11.—The wrong and the right kind of a milk-pail. A, the ordinary type of pail showing sharp angle between sides and bottom; B, the same properly flushed with solder so as to facilitate thorough cleaning. The lower figure represents a joint as ordinarily made in tinware. The depression a affords a place of refuge for bacteria from which they are not readily dislodged. This open joint should be filled completely with solder, (From Bul. 62, Wis.) under pressure (fifteen minutes at 15 pounds pressure) kills them at once. It has been demonstrated by several investigators that freshly drawn milk is not a good medium for bacteria to develop in. In fact, several experiments seem to indicate that milk acts asa germicide to certain varieties of bacteria. For instance, the cholera germ is to some extent destroyed in fresh milk, but it is not known to what extent. Organisms producing lactic acid check the multiplications of these pathogenic bacteria. This germicidal property is said to be more or less common to all the animal secretions. 64 FERMENTS IN MILK Effect of Thunder-storms on Souring of Milk.—It is a common impression that thunder-storms hasten the souring of milk. This was attributed to the electricity in the air accompanying the storm. Experiments by several investigators have proved that electricity does not have any effect on hastening the fer- mentative changes of milk. The reason why milk sours more quickly when an electrical storm is approaching is that the air temperature is usually higher then than at any other time. This higher temperature warms the milk and creates more favorable conditions for the rapid multiplication of the germs present in the milk. It is for this reason that milk sours more quickly during or previous to a thunder storm than at any other time. CHAPTER VI ABNORMAL MILK Colostrum Milk.— Colostrum is the milk yielded immediately after calving. As the time of calving approaches, a cow usually diminishes in her milk-producing capacity. Most cows become dry about two months previous to parturition. If they do not naturally stop giving milk, they should be dried up so as to have a seven weeks’ rest before calving. When the rest has been given, the cows yield, immediately after calving, milk which has a composition and characteristics different from those of normal milk. If the cow continues to give a copious flow of milk up to the time of calving and is not allowed any rest, the difference in the milk yielded before calving and after calving is comparatively slight. The composition of colostrum varies considerably during the first three days after calving. According to Engling, as reported by Richmond, the composition is as follows: Per Cent WiGitG Tian kts aed ereten arene Geno ala 71.69 a Soo Rae Bete aS Ree ERR SOE ee ee ey i Mia eee SISTED RR ENG Wer eae NEA ee Cea neta 4.83 ai ive. cee pemaetner re rie 15.85 SUBAT eet erate tana aater ht cite ees agi 2.48 UNG Sean ee in. 8 acta kates See 1.78 Colostrum greatly changes in composition and appearance as it gradually assumes the characteristics of normal milk. It is at first reddish yellow in color, and has a viscous and slimy con- sistency. It is a food which the newly born calf should not be deprived of, as it seems to be specially suited for the digestive tract of the young calf. 65 66 ABNORMAL MILK It will be seen from the above table that the water content of colostrum is less than that of normal milk. The fat content is also a little lower. The most striking characteristics of colos- trum, however, are the low content of sugar, and the large amount of albumen. Of the latter substance very little is present in normal milk. The mineral constituents of colostrum also run quite high. Its specific gravity varies from 1.046 to 1.079. When it is boiled, the nitrogenous matter coagulates. The colostrum is not considered suitable for food until about four days after parturition. Whenever it can be boiled without coag- ulating, it is claimed to be safe to use. At times a cow’s udder becomes inflamed after calving. In such cases the abnormal qualities of the cow’s milk will extend over a greater period of time than that mentioned above. Salty Milk.—The average chemical analysis of salty milk as calculated from results obtained by the analysis of such milk from four cows, given by Béggild,! is as follows: Wate in geet wt tater Mad inu eke QI .09 Pee ion ere Rane eee eta Orne 2.09 Nitrogenous matter.............. 2.90 DUAL ig he sires ates Set a 2561 ONG ia entee ters Sete e Nei omen a reat 85 It has an average specific gravity of 1.0244. Salty milk does not occur very often, but whenever it does occur, it is difficult, and, so far as known, impossible to cure without drying up the cow. Two samples of such milk have recently come within the authors’ notice. It had the appearance of normal milk, a foul smell, and a very salty taste. The two samples contained 1.7 per cent and 1.9 per cent of fat respectively. They soured and curdled in a normal way at living-room tem- perature in about thirty hours. At this stage they were very foul in smell, and unpleasant in taste. The cows which had produced this milk had both calved about three months previously. It occurred in the month of July, when pastures were quite good. The udders of the cows ' Maclkeribruget in Denmark. BLOODY OR RED MILK 67 were in an apparently normal condition. At first it was thought that some conditions in the pasture caused this abnormal milk. The cows were taken into the barn, and fed on dry food for two weeks, but without any change in the quality of the milk. Gradually they dried up. The secretion of this salty milk was believed to be due to the long time during which the cows had been yielding milk without any rest. They had been given no rest previous to the last calving. It is also believed that this quality of milk will occur more frequently when the cows are near the close of the lactation period. While the above two causes are perhaps the most common, they are not the only ones. Salty milk has been obtained in cases where these reasons could not be ascribed. Bdéggild has found that salty milk has been secreted by cows with abnormal udders. He has also demonstrated that it was the diseased part of the udder from which the salty milk was yielded. The healthy portion of the udder yielded normal milk. It is possible that an obscure, diseased condition of the udder may be the entire cause. Salty milk is of course undesirable in the dairy or creamery. It is very disagreeable to the taste, and in a fermented stage becomes very foul. Bloody or Red Milk.—Bloody, or red milk is caused, first, by an abnormal condition of the cow’s udder, which may or may not be apparent; and second, a red color may be developed in milk after standing, through the action of bacteria. The bloody milk, caused by an inflamed udder, often assumes a reddish-yellow appearance, and may, if not examined care- fully, be mistaken for colostrum. Bloody milk produced by an inflamed udder may be distinguished by small blood particles, which will settle to the bottom, and can be noticed if the sample is placed in a glass test-tube. In bloody milk caused by bacterial growth the blood does not show at the bottom, but instead, previous to stirring the milk or cream, it appears on the surface in small red dots. The red color which commonly occurs in milk is due chiefly to a species of germ called Micrococcus prodigiosus. 68 ABNORMAL MILK Colostrum will show reddish cream on the surface, but no blood- like material will separate out. Blue Milk.—Blue milk is quite commonly found. Formerly it was thought that this color was due to the condition of the casein in the milk, but since more has been discovered in regard to the effect of germ life upon conditions and properties of milk, it has been proved that blue milk is caused by bacteria ! (Bacillus cyanogenus). This particular germ produces the blue color in the milk only when the milk has an acid reaction. When sterile milk is inoculated with this particular germ, the blue color is not produced, but by the addition of a little acid, or by inoculating the milk with the bacteria that produce lactic acid, the blue color is produced. ‘This seems to be one of the instances of symbiotic action of bacteria in milk. There are probably other causes, but they are not known. This germ, according to Aikman, is killed by heating the milk to about 176° F. The germ ceases to work as soon as milk is coagulated. Yellow Milk.—According to Aikman,! yellow milk is caused chiefly by one species of bacteria, named Bacillus synxanthus. This micro-organism belongs to the group of ferments that act upon the fat of milk. There are different shades of yellow pro- duced in milk, caused by different species of bacteria, but the above-mentioned one is considered to be the principal cause. Some produce a brilliant yellow color, while other species first curdle the casein, and then digest or dissolve it into a yellow or amber-colored liquid. Ropy Milk. —Slimy or ropy milk is not common, but is sometimes encountered by milk-dealers and is caused by certain micro-organisms. Aikman mentions the fact that no less than eighteen different and distinct organisms have been identified as associated with this slimy fermentation. Most of the investi- gators agree that two organisms are chiefly responsible for the slimy condition. One of these is Bacillus lactis viscosus,2 which grows best in the presence of air and neither forms acid nor thrives in an acid medium. This germ has been found to be frequently 1C. M. Aikman, in “ Milk, Its Nature and Composition.” 2 Adametz, Landw. Jhr., 1891, p. 185. BITTER MILK 69 present in surface waters. Bouska broke off a sliver from a water tank which, when put into milk, inoculated it with an organism that produced ropiness. The very fact that milk dealers in cities are occasionally troubled with this sliminess in milk indicates that precautions are essential in order to avoid the presence of this ferment. The germ, when it once gains entrance to amilk establishment, is very difficult to eradicate. In order to overcome the trouble it may be necessary to cover the whole inside of the milk-store, and all of the vessels used for handling the milk, with sour coagulated milk. The lactic acid germs present in this milk gain ascendency over the germs causing sliminess and in that way the trouble may be eradicated. Streplococcus hollandicus is another species which produces sliminess in milk. It differs from the ferment mentioned above in that it grows in the absence of air and produces acid. It is used in Holland, in the preparation of the slimy whey (lange Wei) starter which is added to milk used in the manufacture of Edam cheese, just as we use a pure culture lactic acid starter in connection with Cheddar cheese-making. Sometimes milk is slimy when drawn from the cow—most frequently when there is inflammation of the udder. There are, in such cases, no bacteria present in the milk as the cause of the ropy or slimy condition. We quote Russell and Hast- ings: ‘The direct cause of the abnormal condition in milk is the presence of fibrin and white corpuscles from the blood, which form masses of slimy material; in such cases the trouble does not increase in intensity with age, nor can it be propagated by transference to another sample of fresh milk.” Bitter Milk.— This is one of the most common kinds of abnor- mal milk, and like some of the others, may have more than one cause. It may be due to some undesirable food that the cow has eaten, or to the development of certain germs in the milk. If caused by the food eaten by the cow, the bitter taste is recog- nizable immediately after the milk has been drawn. If it develops on letting the milk stand, it is caused by bacterial growth. Several germs have been found to be associated with the pro- 1 Milch Zeit., 1880, p. 982. MILK ABNORMAL 70 yo aduasaid ot] swoys € pue z ul pand “S]UDUUI9J sunvoy oyy sutonpoid “yur uy sua UOl]LJUSULIOJ Asse 3 JO Joyo SuLMOYS—- ZI “Oly MILK FROM COWS WHICH HAVE BEEN IN MILK 71 duction of this bitter flavor in milk. Conn has described a micrococcus which produces a bitter flavor, and Weigmann has described a bacillus which produces a similar effect. Nearly all of the investigators agree that the germs causing the bitter flavors in milk belong to the group which acts upon the casein. The bitter flavor is most commonly found in milk that has been heated and then cooled to a low temperature. The heat destroys the bacteria that produce lactic acid, but does not kill those that produce the bitter flavor, owing to the fact that they are spore- producing. The germs that produce a bitter flavor do not develop in milk that is partly soured, because an acid reaction is unfavorable to their growth. It was formerly thought that the organisms that cause the bitter flavor in milk produced butyric acid. This theory, however, has been largely overthrown, as it has been found that these germs are chiefly of the kind which peptonize the casein and produce gas. Milk from Cows which Have Been in Milk for a Long Period.— The difference in the composition of the fat yielded by cows in different stages of the lactation period does not seem to affect the quality of the milk to a noticeable extent. If the cows have been giving milk an unusually long time, the milk may become abnormal. The impurities in the small amount of milk yielded by a cow almost dried up are quite apparent, and the causes of the presence of these impurities are readily understood. The small amount of milk drawn from such a cow would contain a proportionately larger amount of dirt and germs than would a larger amount of milk drawn from a cow yielding more milk, providing the cleanli- ness of the udder and manner of milking were the same. Cows giving a good quantity of milk always seem to have a cleaner udder. This has been laid to the more vigorous circulation of.the blood in the udder of the cow that yields a larger portion of milk. When cows calve once a year. and have a rest of about seven weeks previous to parturition, if proper precautions are taken 72 ABNORMAL MILK concerning cleanliness, they seldom yield milk from which a first-class quality of butter cannot be produced. In practice calving does not always occur at regular intervals. Several instances have come within the authors’ notice where cows have been in milk for two years or more without coming in fresh. Such a condition happens quite frequently on small farms, where the cows kept are so few that it is deemed impracticable to keep a bull. As a consequence cows are not served at the proper time, and great irregularities in calving are introduced. At times it also happens that cows become barren. In such a case they are usually milked as long as they will produce even a very small quantity of milk. Milk produced under such con- ditions is likely to become abnormal in character. It may remain normal with a slight increase in the fat-content. The abnormal milk, so often complained of, is usually the result of similar circumstances. It is a common belief that milk yielded by such animals always contains a high fat-content, but it may contain very little fat, and may be salty. It may also appear normal, and the cream when separated appear viscous and dead. Béoggild states that at the creamery the milk from one barren cow has more than once produced difficult churning. Milk from Spayed Cows.—H. Lennat has given this kind of milk considerable study. He finds that milk from spayed cows may vary in quality to the same extent as milk from normal cows. The solids of milk, as a rule, increase as the spayed cow advances in the milk-giving period. This is especially noticeable in the fat, sugar, and casein. Such milk is considered to be of extra good quality, and is recommended as being especially suitable for infant-feeding. Milk from Sick Cows.—Too much cannot be said against the use of milk from sick cows. As soon as the cows decline in health, the quantity is noticeably decreased, and the quality is usually abnormal. The kind of milk yielded varies with different cows and different diseases, but it is interesting to note from the study of this subject, by several men, that the milk-secreting glands are quickly affected by disease and are unable to perform their proper functions. Even a slight derangement of the MILK FROM SICK COWS 73 digestive organs may have a marked influence upon the flavor of the milk and butter. When cows do not clean well after calving, the milk secreted by them always has an undesirable taste. During the time of sexual excitement of the cow, milk is usually decreased in quantity, and in a great many instances possesses a very disagreeable flavor. When a cow’s udder is inflamed, the milk usually assumes an abnormal condition. It usually contains large, white slimy lumps. According to Bang,! this condition is caused by a small round bacterium, and is contagious. When this germ is inocu- lated into the udder, the cow becomes feverish and the milk slimy. When cows become infected with tuberculosis to such an extent that the udder shows lesions and nodules, the composi- tion and appearance of the milk is altered considerably. Milk from such cows contains tubercle germs, appears yellowish- brown in color, and has an alkaline reaction. The composition of such milk has been studied in Denmark and reported by Boéggild to be as follows: AVM cle hareceaerare Se ere neta NAL ed rr ca 88.57 at eeS eek toc oti enue SesS Allpummiinord 8: 42s Gr cece 4a Ses ees 5.69 SUSATE srt oasis caine meen ate 1.25 BAS TD eres eu een | Metta tee RIA eee 04 These results represent the average of four samples taken from the diseased part of the udder. It will be seen that the greatest variation from normal milk consists in the small amount of sugar it contains and the high per cent of ash and nitrogenous matter. 1 Maelkeribruget i Denmark, by Boggild. CHAPTER VII VARIATION OF FAT IN MILK AND CREAM As the variations in the per cent of fat in milk and cream are due to such widely different causes, it has been found expedient to divide this chapter into two parts. PART I VARIATION OF FAT IN MILK The percentage of fat in normal milk varies a great deal more than that of any of the other constituents. Dr. Richmond reports that the fat of milk may go as low as 1.04 per cent and as high as 12.52 percent. Such extreme variations are, of course, abnormal. The fat-content seldom falls below 23 per cent or rises above 7 per cent. The fat-content of milk from a whole herd of cows varies only within comparatively narrow limits. The following are the chief factors which cause the fat-content of milk to vary: (1) Individuality of cows. (2) Breed of cows. (3) Time between milkings. (4) Manner of milking. (5) Whether the milk is fore or after milk. (6) Age of cow. (7) Advance in lactation. (8) Feed of cows. (g) Environment. (10) Condition of cow. 1. Individuality.—Whcether a cow will produce milk with a high or low fat-content depends upon something that is inherent in the individual animal. Cows in the same herd, under the same 74 VARIATION OF FAT IN MILK ~] Or conditions as to care, feeding, etc., will produce milk that differs widely in this respect. The secretory organs of the mammary gland are the large controlling factor, and these we cannot change. Even in the same breed we find animals that differ very widely, as the table below, compiled from complete records by Eckles. will indicate. These are average yearly tests for the highest and lowest testing animals in each breed. : : | | | Number | Highest | Lowest | | Breed of Per Cent | Per Cent | Cows of Fat of Fat a ed ETSCV 22 cores. Btehe er 76 | 7.00 | Asay | Shorthorm. ci.4..4 , | 25 | 4.3% 2.50 PROVSHEMM Pans ses sevens 4o | 38F = 60 | 2. Breed cf Cows.—The different breeds of dairy cattle have their distinctive ‘‘ breed characteristics,” and the most important of these are the quantity of milk they produce and its richness in butter-fat. The Channel Island breeds—Jersey and Guernsey—are noted for the high fat-content of their milk; the milking strain of Shorthorns and the Ayrshire breed produce a milk of medium richness, while the Holstein produces a milk somewhat lower in fat content. As to quantity of milk produced the order reverses itself. For all the breeds, excepting the Milking Shorthorn, the table which follows, giving the average production and composi- tion of the milk of the different breeds, is based upon Bulletin 156 of the Bureau of Animal Husbandry of the U. S. Department of Agriculture, which summarizes and digests the published reports of all the American experiment stations upon this subject. 3. Time between Milkings.—Where cows are milked twice a day—the common practice in the United States and Canada— the difference in the per cent of fat in the two milkings is quite marked, if the intervals are very unequal. On the other hand, if the intervals are equal, or nearly so, the difference is not great. 76 VARIATION OF FAT IN MILK AND CREAM AVERAGE COMPOSITION OF THE MILK OF DIFFERENT BREI:DS | | | | Yearly : Per Cent Milk Per Cent Pounds ae 2 oe Breed ea . s of Total Yield, of Fat of Fat : Solids Pounds Jersey.. fideo Dette tlemseroeatens 5508 | 5.14 283 14.9 Guernsey ness soe tances 9 5500 4.08 274 14.2 AYTShiNG 156) 25 eqs aoe aA 6533 3.85 252 12.9 Holstein........ Pea eR inte 3 8690 | 3-45 | 300 1.3 Milking Shorthorn..... ; 5500 | 4.00 | 220 13.0 Experiments made by Ingle bring these points out quite clearly. Five cows were milked at 6 A.M and 3 p.m. during a period of three weeks. The average fat-content of the evening’s milk was 4.26 per cent, while that of the morning’s milk was 2.8 per cent. Following this, for four weeks, the cows were milked at 5.30 A.M. and 5 P.M. and the average evening and morning tests were 3.80 per cent and 3.18 per cent respectively. Even here there was a difference of an hour in the length of the two inter- vals, which would account, largely, for the difference in test. It is claimed, however, that with equal intervals the evening’s milk will test slightly higher than the morning’s milk. This is attributed to greater activity of the fat-secreting cells when the cows them- selves are more active. Milking three times a day, as is the custom in Denmark, increases, to some extent, both the quantity of milk produced and the per cent of fat init. But the increase is not sufficiently marked to induce the average farmer in America to adopt this practice, except in the case of a cow which is an exceptionally large producer. 4. Manner of Milking.—Milking should be done in such a manner as to induce the cow to be sympathetic toward the milker. Hand milking should be performed quickly, but not roughly or in a way that will excite the animal or create discom- fort. The hand should close regularly and quickly from above downward, in such a way as to extract the milk quickly and efficiently. The finger ends should not press into the teats VARIATION OF FAT IN MILK tt uncomfortably, nor should the nails come into contact with the teat to the extent of irritating it. As will be seen in dealing with fore and after milk, the milking must be done thoroughly since the strippings are very rich in fat content. There is a marked difference between milkers. On this point we quote from Decker. ‘‘ By looking over the milking records of the University of Wisconsin, it was possible to pick out the cows milked by a certain milker, for he could (or rather did) Fic. 13.—The wrong way to milk cows. (From Glucose Sugar Refining Catalogue.) invariably get more and richer milk from the same cows than when the cows were milked by other men.” 5. Fore and After Milk.—The first milk drawn from a cow is very low in fat content, containing just a few tenths of a per cent of fat; while the last, the strippings, will test very high, often up to 8 to ro per cent. Van Slyke of the New York Station analyzed the different portions of the milk of a Guernsey cow, with the following results: 78 VARIATION OF FAT IN MILK AND CREAM | | | i Pounds | Per Cent | of Milk | of Fat | First portion... . Bie 0.76 | Second portiona: 205 cae resss 4.1 2.60 | Third PORUON..coacsGueVrss pace 4.6 538 Fourth Pottiomes .:4..0chyeee aes 5.8 9.80 The practical lesson to be drawn from this is that milking should be done efficiently and completely. 6. Age of Cow.—As already pointed out, the richness of a cow’s milk is very largely determined by heredity. She will not produce rich milk during one lactation period and poor milk during another. However, age has its influence. Normally there is a marked increase, from year to year, in the quantity of milk given, with a tendency to a slight increase in the fat-content, until a cow reaches maturity. Then, in the ordinary course of events, we may look for a gradual decline. The following is quoted from Eckles, whose investigations were both extensive and thorough: ‘On the average, a well-grown two-year-old may be expected to produce 7o per cent, a three-year old 80 per cent and a four-year old go per cent of the milk and fat that she will produce when mature.” ‘The average fat-content remains practically constant from year to year, except that after the cow is eight or nine years old the percentage of fat always declines slowly and gradually with advancing years.”’ 7. Advance in Lactation.—This is a factor that materially influences both the quantity of milk produced and its fat-content. When a cow freshens she will probably, if in reasonably good condition, produce milk with a slightly higher per cent of fat in it than there will be a little later. With this exception the quan- tity of milk produced and the per cent of fat in it usually remain fairly constant during the first three or four months, after which there is a gradual decline in the quantity of milk produced and a steady increase in its richness. But cows differ very widely in the rate of increase in the fat-content of their milk as they advance in their lactation period. The following table gives the VARIATION OF FAT IN MILK 79 records of two cows in the same Canadian herd, both of which freshened in the spring and at practically the same time—also the average for fourtecn cows at the Geneva Station: | Cow No. 1 | Cow No. 2 | Geneva (14 cows) SNM Tit hos fect em ce ee ee Ne ae No. | | | 4 Pounds | Per Cent | Pounds | Per Cent | Pounds Per Cent of Milk , of Fat | of Milk of Fat | of Milk | of Fat | Ser eet | rete all rere cree oe! | samen Peon I 540 | brad | O14 | 38 753 A508 2 | 618 | 3 | 704 | ae | 780 3. 74 3 | 622 ae | fie |) aon | pie 3.71 4 723 3.5 | ar | 3.8 036 3.84 5 gq: |) ea | “tog 4.1 588 3.87 6 636 =| 3.90 «| 627 | 44 | 594 3.90 7 bor 4co° |) S04 |} 4.6 | 370 3.94 8 540 4.1 | 502 | Sr 480 3.80 9 | 427 4.1 ) 461 53 375 3.92 10 214 | 4.2 | 47 7.6 282 4.16 II Joveetes | eee Pee PS 168 4.55 | | 8. Feed of Cows.—There was at one time a very gencral belief, which still has its advocates, that the per cent of fat in milk varies with the nature of the food the cow receives; but many investigations made both in America and in Europe have shown that, practically speaking, the richness of a cow’s milk is not influenced by her food. A narrow ration, one made up quite largely of concentrates rich in protein, will stimulate the milk flow, a fact which is well known and made use of by those experienced in the fitting and feeding of cows for high official records; but it does not increase the per cent of fat in the milk. Observations by the Copenhagen (Denmark) Station over a period of ten years, and including about 2000 cows, led the observers to conclude that foods high in protein content may possibly raise the fat-content of the milk to the extent of 0.1 per cent—a very slight increase if actually an increase at all. Lindsay of the Massachusetts Station found that a ration with a 80 VARIATION OF FAT IN MILK AND CREAM large excess of protein stimulated the milk flow to the extent of 15 per cent, but he concluded that the per cent of fat in the milk is not influenced by the food a cow receives. The addition of such abnormal foods as tallow, lard, palm and oleo oils to a cow’s ration, or such a radical change of food and environment as from stable to pasture conditions, may cause a temporary change in the per cent of fat in a cow’s milk, but the change is only temporary. g. Environment.—Such unfavorable conditions as exposure to inclement weather, sudden changes in temperature, and poorly ventilated barns will cause a decrease in the milk flow. Experi- enced cheese and butter-makers have noted a very serious falling off in the output of their factories within a comparatively short time, when the cows were exposed to low temperatures and cold storms. Under continued exposure to unfavorable environment there may be, at first, a temporary increase in the per cent of fat in the milk. Reasonable exercise, under suitable weather conditions, is favorable to both health and a large production, but excess of exercise is not desirable. Where cows are confined to the stable, without exercise, the production may be quite satisfactory, but these conditions are detrimental to the health of the animal and, in the authors’ opinion, are contributory to the spread of tuber- culosis ina herd. In Denmark it is the common practice to keep the cows closely confined, without exercise, during the winter months, and tuberculosis is very prevalent amongst the herds of that country. To secure the best results we must study the comfort of the animal, and under the head of comfort we include favorable temperature, clean healthful surroundings and the avoidance of rough treatment and excitement. 10. Condition of Cow.—TIf a cow be in a high state of flesh when she freshens, her milk will test much higher during the first few weeks than it otherwise would. Investigations made by Professor Eckles of Minnesota University bring this point out very clearly. We submit the following table based upon work done by him: VARIATION OF FAT IN CREAM 81 | | | Time after | No.207 | No. 217 No. 300 Calving Days Per Cent Per Cent Per ‘Cent 2 2.6 Ae AGS 5 4.8 4.2 4.2 To 3.9 3-5 4.1 15 Bo ee | 3:0 20 2.5 3-4 3.6 Months 3 2.6 3.0 3.6 6 2.4 3.5 4.0 9 3.0 3-4 12 | 253 4.1 | | Aver. for Year 2.8 3.4 3.55 Compare the first part of this table with that of the preceding table in connection with ‘* Advance in Lactation Period.” On the other hand, Eckles found that when a cow begins to put on flesh there is the very opposite tendency, namely, for the per cent of fat in her milk to decline. PART II VARIATION OF FAT IN CREAM The percentage of fat in cream delivered to creamcries or for city trade varies considerably from day to day, and a great deal of dissension ariscs from the fact that the producer does not always understand all the factors that are responsible for this wide variation. Extensive work has been done by Professor O. F. Hunziker, Purdue University, and similar work has been carried on at the Danish Experiment Station at Copenhagen. The work done at Purdue and other experiment stations plainly and conclusively shows that there are a great variety of factors and conditions which control the richness of cream. These factors influence the richness of the cream before it leaves the farm and cannot be 82 VARIATION OF FAT IN MILK AND CREAM controlled by the creameryman, who receives the cream after it has been separated. It is physically impossible to produce cream of exactly the same richness from different skimmings under the gravity method of creaming. It is impossible to so operate the spoon, ladle or skimmer as to remove the same amount of skim-milk with the cream each time. Where the skim-milk is drawn from the bottom of the can it is equally impossible to so gage the operation as to leave cream of the same richness in the can at each skimming. Gravity cream, or cream obtained by gravity skimming, is sure to vary in richness, and it is not difficult for the producer to realize the causes of variations under this method of creaming. It is more difficult, however, to convince him that the richness of the cream will vary where the small centrifugal or farm separator is used. The separator is one of the most perfect pieces of farm machinery in use, and is accordingly expected to do nearly perfect work. It is only reasonable that the user of the small centrifugal machine will expect to produce a uniform quality of cream; hence, when he sells this cream and finds that the test is not the same as it was on the previous day he suspects that something is wrong. The small farm separator does produce the same richness of cream from different skimmings, provided that it is adjusted properly, that it is operated in strict accordance with directions which accompany it, and that the richness, condition and temperature of the milk, and the proportion of water or skim-milk used in flushing the bowl to the amount of milk separated, are the same. The following are the chief factors which influence the per cent of fat in cream: (x) Cream screw adjustment. (2) Richness of milk. (3) Rate of inflow. (4) Speed of machine. (3) Temperature of milk. (6) Amount of water or skim-milk used to flush the bowl. 1. The Cream Screw.—The richness of the cream obtained from any farm separator is primarily determined and regulated VARIATION OF FAT IN CREAM 83 by the cream screw. The centrifugal separator has two main outlets, namely, the skim-milk outlet located near the periphery or outer wall of the bowl, and the cream outlet, located near the center of the bowl. When the milk enters the revolving bow] it is separated into two layers, the skim-milk and the cream. The skim-milk, being heaviest, is thrown against the walls of the bowl where it escapes through the skim-milk outlet. The cream is drawn toward the center of the bowl. where it rises and is discharged through the cream screw or cream outlet. The cream screw is a small threaded bolt with a very minute opening. This bolt can be turned so as to move the opening nearer or farther from the cen- ter of the bowl. When turned toward the center it delivers richer cream, because a smaller proportion of the milk is taken as cream. When turned out from the center it delivers thinner cream, because a larger proportion of the milk is taken as cream. 2. Effect of Richness of Milk on Richness of Cream.—The richer the milk, the richer will be the cream. With the cream screw set to deliver a certain and definite richness of cream and all other conditions normal, the separator will deliver a definite ratio of skim-milk and cream. This ratio varies according to the way the cream screw is set. Under average conditions it may be about 85 to 15; that is, for each 100 pounds of milk separated the separator delivers 85 pounds of skim-milk and 15 pounds of cream. If all conditions are the same, this ratio of skim-milk to cream remains constant. Changes in the richness of the milk cannot alter the proportion of skim-milk to cream delivered. No matter how rich or how poor the milk, each 100 pounds of milk will yield 85 pounds of skim-milk and 15 pounds of cream. But because practically all of the fat goes into the cream, the cream will contain more fat from the separation of rich milk than from that of thin milk. This fact is graphically illustrated in Fig. 14. The illustration (Fig. 14) conclusively shows that, all other conditions being the same, 3 per cent milk produces 20 per cent cream, 4.5 per cent milk produces 30 per cent cream, and 6 per 84 VARIATION OF FAT IN MILK AND CREAM cent milk produces 40 per cent cream. Changes in the richness of milk cause changes in the richness of the cream. Any condi- EFFECT OF RICHNESS OF MILK UPON THE CREAM 100 LBS. OF 3% MILK CONTAINS 3 LBS. OF FAT SKIM-MILK 15 LBS. OF CREAM=3 LBS. OF FAT | fesT OF CREAM =20% 100 LBS. OF 4.57 MILK CONTAINS 4.5 LBS, OF FAT SKIM-MILK 15 LBS.OF CREAM =4.5 L8S.OF FAT TEST OF CREAM=30% 4.5 109 LBS. OF 6% MILK CONTAINS 6 LBS. OF FAT | pee ‘as 85 LBS. SKIM-MILK 15 LCOS.OF CREAM=G L&S.OF FAT TEST OF CREAM =40% 3 : 6 x109=20% 75 *1090=40% | vw 75 *100=30% Fic. 14. tion, therefore, that affects the richness of the milk will also influ- ence the richness and the test of the cream. Conditions that May Cause Changes in the Richness of the Milk.—During the early summer months the milk is usually comparatively low in butter-fat. This is caused by such factors as the freshening of the cows, change from dry feed to succulent pasture and a natural and inherent tendency of the cows toward a decrease in the richness of their milk in early summer. Toward fall and early winter the opposite is the case. The advanced state of the period of lactation and the change from succulent to dry feed cause the milk to become richer in fat. It is obvious, there- fore, that in the fall and winter the cream test tends to be higher than in spring and early summer. Again, it frequently happens that even in winter there is a sudden drop in the cream test. This may be due to the fact that some of the cows yielding rich milk dry up or that some cows come in fresh or a new animal may be brought into the herd. The seasonal variations in the richness of the cream may be reduced by turning out the cream screw a trifle in the fall and by turning it in during the spring of the year. VARIATION OF FAT IN CREAM 85 3. Effect of Rate of Inflow on Richness of Cream.—The greater the amount of milk passing through the separator of a definite capacity per hour, the thinner will be the cream. The skim-milk outlet of the bowl is constant. It can dis- charge so much skim-milk and no more. It offers the first avail- able exit for the milk in the bowl. Since it is located at the periphery of the bowl toward which the skim-milk is forced, it discharges skim-milk. All the milk that flows into the bowl in excess of what the skim-milk outlet can discharge, leaves the separator through the EFFECT OF RATE OF INFLOW UPON RICHNESS OF CREAM NORMAL INFLOW | — LARGE INFLOW SMALLINFLOW | 300 LBS. OF 4% MILK 350 LBS. OF 47 MILK 270 LBS. OF 4) MILK CONTAINS 12 LBS, OF FAT CONTAINS 14 LBS. OF FAT CONTAINS 16.6 LBS. OF FAT 255 LBS. 255 Las. SE SKIM-MILK 45 LES. CREAM CONTAINS 95 LBS. CREAM CONTAINS 15 LBS. CREAM CONTAINS 12 LES. FAT 14 LES. RAT 10.3 LBS. FAT TEST OF CREAM =26.7% TEST OF CREAM =14.7% TEST OF CREAM =72% 12 ee Sa ee Gas = ¢ 19.8 00 = 724 ye * 100 =26.7% ge * 100 =14.7%% ig ® 100= 72% | FIG. 1. cream outlet or the cream screw. The cream outlet, being located near the center of the bowl where the cream gathers, delivers cream. The cream outlet then serves as the overflow. The greater the amount of milk running into the bowl in excess of the capacity of the skim-milk outlet, the greater is the overflow, the more milk will leave the bowl through the cream outlet and the thinner will be the cream. If the separator is so adjusted that, under normal conditions, each 100 pounds of milk produces 85 pounds of skim-milk and 15 pounds of cream, a 300-pound capacity machine 86 VARIATION OF FAT IN MILK AND CREAM will deliver 85 300+100 or 255 pounds of skim-milk and the remainder, the overflow, will be cream. In this case the amount of cream discharged will be 45 pounds (300—255=45). If the separator is forced beyond its capacity, that is if more than 300 pounds of milk are run into the machine, the skim-milk dis- charged remains the same and the cream discharged receives the extra milk. Running 350 pounds of milk into the machine, for example, causes the separator to yield 255 pounds of skim- milk and 95 pounds (350—255=95) of cream. If the milk inflow is reduced below the capacity of the cream, say to 270 pounds, the skim-milk discharged remains the same (255 pounds) and the cream discharged is 15 pounds (270—255=15). The effect of these variations in the rate of inflow on the richness of the cream is shown in Fig. 15. The above diagram shows that almost any richness of cream may be obtained from the same milk and the same separator according to the amount of milk that flows into the bowl per hour. A normal inflow produced 26.7 per cent cream, a large inflow produced 14.7 per cent cream and a small inflow produced 72 per cent cream. Even the fullness of the pan or tank from which the milk runs into the bowl affects the richness of the cream. The fuller the tank the more rapidly will the milk flow into the bowl owing to a few inches of additional pressure. If the tank is kept filled to the brim the cream will be thinner than when the tank remains only one-third full. Every separator is equipped with a simple device called the Float ” to regulate the inflow. The float fits into the receiving cup of the bowl. When too much milk flows into the bowl the float rises and partly shuts off the outlet of the milk supply tank. When too little milk runs into the bowl the float recedes and the supply tank delivers more milk. The simplicity of the float has had a tendency to belittle its value in the mind of the average dairyman, with the result that ce on many farms it is not used and has been discarded. Bearing in mind the marked effect of the rate of inflow on the richness of the cream it seems inconsistent to accuse the creamery of inac- VARIATION OF FAT IN CREAM 87 curate testing when the separator float is a conspicuous part of the scrap pile on the farm. 4. Effect of Speed of Machine on Richness of Cream.—The speed of the revolving bow] produces the force—centrifugal force which drives the skim-milk out of the bowl. The greater the speed, the greater the centrifugal force and the more rapidly the skim-milk leaves the bowl. An increase in the speed, there- fore. forces more skim-milk through the: skim-milk outlet. This means less milk for the cream outlet and consequently NORMAL SPEED LOW SPEED HIGH SPEED 100 LBS. OF 4.4% MILK 100 LBS. OF 4.4% MILK 100 LBS. OF 4.47 MILK CREAM CONTAINS 4.4LBS.FAT|CREAM CONTAINS 2.1 LBS.FAT|CREAM CONTAINS 44LBS.FAT Raven cecal teeny 8S. CRE 10 LES. CREAM if 19 LES, CREAM 93 LBS. etary 81 LBS. SKIM-MILK | SKIM-MILK SKIM-MILK | . CREAM CONTAIN 19 LBS. CREAM CONTAINS 7 LBS. CREAM CONTAINS 44 (GS. FAT " ° 2.1 LBS. FAT 4.4 LBS. FAT TEST OF CREAM =44% TEST OF CREAM =11% TEST OF CREAM =63/¢ a ‘ =63% 44x 100 =44% St, 100 =11% 44 x 100 = 03% Fic. 16. richer cream. A decrease in the speed forces less skim-milk through the skim-milk outlet, more milk has to be discharged through the cream outlet and the cream, therefore, is thinner. These facts were established experimentally. A separator was so adjusted that, when run at normal speed (60 turns of crank per minute), it delivered oo pounds of skim-milk and ro pounds of cream. When the speed was lowered to 25 turns of the crank per minute, the skim-milk outlet discharged only 81 pounds of skim-milk, increasing the amount of cream delivered to 19 pounds. When the speed was raised to 75 revolutions per minute, the skim-milk discharge increased to 93 pounds, reducing 88 VARIATION OF FAT IN MILK AND CREAM the amount of cream to 7 pounds. The effect of these variations of speed on the richness of the cream arc shown in Fig. 16. Fig. 16 demonstrates conclusively that high speed yields rich cream and low speed vields thin cream. At normal speed, the cream tested 44 per cent fat, at low speed 11 per cent fat, and at high speed 63 per cent fat. The very low test of cream from a low speed separation is, in part, due to the fact that a large amount of fat (about one-half of the fat of the milk) is lost in the skim-milk. How to Run the Separator at the Right Speed.—The proper speed is indicated on the crank of the machine. It varies from about 4o to 60 turns of the crank per minute, according to the make of the separator. Ifa separator is to yield cream of uniform richness, it must be given the same speed at each skimming. This is possible only if the operator times himself frequently, counting the revolutions of the crank with watch in hand, or by the use of a patent speed indicator. The absence of this pre- caution renders the work unreliable. The general tendency on the part of the operator is to overestimate the amount of work he puts into the machine; the machine is run at too low a speed. Even the same operator may vary the speed very considerably at different times, depending on his frame of mind and physical condition. Again, where different persons operate the machine, there can be but little uniformity of speed, unless cach person makes an effort frequently to count the crank revolutions by the watch. The use of a gasoline engine or some constant power will tend to give a more uniform cream than when the machine is operated by hand. 5. Effect of Temperature on Richness of Cream.—The higher the temperature the thinner the cream. The temperature influences the rate of inflow. The warmer the milk the more rapidly will it run from the supply tank into the bowl. Since the capacity of the skim-milk outlet is fixed, the increased inflow of the milk is discharged through the cream outlet, producing a thinner cream. [Experimental results showed that when the separator was so adjusted as to yield 15 pounds of cream and 85 pounds of skim-milk from every too pounds of milk separated VARIATION OF FAT IN MILK AND CREAM &9 at 90° F., a drop in the temperature to 50° F., caused the amount of cream delivered to decrease to 5.5 pounds and the skim-milk to increase to 94.5 pounds. These results are graph- ically illustrated in Fig. 17. The results expressed in Fig. 17 show that when the tempera- ture of the milk is decreased below normal, the richness of the cream increases. At go” F., the cream contained 26 per cent fat. At 50° F. it contained 4o per cent fat. The increase in the test of the cream from the cold milk would be still greater, if it were EFFECT OF TEMPERATURE UPON RICHNESS OF CREAM TEMPERATURE OF MILK 90-95 F. TEMPERATURE OF MILK 50 F, 100 LBS. OF 3.9% MILK 100 LBS. OF 3.9% MILK CREAM CONTAINS 3.9 L8S. FAT CREAM CONTAINS 2.2 LBS. FAT 5.5 LAS.CREAR 85 LBS. 26% 94.5 LBS. SKIN -MILK SKIM-MILK 15 LAS. CREAM CONTAINS 3,9 LBS. FAT 5.5 LBS. CREAM CONTAINS 2.2LBS, FAT TEST OF CREAM =26% TEST OF CREAM =407 | 75 4100 =26% 226100 =40% Fic. 17. not for the fact that at that temperature a large amount of fat is lost in the skim-milk. The Proper Temperature for Separation.—The best practical temperature at which to separate the milk on the farm is about go’ F. The milk is never in better condition for separation than immediately after it is drawn. It then has a temperature of about go” F. to 95° F. If the milk is allowed to cool to a much lower temperature, as is the case in the winter, when the separator is operated only once per day, or once in several days, it should be warmed up to about go° F. before it is run through the separator; otherwise there is bound to be a considerable variation in the cream test and also an increased loss of fat in the skim-milk. 90 VARIATION OF PAT IN MILK AND CREAM 6. Effect of Amount of Water or Skim-milk Used to Flush the Bowl.—The more water or skim-milk used to flush the bowl, the thinner will be the cream. At the conclusion of the separation there remains in the bow] and in the cream-discharging pan a considerable quantity of cream. In order to save this cream it is necessary to flush the bowl with water or with skim-milk. If enough water or skim- milk is used the cream remaining in the separator is flushed out and discharged into the cream can. The extent to which the cream test is lowered by flushing the bow] will depend on the amount of water or skim-milk used, the manner in which it is added and the amount of milk separated. If just enough water or skim-milk is used to thoroughly rinse out the bowl and the pan or tank, the richness of the cream is not materially changed. An excess of water or skim-milk may cause a considerable decrease in the richness of the cream. If the water or the skim-milk is poured into the supply tank and is allowed to run into the machine gradually, most of it will escape through the skim-milk outlet and the richness of the cream will be changed but very little. If the water or skim-milk is poured directly into the receiving cup of the bowl, with the float discarded, it will run into the bowl much more rapidly and more of it will get into the cream. The smaller the amount of milk used for the separation, the more the cream is thinned down by the flushing. Experimental data show that the cream test may be lowered from 1 to 10 per cent according to the amount and conditions of the flushing. Enough water or skim-milk has been used when the cream discharge begins to appear watery. Hot water or warm milk will drive the cream out of the bowl more quickly and may produce a higher testing cream. The Proper Richness of the Cream.—Too thin cream is not satisfactory because it leaves but a small amount of skim-milk for the use of the dairy farmer, it increases the cost of transpor- tation, it sours and spoils more rapidly, it prohibits the use of a reasonable amount of starter for ripening at the creamery, it does not churn out exhaustively, and yields an excessive amount VARIATION OF FAT IN CREAM 91 of buttermilk. augmenting the loss of fat and therefore reducing the churn vield. Too thick cream is undesirable because it may cause the sep- arator to clog, it increases the loss in handling, it is difficult to properly sample and interferes with the accuracy of the test. The most satisfactory cream tor butter-making is that which tests about 30 to 40 per cent fat. It is desirable to produce somewhat richer cream in summer than in winter to prevent excessive souring in summer and difficult handling in winter. Effect of These Factors upon the Skimming Efficiency of the Separator.—The richness of the milk has no effect on the com- pleteness of the skimming. The richness of the cream, within reasonable limits. has no effect on the completeness of the skimming. The skimming of very rich cream causes a large loss of fat in the skim-milk in the case of certain makes of separators. due to the clogging of the machine. The Rate of Inflow Greatly Affects the Completeness of the Skimming.—Ii more milk is run into the machine than the capac- ity of the machine calls for. there is excessive loss of fat in the skim-milk. If the rate of inflow is reduced below the capacity of the skim-milk outlet. the separator delivers no cream at all. The Speed of the Separator Greatly Influences its Skimming Efficiency.—Excessive speed does not increase the completeness of the skimming. Insufficient speed increases the loss of fat in the skim-milk. A separator run at half speed may cause one-half of the fat of the milk to be lost in the skim-milk. The Temperature of the Milk Affects the Skimming Efficiency of the Separator.—For all practical purposes a temperature of go” F. causes efficient skimming. At lower temperatures there is excessive loss of fat in the skim-milk. The Amount of Water or Skim-milk used to Flush the Bowl Regulates the Amount of Fat Lost in the Bowl and Pan.—If the bowl is not flushed at all, or insufficiently, varying amounts of fat may be lost. If the bowlis flushed until the cream discharge is watery, most of the fat in the bowl and pan is recovered and saved. CHAPTER VIII RECEIVING, SAMPLING, GRADING AND TESTING MILK AND CREAM Receiving and Grading of Milk and Cream.—The man who receives and samples milk at a creamery should be accurate and quick at figures, have ability to grade and select milk, and to stimulate interest in the production of good milk. He should also be able to reconcile and satisfy patrons. The method employed in some creameries of allowing a boy with immature judgment to weigh and sample milk should not be tolerated. The person who weighs and samples milk and cream comes in direct contact with the patrons. Therefore, he is a strong factor in serving the best interests of the creamery. In many of the best butter and cheese factories in the country the head maker or manager in charge is usually found at the weighing can. This gives him the opportunity of studying the raw material from which he is expected to make a high grade of butter or cheese. Some of our large central plants pay the highest salary to the man who has the ability properly to grade the cream and prepare the starters. This requires a fine sense of smell and taste, which is not possessed by everyone. The first step in the receiving of milk is to ascertain the quality of the milk delivered by the patrons. It is now a recognized fact that the best butter cannot be produced from defective or abnormal milk or cream, no matter how many improved methods are employed in the manufacture. In view of this fact, and of the knowledge we now have of the transmission of undesirable germs from one sample of milk to another, and also the probability that some of the patrons will deliver poor milk, it is essential that the milk or cream be graded when it is delivered at the creamery. 92 RECEIVING AND GRADING OF MILK AND CREAM 93 In the grading of milk or cream, different methods can be used for detecting abnormal milk: (1) through the senses, taste, sight. and smell; (2) by the acid tests; (3) by the fermenta- tion test; (4) by heating; (5) by the Babcock test and the lac- tometer. While all of these tests are applicable to the grading of milk, only the first and a portion of the fifth are usually applied to cream. 1. Detection of Abnormal Milk and Cream through the Senses.— In order to detect the different kinds of defective milk one must be endowed with acute senses of smell, taste, and sight. When the milk is in a good condition, it has a pleasant smell and sweet taste,and appears normal. This applies equally to cream with the exception that not all cream for butter-making is sweet. If milk has a disagreeable smell and taste it cannot produce good butter. As a rule, the quantity of defective milk brought into the average creamery is much in excess of that of really perfect milk. As a consequence it would not be practicable to separate all the defective milk into one class and the perfect into another. The question as to where the line should be drawn between the good, medium, and very bad milk or cream, must depend upon the judgment of the receiver, and in a great measure upon the local conditions. Some of the creameries have no facilities for handling different grades of milk, and some sell butter on a market where no sharp distinction is made between good and poor butter. Others have, through experience, satisfied them- selves that under American creamery conditions it does not pay to make too many grades, nor does it pay to grade too closely. Two, or at the most three, grades of butter can at times be man- ufactured in one creamery profitably. It is advisable to reject sour and abnormal milk. If accepted, it should not be mixed with the remainder of the milk, as it might contaminate all of it; or, the sour milk might cause coagulation, and thereby clog up the separators. Ifa can of milk is sour, but otherwise clean, it is not necessarily unfit for the production of first-class butter. If retained until after the sweet milk has been skimmed, it may be run through the separatcr successfully. 94 GRADING AND TESTING MILK AND CREAM 2. The Use of Acid Tests.—Some creameries are now grading the milk or cream according to the amount of acid it contains. Mann’s and Farrington’s acid tests can both be used, but a more rapid and convenient way is to use a solution prepared from Far- rington’s tablets. The solution is prepared by dissolving the tablet in warm water, using an ounce of water toa tablet. When one part of this alkaline solution and one part of milk are mixed together in a cup and the solution still retains a pink color, it shows that there is less than .1 per cent acid in the sample tested. If two parts of alkali and one part of milk are mixed and the mixture remains pink, then there is less than .2 per cent of acid. If the mixture becomes colorless, it shows there is more than .2 per cent acid in the sample. If three measures of alkali to one measure of milk are taken, and the mixture remains pink, there is less than .3 per cent of acid, etc. By means of such a test the acidity can quickly be determined. The sample cups should be numbered to correspond with the number of each patron. The results of the tests should be noticed at once, as the action of the atmosphere affects the color. The acid tests are of value in grading cream, as a sour sample of milk or cream is either old or has been improperly kept and handled. The number of grades of cream and milk and the max- imum limit of acid each grade can contain, are factors which must be decided according to Jocal conditions, by the operator. 3. Use of the Fermentation Tests.—Curdled, ropy, red and blue milk can, as a rule, be readily detected without the appli- cation of a special test, but there are cases when a person’s senses are not sufficiently acute to detect samples of milk con- taining undesirable fermentations. Several instances have recently come within the authors’ notice. A neighboring cream- ery was infested with a peculiar fermentation that caused a very rank flavor in the butter. The milk that came to the creamery was carefully examined, but the source of the trouble could not be located. The cause could not be ascertained without the use of the fermentation test. It is in such instances that a fermentation test is of special value. As a rule, the trouble is first caused by milk from one RECEIVING AND GRADING OF MILK AND CREAM 95 particular patron. This milk may appear to be normal, and yet contain germs which are very undesirable for the manufacture of the best quality of butter. Fermentation Tests. —There are two tests which may be of general use; namely, the “ Wisconsin Curd Test’ and the “Gerber Fermentation Test.” The former is used in cheese factories, but the latter is to be recommended in testing milk for butter-making. Gerber Test—The apparatus for this test consists of properly made glass tubes resting upon a rack which fits into a small round tin tank, about two-thirds full of water. The temperature of this water can be controlled by means of a lamp kept burning underneath, or by the use of steam. The milk delivered by dif- ferent patrons is put into the glass tubes, and these are numbered so as to indicate to which patron each belongs. The tempera- ture should be kept at about 104° to 106° F. for about six hours. Then the tubes are taken out, the milk shaken, and the appear- ance, smell, and taste of the milk noted. The tubes are warmed again for about another six hours, when they are again examined. If any samples contain a preponderance of abnormal ferments, the fact will usually appear in less than eighteen hours. If milk does not coagulate in twelve hours, or become abnormal in some way, it is considered good. The special apparatus mentioned above is not absolutely essential, nor is the temperature employed considered by the authors to be the most suitable to give reliable results. Ordinary sample jars can be used, instead of specially prepared tubes. After the milk has been placed in the jars they can be kept in any convenient place, at a temperature of about 98° F. The best place to keep them is in a vessel containing water, the temperature of which can be controlled. Wisconsin Curd Test.—This test consists of taking some milk in a jar and adding about ten drops of rennet, which coagulates the milk. The sample is allowed to stand until the curd hardens, when it is cut into small pieces with a case knife; the whev is drawn off, and the curd allowed to stand at a temperature of 98° F. Tf there are any undesirable forms of bacteria present, 96 GRADING AND TESTING MILK AND CREAM they will reveal themselves by developing small holes in the curd, usually accompanied by a bad odor. This test is a very ingenious one for cheese-making. In butter-making the Gerber Fermentation Test, or a similar one, is more convenicnt. 4. Grading Milk by Heating.—This test is not very much Fic. 18.—Troemner’s Babcock cream-testing scales. used in creameries; but in cheese factories the heating of milk in order to ascertain its suitability for cheese-making is practiced to a considerable extent. The heating test. which is in common use in Canada, consists of heating a small sample of the milk to be tested to 120° F. If it will stand this temperature without coag- ulating, it is considered to be good milk. If it coagulates when heated to this temperature, it is too sour to be used for cheese. This heating may be considered an acid test. When milk contains about .3 per cent acid, it usually coagulates x : when heated. It should be borne in Fic. 19.—Troemner’s Bab- ; z . ; es cock cream-testing scales. mind in this connection that different samples of milk, containing exactly the same amount of acid, do not coagulate at the same tempera- ture. Some samples will coagulate upon heating when contain- ing a little less than .3 per cent acid, while others will not coagulate until more than .3 per cent acid has developed. In practice the temperature (120° F.) is not always closely RECEIVING AND GRADING OF MILK AND CREAM 97 adhered to. A small portion of the sample to be tested is put into a tin cup, and the cup is put into hot water or over a jet of steam. When the milk is hot its characteristics are noticed. 5. Use of Babcock Test and Lactometer.—These tests are of special value in detecting watered or skimmed milk. When- ever a sample of milk appears watery or blue, it is fair to presume that water has been added. ‘The test for specific gravity and the test for fat can then be applied to such samples of milk. Asa rule composite samples are taken daily at creameries, and the patrons Fic. 20.—Acid carboy trunnion. Fic. 21.—Acid hydrometer. paid according to the fat delivered. For this reason water adul- teration is not very common at creameries, but is practiced to a greater extent in the milk-supplies of cities. The use of the lac- tometer in connection with the Babcock test has already been referred to under the heading of ‘‘ Specific Gravity of Milk.” The Babcock test is now in such general use in America for determining the per cent of fat in milk and cream that no other will be dealt with here. At one time the Oil-test Churn was used quite exclusively for testing cream, but it has gone almost entirely out of use. 98 GRADING AND TESTING MILK AND CREAM The Babcock test always deals with weight. For instance, when we say that a sample of milk tests 4.0 per cerft or that a sample of cream tests 30.0 per cent, we mean that in 100 pounds of the milk there are 4 pounds of fat, or in 100 pounds of the cream there are 30 pounds of fat. For the sake of convenience a sample may be measured into a test bottle instead of being weighed, when the accuracy of the result is not likely to be affected. Milk may be sampled for the Babcock test with a pipette, because the specific gravity of milk is always so nearly the same that the same measure of milk from widely different sources has, for all practical purposes, the same weight, and because milk is in such a liquid condition that it neither holds air nor adheres to the wall of the pipette. Rich cream, on the other hand, has a lower specific gravity than thin cream; moreover, cream is $0 syrupy or viscous in its nature that it will hold air or other gas and stick to the wall of the pipette. For these different reasons, the authors wish to state emphat- ically, that when cream is tested for commercial purposes, as at a creamery, it should never be measured but always weighed into the test bottle. The measuring of cream for the Babcock test, when this test is made for commercial purposes, is a fraudulent practice; and in most of the States and Provinces of the United States and Canada there are laws prohibiting it. In taking the sample for a Babcock test of milk a 17.6 c.c. pipette is used. This will deliver 18 grams of milk, the quantity for which the scale on the test bottle is graduated to read per cent of fat. To this we add 17.5 c.c. of sulphuric acid (specific gravity 1.82-1.83), varying the quantity to suit the strength. The contents are then thoroughly mixed by giving the bottle a rotary motion. The acid acts upon and digests all the solids of the milk, excepting the fat, and heats the sample to a desirable high temperature. The bottle is then placed in the centrifugal tester and whirled for five to six minutes, at a speed suitable to the diameter of the machine, usually 800 to 1000 revolutions per minute. The bottle is then filled to the bottom of the neck with hot water (soft or distilled) and whirled for about two min- utes. A second addition of hot water is then made to float the RECEIVING AND GRADING OF MILK AND CREAM 99 fat into the neck to about the 8 per cent mark, after which the sample is given a final whirling of one minute. The sample is then set in hot water at 130°-140° F. to bring it to the right tem- perature for reading. A pair of dividers is generally used for measuring the fat column in taking the reading. With milk, the reading is taken from the highest to the lowest point, that is, the meniscus of the fat column is included. = TTT x We a LTTE WTAE Fic. 22. PIG, 23: Fic. 24. Tiey.25. FIG. 26. Skim-milk Whole-milk Cream test- o-gram cream Cream test-bottle. test-bottle. bottle. test-bottle test-bottle Babcock Test-bottles. In the Babcock test of cream either a g- or an 18-gram bottle is used. The drift has been decidedly towards the use of the bottle graduated. to read per cent for 9 grams. A 9-gram sample of cream is weighed into the bottle by means of a special cream scale. To this are added about 9 c.c. of commercial sulphuric acid, and the contents are mixed by giving the bottle a rotary motion. When the action of the acid has proceeded far enough— 100 GRADING AND TESTING MILK AND CREAM when the contents have reached a chocolate color—some hot water is added to the test bottle to check the action of the acid. The sample is then centrifuged for five to six minutes, after which hot water is added to float the fat into the neck of the bottle; then the sample is again whirled for two minutes. The reading is taken at a temperature of 130°-140" F’., after a few drops of a colored reader, composed of a light mineral oil with suitable coloring matter in it, have been added to flatten the meniscus. Dividers are used for measuring the fat column in taking the reading. There are three very common conditions which make it dif- ficult to obtain a fat reading: (1) Black, charred, flocculent matter is sometimes found at the bottom of the fat column. This is commonly caused by using too much or too strong acid or by mixing milk and acid at too high a temperature. The remedy is to use less acid or to cool milk and acid before mixing. The black charred matter may also be due to allowing the acid to stand in contact with the milk too long a time before mixing or to pouring acid through the center of the milk. (2) There may bea layer of white flocculent matter at the bottom of the fat column. In this case an insufficient quantity of acid may have been used, the temperature of the milk and acid may be too low, or they may not have been thoroughly mixed. The remedy is to use more acid, to warm milk and acid before mixing, or to shake the mixture thoroughly before whirling. (3) Occasionally there is a layer of impure foam at the top of the fat column. This is gen- erally due to the use of hard and impure water. The remedy is to use pure distilled hot water. For more detailed information on this subject see “ Testing Milk and its Products,” by Farrington and Woll. Does the Babcock Test, as Ordinarily Applied to Cream, Give too High a Reading? —An investigation made by Harry B. Sieg- mund, Analyst, Hendler Creamery Company, and R. Sewell Craig, Senior Food Chemist, City Health Department, Balti- more, resulted in a decision that the Babcock test of cream, as ordinarily conducted, gives too high a reading. The following is a brief summary of the results obtained: BABCOCK TEST OF BUTTERMILK AND SKIM-MILK 101 When the centrifuging was done in a thirty-six bottle, elec- trically driven machine, run at a speed of 1000 revolutions per minute, the average of the tests of a number of samples of cream was I.0 per cent higher than that obtained by gravimetric analy- sis (Rose-Gottlieb test); and where the test was made with a twenty-four bottle steam-turbine machine, run at a speed of 800 revolutions per minute, the average test was 1.5 per cent too high. With the electrically driven machine run at a speed of 1200 revolutions per minute the reading was 0.6 per cent higher than that obtained by the Rose-Gottlieb test. When an electrically driven machine, run at a speed of 1600 revolutions per minute, was used, the Babcock test and the Rose- Gottlieb test gave practically the same results. The conclusion was that with machines run at the lower speeds a little water, or water and acid, remains suspended in the fat, and that it requires the force created by the higher speed machine completely to separate this from the fat. Babcock Test of Buttermilk and Skim-milk—The American Association Test.—In an exhaustive investigation of the losses of fat in buttermilk, conducted by Professor J. W. Mitchell under the direction of the senior author and not yet completed, several points have come prominently to the fore. The first of these is that the losses of fat in buttermilk, in our creameries, are much greater than they are generally sup- posed to be. Many creameries, under their methods of testing, are getting tests of .1 per cent to .2 per cent fat for their butter- milk. Of between 250 and 300 complete records, made by Professor Mitchell and the author, of churnings at different creameries, not one showed a Babcock test as low as .2 per cent. Of course the test was rigorous, but even this was considerably below the chemical analysis. The second point is that there are a large number of factors which influence the per cent of fat in the buttermilk, such as length of time taken to churn, temperature of cream, length of time the cream is held at churning temperature, condition of cream, fullness of churn, speed of churn, etc. This means that 102 GRADING AND TESTING MILK AND CREAM every creamery has its own conditions and problems to meet, and consequently should be in a position to determine, readily and accurately, what its losses of fat in the buttermilk are. It will then be in a position to study how to reduce them. The third point is that the average creamery, under its methods of testing, is not aware of what its losses are. It is not uncommon to note, in creamery records, tests of .1 per cent to .2 per cent for the buttermilk, whereas it is known, from hun- dreds of analyses made in the laboratory of the American Asso- ciation of Creamery Butter Manuitacturers, that the average loss exceeds .5 per cent fat. The loss does not fall far short of a pound of butter to every hundred pounds of buttermilk. Realizing the necessity for a simple test that would corre- spond closely with chemicai analysis for buttermilk (or skim- milk), and that could be operated by anyone capable of conduct- ing a Babcock test, the senior author asked Professor Mitchell to devise such a test, if possible. In his efforts he has fortunately been very successful. The different methods of making a Babcock test of butter- milk, including the new modification of the same, are briefly out- lined below. The following method of testing buttermilk (or skim-milk) has been in use for many years, and is still more generally used than any other. A double-necked skim-milk bottle, graduated to read as close as .or per cent for 18 grams, is used. Most of the bottles read up to .25 per cent—some to .50 per cent. After the buttermilk is well mixed, a 17.6 c.c. pipette is used to transfer 18 grams of it to the test bottle. To this is added 20 c.c. of commercial sulphuric acid (sp. gr. 1.82-1.83). The acid and milk are then thoroughly mixed by giving the bottle a gentle, rotary motion. Care must be exercised, in mixing, to avoid choking the small neck and causing some of the contents to be thrown out through the large neck. The bottle is then placed in the centrifuge and whirled at full speed for about five minutes. Hot water (soft or distilled) is then added to the bottle to fill it almost to the neck and the machine is again run for one or two minutes. Hot water is then added to float the fat into the small AMERICAN ASSOCIATION TEST 103 neck and the bottle is again whirled for one or two minutes. The bottle is then placed in hot water at a temperature of 130° 140° F., after which the reading is taken. It is advisable to use a pair of dividers to measure the fat column. Under this method the reading will be very low—possibly .r per cent to .2 per cent when it should be .4 or .5 per cent. A More Rigorous Test.—A modification of the foregoing is to take a g-gram sample by means of a g c.c. pipette, that is, a half sample. To this is added about 12 c.c. of a fairly strong acid, well up to a sp. gr. of 1.83. The whirling is done in a very high- speed machine and is greatly prolonged—fifteen to twenty min- utes the first time, about ten minutes at the second whirling, and about five minutes at the third whirling, or thirty to thirty-five minutes inall. The reading must be doubled, since only a 9-gram or half sample is taken to a test. This method will probably double, or more than double, the result. But even under this method the test falls considerably below the results secured by chemical analysis. The American Association Test.—A close study of the dif- ferent practical methods for the quick determination of the per cent of fat in milk and its products and by-products reveals the fact that there is a general principle running through them all, that is, there are three factors which operate in all of them. These are (1) the use of one or more chemicals to liberate the fat, (2) the heating of the contents of the test bottle in order to liquefy the fat, and (3) the application of centrifugal force. Where sulphuric acid is the chief or only chemical used it gen- erates sufficient heat, through its strong afhnity for water; but where it is not used at all or is used very sparingly it becomes necessary to heat the sample in hot water before centrifuging it. A number of useful tests have been devised for the quick determination of the per cent of fat in milk, etc. The following are a few of the most outstanding of these: (1) The Lactocrite, devised in 1886 by Dr. De Laval, inventor of the cream separator which bears his name. The chemical used was concentrated or glacial acetic acid, containing 5 per cent of concentrated sulphuric acid. It was necessary to heat 104 GRADING AND TESTING MILK AND CREAM the sample before centrifuging it. This was a pioneer test but is not now in use. (2) The Babcock test, invented by Dr. Babcock of the Wis- consin Experiment Station and published in July, 1890. This test is so widely and favorably known and is in such general use, especially in America, that it seems unnecessary to do more than refer to it. It is simple, speedy and accurate, and the cost of a test is small, a single, cheap chemical, commercial sulphuric acid, being used. (3) The Gerber test, brought out in 1892. In this test two chemicals are used, viz., commercial sulphuric acid and amyl alcohol. It is used quite extensively in Europe. (4) The Sinacid Butyrometer. This test was devised by Sichler of Germany in 1904. No acid is used in the test, hence the name “ Sinacid.”” The chemicals used are sodium hydrox- ide, Rochelle salt and iso-butyl alcohol. It is necessary to heat the samples by placing them in hot water before centrifuging them. All of these tests were designed primarily for the testing of milk and such milk products as cream, and for this purpose they are reliable; but in testing the by-products of the dairy, skim-milk and buttermilk, they all give results that fall con- siderably below those obtained by chemical analysis (the Rose- Gottlieb test). No doubt this is the main reason for the failure there has been to make a thorough study of the losses of fat in buttermilk and how to overcome them. Hence, when the American Association of Creamery Butter Manufacturers began its study of losses of fat in buttermilk it was confronted with the problem of devising a suitable test for the accurate deter- mination of the per cent of fat in buttermilk, Trials were made of different combinations of chemicals, such as, sulphuric acid and amy] alcohol, sulphuric acid and iso- butyl alcohol, and sulphuric acid and normal butyl (z#-buty]) alcohol. After extensive experiments had been made sulphuric acid and #-butyl alcohol were selected as the most suitable combination to use, and for the following reasons: (1) The results, with duplicate tests, are exceptionally uni- AMERICAN ASSOCIATION TEST 105 form and correspond closely to chemical analysis (The Rose- Gottlieb test), as the accompanying table shows. (2) There is much less trouble with a deposit in the test bottles than is the case where the other alcohols are used. (3) Normal butyl (z-butyl) alcohol, being a single alcohol that is readily purified, is free of impurities while the amyl and iso-butyl alcohols are not likely to be. In blank tests made, that is, when water was substituted for buttermilk in a test, a short column of some impurity rose into the neck of the test bottle when the amyl and iso-butyl alcohols were used, but not when #-butyl alcohol was used. (4) The 2-buty] alcohol is quite stable and is not at all likely to be attacked by the sulphuric acid, while the other alcohols mentioned are iso-alcohols that run off into chains and are less stable and are likely to be mixtures. (5) The 2-butyl alcohol does not possess either a pungent or an otherwise offensive flavor or odor, and consequently is much pleasanter to use than the others. (6) The n-butyl alcohol is the lowest in price of the dif- ferent alcohols, and, being stable and free of impurities. is the most reliable alcohol to use. Even the cheaper grade of this alcohol (the ‘ practical’) contains no impurity excepting pos- sibly a slight amount of moisture. Extensive and carefully conducted investigations have shown that the right amounts of commercial sulphuric acid and n-butyl alcohol to use in testing a g-gram sample of skim-milk or butter-milk are as given in the directions which follow: Directions for making a test: Chemicals.—Commercial sulphuric acid. Normal butyl alcohol. 1. Place the chemicals and buttermilk in the test bottle in the following amounts and the order indicated. (a) 2¢.c. of v-butyl alcohol. (b) 9 c.c. of buttermilk. (c) 7 to 9 c.c. of commercial sulphuric acid. Vary amount of acid to suit its strength. The right amount 106 GRADING AND TESTING MILK AND CREAM is being used when the fat column is golden yellow to light amber in color. 2. Mix contents of bottle thoroughly. 3. Centrifuge for six minutes. 4. Add hot water (soft or distilled) to fill bottle to bottom of neck, and whirl for two minutes. 5. Add balance of water to float fat into neck and again whirl for two minutes. 6. Read at temperature of 130° to 140° F. Double the read- ing to obtain per cent of fat. 7. In cleaning test bottle—especially if there be any deposit— first add a small amount of lukewarm water and to this add sulphuric acid. Always add the water first and then the acid— never the reverse. Rinse the bottle well with this mixture and then rinse with hot water. This test gives results corresponding to those of chemical analysis. A test bottle, with a scale reading up to .50 per cent for 18 grams, should be used. The following table, comparing the Babcock, The American Association Test, and Rose-Gottlieb (Chemical) tests, is sub- mitted. Babcock Test ! The American Rose-Gottlieb Association Test Test Per Cent Per Cent Per Cent - \ 38 | 52 | ane 34 47 47 .40 57 | 59 43 | . 60 .60 . 30 | 54 | 53 39 .56 | 59 30 .50 252 34 .50 | 48 1 The Babcock test given in the foregoing table was that obtained from using 12 c.c. of sulphuric acid with a 9-gram sample and centrifuging, in all, about chirty-five ninutes in a high-speed tester. PER CENT OF FAT IN BUTTER 107 Determination of the Per Cent of Fat in Butter. —The methods for the determination of the per cent of fat in butter may be classified under two heads, viz., (1) Scientific methods, such as (a) The Extraction method. (b) Rose-Gottlieb method. (c) Indirect determination of fat. (2) Practical methods, such as (a) The go per cent bottle designed by Hepburn for use in the Babcock test. (b) The Shaw test. Scientific Methods.—The scientific methods are too com- plicated and require too long a time for their completion to be of practical use in a creamery. The Rose-Gottlieb method may be briefly outlined as follows: This method, which was originally designed for the estima- tion of fat in milk, can be used with advantage also for the deter- mination of fat in butter. According to A. Hesse,! about 2 grams of butter are weighed out into a 3 cm. long, half-cylindrical glass tube, or simply wrapped in a piece of stiff fat-free paper of the same form. The tube or paper and the contained fat are then introduced into a Gottlieb cylinder, and hot water is added until the 1o-cm. mark is reached. If the butter docs not melt, the cylinder is placed in warm water until it does. Then 1 c.c. of ammonia and 1o c.c. of 95 per cent alcohol are added, exactly as in the estimation of milk-fat. If the mixture is still warm, the cylinder is cooled in cold water so that the ether which is to be added will not evap- orate too quickly. The cooling must not, however, be carried too far; otherwise the butter will become solid again. Twenty- five c.c. of ether are then added, and the contents of the cylinder mixed by repeatedly inverting it. Afterwards 25 c.c. of petro- leum ether are added and the mixing repeated. After the different layers have separated quite sharply from one another, the clear ether-fat solution is siphoned off in the usual way, the lower opaque layer not being disturbed. Then 1 Molkerei-Zeitung, Hildesheim, 1903, No. 27. 108 GRADING AND TESTING MILK AND CREAM 50 c.c. of ether are poured into the cylinder and at once siphoned off without being mixed with the other liquid. Finally, the residual liquid is shaken with a mixture of 25 c.c. ether and 25 c.c. petroleum ether, and, after settling, the ethereal layer is drawn off. The three portions of ether are naturally all placed in the same tared flask, which is weighed again after the ether has been evaporated and the fat dried. These repeated extractions with ether and petroleum ether are necessary if exact results are to be obtained. If the above directions are carefully followed, it will be found that the Rose- Gottlieb method, while easier and more convenient, and also considerably quicker than the extraction method, gives results which are in very close agreement with those obtained by the latter. The Mojonnier test is a modification of the foregoing, and possesses several features which greatly facilitate the work and shorten the time required to make the test. In the method known as the “ Indirect Determination of Fat,” the percentages of moisture, casein and salt are carefully determined. These are then added together and their total is subtracted from roo to determine the per cent of fat in the butter. Practical Methods.—There are several practical methods that are made use of to a greater or less extent. We shall briefly outline two of these. For making a Babcock test of butter, using the Illinois 9-inch, g-gram, 90 per cent butter test bottle devised by Dr. N. W. Hepburn, University of Illinois, the following directions are given: “ Taking the Sample.—In testing butter it is necessary to exercise great care both in securing and in preparing the sample. “Sampling from a Churn.—With an ordinary ladle cut off the surface of the butter in several places, including each end and the middle of the churn. Then make a composite sample by taking, with a spatula or common case knife, a small sample (ro to 20 grams each) from six or eight different places in the churn where the surface has been removed, putting them into an 8-ounce wide-mouthed glass-stoppered bottle. PER CENT OF FAT IN BUTTER 109 “Sampling from a Tub.—Draw one or two triers from the full depth of the tub and drop the entire plug of butter into the glass-stoppercd bottle. * Preparing the Sample for Testing.—Place the glass-stoppered bottle containing the sample in warm water, shaking vigorously every few seconds until it is thoroughly mixed and is about the consistency of heavy cream, when it is ready to be weighed into test bottle. Caurtion.—Be careful not to get the sample too warm nor in too liquid a condi- tion. If this happens place it in cold water, shaking very frequently, until the sample takes on the desired consistency. Samples should not pour freely, but like thick cream or paste. Little heating and thorough shaking is the rule for suc- cess in preparing the sample. “ Weighing the Sample-—Balance the bottle on the scales and weigh out a 9-gram sample by the method used in weighing cream samples. (Scales as sensitive as moisture-test scales should be used.) “Adding Acid.—First add about 9 c.c. of water then 17.5 c.c. of sulphuric acid. CAuTIoN. —Add the acid slowly and in small portions, shaking after adding each portion to avoid foaming. High-salt samples are most likely to foam. If foaming occurs, vigorous shaking will often prevent the loss of the sample. After the sample is thoroughly mixed with the acid and is dark brown in color, add warm water, filling the test bottle up to the base of the neck. “ Whirling —Place the test bottles in the tester and whirl for ten minutes; stop, fill with Fie ee tiaws water to bring the fat up in the graduated neck, 9 inch, o gram, and whirl again for five minutes. 90 per cent “ Reading.—Set the test bottle in water at fetes ne 140° F., covering the fat in the neck, and allow it to stand for at least five minutes; then read. In read- 110 GRADING AND TESTING MILK AND CREAM ing, cut off all the upper curve on the fat column or add a couple of drops of white mineral oil (glymol) to destroy the meniscus.” THE SHAW TEST FOR FAT IN BUTTER APPARATUS REQUIRED “ Babcock centrifuge or tester. “ Shaw separatory funnels. “Balance which is sensitive to o.o1 gram. (A torsion bal- ance, such as is used in testing for moisture, will answer if it is in good condition.) * Accurate set of metric weights. Fic. 28. —Separatory funnels used in the Shaw test. “ Glass cylinder graduated at 9 and 11 c.c. “zoo-c.c. glass beaker. “ Wooden rack for holding separatory funnels. “ Support for separatory funnels on balance. “In addition to the above a special socket to hold the separa- tory funnels will be required. As shown in the cut, this differs in no material way from the socket ordinarily used in the Bab- 1L. F. Nafis. PER CENT OF FAT IN BUTTER 111 cock centrifuge, except for the opening in the side. It may easily be adapted from the ordinary socket or if preferred the socket may be sent to us and we will make the necessary changes for a nominal charge. Care must be taken that the capillary stem of the funnel does not project far enough through the hole in the socket to strike against the side of the centrifuge while being whirled. It is a good plan to fit a disk of rubber gasketing in the bottom of the socket. SAMPLING THE BUTTER “In the determination of fat in butter, great care must be taken in securing a representative sample and in preparing this for the test. “Several samples from different parts of the tub or churn should be taken with a butter trier. These are placed in a suit- able container, such as a 1-pint Mason preserve jar or a cup, which is placed in water at about 100° F. The sample is then mixed with a spatula or spoon until about the consistency of thick cream. The sample must not be left any length of time in open containers, since some of the moisture will evaporate. Should the sample be kept for any reason for a day or two before it is mixed, it should then be placed in warm water (with the cover on the container) until melted, and then cooled while being vigorously shaken until it solidifies. The reason for this is that on standing some of the water will ooze out and cannot be reincorporated except by emulsifying and cooling while in this condition. Too much stress cannot be laid on careful sampling and mixing the sample, for upon this the accuracy of any deter- mination in butter very largely rests. DETERMINING THE FAT “Tt will be found more economical in some cases if four or multiples of four determinations are made at once. In this case the two double sockets containing the funnels will balance when placed opposite in the centrifuge. If but one or two determina- tions are to be made it will be necessary to balance the centrifuge by putting weights in the opposite socket. First of all, the clean 112 GRADING AND TESTING MILK AND CREAM and dry separatory funnel must be weighed, and this as well as the other weighings involved must be done with care. This weight once found will suffice for all determinations made with that par- ticular funnel, unless by accident some of the glass should be chipped off. A slight scratch made with a file can serve to iden- tify the funnels. A paper Jabel should not be used. If requested at the time of ordering we will number them without additional charge. ‘““ Each time, before using the separatory funnels, they should be lubricated with a properly prepared stopcock lubricant which we supply with directions for its use. “YT. Weighing the Charge.—Counterpoise the small beaker on the balance and carefully weigh out 20 grams of the sample mixed as directed. “TI. Transferring the Charge to the Separatory Funnel.— Place the beaker containing the charge on a radiator or steam pipe until the butter is melted. (This may also be accom- plished by adding a small quantity of boiling water.) Next pour the charge into the funnel kept in an upright position in the wooden rack. No part of the charge must be lost in transferring. With a fine stream of hot water rinse down the sides of the beaker and pour the rinsings into the funnel. (If the salt is to be determined, distilled water must be used. See directions under ‘ Salt Test.’) Repeat this, using not more than a tea- spoonful of water at a time until the funnel is full to within about one-quarter of an inch of the shoulder. The rinsing can be done very conveniently with the arrangement on many steam centrifuges for filling the Babcock test bottles, ie., the rubber tube ending in a glass or metal point and connecting with a water tank heated by steam. The point must be fine, however. Should it be larger than three-sixteenths of an inch, it can be replaced with the tip of a small oil can. Should this arrangement not be at hand, one can easily be improvised from a tin can, a rubber tube, and an oil-can tip. In transferring the melted butter and rinsings, the last drop may be prevented from running down the outside of the beaker by touching the lip of the beaker to the neck of the separatory funnel. PER CENT OF FAT IN BUTTER 1138 “TI. Centrifuging.—Insert the separatory funnel in the special socket, allowing the stem to project through the hole in the bottom and the handle of the stopcock through the open side. Caution.—The socket must always be placed in the centrifuge, with the open side facing the direction in which the wheel revolves. This is very important, if the opening faces the reverse direction the stopcock will be thrown out and broken. Whirl one minute at the same speed used in testing milk with the Babcock test. The centrifuge must be kept warm. “TV. Removing the Water.._Remove the separatory funnel from the socket and allow the water to flow through the stopcock until the fat (or curd) is within one-eighth of an inch of the stop- cock. In this and later operations involving the stopcock one must be sure it does not stick. It must always be under control, and it is best to give it frequent slight movements when the water or acid is running through it to be sure that this control is main- tained; otherwise it might stick at a critical moment and the determination be lost. The most of the salt and part of the curd are taken out by the water. The remainder of the curd and all of the fat stays in the funnel. If it is desired to determine the salt, this wash water is allowed to run into a 250 c.c. flask and the operation described in this paragraph conducted three times instead of but once, the wash water being added each time to the flask. ‘Tt sometimes happens that the water will not start flowing when the stopcock is opened, in which case it can be started by blowing into the mouth of the separatory funnel. ‘“* V. Dissolving the Curd.—Measure out 9 c.c. of cold water, preferably condensed steam, with the glass graduate and pour into the beaker. Add to this 11 c.c. of sulphuric acid of the same strength used in testing milk and cream (specific gravity, 1.82- 1.83) and mix by gently shaking. (CAution.—Always add acid to water and not water to acid, or a serious accident may result.) While still very hot add the mixture to the contents of the separa- tory funnel. Now dissolve the curd by giving the funnel a circular motion with the hand grasping the neck. Centrifuge one minutc, as before. Draw off the acid solution till the fat 114 GRADING AND TESTING MILK AND CREAM layer is within about one-fourth of an inch of the stopcock and repeat the operations in this paragraph. “VI. Freeing the Fat from the Acid Solution.—The fat wiil now be in a clear transparent layer free from curd, and the solu- tion below it will be practically colorless. To separate these two draw off the latter until the fat nearly reaches the stopcock and centrifuge another minute. Now allow the fat to come down through the stopcock till it just reaches the end of the capillary stem. This last step offers no difficulties, providing the stopcock is kept in control, but it requires care. If desired, the acid may be colored with methyl orange. “VII. Determining the Percentage of Fat.—Carefully dry the separatory funnel on the outside with a clean soft cloth and weigh it. The weight thus obtained minus the weight of the empty funnel represents the weight of butter-fat in 20 grams of the sample. ‘The percentage is obtained by multiplying by 5. “Often it is possible to obtain a clear fat layer with but one addition of acid, but in some cases it will be found necessary to add it the second time, as directed. The test for fat alone involves 4 centrifugings of one minute each. The centrifuge should be kept warm and the contents of the funnel in a melted state when the acid is added. The time consumed should not be longer than it takes to test cream with the Babcock test, and the operations involved are simple and easily learned. No difficulty will be experienced in obtaining a clear fat. Occasionally there will appear a slight emulsion at the bottom of the fat layers when the fat is drawn into the stem. This is so small in amount that it does not seem to affect the accuracy of the test to any considerable extent. The emulsion should be weighed as fat and considered as such. CLEANING THE SEPARATORY FUNNELS “The separatory funnels should be washed after each deter- mination, but it is not necessary to dry them before use, providing their weight, when clean and dry, has been found. The cleaning is easily done with hot water and either soap or cleansing powder. They should be well rinsed off with clean water and drained.” GRADING AND TESTING MILK AND CREAM 115 Fic. 29.—Churn room. Kirschbraun & Son, Omaha, Neb. One of the largest and finest creameries in the world. 5 IO Es a ath Yon Fic. 30.—Street view of the first prize co-operative creamery at Carroll, Lowa. 116 GRADING AND TESTING MILK AND CREAM Very few of the creameries have, as yet, begun the regular determination of the per cent of fat in their butter, most of them confining their work on the composition of butter to determina- tions of the per cent of moisture and the per cent of salt. The three constituents of butter outside the fat, are moisture, salt and curd; and where a uniform system of manufacture is adopted, and the churning is done under right conditions and the butter well washed, the curd content is not likely to exceed 1 per cent Fic. 31.—The oil-test churn. or vary more than half a per cent. Consequently accurate determination of the moisture and salt-contents enables a creamery to estimate, very closely, the per cent of fat in the butter. Sediment Test.—Milk should be free from sediment and foreign insoluble material. Producers of the raw material are not always conscious of the necessity of producing clean milk, and of the effects of impurities upon the finished products. Sediments may be seen on the bottom of a glass jar after the NECESSITY OF GOOD MILK 117 milk has stood quietly for several hours. The better way of showing these sediments is to use the Wisconsin Sedimentation Test. The container for this test holds about one pint of milk. A screw cap fits over the top. By means of a small air pump, pressure can be applied and the milk forced through a disk or filter. This disk is removable and the filtered-out dirt on the surface can thus be shown. Necessity of Good Milk.—All authorities agree that the best grade of butter and cheese cannot be made from sour or tainted milk. The two countries renowned for the excellence of their Tic, 32. —-Wizard tester. Itc. 33.—Twentieth-century hand tester. dairy products—Denmark and Canada—owe their success largely to the purity of the milk from which these products are made. Makers who have won for themselves national reputa- tions in cheese- and butter-making have almost invariably been men who insisted on getting first-class milk. The method of classifying milk and cream and paying for each according to quality has been adopted by some creameries. The authors: do not hesitate to say that cream whose flavor is such az to show that it is in a putrefactive or decomposed condition should be rejected as unfit for making an article of heman food. While it is advocated by some that it should be 118 GRADING AND TESTING MILK AND CREAM received, made into butter and sold on its merits, the wisdom of this is to be questioned. Cream that is simply off in flavor is a different proposition. This may, in Justice and fairness, be taken in on its merits and paid for accordingly. The practice of receiving and paying for cream indiscriminately is something which should be condemned and discouraged. The authors have come in contact with many patrons in different parts of the country and have yet to meet the first patron who would seri- ously object to taking his milk or cream home when thoroughly convinced that its condition was such that it should not be received. Patrons, as a rule, respect the maker who keeps his creamery in a good sanitary condition and insists upon being supplied with a good quality of milk or cream. It should be the aim of every creameryman to make the highest grade of butter possible, and thus be in a position to take full advantage of a dis- criminating market, for this is the kind of market that pays the highest prices. Sampling of Milk.—The sampling of milk and cream for fat tests is one of the most delicate problems with which the creamery operator has to deal. If a proper sample is not obtained, the ultimate test will not be correct, no matter how carefully the succeeding steps may be carried out. There are two methods of sampling in use: First, sampling with a small dipper, and second, sampling with a sample-tube, or milk-thief. The sampling of milk for composite samples should be done every day, and the samples taken should represent the average quality and form a certain proportionate part of the milk or cream delivered. in order to get a sample which represents the average quality, the milk or cream delivered must be thoroughly stirred, so as to get an even distribution of the fat. In order to get a proportionate part of the milk or cream delivered from day to day, it is necessary to use a sampling- tube. The sampling of milk and cream with a dipper for composite samples has been in use for a long time, and is still practiced to quite an extent. However, it is fast becoming recognized that SAMPLING OF MILK 119 the use of a suitable sampling tube is much better. It takes a more representative sample of a can of cream, whether it be for the making up of a composite sample or for the testing of an individual shipment. In the case of composite samples of both milk and cream it takes an aliquot portion, or one in proportion to the quantity of milk or cream delivered. The difficulty at one time in sampling cream—and particularly thick cream— with the sampling tube was that the only opening in the tube was at the bottom, and the cream would not flow into it as the tube was lowered. However, this trouble is completely over- come when a sampler like the McKay sampler is used. This is made up of two tubes, an inner and an outer, and a plunger (see cut). Both the tubes have openings up the side. Before inserting the sampler in a can of cream, the outer tube is turned on the inner so that the openings are not opposite each other, or so as to close the sampler, and the plunger is drawn back. The sampler is then lowered into the cream to the bottom of the can, when it is opened momentarily to allow it to fill and is then closed again. In emptying the sampler the outer tube, which is the shorter of the two, is drawn up a little to leave an opening at the bottom, and the plunger is pushed down to force the cream out of the tube. In doing so it cleans the tube completely. This style of sampler does equally efficient work whether used in a creamery or cream station, or in taking samples on a cream route. An investigation made by the American Association of Cream- ery Butter Manufacturers showed the dipper method of sampling cream to be unreliable. In this investigation the cream in the can was first hand-stirred—no less than forty vigorous double strokes being used—and then sampled with a dipper, after which a sample was taken by means of a McKay or tube sampler. In all, thirty-two lots of cream were sampled and tested in this way, and the following short table gives some of the results secured: 120 GRADING AND TESTING MILK AND CREAM | Babcock Test of Sample | Times ae a | a Condition of Cream Difference No. |Stirred | Diane Tube | Dipper ube Sample | Sample Per Cent I 50 Viscous, not very smooth. ...... 41.0 44.0 330 a 40 Smooth and even.............. 39.0 30.5 0.5 3 65 Heavy on top, liquid below, lumpy 245 | 38.5 4.0 4 60 Viscous but good condition... .. . 34.5 B15 I.0 5 44 uve Guid: os crck isa emaneges ts 20;.8 24.5 2.0 6 60 Viscous, slightly lumpy......... 40.5 40.5 | 0.0 7 75 |Top fair, bottom almost solid, | HUMP Yee .dg eee een» + ARS | B8x5° 1 9.0 8 50 5 | 39.5 | 1.0 | (7000 CONMILI. gc cia eek edad 03 4o. While the difference in the test of the samples under the two methods was usually not great, yet the dipper method of sampling proved unreliable. Sampling-tube.—At creameries where milk is received, the sampling-tube, or milk-thief, gives the best results and satis- faction. It is very difficult in practice to get a proportionate sample with a dipper, from day to day. To illustrate: A patron who delivers 200 pounds of milk testing 3 per cent fat one day may on another day deliver 100 pounds of milk testing 5 per cent fat. Ifa dipperful is taken from each for a composite sample, the test of that composite sample will be 3+5+2, or 4 per cent. According to this test, these 300 pounds of milk delivered will contain 12 pounds of butter-fat. In reality 6 pounds of fat were delivered in the 200 pounds, and 5 pounds of fat in the 100 pounds, making a total of 11 pounds of fat. Thus we see that the dipper method is not reliable, and in this case the patron was paid for 1 pound of butter-fat too much for the two days’ delivery. If the sample taken from the 200 pounds of milk had been twice as great as that taken from the roo pounds of milk, then the com- posite test would have been perfect, no matter whether it had been taken with a dipper or with a sampling-tube. If the same weighing-can is used every day, it is possible to maintain an SAMPLING TUBE 121 Tic. 34.—Vat room. kirschbraun & Son, Omaha, Neb. One of the lareest and finest creameries in the world -CREAMERY, StRawpenay Pur, 1d Ftc. 35.—Interior of creamery, Strawberry Point, Iowa. One of the largest whole-milk creameries in the U.S. 122 GRADING AND TESTING MILK AND CREAM exact proportion for a sample by always putting the sampling- tube perpendicularly into the milk at the same place in the weigh- ing-can, and by exercising care in other respects. When the cream is being collected from different patrons by a hauler, a milk-thief often works unsatisfactorily. This is especially true during cold weather. A cream tube similar to the one shown in the accompanying illustration is more effective. \ Sa oa 99 404 0 L 70 304 - 60 [50 204 Lio L so 104 20 ae ee [eet I'tc, 36.—The McKay cream and Fic. 37.—Cream milk sampler. sampling-tube. The way in which the tube is used is apparent from the figure. I{ a certain patron has 4o pounds of cream, the cream is filled to the 4o mark on the scale of the tube; if he has 30 pounds, it is filled to the 30 mark, ete. Sampling Churned Milk.—It occasionally happens that the milk arrives at the creamery slightly churned. This is espe- cially the case during the summer. Usually such milk is sam- pled in this condition, but if it is desired to find the percentage of fat in such milk in its unchurned condition, it is essential to melt SOUR AND COAGULATED MILK 12: the churned fat before sampling. Ii the butter has been churned into a few large lumps, these lumps can be taken out in a pan, or pail, with a comparatively small amount of milk, and _ this heated until the butter has melted. This is then remixed with the milk from which it was first taken and sampled while it is being stirred. The churning of the milk during transit is mainly due to two things: First, to a high temperature of the milk (65° to 85° F.) and second, to hauling partly filled cans a long distance over rough roads. If the temperature of the milk is low (about 50° F.), when it leaves the producer, there is seldom any danger of having churned milk at the creamery. Frozen Milk.—When milk is cooled to 31° F., or below, it freezes. Ice forms near the sides and bottom of the can, until a funnel-shaped cavity filled with milk is left in the center. According to both Richmond and Fleischmann, the icy por- tion contains more water than the unfrozen milk, and the unfrozen portion is rich in solids. According to Farrington, when 25 per cent of the sample of milk was frozen, the icy portion contained about 1 per cent less fat than the original portion. When about half of it was frozen there was no great difference in the fat-content of the frozen and unfrozen parts. In practice, however, freezing seems to have a different effect. When a can full of partly frozen milk is sampled at the creamery, the unfrozen milk nearly always contains less fat than the original sample. This can be accounted for by opening the can of milk and noting the amount of frozen cream on the sides near the top. Whether the unfrozen portion contains less or more fat than the original depends, therefore, upon conditions. At any rate, frozen milk has a composition different from that of the original sample. On this account an accurate sample cannot be had, unless the frozen portion be first completely melted and well mixed with the remainder. Sour and Coagulated Milk.—In order to get a fair sample from a can of sour and coagulated milk, it must be stirred very thoroughly, so as to bring the coagulated milk into a uniform emulsion. A better sample can usually be obtained 124 GRADING AND TESTING MILK AND CREAM with a dipper. If the milk is not too thick, a fair sample can be obtained by the use of the sampling-tube. In order to reduce a can of coagulated milk to a thoroughly uniform quality, it is best to pour it from one can into another. This mixes it much more completely than if the sample were simply stirred with a dipper or any other kind of an agitator. Apportioning Skim-milk.—The amount of skim-milk to be Fic. 38.—Jensen can drier, sterilizer and rinser. (Jensen Creamery Machinery Co.) received by the patron depends largely upon the thickness of cream skimmed, and upon the amount of skim-milk retained at the creamery for various purposes. The amount of skim-milk generally returned by creameries varies between 80 and go per cent of the whole milk delivered. Most up-to-date creameries now make use of skim-milk weighers. Where such are employed, the man who receives the milk hands each patron a check for the amount of milk delivered. This check is put into the skim-milk weigher, and it allows an WASHING CANS 125 amount of skim-milk to flow out, corresponding to the number of pounds indicated on the check. In case a skim-milk weigher is not employed, it is essential Fic. 39.—Hydraulic can washer and dryer. (Creamery Package Mfg. Co.) to have a man at the skim-milk tank to weigh out the proper amount of skim-milk to each patron. If the patrons are allowed to weigh out their own skim-milk, mistakes are frequently made, which result in more or less dissatisfaction. It is quite customary for butter-makers to draw a chalk line on the outside of the can some distance below the surface of the milk. This indicates the point to which the can may be filled with skim-milk. Washing Cans.— The creamery oper- ator should make it a point to have all empty cans thorough- ly washed with warm water, and then steamed and_ steril- Fic. 40.—Hydraulic can washer-rotary type. (Rice and Adams.) ized, after which hot air should be blown through thoroughly to dry the cans. Frequently, bad flavors are transmitted to cream from cans that have been closed up tight before being thoroughly 126 GRADING AND TESTING MILK AND CREAM dried. Where hot air is not used, the cans can be turned upside-down on a platform with openings to allow air to circu- late through the cans, drying them thoroughly before the covers are put on. Drying cans as above described not only conserves the tin of the cans, but also places the cans with the patrons in a clean condition, free from bad odors. It also saves considerable work on the part of the patrons, as well as insuring them a clean, sanitary can. One patron told the author that this cleaning of the can was worth one cent per pound of butter-fat to him. The creamery is equipped to do this can-cleansing better than is the patren and it is repaid for this extra labor in a better grade of cream and in increased patronage. CHAPTER IX COMPOSITE SAMPLES Definition.—In order to avoid testing each patron’s milk or cream every day for fat, a small sample, which represents the average quality and a proportionate part of the whole, is taken from each patron’s milk every day and placed ina jar. A pre- servative of some kind is previously placed in the jar to keep the contents from spoiling. This is called a composite sample. When to Sample.—Some makers prefer to sample the milk or cream delivered every day; others prefer to sample every other day. Some creamery operators, again, sample four or five times in succession at intervals, the patrons being unaware of the time when the sampling is to take place. The most reliable and prac- tical method, however, is to take a sample every day, and test it for fat at the end of every two wecks. When cream is received composite samples do not give reliable results. In fact this system has been very generally superseded by that of weighing and testing the cream of each delivery or shipment. Kind of Preservatives to Add. While there are several pre- servatives that may be used, such as salicylic acid, borax, boracic acid, and bicarbonate of soda, those most commonly used are bichromate of potash and corrosive sublimate (mercuric chloride) either singly or as a mixture. Bichromate of potash, while poisonous, is not extremely so and it imparts a color to the sample which readily indicates its presence. It has, however, two defects; if used in excess it is very much inclined to cause a charred or burnt reading when the sample is tested, and if the sample be exposed to light for any length of time a leathery scum forms on the surface, which it is difficult to dissolve completely by means of the sulphuric acid. 127 128 COMPOSITE SAMPLES Corrosive sublimate is a strong and a very satisfactory preservative; but it is quite poisonous, and where the powder itself, which is white, is used in composite samples some kind of coloring matter should always be added to indicate its presence. According to the authors’ experience, corrosive sublimate tablets can be highly recommended. The tablets contain a color, which, when dissolved, colors milk, so that it can readily be distinguished as not being fit for human food. The tablets are very poisonous, but are more efficient in their preservative effect than bichromate of potash. They can be ob- tained from any creamery- supply house. During the winter, when the samples are kept com- paratively cold, less perserva- tive is needed than in the summer. One corrosive sub- Fic. 41.—Composite samples and rack to limate tablet will keep a Hpk Sanayi gars, half-pint to a pint of milk or cream in good condition for about two weeks in summer, and about three weeks in winter, providing the sample is properly cared for. Some makers are practicing testing at the end of every month during the winter, and every two weeks during the summer. Testing at the end of every month saves labor, but it is not a reliable method to follow under all conditions, as some of the samples are likely to be somewhat impaired after standing so long. Arrangement of Composite Samples.—Pint glass jars with covers are, so far as known, the most convenient vessels to use for composite samples. Shelves should be arranged in the weigh- ing-room on which to keep the bottles. If possible, it is best to have them in a case closed with glass sliding doors. This is neat, and, if the glass doors fit well, the samples are in some measure protected in case of quick, unexpected changes in tem- perature. These sliding doors should be locked when the cream- CARE OF COMPOSITE SAMPLES 129 ery operator is absent from the creamery, in order to prevent any tampering with the composite samples. The best method of arranging the sample jars is to have all the jars belonging to the patrons of each route standing in one group, or on one shelf, if possible. The bottles are num- bered to correspond with the number given cach patron on the milk sheet. The name of the hauler, or the number of the route can be put on each shelf. The samples belonging to those who haul their own milk can be put on another shelf; these can be designated as individual haulers. Such a classification, when the bottles are plainly numbered, will often prevent the mistakes that are likely to occur if the bottles are simply numbered and put into a rack together. Care of Composite Samples.—In the first place, the jars should be kept scrupulously clean. The tests are unreliable if the jars are left covered with milk and molds round the neck from one month to another. When the samples have been tested the jars should be thoroughly cleaned, and, if necessary, scalded, before they are used again. Care should be taken to spill as little milk as possible around the neck, inside as well as outside of the bottle, when the sample is put in. If the milk is spilled there, it gives the bottle an unattractive appear- ance. Very often it becomes moldy, and, as more milk is added and the sample shaken every day, this mold gradually extends down the sides of the bottle. This causes the composite sample to be infested with undesirable growth, and to spoil sooner than it would if greater care were taken in keeping the milk from coming in contact with the sides of the bottle before coming in contact with the preservative. A few drops—but only a few—of formaldehyde added to the sample, where this is necessary, is a good preventive of mold; but this should not be used as a substitute for thorough cleaning of the bottles after each test period. It is important also that the sample jars be well covered; otherwise the moisture evaporates, causing the milk or cream to dry up, and, making the test unreliable by increasing the per cent of butter-fat. A gentle rotary motion should be given each 130 COMPOSITE SAMPLES jar when a sample is added to it to mix the cream, which rises to some extent after the milk has stood a while. Average Sample.—It is sometimes desirable to obtain an average test of the milk from a whole day’s delivery. This can be obtained in two ways: First, by taking a sample from each patron’s milk with a sampling-tube, and putting all the samples together in one jar. The result represents an average test, pro- viding the samples have been correctly taken. Second an aver- age test can be had by boring a small hole in the conductor-head. When the milk passes over this hole, a small portion of it drops through. A vessel of some kind can be put underneath to catch the drops. Such a drip-sample will represent very accurately the average quality of the milk received at the creamery. If it is desirable to keep this sample, a preservative can be added to it. Composite Sampling without the Use of Preservatives.— Pipettes can be obtained holding 5.87 c.c. of milk. These are one-third the size of the ordinary 17.6 c.c. pipette used for the Babcock test. With this small pipette a sample may be taken every day from each patron’s milk, during three successive days, and emptied into the same test-bottle each day. At the end of three days the samples may be tested and the bottles cleaned, ready for use again. Accurate composite samples may be obtained in this way, providing the sample in the pipette is correctly taken each day. No preservative is needed. The preservatives are added to the composite samples to prevent curdling. The test-bottles may be placed on a shelf, or preferably in a rack made to hold them. They should be marked in such a way as to identify them. A good way is to mark them as the composite jars are marked, the number on the test-bottle corresponding to the number on the milk-sheet for each patron. CHAPTER X CREAMERY CALCULATION Find the Average Per Cent of Fat.—In calculating the average per cent of fat from a number of cows, or the milk furnished by the different patrons, the mistake of adding the tests of all the samples together and dividing the sum by the total number of samples tested is often made. Milk from different patrons, or from different cows, will always vary, both in quality and in quantity, and in order to get a correct average test, both quan- tity and quality must be taken into consideration. The wrong way of calculating the average percentage may be illustrated as follows: | | ; | | | Sample | Milk Delivered, Per Cent Fat | | | I | 50 lbs. | 5.0 | 2 | 100 Hs | 3 500 3.0 | 4 | 300 | BUS | 4)16°% | | | 4 The average test, according to the wrong method =4 per cent. The correct way of calculating the average percentage may be illustrated as follows: The average test, according to the correct method, is 3.42 per cent. It will be seen from the example quoted that there is a differ- ence of more than .5 per cent. If the percentage of fat or the 131 132 CREAMERY CALCULATION Sample Milk Delivered Per Cent Frat I 50 lbs. 5.0= 2.5 lbs. fat 2 100 4.5= 4.5 3 500 3.0=15.0 4 300 3.5= 10.5 950 Ibs. 950)32.5 lbs. fat 3.42 number of pounds of milk is uniform, it does not matter which of the two ways illustrated above is used. But as uniformity Fic. 42.—A Russian co-operative creamery in Siberia. (U. S. Government Bulletin.) in either of these respects scarcely ever exists in practice, the only correct way of calculating the percentage is to find the total number of pounds of fat and divide it by the total number of pounds of milk; the result is .o342, which may be written 3.42 per cent. CALCULATION OF OVERRUN 133 It is very common for creamery patrons to test the milk from each of their cows, then add the tests together and divide by the total number of cows tested. The result they will call the average test, and frequently such tests are made use of as evidence against a creamery operator to prove that his tests at the creamery were not correct. The fallacy is evident from what has been said above. The same mistake is also likely to be made in finding the aver- age test from several creamery-plants and skimming-stations. Calculation of Overrun.—The amount of overrun is the dif- ference between the amount of pure butter-fat and the amount of butter manufactured from that given amount of fat. This difference, divided by the amount of fat and multiplied by 100 will give the percentage of overrun. The calculation of the overrun in the creamery should always be made from the fat- basis on which the patrons are being paid. I the fat is delivered in the cream, the overrun should be calculated from the fat in the cream. The overrun calculated from the composition of the butter manufactured would not be an indication of the correct overrun, as there might be serious losses of fat sustained during the different steps in the manufacture, such as from inefficient skimming, incomplete churning, and general losses in the cream- ery. It is possible that butter might show a high content of the substances not fat, and yet not show a good overrun on account of losses; while butter containing only a medium high moisture- content might show as great or greater overrun on account of thorough and efficient work during the different steps of manu- facture. The amount of overrun depends upon: t. Thoroughness of skimming. 2. Completeness of churning. 3. General losses in the creamery. 4. Composition of the butter manufactured. The theoretical overrun, however, may be quite accurately calculated from the composition of the butter manufactured in a well-regulated creamery. In creameries where the condi- tions of separation and churning are almost perfect, the amount 134 CREAMERY CALCULATION of fat lost in the buttermilk and the skim-milk is quite constant from day to day, and should not exceed .1 per cent in the skim- milk and .2 per cent in the buttermilk, according to the Babcock test. Basing the calculations upon the above figures, the theo- retical overrun may be calculated from the composition of the butter as follows: If, for instance, we start with 1ooo pounds of milk testing 4 per cent fat, there will be a total of 4o pounds of fat. If we skim 32 per cent cream irom 4 per cent milk, we should have 35, or 4 of it cream, and the remainder skim-milk, or 125 pounds of cream and 875 pounds of skim-miik. Ji there were .1 per cent of fat in the skim-milk, there would be a loss of .875 pound of fat during skimming. There would then be 39.125 pounds of fat in the 125 pounds of cream (4o—.875 =39.125). If 10 per cent of starter were added to the cream we should get 137.5 pounds of cream testing 28.4 per cent. (125 pounds cream 1.10 =137.5 pounds cream; 39.125+137.5xX100=28.4 per cent fat.) By churning this cream we should obtain about 100 pounds of butter- milk. Ifit tested .2 per cent fat there would be a loss of about .2 pound of fat, making a total loss of fat in skim-milk and butter- milk of 1.075 pounds. Subtracting this total loss of 1.075 from 40 pounds we would have 38.925 pounds of fat left to be made into butter (40—1.075=38.925 pounds of fat). If the butter on analysis proves to contain 82 per cent fat, the total number of pounds manufactured will be 38.925 +.82 = 47.47 pounds of butter. 47-47 —40=7.47 pounds theoretical overrrun, and 7.47+40 X 100 =18.7 per cent overrun (theoretical). It is evident that the losses of fat will vary according to the different conditions. The richer the cream, and the less fat in the whole milk to be skimmed, the more skim-milk there will be; the thinner the cream and the more fat there is in the milk to be skimmed, the less skim-milk there will be, and consequently with the same skimming efficiency less fat will be lost in the skim- milk. The thinner the cream is the more buttermilk there will be. These conditions must be left for the operator to govern according to the conditions present. The actual amount and per cent of overrun as determined WHAT SHOULD THE OVERRUN OF CREAMERY BE? ve or in creameries is calculated as described previously. The formula is as follows: Butter —{fat : ; oer © ore 100 =per cent of actual overrun. Calculation of Churn-yield.—Instead of expressing the increase of butter over that of fat in the percentage overrun. as above, it is often customary among creamerymen to speak of the * churn-yield.”” For instance, they say that their test was 3.90, and their churn-yield was 5, meaning that on the average each 100 pounds of milk contained 3.9 pounds of fat and yielded 5 pounds of butter. The churn-yield is always expressed in per- centage, and is obtained by dividing the total pounds of butter obtained by the total pounds of milk from which the butter was made, according to the following formula: Pounds of butter. : "Danade ai anile 100 =churn-yield. In case cream is handled instead of milk, the same may be obtained by substituting milk ” in the formula. What Should the Overrun in a Creamery Be?—In discussing this problem we shall take 80 per cent as the legal standard for fat in butter. If every churning of butter were to drop to this standard, but none below it-——a thing quite impossible of attain- ment—if the patrons were credited with all the fat the creamery vc pounds of cream” for “ pounds of received, and if there were no mechanical losses, and no fat in the buttermilk, then every 8o pounds of milk-fat received would make too pounds of butter; that is, roo pounds of fat would make 125 pounds of butter, or, the overrun would be 25 per cent. The creamery has some gains and some losses which tend to offset each other. The gains come mainly from two sources, namely, (1) a small fraction of a pound of cream on some, but not all, of the cans of cream. (2) A small fraction of a per cent of fat on some, but not all, of the cream tested. 136 CREAMERY CALCULATION In weighing cream half-pounds should be credited, and in the Babcock test of the cream readings should be made by half and not whole per cents, thus 30.0 per cent, 30.5 per cent, 31.0 per cent, etc., and not 30.0 per cent, 31.0 per cent, ete. Following out this principle, the average gain in weight, per can of cream, will not exceed a quarter of a pound, and the average gain in per cent of fat will not exceed 0.25 per cent. The losses may be enumerated as follows: (1) The Loss of Fat in the Buttermilk.—This will, under present conditions, easily equal o.5 per cent. Our extensive investigation of the losses of fat in buttermilk, including complete records of several hundred churnings in different creameries, shows this to be a very conservative estimate; and tests of hundreds of samples of buttermilk in the laboratory of the American Association of Creamery Butter Manufacturers fully support this estimate. (2) Losses in Packing.—Enough butter must be put into a package to insure its having the proper weight when it reaches the market. (3) Mechanical losses, due to cream adhering, to a small extent, to the different utensils—cans, vats, etc. Under this head may be included the occasional spilling of small quantities of cream. (4) If practically all of the butter is to come up to the standard of 80 per cent fat, the average per cent of fat in the butter will exceed this a little. (5) If the results of the investigation made by Siegmund and Craig, are to be accepted as correct, the Babcock test of cream, as ordinarily conducted, gives a reading that is a little high. Their findings are summarized in the chapter on ‘‘ Receiv- ing, Sampling, Grading and Testing.” As a basis for estimating what the overrun in a_ well-con- ducted creamery should be, an 8-gallon can of cream will be taken as an average shipment and it will be assumed that the creamery, in weighing and testing the cream, credits the patron with 65.0 pounds of cream testing 30.0 per cent, whereas the actual weight of the cream is 65.25 pounds, and the actual test of the cream is 30.25 per cent. It will also be assumed that in a tub of butter CALCULATION OF DIVIDENDS 13 marked 62 pounds, net, there are actually 62.5 pounds of butter to allow for shrinkage. Amount of fat credited to patron, 30 per cent of 65 lbs. =19.50 lbs. Actual amount of fat in cream, 30.25 per cent of 65.25 lbs. =19.738 Weight of buttermilk, 70 per cent of 65 lbs. =45.5 Per cent of fat in buttermilk, 0.5 per cent Weight of fat in buttermilk, o.5 per cent of 45.5 lbs. = .227 |b. Weight of fat in butter, 19.738—.227 =19.511 lbs. : ; 100 Weight of butter made, on basis of So per cent fat, Bo % 19.511 = 24.39 O 62 Weight of butter sold, ae. 24.39 S242 52.5 24.219. 5 : Overrun ———— 100 =24.1% 19.5 In the above calculation no account has been taken either of the mechanical losses or of the fact that the average per cent of fat in the butter will, of necessity, slightly exceed the minimum standard of 80 per cent. In conclusion, then, we would say that while the overrun may, and will, vary to some extent, from day to day and from week to week, the creamery that does careful weighing and test- ing, and credits its patrons with half-pounds of cream and _ half per cents of fat, will be likely to have an overrun for the year of about 23 to 24 percent. Ifit has this it is doing careful, efficient work. On the other hand, if the overrun is much above or below this something is wrong somewhere and needs to be remedied. Calculation of Dividends.—The method of calculating divi- dends will vary according to the agreements between the manu- facturer of the butter and the milk and cream producers. Some manufacturers agree to make the butter for so many cents per pound of butter (usually 3 or 4 cents). Occasionally the cream- ery proprietor agrees to pay a final fixed sum for milk delivered containing a definite amount of fat (usually 4 per cent). These two methods are not in use much at the present time, although in the eastern part of the United States the method of paying the operator so much per pound of butter-fat manufactured is quite common. The two methods most commonly used, especially in the central West, are as follows: 138 CREAMERY CALCULATION (1) Pay so much per pound of butter-fat based upon some standard market price, such as Chicago or New York. The amount paid now by the central plants for butter-fat is usually 2 or 3 cents per pound below “‘ New York Extras,” and the com- pany pays all freight or express charges. (2) Pay per pound of fat based upon the net income of the creamery. 1. The former method of paying for butter-fat has become quite common. Nearly all the hand-separator or central plants are paying for butter according to this method. Payments are usually made at each delivery or every two weeks. Although this causes more work, it is much more satisfactory to the patrons than to pay only at the end of each month. In order to calculate dividends when paid at the end of two weeks or at the end of each month, the first step is to find how many pounds of butter-fat have been delivered by each patron. If composite samples are taken, and these tested for fat at inter- vals of one week, which would make about four tests during the month, and two during half a month, the results of the several tests may be added, and the sum divided by the number of sam- ples tested. This may give the average test, but it must be borne in mind that this method is also likely to give wrong results. Especially is this so when cream is delivered which varies in quantity as well as quality during the different parts of the month. If cream only is being received, it is a good plan to test each patron’s cream every day, as it is more or less difficult to get absolutely accurate composite samples from creams of different richness. Besides this, the patrons can get the test as well as the weight of the cream of each previous day’s delivery, and thus know how their account stands from day to day. A little more labor is involved in doing this, but in the long run it keeps the patrons better satisfied. 2. If the price of butter-fat per pound is being based upon the net income, as is the case in nearly all co-operative creameries, and also in many proprietary creameries, the first step is to find out how much butter-fat each patron delivered during the spe- cified time,—two weeks or a month, whichever may be the case. > oO NDS CALCULATION OF DIVIDE *yeOq Aq PooAlfap YU [Py “UoFaQ ‘Arowevasy Avg soojg— th “OL 140 CREAMERY CALCULATION When this has been obtained, the total pounds of fat delivered by all the patrons are found. From the gross income the total expenses of running the creamery are subtracted. The remainder represents the net income. ‘This is then divided by the total pounds of fat delivered to the creamery, and the quotient repre- sents the price per pound of butter-fat to the patrons. Knowing the price to be paid to the patrons for 1 pound of fat, the sum due to each patron is found by multiplying the price per pound by the total number of pounds of fat each patron delivered during the specified time. In some instances provisions are made for a “ sinking fund.” This is a name given to a fund raised by deducting so much per pound of fat, or per 100 pounds of milk, from each patron’s delivery at the end of each month. ‘This fund is for the pur- pose of paying off a debt gradually, or for raising a fund for new equipment, or other improvements in the creamery. In case such money is to be withheld, it is deducted previous to making the final calculation. Cream-raising Coefficient.—By the term cream-raising coeffi- cient we understand the percentage of the fat removed from the milk during the process of separation. The calculation of the cream-raising coefficient may be illustrated as follows: Suppose we have 100 pounds of milk containing 4 per cent fat, and yielding 85 pounds of skim-milk and 15 pounds of cream, the skim-milk containing .2 per cent fat. Total fat in whole milk = 100 Ibs. x 4 per cent= 4 lbs. Total fat in skim-milk = 85 Ibs. X.2 per cent =.17 lb. Total fat in cream = 4 lbs.—.17 Ib. =3.83 Ibs. 3.83 X 100 <—~—— =95.75 per cent of the total 4 pounds of fat, or the cream raising coefficient. Statement to Patrons.—A complete statement should be made at the time of each settlement and should be accompanied by the check. A statement similar to the following one may serve as an example:! 1 Creamery Butter-making by Michels. STATEMENT OF PATRONS IN ACCOUNT WITH Mr a ae Bor the momthyof 2 = ys Cr. | No. pounds milk delivered | Pounds butter at . byyotia 3 ¢ 3 Sern baaricer oa Suet AMETAMCCLESE: G. 4 &.- aku : Fic. 67.—The Simplex regenerative lic. 68.—The Jensen pasteurizer. pasteurizer (assembled). Sanitation Must Accompany Pasteurization.—The chemical and bacteriological laboratory of the American Association of Creamery Butter Manufacturers analyzes, chemically and bac- teriologically, samples of butter sent in by members. Thousands of analyses are made during the year. It is found that the butter that contains the lowest counts of yeasts and molds is invariably produced in the best creameries. Certain species of bacteria, SANITATION MUST ACCOMPANY PASTEURIZATION 207 yeasts and molds are present in almost all hand separator cream and cause the deterioration of butter in storage; the elimination of these micro-organisms retards such deterioration. Milk or cream that is efficiently pasteurized will contain neither yeasts nor molds. In laboratory work conducted by the Association, butter in which the combined count falls below ten yeasts and molds in tr c.c. of butter is considered good; in some of the best creameries the combined count drops to five or below. There are other things that affect the count of yeasts and molds found in butter. Pasteurization of cream may be perfect, and yet the cream may pass through unsanitary pipes and again be inocu- lated with yeasts or molds. Vats, faucets and churns are sources of contamination. Of the creameries sending butter to the Association laboratory, those whose butter shows the lowest count of yeasts and molds are creameries that are noted for observing extra precaution concerning sanitary methods in con- nection with all utensils that come in contact with cream. They use recording thermometers and automatic valves for regulating temperatures in pasteurization. The first cream passing through the pasteurizer is returned and reheated. Butter made in the creameries above-mentioned sells constantly at a premium. The quality of the cream received by them is no better than that received by other creameries operating in the same territory, which make very inferior butter. Pasteurization expels from the cream vapors and gases, especially carbon dioxide gas; it removes volatile substances and flavors absorbed by the cream or milk. The heating causes the clusters of fat-globules to break up. Due to uniformity of quality and pasteurization, Denmark has been able to secure almost absolute control of the English market. Danish butter commonly sells at a premium over any other butter finding its way to that market, or at least it did prior to the war. One of the authors in discussing this subject with an English merchant, who handled a great deal of butter, asked for an explanation of the preference given to Danish butter. He answered that they occasionally got better butter from some other countries but that it did not run uniform in quality. He 208 PASTEURIZATION said that the Danish butter was mild in flavor and uniform in quality; in other words, it suited the trade and that was all that was wanted, Efficient pasteurization not only enables the manufacturer to make a more uniform grade of butter, but it makes the butter- milk safe to feed to live stock, thus preventing the spread of infectious diseases. It is said by some that if pasteurization were adopted more skill would be required on the part of the butter- maker. With valves for controlling the steam pressure and the use of recording thermometers, uniform pasteurization to any desired temperature can be brought about by a maker of ordinary skill, if he applies judgment to the details of his creamery opera- tion. Methods of Pasteurization.—At the present time there are three methods of pasteurization employed for butter-making. The one most generally used is the flash or instantaneous heating method. Under this method the cream is heated to a high temperature, 180° or 185° F., and quickly cooled, by passing over a cooler, to ripening temperature or to churning tempera- ture, as the case may be. In the vat, or holding, method cream is usually heated to a temperature of 150° to 160° F., held at this temperature for twenty to twenty-five minutes, and cooled to ripening or churning temperature. Some use the combined flash and holding method. Some of the best creameries that use the flash method, or high temperatures, follow what is known as the double system of pasteurizing. Two pasteurizers are attached to each other; the cream passes to the first pasteurizer from the forewarmer, where it is heated to a temperature of about 135° or 140° F. It passes from the first to the second pasteurizer where it is heated to 185° F., or any temperature desired. The live steam is con- nected with the second pasteurizer, and the exhaust steam from the second pasteurizer furnishes heat for heating the cream in the first pasteurizer to 140° F., or thereabout. The heating of the cream in the first pastcurizer increases the fluidity of the cream. Hence, when it enters the second pasteurizer, the heat comes in contact with all particles of the cream, and the efficiency METHODS OF PASTEURIZATION 209 of pasteurization is thereby increased. From general observa- tion of work in many creameries belonging to the American Association of Creamery Butter Manufacturers, the authors feel safe in recommending this system. One of the authors first saw this system in general use at the Experiment Station at Kiel, Germany, something over twenty years ago. Dr. Weigman was heating to r90° F. at that time, and claimed very satisfactory results. The relative merits of the two systems—the vat system where the heating is done through a coil, or the use of a machine con- structed exclusively for pasteurizing milk and cream—depend largely upon local conditions. If the first cost only is taken into consideration, cream can be pasteurized more cheaply under the vat system, as the heating and the cooling are done in the sarre vat. Ina small creamery where space has to be taken into consideration, the vat system is to be recommended. Not only does it require less space but it involves less labor. The objections to the vat system are, first, that the vat is not constructed for a pasteurizer, and, second, that the wear and tear (heating and cooling, and expansion and contraction) will affect the life of the vat. These are items that must be taken into consideration when figuring the cost over a period of years. Ina factory where a large volume of business is transacted, the regular pasteurizer would be preferable. It is much stronger than the vat and is constructed exclusively for the purpose of pasteurizing cream. In addition to this a greater amount of cream can be cared for ina shorter space of time. The cooling is done much more quickly where a regular cooler is used. Another advantage is that the heating and cooling are not done in the same vat, thus avoiding the expansion and contraction of the metals. Some use the method of heating in the flash pasteurizer and cooling ina vat. This does away with the necessity for a cooler, but, as stated above, the cooling is not done as rapidly as it would be if a regular cooler were used. This system works well where the holding system is practiced and lower temperatures are used for pasteurizing. Cream can be run into the ripening vat from the flash pasteurizer, held any desired time and cooled with a coil. 210 PASTE URIZATION Under the regenerative principle the cold cream is heated by the hot cream passing from the pasteurizer. In the outflow, hot cream is cooled by the cold cream flowing into the pas- teurizer. The hot and cold cream then equalize their respective temperatures by passing in different directions. It is claimed by manufacturers of these pasteurizers that they effect a saving of 25 per cent, or more. Most pasteurizers at the present time are constructed of heavy copper coated with tin. The heating surface of some of these pasteurizers is lined with German silver. From the stand- point of heat conductivity there is little choice between these two metals. It is a well-known fact that some metals will conduct heat better than others; the relative heat conductivities of copper and tin are .g18 and .145 respectively. This means that copper will conduct heat nearly seven times as fast as tin of the same thickness, and therefore that copper might be seven times as thick as tin and still transmit as much heat as the tin. From this it can be seen that a heating wall made from copper can be increased slightly in thickness, and thus aid in stability, without affecting the degree of heat conductivity of the wall very much. The heating surface must be strong enough to withstand a slight steam pressure, otherwise the heating wall is likely to collapse or cave in, in case of slight variation in the steam pressure. It used to be a rather common occurrence for the heating walls of the pasteurizer to cave in or collapse in case of a slight variation in the steam pressure. This does not happen so often now. The condition of the cream has some bearing on the heating surface. Sour and coagulated cream burns and adheres to a greater extent than does sweet cream. This is evidently due to the lesser fluidity of the sour cream. Where two pasteurizers are used, this tendency is overcome to a very large extent. Efficiency of Pasteurizers.—Ixperiments conducted by Dr. Storch of the Royal Experiment Station, Copenhagen, Denmark, show that condensed steam offers great resistance to the trans- mission of heat. The comparative heat conductivities of water and copper are .ocor6 and .9 respectively, as found by Dr. Storch. It will thus be seen that copper is 600 times as good a conductor EFFICIENCY OF PASTEURIZERS QL of heat as water is. This would mean that a quiet layer of water 3 mm. in thickness would offer the same resistance to heat as a layer of copper 2 meters in thickness. Consequently a very thin layer of water or condensed steam on the sides of the heating wall would greatly interfere with the economic efficiency of a pasteurizer. In order to overcome this difficulty drip-rings were circled Tic. 69.—Jensen sanitary pasteurizer-regeneratcr and cooler (Jensen Creamery Machinery Co.). round the drum of the pasteurizer, at intervals, on the steam side of the heating surface. The first rings put around the pas- teurizer were narrow, smooth bands. ‘These did not give entire satisfaction, as the condensed water from the top rings would drip on the edge of the lower ones, and cause the water to spatter over the side of the heating wall. Another kind of ring was then invented which was thin, narrow, and provided with teeth like 212 PASTEURIZATION those of a saw. ‘The rings were fastened to the heating-wall at proper intervals at an angle of 45°. The rings were so arranged that the drops of condensed water escaping from the end of each saw-tooth would fall in the hollow between the teeth in the lower rings and thus prevent any spattering of the water against the heating wall. These contrivances greatly increased the effi- Tic. 7o. ~Elyria pasteurizer (Elyria Enameled Products Co.) ciency—as much as 48 per cent—and the capacity of the pas- teurizer experimented with. Cost of Pasteurization.—Dr. Storch in his forty-third report at the Royal Experiment Station at Copenhagen, Denmark, reported that it required 80 pounds of steam to heat 1000 Danish pounds of milk from 40° C. to 85° C. This would be equivalent COST OF PASTEURIZATION 213 under American conditions to about go pounds of steam to pas- teurize 1000 pounds of milk from go° F. to 185° F. According to good authorities, it takes about 1 pound of lump coal to produce 6 pounds of steam, although much depends upon the fireman and the construction of the boiler. Based upon this estimate, it would take 15 pounds of coal to produce 9o pounds of steam. If the coal cost S4.oo per ton, the cost of the 15 pounds would be 3 cents. If the milk tested 3.6 per cent fat, the calculation upon one-sixth overrun of 1000 pounds of milk would produce 42 pounds of butter. The cost of pasteuriz- ing the milk producing 42 pounds of butter would then be 3 cents, and the cost of pasteurization per pound of butter would be .o7 of a cent. The figures submitted by Storch, however, were obtained a number of years ago, and cannot be applied to conditions in this country at the present time. Mortensen, who has given a good deal of thought to the cost under the continuous and vat methods, estimates as follows: Continuous | .. oe) Vat Method, Method, ss ‘ Cents Cents GOSINOMeSteAI AA Vis een ae neat atsaneches heed eal O19 O16 COsiot Waletes << peced ens Pea ret tnt ch ie a tes 099 | O21 Cost-of labor and equipment.2 4 ss) cscesae4 eee gee | 1Sr O54 DUB Leet wseerven sit sere = Peeves ae | 200 | ool The cost in different factories would vary with the cost of fuel. With the high railroad rates prevailing at the present time and the high price of labor, we can estimate the cost at about one-fifth of a cent per pound. In addition to this, the loss of fat in buttermilk seems to be a trifle more in pasteurized than in unpasteurized cream. This may be due to the precipitation of the casein by heat. Pas- teurization is necessary from a hygienic standpoint. It gives a guarantee to the consuming public that all pathogenic bacteria 214 PASTEURIZATION are destroyed. It takes away from the enemies of butter the opportunity of proclaiming that discase may be transmitted to the human family through this article of diet. There is less danger of transmitting disease through butter than through any other dairy product. The senior author has been for moye than thirty years engaged in the butter business in various capacities, from manufacturer to conductor of investigational work, and has never known of a case where any disease was transmitted through butter, from either pasteurized or raw cream. It has been demonstrated in all parts of the world that raw or unpasteurized milk will transmit bacillus typhosus. The first epidemic of typhoid fever which was traced to infected milk was one occurring at Penrith in 1858 (Taylor). Since that time cases have become so numerous that almost all municipalities insist upon efficient pasteurization of milk. In addition to the effect that pasteurization may have on butter, pasteurization of the skim-milk and cream puts both the skim-milk and buttermilk in a condition where there is no danger of transmitting disease to animals. Disadvantages of Pasteurization.—The disadvantages of pas- teurization are, first, the cost of installing equipment, and, second, the additional cost of operation. Due to the increased cost of labor in recent years, it is difficult accurately to estimate the cost. Advantages of Pasteurization—The advantages of pas- teurization far outweigh the disadvantages, and may be sum- marized as follows: (1) It destroys pathogenic bacteria if there be any present in milk and cream, and renders them and their products and by- products perfectly safe as foods. (2) It destroys practically all germ life and enables the butter- maker to produce a more uniform quality of butter. (3) It is one of the large factors which improve the keeping quality of butter. (4) It eliminates some of the taints in cream. CHAPTER XVI CREAM-RIPENING AND STARTERS CREAM-RIPENING Definition.—By cream-ripening we mean the treatment cream receives from the time it is put into the ripening-vat until it is put into the churn; and also the chemical, biological, and physical changes it undergoes during this time. In the whole-milk creameries and in a few of the creamcries receiving only cream, the cream goes into the ripening vat in the morning and no more is added during the day. In most cream- eries, however, cream is taken in throughout the day. This system does not permit of such perfect ripening of the cream; besides, it necessitates opening and closing the vat at intervals. Under this latter system it is important that the cream vat have a fly screen over it, and that one end of it be covered with a cream strainer through which all cream is strained before it enters the vat. Objects of Ripening. To Produce Flavor and Aroma.—— The chief object of cream-ripening is to secure the desirable and delicate flavor and aroma which are so characteristic of good butter. The necessary flavoring substances, so far as known, can only be produced by a process of fermentation. Good butter possesses two characteristic flavors. One is known as palate flavor, or the distinctive butter flavor. The other is what is described by butter judges as a nose flavor or aroma, sometimes described as “ bouquet” flavor. While the flavor and aroma characteristic of good, properly ripened cream and the butter made from it are produced by fermentation, the chemical changes that produce them are not well understood. It is claimed by some that the palate flavor is derived from the volatile fatty 215 216 CREAM-RIPENING AND STARTERS acids, and the aroma from a fermentation of the milk-sugar. Good cream must possess a clean, pleasant. acid taste. For this reason, it is essential to have the acid-producing germs predom- inate during cream-ripening. Buttcr has been made from sour cream from time immemorial. Housewives discovered a great many years ago that butter made from ripened cream had a more pronounced flavor and aroma than butter made from unripened cream. They also found that cream properly ripened would churn more easily and give a Fic. 71 —Prossress vat pasteurizer and cream-ripener. (Davis-Watkins Da‘rymens Mfg. Co.) more exhaustive churning; hence, the practice of souring cream has been handed down to the creameries from the home dairies. Some women became noted for making butter of an exceptionally fine quality, because, in addition to observing cleanliness as the first requisite in making good butter, they selected nice, clean- flavored milk and let it sour naturally; this was added to the cream for the purpose of hastening the souring or ripening. Some of these dairies produced butter which was not only of good quality but also possessed good keeping qualities. In the early days of butter-making it was customary for some to pack their butter in glazed crocks during the latter part of May CREAM-RIPENING 217 or the first part of June, cover it with salt and hold it until the winter months, keeping it in the cellar or some other cool place until it was used up. As dairying advanced and butter began to be made on a large scale in creameries, in various countries, the bacteriologist resorted to the method of isolating certain species of bacteria for the purpose of ripening cream and pro- ducing the desired flavor. It has not yet been proved that any particular species of bacteria is responsible for the production of fine flavor in butter. It is generally agreed that the flavoring substances developed during the ripening of cream are decomposition products of bac- Tic. 72.—Wizard vat pasteurizer and cream-r.pener. (Creamery Package Mfg. Co.) terial growth, and it has been generally recognized that the types producing the lactic acid are the most desirable ones to have present in cream. There are a great many bacteria in milk and cream which produce acid, over one hundred species have been studied and described. It is apparent, however, that only a comparatively few of these produce the best results in cream- ripening. Hence, in the preparation of a natural starter, great care should be exercised in selecting milk that will sour with a pleasant acid taste. At the Iowa Experiment Station, McKay and Eckles con- ducted a series of tests on fermentation by taking milk from different patrons’ herds, placing it in sterile glass bottles and allowing it to sour naturally. It was found that milk which 218 CREAM-RIPENING AND STARTERS began to whey off at the bottom of the jar, soon after coagula- tion, due to certain species of bacteria decomposing the casein, invariably possessed an undesirable flavor. Samples of milk which would remain coagulated for some time and whey off at the top possessed a pleasant acid flavor. By selecting such samples of muk for preparing natural starters, these investi- gators were able to produce starters that gave excellent results in cream-ripening. Butter made at the school that scored the highest at one of the large national conventions, receiving a score of 98, was made from cream that had been ripened by a natural starter. The whole milk, received at the creamery when two days old, was skimmed so as to contain a very high per cent of milk-fat. The object was to concentrate the fat and get rid of as much of the skim-milk with its undesirable bacteria as possible, and then dilute the cream with fresh milk from the herds whose milk showed desirable results when souring naturally. The addition of a starter ripened naturally from the above-mentioned milk, ripened the cream which produced the high-scoring butter. Another test was made in a national contest where dif- ferent parties were placed in charge of the ripening, taking the entire milk as it came in on four different days, and the same method was followed with correspondingly favorable results. In this contest, in which about eight hundred creameries com- peted, the butter made by this method, on these four different days scored the highest, third, fourth and fifth in flavor. This is a further substantiation of what has been reported by various investigators, Storch, Conn and others, that the flavor developed depends very largely upon the species of germ life that predom- inate. Where cream has been pasteurized and inoculated with a starter containing the right organisms, the effects of the starter will be more pronounced than if the cream were manufactured raw or unpasteurized. This is due to the fact that the promis- cuous assortment of organisms in the natural bacterial flora is largely destroyed by the heating process in pasteurization. Bac- teriologists do not agree as to what species of bacteria is respon- CREAM-RIPENING 219 sible for the high flavor and aroma of butter. Conn claims that the germs which act upon the nitrogenous matter of milk are associated with the lactic-acid-producing bacteria in the pro- duction of desirable butter flavors. Weigman asserts that the best results are obtained when a variety of species work together in the cream. He has isolated a single species of germ which produces alcohol and lactic acid as by-products, and which according to experimental evidence deduced by him, is capable of producing the delicate butter flavors. Freudenreich also studied a species of germ which produced alcohol and lactic acid as by-products, and which he claimed was able to produce the 3s Fie. 73.—Cherry vat pasteurizer and cream-ripener. (J. G. Cherry Co.) characteristic butter flavors. Eckles studied the question of flavor production during cream-ripening. He came to the con- clusion that the flavor and aroma substances developed during cream-ripening may be produced by a variety of acid-producing bacteria. He asserts that of the species tried the most common milk-souring organism (Bacterium lactarii) gave the most satis- factory results as a culture for ripening cream. Storch, who has perhaps studied this question to as great an extent cs any of the investigators, maintains that the germs producing lactic acid are essential to good cream-ripening, and that the flavor and aroma products are the results of the joint action of a great many species of lactic-acid-producing germs. Tiemann finds that an addition of a small amount of hydrochloric acid to the cream does 220 CREAM-RIPENING AND STARTERS not produce the characteristic flavor, and indicates that the process of fermentation is necessary to secure the proper flavors. The study, by Hammer and Bailey of the Iowa Station, of the causes of flavor and aroma development in cream-ripening is briefly outlined in the section of this chapter on “ Starters.”’ YMBNUFACTURED By Cds & CHEAMERVAMACHI Nery Tic. 74.—Vertical universal ripener and pasteurizer. (Jensen Creamery Machinery Co.) This is probably the fullest investigation of this subject—in America at least—that has been conducted in recent years. Ripening Temperature of Cream.—In regular practice the ripening temperature of cream usually ranges between 60° and 75°F. The lactic acid organisms and those associated with them CREAM RIPENING 221 in a good starter have the greatest relative growth at 7o° F., or a little above. Generally speaking, it is advisable to adopt a little lower ripening temperature in summer than in winter. For one thing, the cream has a tendency to rise a little in temperature in summer and to fall a little in winter, during the time of ripening; and furthermore, the natural bacterial flora present in summer are more favorable to cream-ripening than those present in winter. With the necessary modifications to meet conditions, 65° to 70° will be found a suitable range of temperature to adopt during the summer season and 70° to 74° during the fall and winter months. The amount of starter used and the length of the ripening period are factors that must be considered in deciding upon the tem- perature to be used. Where a fairly high ripening temperature is adopted a little greater precaution must be taken to prevent over-ripening of the cream, particularly if a liberal amount ot a good, active starter be used. Amount of Starter to Add to Cream.—The amount of starter to add, the ripening temperature and the length of the ripening period are related factors that influence each other. Also the richness of the cream places a limit upon the amount of starter that can be used. Generally speaking, where the separating is done on the farm the richness of a vat of cream is not so great as where the milk is delivered to and separated at the creamery, and consequently it is not practicable to use so high a per cent of starter in the former as in the latter case. The quantity of starter used will range from 1c to 20 per cent, depending upon the ripening temperature adopted, the richness of the cream, the time within which the ripening is to be done, and, to some extent, the cost of the milk or skim-milk used in making the starter. Mixing the Starter with the Cream.—When the starter is added to a vat of cream the coils should be run for a few minutes in order to mix the two very thoroughly. This is necessary to insure uniformity of ripening. Tests for Acidity.— The acid in cream is developed in the milk- serum, and the per cent of butter-fat that cream contains merely takes up space. Hence, in ripening cream some consideration should be given to the per cent of fat in it, as the fat is a neutral 222 CREAM-RIPENING AND STARTERS quantity. For instance, it is not safe to develop as high a per cent of acid in cream containing 40 per cent as could be devel- oped in cream containing 25 or 30 per cent of fat. For this and other reasons it is advisable to use a special test with which to measure the amount of acid developed in the cream. There are two acid tests in general use now in creameries, viz., ‘“‘ Mann’s Test ” and the ‘ Farrington Test.” Mann’s Test.—Mann’s test consists of measuring the acid in Fic. 75.—A creamery equipped with glass enameled tanks and vats. the cream by means of an alkali of a definite strength. The kind of alkali used is usually a tenth normal solution of caustic potash (KOH) or caustic soda (NaOH). These solutions can be made up very cheaply or bought from the supply houses. Mann’s test is based upon measuring out 50 c.c. of cream by means of a pipette. While the test is based on 50 c.c. of cream a 25 C.c. pipette can be used, and the reading multiplied by two, thus avoiding the necessity of using so much cream. Even a smaller pipette could be used, but 25 c.c. is preferable to a smaller quan- tity, which would increase the danger of error. A few drops of an CREAM-RIPENING 223 indicator (phenolphthalein) are added. This indicator gives a red color in an alkaline solution, and no color in an acid solution. The tenth normal alkali solution is poured into a burette, and allowed to run into the 50 c.c. or 25 ¢.c. of cream (which is kept stirred thoroughly) until it begins to turn pink in color. At this point it is neutral. The number of cubic centi- meters of alkali required to neutralize the acid in 50 c.c. of cream indicates the number of degrees of acid. For in- stance, if it should require 32 c.c. of a 7 tenth normal alkali to neutralize the acid || in 50 c.c. of cream, the acidity of the cream would be 32°. (1 c.c. of N/1o alkali=1° Mann’s Test.) Mann’s test reading can be con- eed verted so as to express the results in a, percentage similar to the Farrington test. As 1c.c. of the tenth normal ,,, (ents. tae alkali neutralizes .oog gram of pure lactic Mann’s ac‘d test. Instead acid, 32 ¢.c., as in the above case, would of: the —burette the alkaii neutralize 32 times .oog. This would os ed bik - : Hatgp bottle, as shown in Figs give the amount of acid, calculated in 5, ana 3s. terms of lactic acid, present in the 50 c.c. of cream. This product divided by the 50, and multiplied by 100, would give the percentage of the acid present. Farrington Test.—The same principle is involved in the Far- rington test. The alkali is put up in small tablets, already containing the indicator. These tablets contain a definite amount of alkali, and are represented as retaining their strength. They lose it, however, if they are exposed to the atmosphere. The amount of alkali in each tablet is such that when five of them are put into a graduated cylinder, the cylinder filled up with dis- tilled water to the 97 c.c. mark, and the tablets thoroughly dissolved in it, a solution is obtained, each cubic centimeter of which represents .o1 of r per cent of acid, provided 17.6 c.c. of cream are taken. The tablets can be made up of different 224 CREAM-RIPENING AND STARTERS strengths for the use of different-sized pipettes, but as the 17.6 c.c. pipette is the one which is used in the ordinary Babcock test, directions are given for the use of this pipette only. For a more detailed description of the acid tests see ‘‘ Testing Milk and its Products,” by Farrington and Woll. Degree of Acidity that Cream Should be Ripened to.—As to — _, Fic. 77.—Arrangement for keep- Fic. 78. ing alkali for the Mann’s test. the per cent of acid that should be developed in cream, this will depend upon such factors as the richness of the cream, the market demands as to fullness of flavor in the butter, whether the cream is sweet cream or cream that has previously soured and been neutralized, and the length of time the butter is likely to be held in storage. STARTERS 225. As has already been pointed out, rich cream should not show as high a per cent of acid when ripened as cream with a lower fat-content. If it should do so it is really a riper cream, that is, the skim-milk portion of it has been ripened to a higher degree of acidity. Where cream has soured and been neutralized before pas- teurization, it is advisable not to ripen to as high a degree of acidity as might be developed were the cream sweet to begin Fic. 79.—Apparatus for the Parrington acid test. with. Especially does this apply when butter is likely to be held any length of time. Unless market conditions demand it—and it is only in very exceptional cases that they do—it is not advisable to ripen average cream, or cream with a fat-content of about 30 per cent to an acidity of over .50 to .55 per cent. It is safer to err a trifle on the side of underripening rather than to overripen cream. STARTERS Definition.—By the term starter, in cream-ripening, we understand a medium containing'a preponderance of desirable germs present in a vigorous condition. 226 CREAM-RIPENING AND STARTERS History.—The use of starters in the dairy industry dates back a great many years. The fact that starters helped in the manufacture of dairy products was recognized years ago by practical men even before scientists recommended the use of pure cultures. In European dairy countries the use of the buttermilk borrowed from a neighboring factory to add to the cream in order to overcome abnormal conditions, was a common occurrence. In Holland, sour whey borrowed from some other factory was used to overcome gassy fermentation in cheese- making. While the reasons for this were not well understood, the underlying principle involved was that of overcoming the undesirable fermentation by adding ferments of an antagonistic kind. The introduction of commercial starters for cream-ripening dates back to 1890, when Professor Storch recommended their use In creameries in Denmark. After commercial starters had been used long enough in that country to demonstrate their worth, they were introduced into this as well as practically all the European countries, and are now used quite extensively. Classification of Starters.—Generally speaking, the different kinds of starters are included under the names (1) Natural, and (2) Commercial. The latter are prepared from a culture of bacteria obtained from the laboratory. The former, or nat- ural, include a great many kinds of dairy products which are supposed to contain a preponderance of those germs which are involved in the production of desirable flavors in butter. Buttermilk, sour cream, whey, and sour whole or skim-milk, are classed under this heading. While all these may be termed natural starters, and at certain times the use of any one of them may produce better results than if no starter at all were used, it is not safe to rely upon them to bring about better results than could be obtained without the use of starters, because these products are likely to be contaminated in a large degree with undesirable germs. Preparation of Natural Starters.—The best natural starter is usually obtained by selecting a number of different samples of the best milk coming into the creamery and putting them STARTERS 227 into cleaned sterile glass jars. The samples are allowed to stand until sour at about 70° F. The sample which coagulates into a smooth uniform curd, and has a pleasant acid taste and smell is selected and used as a mother-starter. When a large quantity of selected pasteurized milk or skim-milk is inoculated with this and cooled to and held at a temperature of about 70° F., until it begins to coagulate, it will usually prove to be a starter which is equal, and often superior, to a commercial starter. Commercial Starters or Cultures.—Experiments have amply proved that certain species of bacteria are chiefly responsible for the butter flavors developed in cream during ripening. This fact has given rise to the use of cultures prepared in a commercial way. These cultures contain, in a vigorous condition, the germs which produce the desirable flavors and aroma. The cultures are put up in laboratories specially provided for this kind of work. Some of the laboratories put these cultures up in liquid form while others put them up in a dry or powder form. The liquid starters consist of a sterile nutrient medium, milk or beef broth, inoculated with the culture; while the starters in dry or powder form are prepared by mixing the liquid culture with some suit- able substance, such as milk-sugar, and drying this mixture at a temperature low enough not to injure the germs present in it. The cultures that are put up in the liquid form will not keep so long, and it is not safe to use them after they are about nine days old. The cultures which are put up in powder form have the advantage that they can be kept for a much longer time and still retain their vitality. Both kinds as a rule are good while they are fresh. We give a list on next page of the commercial cultures with which the authors are familiar. Technically speaking, most of the commercial cultures sent out from the different laboratories, to be used in the preparation of starters for milk- and cream-ripening, are not pure cultures of lactic acid organisms, although they are commonly spoken of as such. A pure culture is one which contains just a single species of organism, and most of these cultures contain more than one. The commercial cultures are, however, limited as to variety of species contained—usually two and at most three and do not 228 CREAM-RIPENING AND STARTERS contain a promiscuous variety of organisms. It is for this reason that they are commonly designated as pure cultures. Lactic Acid Culture S. C. Keith, | Charlestown, Duplex Culture Liquid Mass. J 3oston Butter Culture J O. Douglas, Boston Butter Culture ) Boston, Duplex Culture , Liquid Mass | Lactic Acid Culture J Ameri- al esas | Ericsson’s Butter Cul- | ee ae St. Paul, au, and ist Minn. i Ger Chr. Hansen’s Lab- oratory, Little | Lactic Ferment Powder Commercial dicta ae: J Sata Parke, Davis & Co., | This culture is put Detroit, Tlavorone up in tablet and Mich. J capsule forms Dipuenie dite | Danish Lactic | Tvede, Copen- \ id erent Powder hagen, Den. J renee eceacat J Hjort & Fog’s loreign Laboratory Cul. | Lactic Copenhagen, | Den. S. P. Storm, | Tillitze, Naks- Starter kov, Den. J Extensive work done by Hammer and Bailey of the Iowa Station not only supports what has just been said regarding commercial cultures, but also goes to prove that while the organism which predominates in a good culture or starter is the common lactic acid organism (Streptococcus lacticus), there must also be associated with this, an organism or organisms, which will develop volatile flavor and aroma-producing acids. Hammer says that it seems that there is no longer any question that starters are mixed cultures, and that even a pure lactic acid culture sent out from a laboratory very soon becomes a mixed culture containing volatile acid-producing organisms. These findings by Hammer and Bailey are supported by the work done by Storch in Denmark, and Beckout and Ott de Vries in Holland. STARTERS 229 According to Hammer, the lactic acid, which is non-volatile, produces an acid flavor but very little of the flavor and aroma so characteristic of a good, well-ripened cream and the butter made from it. The organisms which he has found to be the most suitable associate organisms of the lactic acid organism (Strep- lococcus lacticus) are Streptococcus citrovorus and Stre plococcus paracitrovorus. S. citrovorus acts upon the citric acid of milk and cream (hence its name), and also to a certain extent upon the lactic acid, and converts these into volatile, flavor- and aroma- producing acids. S. paracilroverus, in addition to performing the same function, also develops and uses another product. A good starter is one which will develop a fair proportion of the volatile, flavor- and aroma-producing acids without the development of an excess of acidity; that is, it will afford all the advantages to be gained from the proper ripening of cream without the disadvantages that come from ripening it to too high a degree of acidity. The great problem is that of the maintenance of a proper balance between the lactic acid organism (S. Jacticus) and the associate organism or organisms which develop the volatile, flavor- and aroma-producing acids. One of the large factors in maintaining this balance is a proper ripening temperature in both starter- and cream-ripening. Hammer mentions 70-72° F. as a very favorable range. A temperature much above this is more favorable to S. /aclicus than to S. citrovorus, that is, it will enhance the development of lactic acid to a greater extent than that of the flavor- and aroma-producing acids, and throw the ripening out of balance. It would seem then that the big problem for our laboratories, in the preparation of commercial cultures, is to supply a culture which, if properly handled in the creamery, will develop a reason- able amount of suitable, volatile flavor- and aroma-producing acids without the development of excessive acidity in the cream; and that one of the large problems for the creameryman is proper temperature control in both starter and cream-ripening, so as to enable flavor production to keep pace with lactic acid produc- tion. It would seem to be quite a safe practice to ripen the cream at a temperature of 70° F., provided care is taken to cool 230 CREAM-RIPENING AND STARTERS it early enough to prevent the development of acidity from going too far. Under the varying conditions that exist in the dif- ferent creameries each creameryman will have to decide for himself the temperatures that best suit his conditions. What the authors have aimed to do is to state the underlying prin- ciples of successful starter and cream-ripening, and what they would urge most is the intelligent application of these prin- ciples. Preparation of Commercial Starters.—All of the starters mentioned above have been tested and are known to produce good results. The first step in the preparation of a mother- starter (starterline) is to prepare preferably a glass jar or bottle by thoroughly cleaning and sterilizing it. Glass jars are used in preference to any other vessel, because if they are unclean in any way, it will be apparent. Secondly, there are no seams and no places on the inside which will corrode, and in that way retain unnoticeable dirt; and in the third place, the nature of the coag- ulation can be readily observed through the glass. Mason jars and sampling bottles are suitable. The kind of bottle which is used for marketing milk gives very good results. The second step consists in selecting suitable milk. The milk must be in as pure and sweet a condition as possible. A good starter can be produced from either whole or skim-milk. At one time skim-milk was given a decided preferetice for use in the making of starters. But the views of some of our leading bacteriologists and practical creamerymen, experienced in the preparation and use of starters, have changed upon this point and they now express a decided preference for the use of whole milk starters. The reasons for this preference may be briefly stated: The whole milk is generally more easily selected; it is the practice in some of our best creameries to have some farmer supply milk, produced under special sanitary conditions and cooled promptly to a low temperature, for starter purposes. The trouble of separating and a possible extra source of contam- ination are avoided. The presence of the fat in the milk serves two useful purposes; first, the cream that rises seals the starter over and prevents contamination, and second, the exclusion of STARTERS 231 air prevents the development of certain injurious organisms, which may be present and which require air for growth. However, fine starters can be made from either whole milk or skim-milk, and the point of first importance is that the milk used be sweet and in a clean, sanitary condition. The milk which has been selected for the mother-starter, or starterline, is then pasteur- ized. The pasteurization is best accomplished by the intermittent method. If considerable milk is to be pasteurized it is best to make use of a clean, steril- ized starter can. If only a small portion is to be pas- teurized, just enough for the mother-starter, the milk can be put directly into the jars. The jar half full is about the proper amount of milk to use. The directions sent with some pure cultures recommend as much as half a gallon or a whole gallon Starters. The inner compartment will of milk. As a rule better hold a pail of water and the bottles for results are obtained if only the mother-starters. The temperature ‘| : 5 can be kept at any desired point by the about a pint of milk is use of warm or cold water. The four- taken. If the milk for the inch space between the walls is filled with mother-starter is pasteur- hay or mineral wool. (Dairy Bac- iat in: the glass hotties teriology, Russell and Hastings.) or jars, it is advisable to set the bottles containing the milk into cold water,—covering the jar so as to prevent outside con- tamination,—and then heat up the water gradually. Care should be taken not to insert these bottles suddenly into scalding hot water, or to let the steam strike them, for either is likely to crack the bottles. Care should be taken also to exclude water from milk used for starters. It is advisable to heat this milk, for Fic. 80.— An Incubating Chamber for 232 CREAM-RIPENING AND STARTERS the starterline, as high as possible in hot water, say up to about 200° F. The sample may assume a cooked taste, but this will soon disappear after the starter has been carried on a few days. The milk should be left at this high temperature for about ten or fifteen minutes. A longer time does no harm. Then the milk is gradually cooled to about 80° F. This high temperature is desirable, because the germs present in the commercial culture may be somewhat dormant. This high temperature would tend to revive them more quickly than a lower temperature. Great care should always be taken to cool the milk previous to inoculating it with the pure culture, otherwise the germs present in the culture will be destroyed. Inoculation.—The next step is to inoculate the prepared milk with the culture obtained from the laboratory. The bottle which contains the culture is carefully opened, turned over and emptied into the pasteurized milk. It should be held down closely to the mouth of the jar containing the sterile milk, in order to prevent, as far as possible, the entrance of the air and the consequent danger of contamination. Then the milk containing the culture is thoroughly stirred and set away in a room where the temperature is about 70° F. This will gradually cool the milk from 80° to 70° F., and in about twenty to forty hours the milk will sour and coagulate. Germs in nearly all of the liquid cultures are rather slow in acting upon the milk, undoubtedly due to the dormancy of the germs, and toa comparatively few of them being present in the culture. When the powdered cultures are used, a little more care is essential to get the powder thoroughly mingled with the milk. It is a trifle more difficult to get the powder thoroughly mixed with the milk than it is to get the liquid cultures mixed. If anything is used with which to stir the sample, it should be sterilized before com- ing in contact with the milk. This applies in the preparation of all cultures. In testing or sampling the mother-starter, nothing should be allowed to come in contact with it unless it has pre- viously been thoroughly sterilized. The powder cultures are usually more vigorous in their effect than most of the liquid cultures now on the market. The powder cultures usually STARTERS 233 coagulate the sample in about twenty-four hours, and if the operator is used to handling the liquid cultures, he should watch the mother-starters prepared from powder cultures, so that they do not get overripe. It is very essential that this should not happen. The time when the germs are most numerous and most active in the starter is about the time when the sample coagulates. As soon as this stage has been reached, or just previous to coagulation, the starter should be cooled down to at least 50° F., or lower if possible. This prevents any further growth of germs and the sample can thus be kept a short time without injury. Directions usually accompany each of the cultures, but the above will be found to produce good results with all of those mentioned in the above list. By putting from 2 per cent to 5 per cent or more of the mother-starter into a large sample of pasteurized milk, any desired amount of starter can be prepared. In selecting this amount of milk, as much care as possible should be taken in order to select the best kind of milk, and keep it from being con- taminated. When this large sample of starter is at the proper stage of coagulation, it should be used at once, or else cooled down to about 50° F. The amount of mother-starter with which to inoculate the large sample of starter may vary a little without any bad effects. If the large sample of starter is to be ready for use in a short time, a larger portion of the mother- starter can be used for inoculation. If the temperature at which the starter is set and the amount of mother-starter used for inoculation are the same from day to day, the starter will be ripe at nearly the same hour every day, and, consequently, more uniform ripening results can be obtained. The noticeable coagulation of the starter when milk or skim-milk is used will usually take place when there is about .6 per cent of acidity. A slight coagulation will take place when there is about .5 per cent of acidity, but it is hardly noticeable. The coagulation- point may vary with different samples of milk. If a mother-starter is to be kept any length of time it should be inoculated into a sample of good fresh pasteurized milk about 234 CREAM-RIPENING AND STARTERS every other day. If a mother-starter, or starter of any kind, is allowed to stand too long at a low temperature, the desirable germs will become dormant, and some undesirable germs will gradually gain a foothold. It is a good plan to carry any mother- starter along for two or three days before it is used to inoculate a large sample of milk. When the mother-starter is first pre- pared it sometimes possesses an undesirable taste and smell from the medium in which the germs were put up at the laboratory. This smell and taste are eliminated by carrying it on two or three days previous to its use. After inoculation and the proper mixing of the mother- culture with it, a new starter should not be disturbed during the ripening process. A good starter, when ready for use, will have a soft, close coagulation, without any gas openings or wheying off (particularly at the bottom); it will, when mixed, break up readily and form a smooth, creamy liquid entirely free of lumps, and will possess a pleasant acid taste and a character- istic aroma that is delicate and agreeable. It is of vital importance that a starter be prepared and kept in specially sanitary surroundings. While not absolutely essen- tial, it is advisable, if possible, to have a small room, suitably constructed and equipped, as a starter room. The chief equip- ment of such a room would consist of, (z) Quart sealers or bottles in which to prepare the mother- culture from day to day. (2) A small galvanized iron tank or box in which to sterilize bottles, thermometers, dippers, etc. It should have water and steam connections. (3) A small incubating chamber in which to keep the mother- starters. This is a small insulated box or chamber lined with galvanized iron and well insulated so that the temperature can be kept at any point desired. (4) A suitable starter can, one of suitable size, in which heating and cooling can be accomplished readily, and which is well insulated so as to hold temperature. One of our largest creamery companies, a company whose butter has won an enviable reputation in the New York and other STARTERS 235 eastern markets, follows a system of handling and ripening cream, in all of its creameries, which is worthy of consideration. The acidity of the cream is reduced to about 15° Mann’s Test (.27 per cent) for pasteurization, milk of lime being the neu- tralizer used. The cream is then pasteurized at a high tem- perature, 180° to 185° F., after which it is promptly cooled to ripening temperature. Before adding the starter the acidity is further reduced to 5° to 8°, Mann’s (.o9 to .14 per cent), if it has not already fallen to this during pasteurization. If there be any probability of trouble with metallic flavor the acidity is reduced still lower—to 2° or 3°, Mann’s test (.04 or .05 per cent). A carefully prepared starter, which is active and possesses a desirable, clean flavor, is then added, and the cream is ripened and held overnight. The aim, in ripening the cream, is to develop an acidity of about 30° Mann’s (.50 to .55 per cent) for churning. Great care is exercised in connection with the raw material and the preparation and use of the starter, and equal care is taken to avoid subsequent contamination of the cream, due to faulty or unclean pipes or utensils. As to the raw material for the starter, the practice is to arrange with some farmer to supply milk produced under special sanitary conditions, and promptly cooled and held at a low temperature until shipped. A special room is fitted up as a starter-room and this is placed in the charge of a man skilled in the preparation and use of starters. The butter made from cream, handled and ripened as indi- cated, possesses not only a fine, full flavor and aroma when made, but good keeping qualities as well. The butter made by this company commonly sells at a substantial premium over Extras and Specials. Milk Powder for Starters.—According to experiments con- ducted at the South Dakota Experiment Station, Bul. 123, milk powder solutions may be successfully used instead of the natural milk for starters. In many large central creameries, skim-milk is difficult to ob- tain. In such places milk powder can be and is successfully used. Milk powder is of about the same consistency as flour and 236 CREAM-RIPENING AND STARTERS dissolves in cold water with similar difficulty. To make the milk powder dissolve as quickly as possible, weigh out the required amount of water into the starter can. Turn the steam on and heat. While the water is heating weigh out the required amount of milk powder. Use powder at the rate of 3 ounces to t quart of water. Add the milk powder to the water and stir violently. If little lumps remain stir every five or ten minutes during heating. Continue to heat or pasteurize as though it were normal milk. The remainder of the processes involved in making this into a starter are the same as already described. Length of Time a Starter Can be Carried.—In this country, even if special precautions are taken, it seems almost impossible to carry on a starter for more than four weeks without having undesirable ferments enter. The length of time a starter can be carried undoubtedly depends upon conditions, and the care with which it has been handled. When a starter is properly prepared, cooled gradually before coagulation, and not over- ripened, it will contain a smooth soft curd, and retain its mild acid flavor for. at leasta month The Danes, who use starters in butter-making more regularly than any other people, are able to carry a starter along for six months or more without renewing it. It is a good plan to keep at least two different kinds of starter by carrying them on from day to day insmall quart jars. Then if one should happen to “ go off,”’ the other one can be used instead. Poor Starters.—Many unsuccessful results from the use of starters for cream-ripening have been reported. The failure can be traced to the improper use of starters. If starters are good they will never bring about poorer results than are obtained without the use of them. Owing to the fact that it is difficult to keep the same starter in a good condition very long, many starters are used which develop abnormal fermentations in cream. A slightly acid, somewhat bitter taste, and a slimy condition of the starter are defects which are very common. These condi- tions seem to be brought about chiefly by overripening it at a high temperature, and keeping it a long time at a low tempera- ture before using it. Slimy fermentation is very common in starters which have been carried on for a time. Whenever this STARTERS 237 slimy ferment develops in the starter it can be noticed both in the cream and in the starter by the failure of the acid to develop so rapidly as when the proper acid-producing ferment is present. It seems almost impossible to develop any more than about .5 per cent of acidity in 30 per cent cream, while if the proper fer- ment were present, about .7 per cent could be developed. A decrease in the quality of butter accompanies the development of this ferment in the cream. Whenever it is found that a starter is not in good condition, it should not be used, as a poor starter is worse than none at all. The buttermilk from the previous cream can sometimes be used advantageously until a new starter can be prepared. Underripening and Overripening of Starters.—The effect of overripening starters has already been mentioned under the “Preparation of Mother-starters.” The question of under- ripening starters is also of importance. It is a well-known fact that just about the time when the milk begins to turn sour, that is, when the sourness can just be recognized by the taste, it has a rather disagreeable flavor. After more acid develops the undesirable flavor largely disappears, and the milk assumes a clean, desirable acid taste. The reasons for this have been stated by Storch, the well-known authority on starters. He claims that this disagreeable flavor is due to the action of unde- sirable organisms, during the first souring stage. As the souring progresses these germs are subdued and gradually crowded out by the desirable acid-producing types. In the preparation of a starter the probabilities are that some of these undesirable types of germs are present. At least it is safer to go on the assumption that they are present. This makes the underripening of starters just as important to guard against as overripening. Amount of Starter to Use.—The amount of starter will vary under different conditions. It may vary from none at all to as much as 50 per cent of the cream to be ripened. The quality of cream is one of the factors that need to be considered. Raw cream and old cream both require a large starter, especially if the cream is thick enough to permit of being reduced in thick- 238 CREAM-RIPENING AND STARTERS ness. Good pasteurized cream does not need a larger starter than about 10 per cent of the cream to be ripened. The amount of starter to use also depends somewhat upon the general creamery conditions. In some creameries all the cream is received in a very sour and poor condition, and facilities for getting milk for preparation of starters are often very poor. Under such conditions it is questionable whether it would be profitable to use starters at all. The amount of starter to use chiefly depends upon the degree of rapidity of ripening desired, and upon the temperature of the cream. If it is desirable to ripen quickly, a comparatively large amount of starter (15 per cent to 25 per cent) should be added, and the ripening tempera- ture should be comparatively high (about 70° to 74° F.) If slow ripening is desired, less starter may be used. Enough, however, should be used to control the fermentation in the cream (about 10 per cent to 15 per cent), and the ripening temperature may be lower, between 60° and 70° F. More starter should be used in the winter. Use of Starter-cans.—In the past, ordinary tin shot-gun cans have been used in most cases for the prepara- tion of starters, and have given good results. Some makers still use such cans. The earliest starter-cans were made of light material and did not last long. These defects, however, have largely been done away with, and the use of starter-cans certainly is an improvement over the old ‘ method of preparing the starters in Fic. 8t.—Improved Victor Starter several smaller cans. a (Creamery Package Mfg. These starter-cans are jacketed, os so that the temperature can be con- trolled by using hot or cold water, or ice, as demanded, in the jacket. All of the starter-cans have an agitator, which is operated with a belt. CHAPTER XVII CHURNING AND WASHING BUTTER Definition.—By churning we understand the agitation of cream to such an extent as to bring the fat-globules together into masses of butter of such size as to enable the maker to sep- arate them from the buttermilk. The agitation may be brought about in several different ways, Fic. 82.—-Ancient method of churning Fic. 83.—The Dash churn. in skin bags. and by different shaped devices, which are called churns. The methods of churning, like the process of separation, began with primitive methods. The ancients churned their milk, without separation, in bags made from the skins of animals. The next step in advance was to place milk or cream in bottles or jars, and then to shake them. This latter method of churning cream in bottles is yet in use in many of the smaller households of Europe, where the amount of cream is limited to a small quantity donated 239 240 CHURNING AND WASHING BUTTER by cow-owners. The next step toward churning on a large scale was to get a large wooden box or barrel run by power or by hand. The churns which are in use at the present time in American butter-factories are termed ‘combined churns.” They are so arranged as to admit of churning, washing, salting, and working without removing the butter from the churn. This style of churn is now being introduced into Europe. Owing to their superior worth they will soon be in genera] use there as well as here. They keep flies away from the butter during fly time; the temperature of the butter can be controlled in the churn, and the handling of the butter during salting and working is obviated. CONDITIONS AFFECTING THE CHURNABILITY OF CREAM Temperature.— The temperature of cream is one of the most influential factors in determining its churnability. The higher AEDLLNOD ROL YEDDA DEERE ELD DESL itt Tia Fic. 84. - Dual Churn (Creamery Package Mfg. Co.) the temperature of the cream, the sooner the churning process will be completed. Too high a churning temperature, however, is not desirable. It causes the butter to come in soft lumps instead of in a flaky granular form. This is deleterious to the quality of the butter. It causes, first, a greasy texture of the butter, and, second, the incorporation in the butter of too much buttermilk. This buttermilk contains sugar, curd, and water, CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 241 which, when present together in butter, are likely to sour and in other ways injure the butter. Curd and sugar should be excluded from butter as much as possible, in order to eliminate food for bacteria which may be present. An excess of curd is also favorable to the formation of mottles.! Too low a temperature is also un- desirable, although it is better to have the temperature a little low rather than too high. When the churning tempera- ture is too low, difficult churning is likely to occur. Cream at a low tem- int 8 — Second aes perature becomes more viscous. On Ball agitation in the churn such cream, if it is very thick, will adhere to the sides of the churn and rotate with it without agitating; consequently no churning will take place. Too low a temperature brings the butter in such a firm condi- tion that it takes up sait with difhculty, and when this hard Tic. 86.—Perfection Dreadnaught Churn (J. A. Cherry Co.) butter is being worked, a large portion of the water in the butter is expressed, and the overrun will be lessened to a great extent without increasing the commercial value of the butter. The degree of hardness of the fat in the cream is the govern- ing factor in deciding the churning temperature. The churning 1 Bul. No. 263, Geneva, N. Y. 242 CHURNING AND WASHING BUTTER temperature will vary a great deal in different localities. The hardness of the fat depends upon (1) the season of the year; (2) the individuality of cow; (3) the stage of lactation; and (4) the kind of food fed to the cows. All these factors influence the melting-point of butter-fat. The higher the melting-point of the butter-fat is, the higher the churn- ing temperature, and the lower the melting-point of the fat, the lower the churning temperature. t. During the spring the cows yield milk containing a larger pro- portion of soft fats; consequently the churning temperature is always lower in the spring than in the fall or winter. During winter, when the cows are fed on dry food chiefly, the harder fats increase in quantity, and consequently a higher churning temperature is necessary during that time. Fic. 87.—Sectional view of Perfec- tion working butter. Tig, 88. Disbtow churn (bavis-Watkins Vairymen's Mfg. Co.) 2. Some animals produce milk containing a larger propor- tion of softer fats than do other animals. It is said that the difference in this respect is more marked in certain breeds. It is maintained that the cows of the Jersey breed produce milk CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 245 containing a larger proportion of the softer fats than do those of any of the other breeds. 3. The period of lactation also affects the melting-point of butter-lat. When a cow is fresh she yields a larger proportion of the soft fats than she does later on in the lactation period. Just how much this change in the hardness of the fat is due Vi, ‘A to advance in the lactation Ly as \\ period and how much to |{ a 1 change from succulent to dry | he re x I, feeds is not definitely known, a aay a i since the two parallel each \\ ia other so closely, it being the common practice in this coun- try to have the cows freshen in the spring. According to investigations conducted at the Purdue Station,! the melting point of the fat lowers as a cow advances in her lactation period, provided she is fed the same feeds throughout the year. If these findings be correct, they mean that the influence of the feed is much greater than that of the stage of lactation, since the broad truth stiJl remains, that under our conditions the propor- tion of hard fats increases as the lactation period advances. Witn this increase in the proportion of the hard fats in the advancement of the lactation period, the fat-globules become smaller. This, together with the increased hardness of the fat, causes difficult churning at times. It readily can be seen that the larger the fat-globules are the greater are the chances for these globules to strike each other during agitation in the churn- ing process. 4. The nature of the food fed affects the melting-point of butter to a considerable extent. Cotton-seed and its by-products Sa ce Fic. 89.—Sectional view of Disbrow. have been demonstrated thoroughly by several investigators to cause butter to become hard. When a large amount of cotton- seed is fed, the butter assumes a crumbly, tallowy, hard condi- 1 Purdue Bulletin 159 244 CHU tion; while linseed meal, and practically RNING AND WASHING BUTTER all succulent foods, tend to decrease the melting-point of butter-fat. According to the above Fic. oo.— Master dual churn (Creamery temperature may vary between it can be concluded that the churning Package Mfg. Co.) wide limits, but the average desirable churning temperature under normal conditions is between 50° and 60° F. It may, and Fic. or. —Simplex churn (D. H. Burrell & Co.) does, go outside these limits at times; for in- stance, eries find it necessary to churn at a tempera- ture under so” F. in the early part of the many cream- summer season, when the grass is very young and succulent and the proportion of soft fats is very high. Any con- ditions which tend to harden the butter-fat will require a comparatively high churning temperature; and any conditions tending to soften the butter-fat will require a CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 245 lowering of the churning temperature. The lower the tempera- ture at which the churning can be successfully accomplished, the more complete will be the churning; that is, the less fat will remain in the buttermilk. Influence of Length of Time Held at Churning Temperature.— The length of time that cream is held at the churning tempera- ture is a factor that must be considered. If it be found necessary to churn cream soon after cooling it, it should be cooled to a lower temperature than would otherwise be necessary. Cream should be held at least two hours at churning temperature before it is churned—better a longer time. It takes this length of time at least for the fat, which is a poor conductor of heat and firms slowly, to reach the temperature of the serum of the cream and become firm. In the same creamery, with cream of the same richness, we have observed that cream churned immediately after cooling would churn as readily at 51° to 52° F. as cream held at 56° F. overnight and churned without change of temperature. The per cent of fat was much lower in the buttermilk from the cream held overnight than it was in that from cream churned soon after being cooled. Richness of Cream.—The amount of fat in the cream affects the churnability of it considerably. The richer the cream the sooner will the churning be completed, that is, providing the cream is not rich enough to be so thick as to cause it to adhere to the inside of the churn and thus escape being agitated. If rich cream is churned at a high temperature the butter will come in a remarkably short time, providing all other conditions are ravorable. Thin cream churns much more slowly, and can be churned at a higher temperature than thick cream, without injuring the quality of the butter. When rich cream is churned at a high temperature, and the butter comes in a short time (about ten minutes), the butter will usually be greasy in body, and will contain a great deal of buttermilk, which will be more or less difficult to remove on washing. When thick cream is being churned, the butter does not break in the form of small round granules, as it does when thin cream is churned. 246 CHURNING AND WASHING BUTTER When thick cream is churned at as high a temperature as is consistent with getting a good texture, the best results are obtained. In the first place, rich cream produces less butter- Fic, 92.—Victor heavy duty churn (Creamery Package Mfg, Co.) milk, consequently less fat will be lost in the buttermilk. This would tend to increase the overrun. Secondly, the breaking of the butter at the end of the churning will be such as to cause T'ic. 93.—Sectional view of four roll Victor working butter, the granules to appear large and flaky, rather than small and round. The more flaky granules of butter will retain more moisture than the smaller, harder granules under the same treat- ment. Experiments show that when different thicknesses of cream (thin cream containing on an average 22 per cent of fat, and thick cream 36 per cent of fat) are churned, there is a dif- ference of about 3 per cent in the mois- ture-content of the butter. The aver- age churning temperatures of cream and wash-water in these experiments were 56° and 53° F’. respectively. When thick cream is churned, and the temperature is mod- CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 247 erately high, it is almost impossible to churn the butter into granules. This condition causes butter from thick cream to contain more moisture than butter from thin cream. Amount of Cream in Churn.—When the churn is about one- third full, the greatest degree of agitation is obtained, and con- sequently a quicker churning. If a small amount of cream is being churned, it is often difficult to gather the butter properly. Fic. 94.—Danish churns and frame for holding them. If the cream is thin, the granules are thrown about in such a way that they are gathered with difficulty. If the cream is thick, the small amount of cream will adhere to the inside of the churn, and in that way delay the completion of the churning. It is a common opinion that less overrun is obtained from a small churning than from a large churning. It is safe to say that if it were possible to maintain all conditions alike, especially as to temperature and degree of churning, there would be very 248 CHURNING AND WASHING BUTTER little difference in the moisture-content of the butter made from churnings of different sizes. When there is only a small amount in the churn, the atmospheric temperature is likely to raise or lower the temperature of the cream. If the atmosphere is warm, then the butter from the small churning is more likely to be soft. A small amount of cream in the churn is also more likely to be overchurned than a larger amount of cream. These two factors would tend to increase the amount of water in the butter. In mixing the salt with a comparatively large amount of butter, less working is necessary. Much of the butter is mixed in the churn without going through the workers, and con- sequently less moisture will be expressed from the butter. With the same number of revolutions of the churn the butter from the small churning is worked correspondingly more than the butter from a larger churning. Medium firm butter, to a certain limit, loses about .2 per cent of moisture for every revolution that it is overworked in the absence of water. Degree of Ripeness.—The riper the cream is, all other con- ditions being the same, the easier it will churn. Sweet cream is viscous, and consequently the fat-globules will not unite as readily. The acid developed in the cream seems.to cut or reduce the viscosity of the cream, although it causes it to become thicker in its consistency. Cream in an advanced stage of ripening is brittle, so to speak; that is, if a sample of the properly soured cream is poured from a dipper it will not string but break off in lumps. If very thin cream is overripened, the curd is coagulated. When this thickly coagulated cream is churned, the solid curd breaks up into small curdy lumps. These small lumps of curd are likely to incorporate themselves in the body of the butter and injure its quality, and also its keeping quality. If thin cream has been overripened, it should be strained well, and care should be taken not to churn it to such a degree as to unite the granules into lumps before the churn is stopped. If the churn is stopped while the butter is in a granular form, the most of these curdy specks can be separated from the butter by copious washing. Some specks are likely to remain in the CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 249 butter when the cream is in such a condition, but by following the plan outlined enough of the specks can be removed from the butter so that its commercial quality will not be injured. The degree of ripeness of cream does not have any effect upon the composition of the butter, except in increasing the curd content as mentioned. Nature of Agitation—The nature and degree of agitation of cream affect the churnability considerably. Many different kinds of churns are on the market at the present time. The rotary drum-churns, now used almost universally in this country, are claimed to give the greatest degree of agitation; that is, providing the churn revolves at a proper rate of speed. If the speed is so great as to cause the cream to be influenced by the centrifugal force generated, rotating it with the churn, then no agitation will take place. Consequently the churning process will be delayed, if not entirely prevented. If the speed of the churn is too slow, the degree of agitation of the cream will not be at its maximum, as the cream will tend to remain at the lowest portion of the churn without being agitated. In the old-fashioned dash-churn the cream was not exposed to much agitation. In Europe the upright barrel-churn with rotary stirrers inside is mostly used. It is slower than American churns, but gives good satisfaction. Extensive investigational work conducted by the American Association of Creamery Butter Manufacturers, under the direction of one of the authors, has shown that there are several factors which have a direct bearing upon the exhaustive- ness of the churning of cream. With very sour cream that has been pasteurized, the loss of fat in buttermilk is much larger than is generally recognized by buttermakers. The average loss of fat in buttermilk, according to hundreds of analyses made by the American Association of Creamery Butter Manufacturers, is more than five-tenths of one per cent. The loss of fat in buttermilk varies somewhat with the seasons of the year. During the hot weather in the summer months, especially in the flush, the loss of fat in buttermilk is greater than in the fall and winter months. One creamery 250 CHURNING AND WASHING BUTTER that makes a practice of testing its buttermilk daily reported to us that for the months of June and July their average loss was .85 per cent, some samples running as high as 1.25 per cent. Their tests were made by the Mojonnier method. So there is no question concerning the accuracy of the results obtained. The high per cent of fat found in buttermilk during the period when cream is very sour is no doubt caused by the high acid coagulating a portion of the casein into small hard lumps, which are not entirely broken up by the process of neutralization or churning. Another thing that will affect the loss at this period is, the amount of cream received is very large; buttermakers are crowded with work, churns are filled too full, and cream is not held for a long enough period at churning temperature to thoroughly chill the fat. The result is that the large globules unite quickly in the process of churning, due to the soft condi- tion of the fat, and the smaller fat globules are carried off in the meshes of the casein into the buttermilk. It may be possible that the high acid in the cream partly removes the film from the larger fat globules, and in the process of churning they break up into smaller particles of fat. We have no positive knowledge that this is the case. Jn the investigation pursued by the American Association of Creamery Butter Manufacturers it was found that where the churn is filled about one-third full and the cream is held for several hours, or overnight, at churning temperature a more exhaustive churning is obtained than where cream is placed in the churn immediately after being cooled. Where the lack of churn or vat space compels quick churning of the cream, it is better to cool the cream down four or five degrees below the normal churning temperature. The temperature that cream can be churned at will depend upon the per cent of fat in the cream. Cream that contains from thirty to thirty-five per cent fat can be churned at a very low temperature, especially cream that contains a high per cent of acid. The speed of the churn has also a direct bearing on the temperature at which cream can be churned, and also a bearing CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 251 on the loss of fat in the buttermilk. The speed of the churn will depend, to some extent, upon the diameter of the churn and the kind of churn used. We find the following speeds give very satisfactory results: Simplex churn, 24 revolutions per minute. Disbrow, Victor, Dual and Perfection churns, from 32 to 35 revolutions per minute. Where a churn is run at a low speed, the temperature of the cream will have to be higher to cause the fat globules to unite, due to the lack of sufficient agitation. From microscopical examination made of buttermilk, where the loss was high, it was found that the fat seemed to be lodged in the meshes of the casein. When placing buttermilk in bottles in the laboratory and permitting it to stand overnight, and taking samples from the upper or watery portion, the test of fat in this liquid portion was very low, while in the lower por- tion, which contained the casein, the per cent of fat was exceedingly high. The following tests of the upper and lower portions of twelve samples of buttermilk from different churnings were made after allowing the samples to stand in half pint bottles overnight. About half the liquid, or the upper portion of the buttermilk, was decanted from the bottle in each instance, and a comparison of its test was made with that of the lower portion. Number Test of upper Test of of sample liquid portion lower portion = | I 48 | 1.07 2 20 50 3 20 50 | 4 218 | 56 5 .38 60 | 6 02 1.00 | 7 .30 30 8 14 38 | 90 18 | 44 10 I4 | iF | II 18 | 7 252 CHURNING AND WASHING BUTTER Cream that is separated from sweet milk at the creamery can be ripened or soured to a fairly high degree of acidity without having the lumpy condition referred to above, and a very exhaustive churning can be had from the same, whether pasteurized or unpasteurized. Where various lots of sour cream are received at the creamery, the average per cent of acidity of the entire lot when mixed together may not be very high, but some portions of this cream possibly have contained an acidity of well over 1 per cent; hence, the loss of fat in such cream would be greater than if the cream had been separated from sweet milk and where the souring was under the control of the maker. To get an exhaustive churning with sour cream, the same should have the acidity reduced to a low degree. Partial neutralization has the effect of putting the casein in a more flocculent condition; hence, the loss is not as great. Neutralization should always be done before pasteuriza- tion, as otherwise the heat of pasteurization will precipi- tate some of the casein into hard lumps, which will not be broken by the agitation of the churn in the process of churning. As far as the working of butter goes, any of the modern churns will do efficient work, especially when the maker has got himself accustomed to the churn he is operating. Size of Fat-globules.—Cream containing large fat-globules churns more quickly than cream containing small globules and a more exhaustive churning can also be obtained from it. It is, however, impossible to obtain cream which does not contain any of the small globules. The minute globules are always difficult to remove from the serum, whether it be in the churning or in the separation. In the churning there is a certain force which always tends to hold the globules in place. This force acts in a correspondingly greater degree upon the small globules. They are held in position and move only when the cream is exposed to agitation. Cream containing larger globules allows them to escape from their position with greater ease than does cream containing the minute globules. The globules which are not COLOR 253 removed from the buttermilk during the churning process are largely of the small type. Straining of Cream.—Before the cream is transferred from the ripening-vat to the churn it should be strained through a fine perforated tin strainer. This can be conveniently done during the changing of the cream from the ripening-vat to the churn. Special strainers are now manufactured which can be hooked onto the churn, and the cream can run directly from the ripening-vat through the strainer into the churn. This straining of the cream separates all the lumps which «re likely to appear. It also separates any other coarse impurities which may be present. If these impurities were not separated they would probably be embodied in the butter and cause an unsightly Fic. 95.—Cream and milk strainer. appearance. They would also be likely to injure the keeping quality of the butter, but this would depend, of course, upon the character of the impurities. Color.—In order to maintain a uniform color in the butter during the different seasons, it is essential that some artificial color be added at certain times. During the lattcr part of May and the early part of June the butter has a rich yellow color, which is accepted as the standard color of butter. This is often referred to as the © June color.” There are several different butter-colors on the market, for which special merits are claimed. All the colors, so far as known, are efficient in imparting color to the butter without materially coloring the buttermilk. A good butter-color should be a sub- stance which does not impart a bad smell or taste to the butter. It should possess strong coloring properties, so that very little 254 CHURNING AND WASHING BUTTER of it would have to be added in order to impart the desirable color. It should not be injurious to health. Some colors are prepared from the fruit of the annato tree, which grows in the East Indies and South America. The coloring matter on the inner part of the covering of this fruit is dissolved in a suitable oil, such as sesame or hemp. Before any of the proper commercial butter-colors were put upon the market, extracts of carrots, marigold, saffron, and annato were used. The yolk of eggs has also been used to some extent. It is said that carrot-juice is the most healthful butter-color. The amount of color to add depends upon the market require- ments, and upon the season of the year. As was mentioned before, in June little or no color should be added. As the summer season advances the amount of color added can be gradually increased. During winter, while the cows are on dry feed, the maximum amount of color is generally used. Color require- ments of the butter vary considerably at the same season of the year. American markets demand a higher color than European markets. The northern markets desire a light straw color, while the southern markets want a deeper color, almost an orange color. The Jewish trade requires uncolored butter. In some of the European countries no color is used. The English market, which is the greatest butter market in the world, demands butter that has a very light straw color. The main object in coloring butter is to maintain a uniform color during the different seasons of the year. The amount of color to add during the different seasons will usually vary between none and a trifle over 2 ounces for every too pounds of fat. The color should be added to the cream before the churn has been started. If this has not been done, the butter can be colored by mixing the color with the salt. The salt should then be well distributed and worked into the butter until the body of the butter assumes a uniform color. The chief objec- tion to this method is, that it is difficult to work in the color thoroughly without injuring the butter. The sole object in adding color is to give the butter a more bo our Ou WHEN TO STOP THE CHURNING attractive appearance. It neither adds to nor takes from the flavor or food value of butter. Hence the shade of color should be such as will make the butter most attractive in appearance. This varies somewhat with the market to which the butter js going. When to Stop the Churning.—Different makers have various ways of ascertaining when the churning process has becn com- pleted. Some determine the proper churning stage by the size of granules, others by the height at which the butter floats in the buttermilk. Others again depend upon the appearance of the buttermilk. It is well to let all of these factors influence the operator in deciding when the churn should be stopped, as no one of them may be a sufficient indication. The size of the granules is the most common factor that determines the time when the churn should be stopped. It has been a general rule in the past to stop the churning when the granules are a little larger than wheat-kernels. As a rule it is safer to carry the churning on a little further until the granules increase to the size of corn-kernels, irregular and flaky in shape. At this stage the buttermilk will usually appear bluish in color, and the butter is raised above the buttermilk a considerable distance. When the butter is churned to too small granules, many of them will go through the strainer into the buttermilk, and cause a considerable loss. When butter in such shape is washed in medium-cold wash-water, the granules continue to remain in a separate state. When salt is added, the moisture is extracted from them, and the water is likely to be caught in holes and crevices during the working and cause leaky butter. If the churning is carried on a little further, the granules will not escape into the buttermilk, the churning will be more complete, and the moisture will be incorporated in a better con- dition. Overchurning should be avoided as much as underchurning. If butter is overchurned in the buttermilk, it will retain a large amount of the buttermilk, which will be very difficult to remove by washing. Overchurning butter, especially at a medium- high temperature, is very effective in increasing the moisture- 256 CHURNING AND WASHING BUTTER content of butter, and should be guarded against for that reason. Butter containing more than 16 per cent water is not permissible on the American market. When cream is in a poor condition it should not be over- churned, as the incorporation of buttermilk produces a very rank and unclean flavor in the butter. Cream in such condi- tion also contains many undesirable germs, which, when incor- 1 2 3 4 5 I'ic. 96.—Butter from 1 pound of fat in cylinders, showing the effect of differ- ent percentages of water upon quantity. The water-content of these samples ranges between 8 per cent and 19 per cent, porated into the butter, will cause it to deteriorate to a great extent.. When the cream is in poor condition, the churn should be stopped as early as is consistent with the completeness of churning. The buttermilk should be removed and the butter washed thoroughly in clean, pure wash-water. If the wash- water is added while the butter is in this granular condition, the buttermilk can be very effectively removed. If one washing is not sufficient, wash three or four times. In such a case the tem- CONDITION OF WATER IN BUTTER 257 Fic. 97.—Butter sample, Fic. 98.—Butter sample, 15.01 per cent water. 15.31 per cent water. Fic. 99.—Butter sample, 13.37 per cent water; leaky, 2 per cent brine. Microscopical views showing condition of water in butter. Tig. 97 shows that the water has been incorporated in the form of very minute particles. Storch found from nine million to sixteen million water particles per cubic millimeter. Such butter appears dry and a little dull. Vig. 98 shows the water incor- porated in medium-small particles. There were on an average three and three- fifths millions of water particles per cubic millimeter in such butter. Fig. 09 shows condition of water in leaky butter. Storch found about two and one half million water particles per cubic millimeter in butter having such a body. (Views by Storch.) 258 CHURNING AND WASHING BUTTER perature should be low. If the temperature of the wash-water is high, and the butter is washed excessively, it will contain too much moisture when it is finished, and is likely to be salvy. If washed with water at a low temperature the butter will not incorporate so much water. What it does incorporate in excess, will, as a rule, be expressed during the working of the butter—a result due to its firmness. If the attempt is made to incorporate water by working the butter in water after the salt has been added, while the butter is in a hard, granular condition, it will usually appear leaky. Tf cream is in a good condition, overchurning to a small extent does not produce any bad results. The germs which are present in pure and well-ripened cream are not deleterious to the keeping quality of the butter. The amount of butter-milk incorporated in the butter is not sufficient to cause any bad effects upon its quality. If the cream is in proper condition it is dificult to incorporate any more than 3 per cent of curd into the butter. While overchurning is not to be recommended, if it is at any time desirable, it should be done in the washwater rather than in the buttermilk. Churning Mixed, Sweet, and Sour Cream.—When two lots of cream are to be churned, one sweet and the other sour, they should be churned separately. If the two lots of cream are mixed together, the sour cream churns more quickly than the sweet cream. As a consequence the churn is likely to be stopped before the fat from the sweet cream has been completely separated from the serum. At some of the creameries conditions are such that the oper- ator may be tempted to mix the two lots of cream. Where sweet cream arrives at the creamery just previous to churning time, it is advisable not to mix the sweet cream with the sour. It is, as a rule, better to carry the sweet cream over to the next churning, or, if necessary, churn it separately. Difficult Churning.— Difficult churnings in creameries are not very common. In farm butter-making they are more fre- quent, especially in the fall. At this time the cows are usually well advanced in the period of lactation, and early in the winter DIFFICULT CHURNING 259 they are often fed on food which causes hard butter fat, as described under ‘ Effect of Food upon Fat.” In the fall or early winter, a large portion of the milk is usually obtained from strippers, or cows almost dried up. Such milk contains a large portion of the small fat-globules. Difhcult churning resulting from such conditions can usually be remedied by ripen- ing to a higher degree of acidity and churning the cream at a higher temperature. Complaints are occasionally heard of difficult churning which cannot be remedied by such treatment. Sometimes cream froths, and will not agitate in the churn. Such a frothy condition has in some cases been found to occur even though the cream may seem to be in an ideal condition for churning. It is believed by some, notably Hertz, that such a condition in the cream is brought about by a disease of the cow. Weigman has studied and isolated a ferment which caused a soapy condition of milk and cream. It is possible that such exceedingly difficult cases in churning may be due to a disease of the cow, and it may also be due to certain ferments that produce a soapy condition of the cream. Ui thick cream at a very low temperature is put into the churn, it sometimes causes difficult churning. When such cream is first agitated in the churn it incorporates considerable air. This air, together with the various gases developed at a low temperature, does not readily escape. The viscosity of it is so great that it will not release the air present. As a conse- quence it assumes a still consistency, much the same as the beaten white of an egg. If cream froths in the churn as mentioned, a little warm water thrown on the outside of the churn will often start the agitation. of the cream within. If a combined churn is used the rollers may be put in gear, and the churn revolved in slow gear. This will often start the cream to agitate. If these two remedies are not sufficient, a little water, lukewarm if necessary, may be added directly to the cream. By letting the churn stand a short time, the cream will usually condense into a liquid form again, and many times the churning process can then be completed. This latter method, however, usually 260 CHURNING AND WASHING BUTTER requires more time than can be profitably spared. If the churn- ing difficulty is of a serious nature the remedies are: (1) If produced by a certain cow, or herd, find out whether it is produced by a fermentative process, or by other abnormal conditions of the cow. (2) Change the food of the cow. A succulent food will usually cause the cow to secrete more milk, and of a different nature. (3) If produced by a ferment, endeavor to control the fer- mentation as previously described. (4) Ripen the cream to a higher degree of acidity. (5) Skim thicker cream and churn at a higher temperature. The last three methods will cure most cases of difficult churnings. Keeping Churn Sweet.—It has been mentioned before that butter absorbs foreign odors very readily. If the churn is not kept in a pure, sweet condition, the butter will be exposed to the undesirable odors and its commercial quality will be impaired. The best butter cannot be produced in a foul-smelling churn. As churns often are not used every day, they very readily assume this impure condition, and it is essential that special care be taken in keeping them clean. The best method of keeping churns in good condition is to rinse the churn in two waters at the end of each churning. The first rinsing should be made with lukewarm water, the second with scalding hot water. Some prefer to turn the churn over with mouth down. Others prefer to allow the cover- hole to turn up. When the churn is turned with the cover- hole down, the remaining steam on the inside of the churn will not escape. It will condense inside of the churn, and cause the churn to remain in a damp condition overnight or even longer. If the churn is turned with the cover-hole up the dust and other impuritics, if present, are likely to settle into the churn. A good way is to turn the churn over so that the cover-hole points to one side. ‘The churn should be thoroughly drained first, other- wise some water will remain in the bottom. When the churn is left with the cover-hole at one side, the steam can escape, KEEPING CHURN SWEET 261 and the heat absorbed from the wash-water will dry the churn thoroughly. Many makers rinse the churn only once and use scalding hot water. This method is likely to scald the remaining curd on to the wood; secondly, one rinsing is nct enough to insure a clean churn. The first rinsing with lukewarm water removes the major portion of the buttermilk and brine, and to a certain extent warms the wood of the churn, so that when the second rinsing with scalding hot water is completed, the churn has been thoroughly scalded. In addition, the churn is clean, and no food is left on which germs can thrive. The churn is also left warm, and in that condition will dry quickly. Some makers prefer to keep the churn in a good condition by sprinkling salt on the inside after washing. This is not to be recommended, as all churns contain more or less iron-ware on the inside. Salt, while a fair germicide, causes the formation of rust on all iron with which it comes in contact. After a time this rust will scale off to a certain extent and become incorporated with the butter. If the churn is treated daily in the manner described above and then at the end of the week treated with slaked lime, it can be kept in a good sweet condition. The lime should be freshly slaked and in a liquid condition when put in the churn. A pailful or two of this fluid will be sufficient for each churn. By rotating the churn a few times the lime will be spread all over the inside of it. Let the churn remain in this con- dition until ready for use again. When ready for use, put in 'some warm water, and the lime will readily come off. But if it has been allowed to remain in the churn too long, it will form a lime carbonate, and will be more difficult to remove. Lime is one of the best disinfectants and deodorizers that can be used in a creamery. Some of the best butter-makers use it every day on all the wooden utensils, such as butter-workers, churns, etc. Lime can be used more advantageously in Amer- ican creameries than it is to-day. Many creamerics would be in a much sweeter and purer condition if they were given a good coat of whitewash on the inside once a month. Refrigerators, wooden utensils, and rooms of any kind can be kept in a good, 262 CHURNING AND WASHING BUTTER sweet and pure condition by whitewashing or sprinkling a little lime on them. In the preparation of a new churn for use it is a good plan to treat it with milk of lime in the manner already described. Tt will fill the pores of the wood and harden it, and remove all danger of imparting a woody flavor to the butter of the first churnings made in the churn. To Prevent Butter from “ Sticking ” to the Churn.—At times churns get into a condition in which butter sticks or adheres to them more or less. Sometimes it requires treatment with a weak acid solution to overcome this difficulty, and sometimes treatment with an alkali solution is needed. If treatment with acid is what is needed, a weak solution of either sulphuric or muriatic acid may be used—say a pint to 100 gallons of water. The acid must be added carefully to the water in the churn and none of it must be poured directly upon the wood. The churn is revolved with this solution in it, for about five minutes at a time, at intervals extending over a period of several hours. It is then rinsed with warm water and then with water containing a little of some good washing powder, such as Wyandotte. If treatment with an alkali solution is needed, which is the case if fat has soaked into the wood, a suitable washing powder may be used to remove the difficulty. The following is an extract from a letter received from one of our leading creameries which had written for and received suggestions from one of the authors for overcoming this difficulty: ‘‘ We received your letter in regard to the trouble we had with the butter sticking to our churn. We are pleased to advise that we have apparently eliminated all of this condition. When we received your letter suggesting remedies which might stop this condition, we at first used the muriatic acid but without any results whatever. Then our butter-maker took about three pails of Wyandotte, put in a small amount of water and heated with steam until he made a sort of a paste out of it. He then put it in the churn and gave it several revolutions and let it stand overnight, then washed it out thoroughly with hot water. The first time it seemed to help it very considerably, so we gave it another dose a day or two WASHING OF BUTTER 263 later and it has relieved the whole condition. He is of the opinion that if this is used when the butter shows any ten- dency to stick to the churn, it will keep the churn in good con- Pi dition right along. WASHING OF BUTTER Purpose of Washing. The chief object of washing butter is to remove as much buttermilk as possible. The more impure the cream is, the greater is the importance of getting the butter thoroughly washed. In the winter, when it is cold, and the cream is in good condition, some makers do not wash the butter at all. But this is not a safe method. The removal of the buttermilk constituents should be as complete as conditions will permit. Temperature of Wash-water.—The temperature of wash- water should be as nearly like that of the cream when churned as is consistent with the other conditions. It is quite a regular practice in many creameries, particularly in summer, to temper the wash-water to about 2° below the churning temperature of the cream. Extreme and rapid changes in temperature should always be avoided. Occasionally it is necessary to use water that is colder than the cream; at other times it is necessary to use wash-water at a higher temperature than that of the cream. If the butter churns soft, do not use ice-cold wash-water to chill the butter, as it has a tendency to give butter a tallowy appear- ance. Neither should hard butter be quickly softened by using wash-water at a very high temperature, as it is likely to cause the butter to assume a greasy and slushy texture. If it is necessary to change the degree of hardness of the buiter, change it grad- ually by using water at a moderate temperature and allowing the butter to be in contact with it a longer time without agitating it much. The regulation of the condition or degree of firmness of butter, for the proper working of it, should never have to be accom- plished to any great extent by means of the wash-water. This is not the real purpose of washing butter. If the churning tem- 264 CHURNING AND WASHING BUTTER perature of the cream be right, the butter will be in proper con- dition for washing and working. If the churning temperature be not right it is difficult through any device that may be adopted subsequentlysuch as tempering the wash-water—to bring the butter into the best condition for salting and working. Regulation by means of a change in temperature of the wash- water will prove a partial, but not a complete remedy—par- ticularly if the butter be very soft when it comes. Unless the butter is of very poor quality, excessive washing should be avoided. Cold water is said to absorb a considerable portion of the flavoring substances. If the quality of the butter is poor, many of the undesirable flavors and odors are removed by excessive washing; while if the butter has a fine, rich flavor, it should be retained, and not extracted by washing the butter more than is needed. No definite temperature can be given, as the temperature of wash-water must vary according to the hard- ness of the butter when churned. If the temperature of the wash-water is too high, and the churning in the wash-water is continued a very long time, much water will be incorporated in the butter. If the butter is quite firm in the first place, and the temperature of the wash-water is not above 60° F., there is not much danger of getting too much water in the butter. Rapid changes in the degree of hardness of the butter in the presence of water are conducive to a high moisture-content. Very soft butter chilled in very cold water, and hard butter softened in very warm wash-water are two conditions which should be avoided. As to the quantity of wash water that should be used: with cream of average richness, it will be about the same as that of the buttermilk; with very rich cream a little greater. In washing the butter the churn is usually run from ro to 15 revolutions on high speed. Some, instead of following this practice of churning the butter in the wash water, run the churn about 2 to 5 revolu- tions at slow speed with the worker in gear; modifications and combinations of these two methods are made. [or instance, where butter is first washed or sprayed and a second wash-water is used, some adopt the practice, during the second washing, of WASHING OF BUTTER 205 revolving the churn a few times on high speed while others put the rolls in motion using the slow gear. Butter from cream of good quality, churned at the right temperature, needs less washing than butter from cream of poor quality or butter churned at too high a temperature. Two washings should suffice when the cream is of good quality, and with such cream some wash the butter only once if the wash- water runs off clear. In order to possess good keeping qualities, butter must have the buttermilk well washed out of it. Butter from cream of poor flavor requires more washing than butter from cream that is clean in flavor. Kind of Wash-water to Use.—In the washing of butter, it is very essential that water used should be the best obtainable. The creamery water-supply is evidently much better now than it was years ago. Pond-wells and shallow wells are gradually passing out of existence, but there are yet many shallow wells from which water is drawn for creamery purposes. Water from wells may appear to be pure, and yet contain germs which are deleterious to dairy products, and especially to the keeping qual- ity of butter. That water of average purity contains such germs has been demonstrated in this country, as well as in foreign countries. Shallow well water contains on an average about 15,000 germs per cubic centimeter, but Miquel has found that a rapid power of multiplication characterizes the bacteria in pure spring-water, while in impure water the multiplication is slower. Water containing only this number of germs is, as a rule consid- ered very pure. Most creameries, however, pump their water into a tank overhead in the creamery, where it is contaminated with bacteria and impurities of different kinds. Shallow wells are usually surrounded with conditions which do not guarantee a creamery pure water during the different seasons of the year. In the spring, when rains are frequent and heavy, unwholesome surface-water is likely to seep in through the sides. Such wells may also serve as traps for small animals. The presence of an animal in the well is sure to cause undesirable odors and a multitude of undesirable and putrefactive organisms. Water from deeply drilled wells, even if it is pure in so far 266 CHURNING AND WASHING BUTTER as its germ-content is concerned, is in many cases turbid and sandy, and needs to go through a process of purification as much as does the shallow well water. METHODS OF PURIFYING WASH-WATER There are two practical and effective methods of purifying wash-water, viz., (1) Filtration, and (2) Pasteurization. Which of these two methods is the most practicable and the most effective in the creamery depends upon the conditions and upon the quality of the water. In the case of water from deep wells, which contains little or no organic matter, but at the same time is infested with undesirable germs, pasteurization is perhaps more expedient. Filtration, if the same degree of thoroughness is to be reached as in pasteurization, is a comparatively slow process. Pasteurization of wash-water is a trifle more expensive than filtration. Wash-water can be pasteurized at the same time that the churning is being done, thus economizing in time and fuel. Pasteurization is quite effective in rendering the water germ-free, but it is not so effective in removing any organic matter or other tangible impurities which may be present. If the creamery does not already have a pasteurizer, filtration can be employed very profitably, and under average conditions it will perhaps give the best results. Filtration.—Filtration is inexpensive, and is a very efficient method of purifying wash-water. It seems strange that bac- teria can be removed from water by passing through layers of sand, gravel, coke, and charcoal, but such is the case. Filtra- tion is applicable to all kinds of water; even if the water appears pure, it is well to filter it. Fewer germs and fewer varieties of micro-organisms are apparently found in deep well water than is the case in water from surface-wells; hence the ferments which are present will have a free field for developing in the absence of competing forms. If a sample of water which is rich in micro-organisms is violently shaken with a certain amount of charcoal, coke, chalk or similar substances, and then left for a time to settle, the pure layer of water at the top will be METHODS OF PURIFYING WASH-WATER 267 almost entirely free from germs, and in some cases entirely sterile. It used to be thought by older German investigators that these different filtering substances had almost miraculous power of removing organisms from water. The factors which are to be considered in successful filtration (1) Storage capacity for unfiltered water. (2) Construction of filter-beds. (3) Rate of filtration. (4) Renewal of filter-beds. (1) Concerning the storage capacity, nearly all creameries have storage-tanks overhead in the creamery; so far as that is concerned, however, filtration can be successfully carried on continuously as well as intermittently. (2) The construction of the filter-bed used in the experi- ment carried on at the Iowa Experiment Station, Ames, Iowa, is as shown in Fig. 101. The approximate proportionate depth of each layer in the bed is as follows, beginning at the bottom: Two inches small flint stones; 22 inches fine sand; 12 inches fine coke; 9 inches charcoal; 2 inches fine stone or coarse gravel. The layer of fine sand should not be less than 15 inches. It has been asserted that a few pieces of old iron mixed in the filter-bed are beneficial. Alum, lime, and copperas have been recom- mended for clarifying and deodorizing very impure water. As these substances are soluble they should not be used in filter- beds, which are intended for the filtration of water for potable purposes. The filtering-can was made from 22 galvanized iron. The height of can is 48 inches; diameter, 18 inches. The bottom of the can is slanting towards the faucet, or opening. Thus no water is permitted to stand on the bottom and afford oppor- tunities for germs to accumulate. On the inside are three plates. One lies horizontally, near the bottom, and upon it the filtering- material rests. Another lies on the top of the fine sand. Both of these plates were perforated with many small holes. Near the top is placed a concave plate with a hole near the center. This plate directs all the water to the center of the filter-bed, and thus the water gets the full benefit of the filtering process. The 268 CHURNING AND WASHING BUTTER total cost of this filtering-can when complete was $11.11. Since the time when this can was constructed prices have advanced considerably. (3) The rate of filtration is necessarily governed by the depth of the filter-bed, the character of the material used, and its Coarse gravel 27 ae Charcoal 18— Fine sand Grave] @ Coarse gravel f 3 FIG. 100. Fic. ror. Fic. 100.—Tilter-can; 1, overflow; 2, inlet of tap-water; 3, outlet of filtered water. Fre. ror.—Cross-section of filter-bed and can: 1, overflow; 2, inlet; 3, outlet of filtered water; 4, perforated galvanized-iron plate; 5, perforated galvanized- iron plate; 6, concave galvanized-iron plate with hole in center. fineness. The water passes through the charcoal, coke, and gravel quite rapidly, yet the substances are very strong barriers to the passage of micro-organisms. The sand layer does not admit of such rapid filtration. Fine sand, however, is one of the best filtering substances that can be had. The rate of filtra- tion can be regulated by increasing or decreasing the depth of the METHODS OF PURIFYING WASH-WATER 269 fine-sand layer. In a general way, the slower the rate of fil- tration is, the more thorough it is; and, vice versa, the more rapid the rate of filtration, the more incomplete is the removal of the bacteria. If the filter-bed is constructed as described above, the rate of filtration will be about 18 gallons per hour, and about 96 per cent of all the germs present will be removed, together with the impurities present in suspension. (4) The filter used at the Iowa Experiment Station was in constant use for about three months, without having been changed. At the end of this time it did as efficient work as at any previous time. The length of time a filter-bed can be used without being changed depends upon the purity of the water to be filtered, and also upon which kind of filtration is used, the continuous or the intermittent. The more impure the water which has to be filtered, the oftener the filter-bed should be changed. Whenever the rate of filtration is decreased to such an extent as to make the process impracticable, the filter-bed should be taken out and cleaned. If the water to be filtered is of average purity, a change of the filtering-material once every four months is ordinarily sufficient, no matter whether continuous or intermittent filtration is used. o ° ay | bH = Fic. 123.—Septic tank for creamery sewage disposal. (By Prof. J. Michels.) The tank should be located in the ground with the top within a foot or two of the surface. It may be constructed of planks. Brick, stone, or concrete is preferable for durability. The tank should be built air-tight except in two places, D and E. of contamination by mold. Comparison was made of the fol- lowing methods: (1) Soaking the tubs overnight in cold water. (2) Boiling five minutes in a saturated brine solution and leaving in the brine overnight. (3) Soaking overnight in a brine containing 9 per cent of commercial formalin (which is a 4o per cent solution of formalde- hyde). (4) Coating the tubs on the inside with paraffin. (5) Immersing the tubs for a few seconds in paraffin at a temperature of 250° to 260° F. Rogers comments upon the table giving results of his investi- gations and makes some general observations, as follows: 1 Bulletin 89, Bureau of Animal Husbandry, U.S. Dept. of Agriculture. 301 TUBS AND BOXES TREATMENT OF Cc m as D ie} iS} = (eurquoyy PS yng) “urd 1o0p,p 1,42 apeog “AraueaId v Jo ur] q—'tz1 “og ie . WOOY Y3IMOd Yya11048 J ‘ pel XP NV1d ¥OO135 WHOdL Vd 6 Of X £2 LL X 6,2 BaDVYOLS G1090 3d018 2 YaLLnd SNIONG [VEX WOOY 3YOLS Bas .2 19,9 X92 WOOY ONIAIZO3Y IN AEX 92 3901440 302 PREPARING BUTTER FOR MARKET “Tt will be seen from this table that all of the untreated tubs became moldy. Of the six tubs treated with hot brine, one was badly molded, one was slightly molded and one had mold on the outside. Of the six tubs soaked in the brine- formaldehyde mixture, one was badly molded. None of the tubs coated with paraffin showed any mold whatever, and the same was true of those dipped in paraffin. “To treat tubs by the brine-formaldehyde method or the hot-brine method a vat should be made large enough to hold submerged the tubs used in one day. The cost of either of these two methods is insignificant as the bath may be used repeatedly. The objections to these two methods, in addition to their inef- ficiency, would probably be found in the discoloring of the wood and, with the hot brine, in the excessive weight and swelling of the tub.” Paraffining of Tubs.—From the investigations made it would seem that the most efficient method of treating tubs or boxes for the prevention of mold is to paraffin them on the inside. Before tubs are paraffined they should be thoroughly steamed. In extreme cases, where tubs are very open, it may be necessary to soak them, but only in such cases. Whether soaked or not, the tubs should be steamed just before paraffining them. This swells and tightens the tub, and heats the wood and opens its pores so that the paraffin will penetrate it sufficiently and at the same time form a nice, smooth coating. The par- affin should be heated to a temperature of about 250° F. If much below this it is apt to cause the coating to be thick and patchy, and if much above it is likely to soak into the wood and not form a proper coating. The easiest way to heat the paraffin in a creamery is to place a steam coil in the bottom of the paraffin tank with a valve or dripcock on it to allow the escape of condensed steam. Where the work is done in a small way, the paraffin can be applied in one of two ways—either by means of a brush or by pouring some paraffin into the tub, rotating it to cover the whole surface and then placing it mouth downward to drain the sur- plus paraffin from it. But in a creamery of any size a suitable PARAFFINING TUBS REDUCES LOSS FROM SHRINKAGE 303 apparatus for spraying the inside of the tub with paraffin should be used. As it only requires about 3 ounces of paraffin for a tub that holds 60 to 65 pounds of butter the cost is not great, and the work entailed in paraffining is no greater than that of either of the other treatments mentioned. Paraftin furnishes no food for molds; if there be any mold organisms on the wood they will probably be de- stroyed to a very great extent, if not entirely, either by the hot paraffin spray or through the ex- clusion of the air which they require for growth; and, even failing this, the coating of paraffin shuts them off from the parchment paper and the i Fic. 125.—Tub parafhner. (Creamery butter. Furthermore, as Package Mix, Co), paraffin is impervious to water, the space between the liner and the tub remains filled with water or brine which excludes the air and retards or pre- vents the development of any molds that may be present. Paraffining Tubs Reduces Loss from Shrinkage.—Another strong inducement to paraffin tubs is the saving in shrinkage, due to the prevention of the escape of moisture. In an experi- ment made by Rogers, during his investigations, he found the shrinkage, during a period of eight days in creamery storage and in transit, on butter packed in paraffned tubs and in tubs soaked in brine, respectively, to be as follows: | Wercut oF BUTTER | : Number of | LEOUNDE, Shrinkag' Treatment of Tubs Tat : age ubs i Neha ein @ . s When! Packed| After Eight | Pounds | Days Parathine des. s cet-3:c ae onrt \ 12 75 Tae 756 i, Sodkedin a aatice wens | 12 7603 759 72 304 PREPARING BUTTER FOR MARKET Thus the saving in shrinkage, through paraffning, was 6 pounds on 12 tubs or half a pound per tub. With unsoaked, paraffined tubs the tare should be marked on the package. Such tubs may be as much as 2 pounds lighter than soaked tubs. Treatment of Parchment Paper.—As parchment paper is a good medium for the growth of mold organisms and may harbor the spores, though showing no growth of mold, it is quite as important to treat it as to treat the tubs for the prevention of mold. One method of treatment for parchment paper is to soak it for at least ten minutes, before using, in a saturated solution of brine at or near the boiling point. Russell and Hast- ings! say, ‘‘ A most efficient way of treating paper, either for tub liners or print wrappers, is to place same in boiling water for a few minutes.” As formalin is very destructive of mold, another very efficient treatment for parchment paper is to soak it in cold brine or water containing formalin. YEASTS AND MOLDS IN BUTTER Bacteria are not the only micro-organisms found in milk and its products. There are also yeasts and molds, the mold most commonly found being Oidium (plural Oidia) lactis, or the ordinary white mold which frequently appears on the surface of sour milk or cream. What may be desirable in connection with one dairy product may be the reverse with regard to another. For instance, Freudenreich and Marchel have shown that in the ripening of certain Swiss and Belgian soft cheeses the common white mold (Oidium lactis) plays a principal part. In these products its presence is not only desirable but necessary. On the other hand, it is found that where yeasts and molds are present to any considerable extent in butter, it is not nearly so likely to possess good keeping qualities as if they were not present, even though its flavor when made be quite satisfactory. They may be present in cream in quite large numbers, when it 1 Dairy Bacteriology. YEASTS AND MOLDS IN BUTTER 305 arrives at the creamery, but if it be efficiently pasteurized and kept from subsequent contamination, the mere fact of their presence in the raw cream does not mean that the butter made from this cream will be either defective in flavor, when made, or lacking in keeping quality. A study, by Bouska and Brown, of a large number of pack- ages of butter placed in cold storage showed that the number of yeasts and molds present in butter, when made, is a fair cri- terion from which to judge of its keeping quality. To put it in another way, the number of yeasts and molds present in butter, as it comes from the churn, is a good indication as to the efficiency of pasteurization and the subsequent handling of the cream to prevent re-contamination. The laboratory of the American Association of Creamery Butter Manufacturers has, for a number of years, made counts of the number of yeasts and molds in samples of butter sent in by its members, for this purpose. As a result of this work, and the advice and assistance given, many of the creameries have so improved their methods and equipment as to practically elim- inate yeasts and molds from their butter, and make a product possessing good flavor when fresh and good keeping qualities. Where the number of yeasts and molds in butter is reduced to ten or less per cubic centimeter—colonies counted without the aid of a magnifying glass—this is regarded as excellent work; and several of the creameries have reached this stage of effi- ciency. A strong effort should be made by every creamery to keep the number of yeasts and molds as low as possible, that is, to thoroughly pasteurize the cream and prevent subsequent contamination. Whether or not the yeasts and molds present in butter are a direct cause of deterioration is not definitely known, although there are reasons for believing that this is not necessarily so. Hastings found yeasts to be present in butter which won first prize in a Wisconsin educational contest. The presence in butter of yeasts and molds in large numbers usually means the presence of other undesirable organisms in the cream, due to one or more of the following causes: 306 PREPARING BUTTER FOR MARKET (1) Inefficient pasteurization, the pasteurizing temperature being too low or not maintained throughout the run, or some of the cream at the beginning or end of a run not being pasteurized. (2) Lack of thorough cleansing or sterilizing of the utensils and conduits—pumps, vats, faucets, pipes, churns, etc. (3) The use of a defective starter—one that has become contaminated with yeasts, molds and undesirable bacteria. Once this occurs it will propagate itself from day to day until there is a change of mother-starter. It must be remembered that although the pasteurizing may be thoroughly done its good effects may be largely nullified through subsequent contamination. Hence the final test of the efficiency of pasteurization, in creamery work, should really be the freedom of the butter from the ferments which cannot fail to be eliminated by proper pasteurization, and the processes that should accompany it. Another test of the thoroughness of the pasteurization of milk or cream for butter-making pur- poses is the Storch iest, which is outlined in the chapter on Pasteurization. MOLD ON BUTTER The development of mold on butter constitutes a defect that causes large losses. Mold not only greatly mars the appearance of a package of butter but affects its flavor as well. It develops not only on the outside of butter but along the surfaces of any crevices or pockets there may be and works its way into the butter. Upon this point we quote Thom and Shaw of the U.S. Department of Agriculture:! ‘In closed packages, wet or damp cellars, or carelessly packed masses with cracks or fis- sures in which moisture collects, mold may seriously injure the appearance of butter packages or actually induce great changes in the butter itself.” No score is given to moldy butter. As to the character of butter that affords the most favorable conditions for the growth and development of mold organisms, if any be present, these same authorities say, ‘ Excess of curd 1“ Moldiness in Butter,” Journal of Agricultural Research, Vol. III, No. 4. MOLD ON BUTTER 307 favors mold growth. Well-washed butter is less subject to mold. Leaky butter—butter from which water or buttermilk exudes and collects in the wrappings or the container—fur- nishes the best conditions for the beginning of mold growth. From these wet areas colonies may spread to the butter itself.” These facts point to the necessity of churning at the nght tem- perature, washing the butter properly with water at the right temperature and properly working it, so as to free the butter of excess of curdy matter and buttermilk and make a butter that is not porous but close, and in which the moisture is incorporated in fine particles instead of larger droplets. They also show the importance of packing butter closely so as to free it of air pockets and fissures. Conditions Favorable to the Growth of Molds.—Like all other plants, large and small, molds require certain conditions for growth. They differ from ordinary plants in that they do not require light for their growth, but grow rather better in the absence of light. They require suitable food, but find this in or on almost any organic matter, animal or vegetable, such as bread, meat, leather, cheese, etc. They require moisture, and hence develop rapidly in damp rooms and on damp surfaces. They require a certain amount of air and will not grow in the absence of it. As to temperature, while they develop most rapidly in a reasonably warm atmosphere, many of them can accommodate themselves to a wide range of temperature. Discolorations.—The colors produced by molds range from such light colors as orange-yellow to such dark colors as green, a smudged or smoke color and black, according to the type of mold present. Propagation of Molds.—Molds reproduce themselves by means of buds (conidia) and spores, and these float so freely in the air that practically no exposed surface is entirely free of them, and all they need for development is the suitable condi- tions we have already outlined. Sources of Mold on Butter.—The two most common sources of mold on butter are the tubs or boxes in which it is packed and the parchment paper. Wood that is green, sappy or damp 308 PKkEPARING BUTTER FOR MARKET is a good medium for the growth of mold; so also is parchment paper, particularly if it be at all damp. Hence the tubs should be made of well-seasoned wood of good quality, and both the tubs and the parchment paper should be kept in a clean, dry place. In the planing of the tub staves the planer should be sufficiently sharp to insure a smooth surface. CHAPTER XX THE COMPOSITION OF BUTTER AND FACTORS THAT INFLUENCE ITS CONTROL Acts and Rulings as to Composition of Butter.—We have only one Federal statute that deals specifically with the com- position of butter, and this applies only to the District of Columbia. This Act was approved March 2, 1895, and requires that butter must contain 83 per cent of milk-fat, not more than 12 per cent of water and not more than 5 per cent of salt. No attempt has been made to enforce the above statute, no doubt due to the fact that creameries could not comply with the same under the ordinary methods of butter-making. Act of August 2, 1886, defines butter as follows: “That for the purpose of this Act the word ‘ butter’ shall be understood to mean the food product usually known as butter, and which is made exclusively from milk or cream, or both, with or without common salt, and with or without additional coloring matter.” Act of May 9, 1902, known as the “adulterated” law, reads as follows: ‘Adulterated butter’? is hereby defined to mean a grade of butter produced by mixing, reworking, rechurning in milk or cream, refining, or in any way producing a uniform, purified, or improved product from different lots or parcels of melted or unmelted butter or butter-fat, in which any acid, alkali, chemical, or any substance whatever is introduced or used for the purpose or with the effect of deodorizing or remov- ing therefrom rancidity, or any butter-fat with which there is mixed any substance foreign to butter as herein defined, with intent or effect of cheapening in cost the product or any butter in the manufacture or manipulation of which any process or 309 310 COMPOSITION OF BUTTER material is used with intent or effect of causing the absorption of abnormal quantities of water, milk, or cream; that ‘ process butter” or “renovated butter” is hercby defined to mean butter which has been subjected to any process by which it is melted, clarified or refined and made to resemble genuine butter, always excepting ‘adulterated butter’ as defined by this Act.” The ruling made by the Secretary of the Treasury, the Sec- retary of Agriculture and the Secretary of Labor fixes the legal standard of moisture in butter as 15.99 per cent. According to this ruling, butter that contains 16 per cent would be classified as adul- terated butter. No allowance is made for chemical errors in testing. While the chemists allow .2 per cent for error, the Internal Revenue, in enforcing this ruling, makes no such allowance. In some districts the courts have sustained the Internal Revenue Department; in other dis- tricts they have not. Some judges have ruled that the Congress of the United States is the only body that has the power to fix definite stand- eee eee ards for food products. No doubt the Act of May 9, 1902, refers to methods that were used at that time for the purpose of incor- porating abnormal quantities of water. Compounds for Increasing Yield of Butter.—The Internal Revenue ruling is based entirely upon the ‘adulterated ” act. Prior to the adoption of the law of 1902 no attempt was made by the government to enforce any regulations concerning the manufacture of butter. At this early period various com- pounds were used for increasing the yield of butter. In 1893 the United States Department of Agriculture pub- lished Farmer’s Bulletin No. 12, “ Nostrums for Increasing Yield of Butter,” by Dr. H. W. Wiley, Chief of the Bureau of NEED FOR REGULATIONS 311 Chemistry. The analyses published in this bulletin reveal the fact that the compounds used increased the yield of butter. Analyses reported by Dr. Wiley: Water Fat Ash (Salt) Casein 49.55 45-45 1.34 3-36 31.93 67.30 15 -63 In 1900 experiments were carried on by Dr. J. B. Weems and Prof. F. W. Bouska at the Iowa Experiment Station. They tested out a number of compounds for increasing the yield of butter and got the following results: Water Fat Ash (Salt) Casein 41.54 53.04 2.46 2.96 The second recipe was composed of the following ingredients: MIUIMNACAPOLSSUlis gM cece ala eaiena amen 4 ounces Guia Ga Clas, PUL Eas cia k hie sen Wee es rT ounce DEE Clea ILC Ae eae shat ane Rene ge er Ree RRA Paine cea aaa 2 ounces 2 drachms PUTGRDe PSIN tes te ens ar ot een aati 5 grains Giving butter of the following composition: Water Tat Casein Ash (Salt) 49.04 41.46 5.05 3.84 In addition to the above, samples of suspicious butter were sent to the Station from a Chicago Commission House, which showed, Water Fat Casein Ash 59.61 PT RT ng ee) 7.36 42.76 44.92 5.10 7.22 Need for Regulations.—From the above it would seem that there was a necessity for some definite regulations concerning the standard or composition of butter. Possibly the Internal Revenue people, in endeavoring to enforce their ruling of 15.99. per cent, have been rather exacting in some cases where prosecu- tions have been made. In many cases, where the butter was found to slightly exceed 312 COMPOSITION OF BUTTER the limit set by the Internal Revenue Department, creameries were assessed ro cents a pound tax on the butter, $50.00 a month license, or $600.00 a year, and an additional 50 per cent for not taking out a license. In some of these cases a few pounds of butter were seized from a churning. Many creameries have paid these assessments to avoid the notoriety of going into the courts and defending their rights. Not only did the creamery pay the above tax, but the dealer in butter was assessed $480.00 for a year’s license for handling so-called adulterated butter. Creameries cannot sue the government for the refund of this money. The only way they can get into the courts is to sue the local agent. In many cases that have come up in the courts, expert butter-makers have appeared as witnesses, some in behalf of the government and some in behalf of the creameries. Some butter experts have made affidavits that the composition of butter can be controlled and others have made affidavits that it cannot be controlled. This diversity of opinion among so- called experts no doubt has been due to lack of experience on the part of some of the men testifying. No doubt all wit- nesses appearing were honest in the testimony given. Control of Moisture in Butter.—After spending over thirty years in the butter business in various capacities and conducting a vast amount of experimental work in an endeavor to control the composition of butter the authors are convinced that the moisture-content of butter cannot be completely controlled at all times. Extensive investigational work was carried on at the Iowa Experiment Station on this subject from r1gor to 1903. The object of this work was not to incorporate water in butter but to get butter to run uniform in composition throughout the year. Prior to this investigational work the senior author had a number of analyses made of the butter produced in some of the best creameries during the entire year. In this investigation the fat-content, the moisture-content and the salt-content were found to vary greatly. In the winter months the moisture- content might be as low as io per cent, and in the summer months as high as 17 per cent. These creameries were not making any effort to contro] the composition of their butter. CONTROL OF MOISTURE IN BUTTER 31e Ow They had their cream in such a condition that it would churn in about forty-five minutes and the butter granules would be so firm that the butter could be worked sufficiently to prevent mottles and leaky butter. Butter was churned nor- mally to granules about as large as wheat. A number of conditions was responsible for this wide Fic. 127.—Rubber mop. variation in the composi- tion from season to season, such as washing with too cold water in the winter months and churning at too high a tem- perature in the summer months. Feeding cows on dry feed during the winter months has an effect upon the composition of fats. There are more of the high-melting fats present; consequently, the butter has a higher melting point. In the early days of the creamery business practically all butter was worked on the table worker. It was the custom of many makers to work their butter twice. After having the salt incorporated they would set it in the cooler for three or four hours or leave ic until the next day. This had a tendency to make butter with a lower moisture-content, as the second working would invariably start a fresh flow of moisture from the butter. The invention of the combined churn and other modern creamery machinery enabled the butter-maker more easily to control the composition of the butter. The combined churn has been a great benefit to the creamery industry. It keeps the butter in a more sanitary condition and prevents flies and dirt from coming in contact with it. The butter can be worked in one working so that it will be free from mottles and in a con- dition to be packed directly in sanitary packages. Hence it is not surprising that the combined churn is being universally adopted throughout the dairy world. It is only reasonable to suppose that since the adoption of the combined churn the moisture-content of butter would run 314 COMPOSITION OF BUTTER somewhat higher than under the old method of working on the table worker, due to the variation of temperature, which affected the hardness of the butter when it received its second working. Many of the earlier analyses were of butter that had been manufactured under the earlier conditions outlined here. Hence, it is not surprising that the composition varied greatly. The composition of butter may vary greatly in different localities. There are two instances that have come under the observation of one of the authors; these will be designated as Creamery A and Creamery B. Both creameries were located in the northern part of Iowa. Creamery A in the latter part of the month of May, 1908, sent word to the Iowa Experiment Station that they were unable to keep the moisture-content of their butter below 16 per cent. Hence, they naturally feared that their butter would be seized by the Internal Revenue authorities, and that they would be prosecuted for making adulterated butter. They maintained they had had some butter experts there to help them out but that they had failed to accomplish the desired results. The authorities of the Iowa Experiment Station sent them a graduate of the school, Mr. C. L. Mitchel, who had had a great deal of practical experience before going to college. He found that the butter-maker was churning at as low a temperature as 44° F., and was trying every method that he knew of to hold the moisture below 15.99 per cent, the limit fixed by the Internal Revenue Department. Mr. Mitchel churned out two churnings at the same temperature and got a moisture-content of between 17 and 18 per cent. He therefore changed his methods and raised the temperature to 52° F., and after completing his churning worked the butter through the rolls several times to expel a portion of the moisture before applying the salt. This method worked out very successfully. The rolls expelled con- siderable moisture before the salt was applied. As soon as the salt was applied it attracted the moisture and the result was that sufficient moisture was easily expelled from the butter to enable him to make butter that contained moisture below the required standard. This method is now practiced in some of the ANALYSES OF COMMERCIAL BUTTER 315 large creameries, especially in the early spring months when the grass is inclined to be slushy and wet. Butter of this character has a tendency, however, to be slightly greasy or overworked. Creamery B was situated in the northwestern part of the state. Mr. J. C. Joslyn, who is generally recognized as one of our lead- ing butter authorities, had charge of this plant. Prior to the experience that Mr. Joslyn had with this high moisture he was under the impression that if any butter contained more than 16 per cent moisture, this excess moisture was intentionally worked in by the maker. One day, however, he had a churning where the method as far as he knew was similar to that he had been pursuing to make the best butter. This particular churning of butter, upon testing, showed a moisture-content of 18 per cent. The peculiar thing about this butter was that the moisture was so incorporated that he was unable to expel it, even by reworking the butter. The authors have heard of only a few instances of this kind. The only way whereby Mr. Joslyn succeeded in reducing the moisture was to put the butter in a cooler for two days and then break it up into small pieces and rework it. In this way he was able to reduce the moisture below the point permitted by the government regulation. One of the authors, in visiting the Experiment Station at Copenhagen, was informed by Dr. Holmes, Dr. Storch’s first assistant, that they had found in their educaticnal scoring contest in Denmark a few firkins of butter that ran as high as 18 per cent moisture and were perfect in body and general appearance. They were unable to give any explanation for the occasional production of a churning of this kind. The finding of excessive moisture in butter is not a new experience in the butter business. ANALYSES OF COMMERCIAL BUTTER PUBLISHED BETWEEN THIRTY AND FORTY YEARS AGO Blyth says: “ There is no standard followed or fixed with regard to the percentage of water. In those cases in which the fat is below 8o per cent, the deficiency of fat is usually from excess of water, 316 COMPOSITION OF BUTTER and seeing the variable quantity of water found in butter, it is wisest not to certify on the grounds of water alone unless there is sufficient to lower the percentage of fat below 80 per cent. “ At the Bath Police Court (January, 1879), a dairyman had been summoned for selling butter, the proximate analysis of which showed a considerable addition of water. An appeal to the Somerset House elicited the following certificate: “We hereby certify that we have analyzed the butter and declare the result of our analysis to be as follows: Per Cent Weal Cle seers tana testa eoheha orn ated ALT aga eaten 23.29 BS ULLEL Ta Wha as eee Slits Mico aia tents cohon teearaess Aue 74.69 Sal | Cereeeere nea prune Okie beet Sather ete 78 Curd cand euoe aucun hal eee ack SA 1.26 “ The result of our analyses of numerous samples of ordinary commercial butter obtained from different parts of the country, including the south of England, shows that the portion of water is very variable and that it occasionally amounts to as much as 1g per cent.” James Bell obtained, for 117 samples of butter collected in various parts of the kingdom, and asserted by him to be genuine, proportions of water varying from 4.15 to 20.75 per cent. Lewkowitsch in his work says: ~ “The proportion of water in butter should not exceed 16 per cent.” He gives the following table to illustrate the amount of water present in butter on the English market: Samples Containing No. of Per Cent of Water aries == ——1| Above Samples : aa Observer e ; Irom I'rom 16 Examined 11 to 14 10 to 16 English and foreign. 560 83.8 | 04.2 9 Vieth English. coca ae 143 9039 85.4 ai H. D. Richmond Orig Ms ges.e gare macs 8 417 88.2 07.2 1.0 H. D. Richmond ANALYSES OF COMMERCIAL BUTTER 317 The above analyses reveal the fact that the moisture-content of butter was as high and as variable as at the present time. Even ct that early date Blyth fixed 80 per cent as the minimum fat-content for butter. The composition of butter in the carly days was more variable than it is at the present time. This is to be expected from the fact that more efficient machinery and methods are now used for controlling the temperatures, and that butter-makers have a better understanding of the effect of tem- perature on the control of moisture. Butter made at the present time will undoubtedly compare very favorably with butter made in earlier years. Standards in Different Countries——Most of the European countries have limited regulations to specifying the moisture- content of butter rather than the fat-content. The Inter- national Dairy Congress held in Brussels in 1910 passed resolu- tions favoring 18 per cent moisture as the maximum amount. England has a 16 per cent moisture regulation for butter, and 24 per cent for blended butter. France has an 18 per cent regu- lation and Belgium an 18 per cent regulation for moisture. Denmark has a 16 per cent regulation for export and 20 per cent for home consumption. Canada has a 16 per cent regulation. Germany has an 18 per cent regulation for moisture for unsalted butter; for salted butter her standard requires 80 per cent fat and not more than 16 per cent moisture. Italy has an 82 per cent fat regulation. Queensland has a 16 per cent moisture regu- lation and 80 per cent fat. Victoria has an 80 per cent fat and 16 per cent moisture regulation. Possibly the reason that some of the European countries have adopted a moisture rather than a fat standard is that it is much easier to make a moisture determination than a fat determina- tion. as in dealing with moisture we are only dealing with one agent, and with the fat determination we have three agents to deal with, the salt, casein and moisture. A 16 per cent moisture and an So per cent fat standard for butter would be practically the same. Taking 3 per cent for salt and 1 per cent for casein, this would Jeave 8o per cent fat, providing the moisture were carried to the limit, which is not a wise or a safe proposition. 318 COMPOSITION OF BUTTER The consumer in purchasing butter buys it for its food value or fat-content. Therefore, it is only reasonable that the cream- erymen should be willing to have all their butter contain at least So per cent fat. No doubt the reason so many of the European countries have recommended a high moisture-content of 18 per cent is that they use less salt in their butter. An 18 per cent moisture, according to their methods of salting, would be about the same as 16 per cent in this country. The authors are very much in favor of a definite standard for butter, the minimum fat-content being 80 per cent and the moisture-content 16 per cent. Some tolerance or allow- ance seems necessary, as butter may vary in moisture, especially from one end of the churn to the other, as much as 1 or 13 per cent. Factors that Aid in Moisture Control.—The two principal factors that aid in the control of moisture in butter are the per cent of fat in the cream and the temperature at which the cream is churned. Where the fat runs uniform and the cream contains a high per cent of fat, the moisture can be controlled quite accurately by observing the size of the granule and controlling the temperature of churning. Bulletin No. ror of the Iowa Experiment Station, page 167, gives the results of some churnings made by the senior author in a demonstration to short-course students during the month of January, 1908. This butter was worked in a Victory churn. The cream for these particular churnings was separated from whole milk by the Randall Creamery Company, Randall, Iowa, and shipped to the Iowa Experiment Station. Upon arrival the cream tested from 42 to 45 per cent. After reducing with a starter, holding the cream over night and churning the next morning, the results given in the accompanying table were obtained. Butter proper contains, besides the water, fat, protein and curd, a small amount of milk-sugar, .35 per cent, and ash from 14 to .16 per cent. A butter-maker, to be successful, must study his conditions from day to day and from week to week; otherwise, during a rainy season when the grass becomes slushy, the moisture-content is likely to vary or exceed the limit, even FACTORS THAT AID IN MOISTURE CONTROL 319 | | | Tem | Ch 3ut- | Per | Per But- jellies pera- | Rev. | Amt le | Per - Lbs. of] Tem- ter- | | | Cent | : Date | Churn Gee Cent | ter- : wey tare for | of Ones Cent AS Pest. | Bat. [RES | ES | ok | Salt | Butter . . Total | Total | . Salids.| DOP || Bat Solids | Bagh) Beer! Sohids, Solids Fat Fe || % Cao aa Ces Gea he OG, ¢| 3 Alabama...... | None; municijpal conitrol | Nee California's «isc erg BRS! 43) 9.25 18 80 Lo dQOr Shp ge |i pacer Colorado... oc: | j 855° 3625 9.25 | 1 B25 | 35 | 28 ve Connecticut oy T1475) 8s5- 3.25 | District Columbia 9 Bas coer ae ee) 283 «| | | None; |munict|pal con|trol | | | None; munici!pal con trol | f2. | B.8 tgyes 9.25 18 | 82.5 | 50 | 28 | 7 | ars | Bas: 13 | | 28 ee) 11 8 3 9.25 82.5 | 130 28 ie} Illinois. . . Saab} | 9.25 Le ag | 82.5 | 50 | 28 Fay Indiana. . {B.8 |3.88 9.25 18 82.5 50 28 | LOW a: Sega hah aed 12.5 | 13 ; | 80 Kansas sa .cicisGulaiaisioue | : I3 25 3 Kentucky 12 | sSie5: > 1 3a25 G,.2'5) | 82.5 50 28 ees: Louisiana. ne S55. Isis 8.00 | 3 | $2.5 50 28 To Maine. . x4 TE75| 8.5 (3.25 | Marvland. ES: 3 5 | 5 . 3 Massachusetts. 12 T5| 353.5 = hs! 15 Michigan....... T2325 |; ? oe As | Minnesota...... 13 | 3.5 | 20 80 | Sia | Missouri. 8.95 |3.25 | 9.25 18 Bes. | So: | 28 bene) Montana. r2 9 3 15 | | Nebraska. . rs 3 : 18 New Hampshire. . 12 9 18 80 New Jersey.. 12 3 A 16 New Mexico....... None; |munici/pal con|trol New York......... II.§5 See 3 ek 3 North Carolina B25 3.05 9.25 | 82.5 | “50 | 28 ie North Dakota 12 man 3 | 5 | Ohio. «5.5 12 13 | | 80 ge) Oklahoma. T2x5, 3 18 28 a ORE BOM ess coches. sara a me 12.2 | 9 3.2 | | 20 | 130 22 tS) Pennsylvania. . None; | ‘munici ‘pal con trol 15 | Porto Rico.... 12 ers | | Rhode Island. 12 | lass | South Carolina. , | |None; municilpal con| tral South Dakota..... | 835) Ses | 9.25 18 | 80 450 | 28 7.7 Tennessee. . | | 8:5: |3:.2'5 18 82.5 | 450 28 Fee) SPEXAS' alsja-i chase she [Bag Bees AU Gaienctnatade cs | | 9 I3'e2 | 18 | 80 28 7 Vermont...... §72.5 | 9.25 |4 Virginia. we Al mee 825 sees G25) | 218 82.5 450 28 yori Washinegton.... este) 8.975. 13-25 9.3 18 : 130 | Wisconsin... | Seen 9 | 18 82.5 Sor. || -28 8 Wyoming.. | 12 coe aed. — | | 80 120 | 3 1 Per cent of fat. 2 Not over 12 per cent water or 5 per cent salt. 3 Proportion of fat to total solids must be the same as in the crude milk. 4 Per cent of fat in total solids &’ May and June, 12. 387 388 APPENDIX METRIC SYSTEM ! METRIC SYSTEM OF WEIGHTS AND MEASURES AND TABLES FOR THE CONVERSION OF METRIC WEIGHTS AND MEASURES INTO CUSTOMARY UNITED STATES EQUIVALENTS AND THE REVERSE. In the metric system the meter is the base of all weights and measures. The meter was intended to be, and is very nearly, one ten- millionth part of the distance measured on a meridian of the earth from the equator to the pole, and equals about 39.37 inches or nearly 3 feet 33 inches. The meter is the primary unit of length. Upon the meter are based the following primary units: the square meter, the are, the cubic meter or stere, the liter, and the gram. The square meter is the unit of measure for small surfaces; as the surface of a floor, table, etc. The are is the unit of land measure; this is a square whose side is ro meters in length, and which contains roo square meters. The cubic meter or stere is the unit of volume; this is a cube whose edge is 1 meter in length. The liter is the unit of capacity;, this is the capacity of a cube whose edge is one-tenth of a meter in length. The gram is the unit of weight; this is the weight of distilled water contained in a cube whose edge is the one-hundredth part of a meter; a gram is therefore the one-thousandth part of a kilogram, and the one-millionth part of a metric ton. 'From The American Chamber of Commerce. APPENDIX 339 MEASURES OF LENGTH Metric Denominations and Values eae inDenominations in Use Myriameter Kilometer 10,000 meters 1,000 meters roo meters Io meters I meter .I meter -or meter .oor meter | 6.2137 miles .62137 mle, or 3,280 ft. 10 in. (328 feet 1 inch [393.7 inches 39.37 nches 3.937 inches 3937 inch .0394 inch M EASURES OF SURFACK Metric Denominations and Values Equivalents in Denominations in Use ' Hectare. . | 10,000 square meters 2.471 acres BATES ccnas ae unie 100 square meters | 119.6 square yards Centare.. ... I square meter 1550 square inches | MEASURES OF CAPACITY Metric Denominations and Values | Equivalent in Denominations in Use 5 No. of Names Liters Kiloliter or stere. .| 1000 Hectoliter....... 100 Dekaliter....... Io Litets sad peewee I Deciliter........ Ba Centiliter........ .O1 Milliliter........ .OOI Cubic Measure i Liquid or Wine Dry Measure Me: ? Measure 1.308 cu. yds. 1 cubic meter \264.17 gals. .1 cubic meter 2 bush. 3.35 pks. | 26.417 gals. rocu. decimeters |g.08 quarts 2.6417 gals. 1 cu. decimeter .9o8 quart 1.0567 qts. .1 cu. decimeter|6. 1022 cu. ins. 845 gill ro cu. centimeters | .6102 cu. in. . 338 fl. oz. zr cucentimeter | .o61 cu. in .27 fl. dram i 390 APPENDIX WEIGHTS Metric Denominations and Values Equivalents in Denominations in Use : Weight of What . : Names Pa of Quantity of Water at Avoirdupois Grain Maximum Density Weight Metric ton........... 1,000,000 1 cubic meter 2204.6 pounds QOuintals vanes seaekes 100,000 1 hectoliter 220.46 pounds Myriagram.......... 10,000 1 dekaliter 22.0460 pounds Kilogram or kilo..... 1,000 1 liter 2.2046 pounds Hectogram sc 5.0866 100 1 deciliter 3.5274 ounces Dekagram........... Io ro cubic centimeters . 3527 ounce Grane betes Sale wanna I 1 cubic cent meter 15.432 grains Derigratns.. 1c eeseead «t _t cubic ecntimeter 1.5432 grains CentigraMy isos acest 6 .or |rocubic millimeters .1543 grain Milligram........... .oo1| 1 cubic millimeter .0154 grain COMMON MEASURES AND WEIGHTS, WITH THEIR METRIC EQUIVALENTS The following are some of the Measures in common use, with their equivalents in measures of the Metric System Common Common eeeaciee Equivalents MEeAsires Equivalents 1 inch 2.54 centimeters 1 cord 3.624 steres 1 foot . 3048 meter 1 liquid quart -9465 liter rt yard .9144 meter 1 gallon 3.86 liters 1 rod 5.029 meters 1 dry quart 1.to1 liters 1 mile 1.6093 kilometers 1 peck 8.811 liters 1 square inch 6.452 sq. centimeters 1 bushel 35.24 liters 1 square foot .0929 square meter r ounce av’d’p | 28.35 grams 1 square yard . 8361 square meter 1 pound av’d’p .4536 kilogram 1 square rod 25.29 square meters t ton (2000 Ibs.) rt acre .4047 hectare 1 ton (2240 Ibs.) r square mile [259 hectares I grain troy 1 cubic inch 16, 39 cu. centimeters r ounce troy cubic foot .02832 cubic meter 1 pound troy HO cubic yard .7646 cubic meter 31 .9072 met. ton .or6 metric ton 0648 gram 104 grams 3732 kilogram APPENDIX 391 TABLE FOR THE CONVERSION OF METRIC WEIGHTS AND MEASURES INTO CUSTOMARY UNITED STATES EQUIVALENTS AND THE REVERSE. Vrom the legal equivalents are deduced the following tables for converting United States weights and measures: METRIC TO CUSTOMARY Linear Measure Meters= Inches Meters= Feet Meters = Yards Kilometers = Miles I= 39.37 I= 3.28087 I=1.003623 I=0.62137 2= 78.74 2= 6.56174 2=2.187246 2=1.24274 3=118.11 3= 9.84261 3=3 3.280869 | 3=1.86411 4=157.48 4=13.12348 4=4.374492 | 4= 2.48548 5=106 85 5 = 16, 40435 5=5.408175 | 5 = 3. 10685 6= 236. 22 6=19.68522 6=6. 561738 6=9. 99592 7= 275.59 7 = 22.960009 | 7=7.055301 | 7=4 24959 8 = 314.96 8 = 26. 246096 8=8.7480984 8=4.97006 9= 354-33 9= 29.52783 9=9.842607 | 9=5 59233 CUSTOMARY TO METRIC Lincar Measure Inches=Centimeters}| Feet=Meters | Yards=Meters | Miles= Kilometers I= 2.54 I=0. 304705 I =0.914303 I= 1.60035 2= 5.08 2=0.609506 2=1.828787 2= 3.21869 3= 7.62 3=9.914303 3= 2.743179 3= 4.82804 4=10.16 4=1. 219101 4= 3.657574 4= 6.43739 5=12.70 5 =1.523980 5 =4.5719606 5= 8.046074 6=15.2 6=1.828787 6=5.486358 6= 9.656008 Y fee ©: 7 = 2.133584 7 =6. 400753 7=I11. 20543 8= 20.32 8= 2.438382 8=7.315148 8=12.87478 Q= 22.86 Q=2.743179 g=8. 220537 g=14.48412 APPENDIX SQUARE MEASURE Cuspic M&rASURE Square Centi-| 4 Med ans wietere= Square Meters | Square Meters |} Cubic Meters Cubic Feet S Inches} = >4uare Feet | =Square Vards|| =Cubic Feet |=Cubic Meters quare Inche I1=0.155 1=10.704 I= 1.196 I= 35.315 I =0.02832 2=0.310 2= 21.528 2= 2.392 2= 70.631 2=0.05663 3=0. 465 3= 32.202 3= 3.588 3 = 105.947 3=0.08495 4=0.620 4= 43.055 4= 4.784 4=141. 262 4=0.11326 5=0.775 5= 53-819 5= 5.980 5=176. 584 5 =0.14158 6=0.930 6=64.583 6= 7.176 6= 210.899 6=0. 16990 7=1.085 7=75-347 7= 8.372 7 = 247. 209 7=0. 19821 8=1.240 8=86.111 8= 9.568 8= 282.525 8=0. 22653 Q=1.395 9=96.874 =10.764 9= 317.840 9=0. 25484 SQuaRE MEASURE Liqgum MEASURE Square Inches| Square Feet | Square Yards|| Centimeters ; ; = Square = Square = Square = Fluid ie Dieta Centimeters Meters Meters Ounces Quarts Gallons I= 6.452 I =0.09290 1=0. 836 I1=0.338 I=1.0567 |1=0. 26417 2=12.903 2=0.18581 2=1.672 2=0.676 2=2.1134 |2=0. 52834 3=19.354 | 3=0.27871 | 3=2.508 3=1.014 | 3=3.1700 |3=0.79251 4= 25.806 4=0.37161 4=3.344 4=1.352 4=4.2267 |4=1.05668 5 = 32.257 5 =0. 46452 5=4.181 5=1.691 5 =5. 2834 |5=1.32085 6=38.709 | 6=0.55742 6=5.017 6=2.029 | 6=6.3401 |6=1. 58502 7=45.160 | 7=0.65032 | 7=5.853 7= 2.308 | 7=7.3968 |7=1. 84919 8=51.612 8=0. 74323 8=6.689 8=2.706 8=8.4534 |8=2.11336 9=58.063 | 9=0.83613 | 9=7.525 9=3-043 | 9=9.5101 |9= 2.37753 Dry MEASURE Ligumi MEASURE Hectoliters = Bushels = Fluid Ounces = Quarts = Gallons = Bushels Hectoliters Centiliters Liters Liters I= 2.8375 I=0. 35242 T= 2.057 1 =0.94636 I= 3.78544 2= 5.6750 2=0.70485 2= 5.915 2=1.89272 2= 7.57088 3= 8.5125 3=1.05727 3= 8.872 3 = 2.83908 3=I11. 35632 4= 11.3500 4=1. 40969 4= 11.830 4= 3.38544 4=15.14176 5=14.1875 5=1.70211 5=14. 787 5 =4.33180 5 =18.92720 6=17.0250 6=2.11454 6=17.744 6=5.67816 6=22.71264 7=19.8625 7=2.406096 7 = 20.702 7=6.62452 7 = 26. 49808 8 = 22.7000 8= 2.81938 8= 23.659 8=7.57088 8= 30. 28352 9 = 25.5375 9= 3.17181 9 = 26.616 9=8.51724 0 = 34. 06896 APPENDIX (WeEIcHT AVOrRDUPOIS) 393 : kil s= Kilograms = ; Centigrams = ee oe tlogtams: Metric Tons = Long ; Ounces Avoirdu- | Pounds Avoirdu- Grains : : Tons pois pois I=0.1543 I= 35.274 I= 2.20462 I1=0.9842 2=0. 3086 2= 70.548 2= 4.40924 2=1.9084 3=0. 4630 3=105.822 3= 6.61386 3= 2.9526 4=0.6173 4=141.096 4= 8.81849 4= 3.9368 5=0.7716 5 =176.370 5=11.02311 5=4.9210 6=0.9259 6=211.644 6=13.22773 6=5.9052 7=1.0803 7= 246.918 7=15.43235 7=06. 88094 8=1. 2346 8= 282.192 8=17.63607 8=7.8736 9=1. 3889 9= 317.406 9=19.84159 9=8.8578 Grains = Centi- Ounces Avoirdu- Pounds Avoirdu- Long Tons= Metric grams pois = Grams pois = Kilograms Tons I= 6.4799 T= 28.3405 I=0.45359 I=1.0161 2=12.9598 2= 56.6991 2=0.90919 2= 2.0321 3=19.4397 3= 85.0486 3=1. 36078 3= 3.0482 4= 25.9196 4= 113.3981 4=1.81437 4= 4.0642 5 = 32.3095 5=141. 7476 5= 2.26796 5=5.0803 6= 38.8703 6=170.0972 6=2.72156 6=6.0063 7= 45.3592 7= 108.4467 7=3.17515 7=7.1124 8=51.8391 8= 226.7962 8=3.62874 8=8.1284 9= 58.3190 9 = 255.1457 9= 4.08233 9=9.1445 INDEX Abnormal milk Acid, butryic, capric, caprylic, myristic, oleic, palmitic, stearic. carbonic, hydrochloric, phosphoric, sulphuric. . citric. lactic. ... salicylic. . sulphuric tests... ne Hee Acidity of milk... : of ripened cream in relation to richness of cream. . . of starters. . tests for.... Adhesion of milk... Albumen in milk. Albuminoids in milk . Alkali of various strengths for measuring acid in milk and cream. American Association Test for buttermilk and skim-milk Amphoteric reaction of milk. . Antiseptics. . ae Ashi ine Malena wed geecad aes» = Babcock test for fat... causes and remedies for common defects in clearness of fat issn Bacteria in milk, aroma and flavor producing. as a cause of deterioration of butter. classification of........... conditions favoring development of desirable and undesirable in cream ripening. kinds of germs found in milk. number of, in milk. size and shape of sources Of......... unfavorable conditions for Belt, pulley and speed calculation. Boiler, cleaning of.. priming of... . 94, 221 396 INDEX Breeds, composition of milk from various ek Aint tered eae eS Brine,. salting butter with......... ee ae aie, . Paibeitha se ae tautee OFT soaking tubs in.. . ; cin 300 Butter,. appearance or style of... ; Hawn! Bate classification and grades of, as outlined by N. Y. and Chicago Mercan- tile Exchanges. ... rsh ; : NOt Rl egy BAD COlOK Obie cc ea ws acaba. ane e aes Ziad + +2253, 341 composition of. . ; Seneca cost of manufacturing... .. Saks sui ie + B07 exportation of... . . : , Seitanhad 350 HavorOfvagna sainzs ean : ‘ . . B4r for storage. . . ‘ . 3575 300 judging and grading of ; ; ; .. 340 keeping in creameries.... ies : .. 296 making of, on farm. Seeus 7 (280 mottled, causes and remedy. J oaMisEMGN iG wd de ndGh Brot a : .. 279 package, style of........ ; 204 PAChiNGiOl: aw ckssr ees : . 204 preparing for market... int ; . 204 printing of....... MEae : : , : 299 saltiness of......... : ne 8) storing in creameries.......... ‘ .. 2096 tests for fat in...... Brey hate serrate ms eee ee : oo OF texture or body of..... : : ‘ ae B42 treatment of............. pees 300 washing, and kind of wash-water. 263, 265 Working Of .cucdvoegne eee: ed ‘ Ae BAK d ...291, 360 Butter-making, History of........... eee eee : : ie Buttermilk, testiof...< cogs cacesis: Rebtae . IOT, 103 removal of............. Ree Se eae 24263 Butyrts 2 sese2d 2% a ae 1a abe oearerteepugi ais athens okie. MLS Calculation of amourt of salt to add to butter. . . .. 272 average per cent fat. : an ZT churn yield. ... ; hon aw ee Cs cream-raising coefficient . 140 dividends........... : a Paso ety, overrun,...... . 133 solids in milk. ....... , , . 35 CansiStarteinn: caranencudien feat ast 238 WaShING Obs tosineens cemesa ti Candie : 2 L25 Care of cream on farm........ 176 Casein in milk, condition of....... : en . 17 Centrifugal separation of cream... . , ‘ ‘ 154 Churn, keeping in good condition... . F : _ 260 Churn yield, calculation of... heats x Star teat eevee e Churned milk, sampling . apshietadcainaatbat EGE GaNAee ae mace INDEX 397 PAGE Churning, amount fora... .......... hod hie Radetich e 247 color... 2: 253 conditions affecting. . . : 240 definition of degree of ripeness..... difficult, causes and remedy for. mixed, sweet, and sour cream nature of agitation for... . richness of cream for. . size of globules... . straining of cream previous to.. temperature... when to stop.. PPRResE Ts Citric acid in milk. . . Pee Aa sat ane Cold storage .. es benefits of. cost of.. history of mechanical refrigeration. Cold storage butter, should it be branded. . Color, Dawes .4 45 : Coloring matter in milk. . Commercial starters ............. ee , preparation and use of. . Composite samples ............... ‘ arrangement and care of. preservatives for. sampling apparatus for. Composition, of butter. .......... : ; sity 300 acts and rulings as to... ; : 300 analysis thirty years ago... . : poate SES of colostrum milk.. ; eee eee 65 compounds for increasing yield... ...... Ronidosaeate 310 control of moisture. . . eee 2 Ratue cx wala ast7 312 of dairy salts.......... ee bao nee COTS. different kinds of milk. ...... ee ae eee ichicantat te 5 need for regulations. . ; eS COnp een: 311 of salty milk... . — Sree wa 66 separator slime. . . : pabodeag TOO Lubercul Ouse tall echoed cet but eyes roas wee eae haan 73 Ccentinuous method of pasteurization. . we Aha hate! “ Cooley” method of cream separation. .. ee ee 150 Cooling facilities, for creameries. . . ; : citi june BOD cooling systems. ... Peles one oe eee 362 mechanical refrigeration. ... Datura Ge... + peek aes BR eka eS Shee ate Ee Ree SEAS 305 398 INDEX PAGE Gows\breeds of) icc nina vacances paw adie Oe DeRE thats Euabaineeae aes pe 75 Cream, -acidityof, for.churning, ois o\cskrareceasseaadaia sigh yasme iad baw as 224 care of, on farm. 2 PRUE ee eet) isn Gee tole hee 176 effect of cleanliness on quality of. SAAS ESe LA Fe TCADA Ca 176 grading of. Daa hdstatrte stata eu caneshaceee Poa tetera ee nea 03 methods of igneemng of. ates eat ea crete 179 Neutralization) Ofis wa czidee as ee ee eae ess Fe BS cece ens eda 184 PasheUni7ationrOl rie Ui kisie aca deus Game iane. Aa goad hee arses 201 SO UIT A re See sate k Bet Sey titi ek eau occa ar Gah fe tah ect a INE AN 189 TIPENM NOL : eresemmrarmediaea he ee prs HOCHDS AL MeGa EER EAM oS 215 Sampling Ofs cass neicirson tan s0s garccane aa sbousshahovevedtt af x setyalalaldeal govedired a tegd desta 118 Creamery sewage disposal............ a abr net islahite. otis ivn ptt crate et aa 299, 300 Curdy specks in butter... SSE Rae? O24 FREE AOR AL 285 Deep-setting system of cream separation............... 150 Defer ts found in butter . me, ee cee ee EET er ree 32 advancéan lactationesw-accueosatcnweaartneyeaanee Gok 32 Cheesy flavor sane. Wee Qidars. dition ernst Wedet etess ats 324 faulty: factory conditions:<% scence oedh See ed tue 325 PEEC SA ONS a ee Sustnthel ete ah acuta messi Se acae hens 32 PV STA Vg Pei tre t 6 8, Oc Naa es Shera tah ce on Say Uae ek RERNYAan as BN 336 flat or insipid fate ORG. PREG A Pay Aude eRe aaa 32: flaviors: bysabSorp UlOlis-g.o7se.ascrcamentroe scopes eis seb aA = 324 garlic..... Ae Seka eke duty see ences eee aaa ee 327 meétalliefayors.: pearqutruetegisasgheaness eee 335 SOUL NAVOR sees Fee bees 325 stable flavors....... ~32o tallowy flavor......... 332 Difficult churning, causes and remedy................ 258 Dilution, effect of, on creaming.......... 153 Disinfectants weceres ease ees se oaeeee ge a Ae eu gaoad MERRIE See E 59 Electricity, effect of, on germs in milk... 2.0.00. 020002 64 Enzymes in milk ............. Reena ae epee Ceara te 22,54 classification... . ede ausigs te Sieaepern nee erR NST 54 EMECts OL EatIOIM. arid sess pede y sccen dignedaedlgl exemhaym crave hy gious anes 41 tests for... .. 42, 201 EX POre DULLER. Gach ites aka SGM aN EON hed Ga ee taGs at UCN a Aes para eNe 350 Harring LOM Lest. aay eyyed eu etary ht eevee tusceetnm ereea yh oe eer eR Anes 223 Pato in DUtterin nc cea c een nae e saied g's He ON Mad A EH WeKeRee oe Maye R Ee 309 Mille eacndeenaa 8 COMIPOSILIONPOL yc memmnacigiiin s Saag mews SRAM RAS Ss bacee Perohee 15 condition of... . = AE RRELARG Stn’ Sec sRS RITA ail tata tae DAD Savi as II CHECESIOL ENVITONIMEN Es fi Givecina Rody eda a eachereee ko. GERARD 80 Heat: Ollie mi qoananda caovce geome muds venemaaueneenaes 42 various feeds on composition of. INDEX PAGE Bat, inrmilkelycendesion. vaigcu gu nqalsys scenes dea wh pee eRe ey 10 Ply Genel perara neal dae sh ao RTs see OST eat Se 15 melting-point of. . Per a aati Samarra ata a bry ere 10, 14 membrane enveloping fat globules 11 microscopical appearance of. ) non=volatiles......¢40.+% 14 paying for, as compared with fat in cream 143 PIOPErieS: Ob: cncsi gia. ceee 10 separation of. . 149 size of globules... . 8 testing for 98, 99, 103, 107 Volatiles, 2cniua xa ook Rate SEY Mend AOE AR EIR Y peer ae 13 Feeds etlectsvGmamlle wy Mec te tees nar G Seas Hoe ae eae ND Bete aloes 70 Fenmeéntations, Gétection Of...