Mi A AAA LAB AY LAAs Frys BØGE HAMAR rete OCA 2 tH Ae ro 4 ie HOR) ae sy Hess IRAK x 6 220,7 MHA AE rele Fatale eel KALK AG no Ne RER ise eRe KARA RG HER ICES ? PoP RP Me Par? AOK 2. y KP (GG rere At As 3 OG ‘ i AAA Hira 4 å > f AA AAEM A KAKA Nets) vr. i m (4 42 CMH AA A? AAN ) MMO AANG KAAS ? AAA Ae É MAASE ott! PSP 4 x, eaeansatt UKE Bie i ARIK) 3339 >) ? Wt im i ) Pe aaron ’ ? > 3 UA | %, UGL 4 ry) ACT hts KU AEL i 406 Ki CO) uy vy? SE kee AEG CAAA Aa LÆ MU CM MM AS, eA? CEOOOCKOUUUES BOCs EMAAR? RAK AR Ae É ‘ RNa? K RO stately nly HUME 4444400 Ma Rene KA KIG ”». ae 44500 ”” . ‘4 * AAA P, fs reap? ve (AAA lg nee i AMG ”” Mi AAAS É > 4 ei ¥ pee ' >) ty : 1) DEDE (444 Sl) ( AK ve ee ? (CA Ps i ? be (RAN AA AAA f RAL HAM AA OD EN by ASM HMMA AA Me Ae CHAS Ndi) DP UM ANA ANAS 1d ECL ” 3 14 HANSAEN ba yt UMA MEK KA A HMA ne MMMM DDD NED b RMU MAG 4 ay UME ASSURE AHS Hb Py AMAA AAS ny hy (44 DDD BEDS 9) Ry) y DDD 3 MSM KANN 4 1d OK 40 VER NOOK oat ACN (HG, Pda PED DLP D 44100600 AL td SS PPP PAP PLP Rhy y?y Db? LP MOMMA PID PPMP PPD? or bby Py) NAAR tel plete HAM DD PEI P DPhp PP 44048 BAe KEN UNA ANTAG OK KANALER AANG HAN AANG BAAS ALMA LASSES GEN NNE KAMARA Aad HM HER HAG, ACMA ; SOK AG pert MMM AMAA EE > FAKTA PP yeah phot ae GR Add EA Aa 42004464 FDD (4 EEC bear PDs AAAI HC CA AAS y (ÆG BNP PSP PD >) AAA MAA Mid ” MANGO GOG UN A 4 é 414444 y a PPP > CRAG yb ‘as 6 yh bo 4 yyy a H 444 ALLANS DOCH SMM RAM ” ¥ SAGS i 44 KUMAR DEG ) 406 MANSON HR > COMMA AUG by 440004; DPoPy) ” 4 ry asad pera? ry ; i] ae fF »y HABA Ad rr PreParata tery arb e AAAS 2550 CH ÆG ØDE AH RAS AAL SEN oe AMARA, MMMM eC 4 HMMA KASSE KANN ermal eros pom aT Day 444307 Po (20 j ) ) (MAA i Q 141440 (2 SARI UUM RK MAR HMMA AM aU ) 4 RMR H HRM RAT ye MAT aes A GOGH » RS Hid AAAKAZ (HAMMAR Baik 4 tag ye) SMSC A ee OSSE MAM AAS ANNE earner nM MINI yl lyr hppa iy REM HMMM MCI CEH yyy NMA AAU KK Ae ATO OAR id 4) UMMA RA KASSE AAU EM KAAS BAA Ut HAMS UEC RA COR UUM) AAAI a A DOOR ACA USAC HKG KANONEN ALEN AMAA HANNS 3°) MANGA RP OPI MD PLP arora” SMM HIG AMAA ARAM EAA AL AANA AALS ie SOC MOM eae) CAAA (4: MAHAL ican HH AD (AKAs MAA BENN KASSE BAAD MM HCA ed 4404 HMA ARATE eid ete 4468 AOS ACA 4) AU CA Pa AA AMAL UMMA MA MARAE EKG USE HAG; OOO Ua MAHAR AR HAHA Ged HEM HOCH Ah ata dE ES MARIE wd ee ’ 233) OH: USM A A, ALAM AH AH Aa Drrsnrrite Ni Hans PANDO» eshte yryty: 13535352; DDD DS) LAK AHA AGGGGNE SDR Hare Hee fy Dp phbhntemrD bhi HOMANN LRN RUPP PUPP ROH yh Faery ODMH neta! Pte? MAA NA ANCA A AULA AES LMA ads (404 ASE, 1444 44006 LUN KARHHAKM ANER AIU GUN KH AC Cad iy (440 PERU HOE AAS y MM UC AT ALA > yy? ) » ANUS »? Bees vray 7, PLP? PPh? > AM So RING ENGER EEK ANSER Dø Papen Oe yi UE LSE RAMAN AY 4% Ne HHH 37 MMA RA MMU > 5 (AMG (MAA, KANN < 3 Aaa aes K MICA CS NDR PS) KH HAS KNAS KHA GG C00 ede Rano Ra a AR SDI ERIR DE, fy if Hae (44 , SAM 4460 EKS MUSE ASS y SAMAK 4444400 Diet DR re OSSE SAGLAK 2 x , AE MUSE KS AUER A Moller ) ) NED HUGGER KK KEN BA ey) 1) BÅD) AA: BED RR NER OR? RRA IBID EDB SE ED RD DE DES HKG KEANE IKA HAN VASKE K KK nn Hm Pyrat teeter a? Pp ny ' HRK EN EA KANSAS HUNNEN dS AH AURA DpDyMy Py) USR KG URNE SE AE HAGE KA BEDRE SS DDS ED ED, ELLER SENER Payton NUNC AHA KANU HA KKG PHAM eK RANA GG GAGE BED EDER RED ni KRU) BRØND DD) 57) Solan orn Mae Pitot Oe HHA, ØB AD: 4 ; 5 ; 3 NG Kis > HA; vy (4 MALEK RD PP RU r/min rane dy 446 % ot, (VE PAP DID DIR rr ty tity Dryer ea Dr yr Para yey niin LAGE AG HD, ti Re åg GG He i Bests y (A Aes ( i SDN LE MUS Ay, MK HIG DIR CUS } , ' PCA MAIR he Net Sd) y CAE Ba HAMM? HAGE yy) otyha ts Drona MUR HH Wire» Doo PPR DDO Wd Me . ) (9 ) Sd Para y? arb? bb LD CASO he (4) MS: ony? aryl PID? ( KOO HA: SCH WaPePneptprpetoeeraypybraebr by bobs DO PL MeR MDP NRA ire? ar yre AAA YK LOLA, yy (3 kelte yr ory PAA GEAR ts tae Sank kee DOM NG ” (KKG IMT) alate yy eb heheh bb HO wd KNKKA MH MMPS MPa PLt tara a br brbr DED ba DAD NV RKY, Vay ASA AHA NAAR DN Peete oar ibn ILD PPh hh (KANON Dyb Aaah CORA LY MAA 39) MARA, Sit) ERROR RNa seat AAR ARN Es dtd aunt MAMAN es Py ‘4 W as YY? CA ROS Pi yy ry Malton mene HAMAR GSE Doan | NGC GG Per bgt penance 4444 WPM, LAG gt GLAN 7 7 4 4, ) dte Hs AAA, un Had iby, Py ope yy RAHA AAAS COC) CANA AG KAO AA, See COU +, WRIA HA a eee RIC KK KLAGE Worry KABA AI AG JUG boy ’ eK DD! » Yt ONG meek ne Gone N@ COPYRIGHT DEPOSIT: ESSENTIALS OF MILK HYGIENE A PRACTICAL TREATISE ON DAIRY AND MILK INSPECTION AND ON THE HYGIENIC PRODUC- TION AND HANDLING OF MILK, FOR STUDENTS OF DAIRYING AND SANITARIANS BY C. O. JENSEN Professor in the Royal Veterinary and Agricultural College of Copenhagen, Denmark. TRANSLATED AND AMPLIFIED BY LEONARD PEARSON Dean of the Veterinary Faculty of the University of Pennsylvania, State Veterinarian of Pennsylvania, Member of the Advisory Board of the State Department _ of Health, and Member of the Board of Health of Philadelphia. SECOND EDITION—REVISED ILLUSTRATED PHILADELPHIA AND LONDON fob LIPPINCOTT COMPANY PD ET LIBRARY of CONGRESS Two Copies Recetved FEB 6 1909 Copyrignt entry alr. V\ADA CLASS Ge XXc No, 30 21 COPY 3. COPYRIGHT, 1907, By J. B. LIPPINCOTT COMPANY COPYRIGHT, 1909, BY J. B. LIPPINCOTT COMPANY Electrotyped and printed by J. B. Lippincott Company The Washington Square Press, Philadelphia, U. S. A. FEREFACE TO THE SECOND EDITION. THatT a new edition of this work is called for one year after the appearance of the first edition is gratify- ing evidence of widespread interest in the subject of milk hygiene. A few corrections and changes have been made in the text and new matter has been added to give in detail what may be regarded as the official method for the examination of milk for bacteria and cells. Luk. me BELORS" PREFAGE. (TO THE ENGLISH EDITION.) In the hygienic movement of the times the control of the production and handling of milk has not been given a prominent place. But the significance of this subject is now plain and everywhere efforts are being made to institute such a control or to improve it. The efforts of cities to secure a wholesome supply of milk must of course differ and be adapted to local conditions, but they must all be governed by the same principles and rest on exact knowledge of the composition of milk and of the dangers that are to be avoided. In the preparation of this book it has been my hope that it would not only be of use to my Danish col- leagues, but that my colleagues in other countries would find it to be of service to them. For this reason I pub- lished a Danish and a German edition simultaneously and for the same reason I have been very glad to grant Prof. Pearson’s request for permission to prepare an English edition. C. O. JENSEN. TRANSLATOR’S PREFACE. THE production of market milk is a rapidly growing industry. The demand for milk in cities is continually increasing and there is reason to believe that the rate of increase will advance. The milch cow transmutes the pasturage and forage of the farm into edible protein, lactose and fat—into units of nutriment for man—at less than one-half the cost of similar units in beef produced by the steer. Milk is not only the most economical but, when pure and undefiled, it is among the most wholesome and it is the most easily digestible of all foods of animal origin. These are the strongest possible reasons for its extended use. On the other hand, there is no other food that, under ordinary conditions, is so exposed to contamination, that is so easily contaminated or that so fosters contami- nation as milk. Hence the necessity for the study of milk hygiene. The subject is a broad one. Milk hygiene involves some knowledge of the physiology of cows, especially with relation to breeding, lactation and nutrition; of comparative pathology, particularly the various dis- eases of the udder of the cow, the abnormal conditions | that affect milk secretion, and the infectious diseases of cattle and of man that may be transmitted by milk; of bacteriology, in regard to the pathogenic organisms and the saprophytes that occur in milk, their effects, their behavior under various conditions and especially at different temperatures; of the chemistry of milk and its adulterations and, besides these, there must be added vii TRANSLATOR'S PREFACE certain, important chapters from animal husbandry, dairy husbandry and dairy industry. Until quite recently, milk inspection in the United States has been carried on by untrained men who have had little, if any, knowledge of the sources or nature of the contaminations of milk or of the means by which they must be avoided; their whole technical equipment has consisted in a few rule-of-thumb tests to detect gross adulterations. A large number of milk inspection services are still organized on this basis. In several cities, however, attention has been paid to microscopic and bacteriologic examinations of milk, and it has been shown that a very large proportion of the supply fails to meet even a moderate standard for cleanliness, thus re- vealing the need for measures at the seat of production and during transit to prevent injurious contaminations. It is becoming increasingly manifest to sanitarians that more must be done to protect consumers from the unwholesome conditions and the diseases propagated and transmitted by milk and the broader men in dairy industry realize that milk must be made safe and be pro- tected if it is to find and retain its proper place in the dietary of the people. This makes a demand for a discussion of milk hygiene from the standpoint of the sanitary supervision of market milk—from the side of the man who is to do the practical work of protecting the milk supply—and it is this demand that Professor Jensen’s book is planned to meet. LEONARD PEARSON. vill CONTENTS. VPS SONTR TEV ETON RE eS cae ea Bro a lS A a PRONTO ETT S" COMPOSITION. 62,055 %:0 40 ere sees seat este ehee cee’ The milk glands and milk secretion; the constituents of milk; the composition of milk of different species of animals; variations in the composition of cow’s milk; changes in secretion during diseases of the udder; excretion of foreign matter with milk; changes in milk caused by micro-organisms; changes in milk at high temperatures. HARMFUL PROPERTIES WHICH MILK MAY POSSESS............-.- Exeretion of poisonous substances with milk; addition of preservatives; absorption of odors; transmission of infection from cattle to man; contamination with organisms of specific diseases of man; contamination with other bacteria; admixture of dirt. BASEREDE ATION AND STERILIZATION « « <«ctsccsdececetseeeocelese Pasteurization; sterilization. ewer On MUGK FOR INWANTS. SETS EET oa ee se women sa The digestion of milk by infants; comparison of cow’s milk with mother’s milk; modified milks and special milk preparations; relation of milk to infant mortality. PUBLIC CONTROL OF THE PRODUCTION AND HANDLING OF MILK... Development of city milk supplies; laws and regula- tions for the control of milk; regulations regarding the production of milk; the health of the herd; feeding cows; eare of the stable; milking; health of the attendants; the water supply; the care of milk on the farm; transportation ; regulations concerning sale and delivery; labeling milk; milk packages; public supervision to prevent adulteration; methods of examination; sampling; specific gravity; fat determination; total solids; adulterations and their detection ; public supervision to prevent the sale of deteriorated milk. 1x 60 157 x CONTENTS THE MILK SUPPLY OF COPENHAGEN........ wale ecee ols leuele eel a APPENDIX I. GERMAN INSTRUCTIONS FOR PRODUCING NURSERY IVE 42 ar Be SR ae eis oe eee EN SSD Fe SER SR NERE SERENE meer 20m) ÅPPENDIX II. THe MILK COMMISSION OF PHILADELPHIA....... 267 APPENDIX III. A Scorer CARD FoR DAIRY FARMS.............-. 213 APPENDIX IV. THE MILK Commission oF Essex Co., New JERSEY ore icible oie a been ala Sane ejede EDR ahello. RESENS toe cr 275: APPENDIX V. REPORT OF THE ROYAL COMMISSION ON TUBER- _ CULOSIS io: ois 3 cre Bib ANE ae Se ate doe) Rare, avalon ERR ER ERE SERENE 285, MILK HYGIENE. PART I. INTRODUCTION, Cow’s milk has a peculiar place among our food stuffs in that it is not only an important and indispens- able part of the daily dietary of most people, but it is being used more and more for the feeding of infants and, indeed, is often almost the exclusive food for children during the first years of life. ft is, therefore, quite natu- ral that at present when the science of hygiene is receiv- ing so much attention—especially in relation to the large cities—that there should be a demand for a reliable supervision of market milk. It is true that the milk trade in cities has been subject to a certain inspection, but attention has been directed to only one side of the question, to the possibility of adulteration, and to pro- vide that fat is not removed and that there is no alteration in the composition of the milk. From the standpoint of hygiene this is merely of secondary im- portance because it is in other ways that milk acquires dangerous properties and may, indeed, become the means of spreading virulent diseases. A properly organized milk control of the present day can not, therefore, be restricted to determining that milk offered for sale is unadulterated. On the contrary, it must be its chief purpose to prevent milk possessing injurious properties from coming into the market and to prevent market milk from acquiring such properties during the time that it is being handled and stored. Since it is possible only by means of a thor- ough, tedious examination to determine whether a given 9 10 MILK HYGIENE sample of milk is unwholesome, milk control can not be restricted to a simple inspection of the milk or to taking a sample for further examination. To imsure real safety, the inspection must be broadened to cover the health and feeding of the cattle, the cleanliness of the producing plant, the method of handling and caring for the milk and the condition of health of the people who come in contact with it. Milk control is, for the reason stated, more difficult and more expensive than, for example, meat inspection, and this is undoubtedly one of the principal reasons why the control of milk produc- tion and the milk trade is so defective in most countries. During recent years, a somewhat comprehensive con- trol of the milk trade in its various relations has been earried out in a number of large cities, but a thoroughly satisfactory system does not exist and will be difficult to establish on account of its cost. In Denmark, a long step has been taken in the matter of milk control through the voluntary initiative of a single large com- pany which, at a time when milk hygiene was receiving little attention, inaugurated a very comprehensive system of control, and thereby set an example that has been followed by other large companies, not only in Copenhagen but also in foreign countries. These com- panies have, in some respects, carried their control to a point far beyond that contemplated at the time by the public authorities. Copenhagen is on the point of supplementing its health laws in relation to the milk trade within its limits. As it is chiefly through the work of Veterinarians that meat inspection has gradually increased and is now conducted in a scientific manner, so, to a large extent, we have to thank the Veterinarians for the fact that the control of the production and sale of milk is grow- INTRODUCTION tt ing steadily. Not only is important scientific work being carried on by them in several directions, which supplements the work of chemists and physicians, but the necessity for milk control is constantly being pointed out in meetings of veterinarians, in the International Veterinary Congresses and in the Congresses for Hygiene. A special journal is devoted to questions pertaining to milk hygiene, in conjunction with meat inspection, and separate courses in milk hygiene are given in many Veterinary Colleges. What follows is essentially the substance of lectures given by the author in the Veterinary and Agricultural College of Copenhagen. On some points in the prepara- tion of the book, the lecture notes have been expanded; for example, in citing the instances of disease resulting from milk possessing injurious properties. Since vet- erinarians are frequently consulted, by sanitary officers and by dairymen, in regard to the adulteration of milk, it is considered to be desirable to discuss rather thor- oughly the composition of milk, the variations that occur under different conditions, and the adulterations. It is also considered to be appropriate to briefly treat upon the use of milk as food for infants. Division oF SUBJECT The subject matter of this book is divided into the following parts: Milk and its composition. Injurious properties that milk may possess. Pasteurization and sterilization of milk. The use of milk for infants. In order to prevent the expansion of the book to unnecessary proportions, the hygiene of other dairy products as cheese and butter, and milk preparations as condensed milk, milk powder, etc., is not discussed. PAR FARE MILK AND ITS COMPOSITION. I. THE MILK GLANDS AND MILK SECRETION. THE tissue of the milk glands is shown by macro- scopic examination (Fig. 1) to be composed of small lobules separated by bands of connective tissue in which lie the larger blood vessels, the nerves and the excretory ducts and in which there is sometimes a considerable quantity of fat tissue. The gland tissue itself is com- posed of complexly branching glandular tubes which, during the period of lactation, are provided with numerous globular distensions, so that the type of the milk gland is intermediate between that of the alveolar and tubular types. The glandular pockets are provided with a membrana propria (Fig. 2) and are lined with epithelial cells. In young and farrow animals, the cells are thin and square or high and narrow, and resemble superficial epithelium. During the period of lactation these cells become large and tense. This epithelium is usually composed of but a single layer, although, in old cows, it is sometimes found to be composed of several layers. Toward the end of gestation, the secretory function of the udder begins with the production of colostrum or the so-called ‘‘beast milk.’’ This is a thick, reddish or yellowish fluid with a taste more salty than that of nor- mal milk, and under the microscope (Fig. 3) it 1s seen that it contains numerous free fat globules and a large number of round or mulberry shaped cells—the so-called colostrum bodies—that are filled with fat globules. 12 HIG. 1. One entire lobule is shown and agnification. Section of udder tissue of a cow. Low m Microphotograph. parts of five others, Section of the udder tissue of a cow. High magnification. Shows individual glandular pockets with their endothelial lining and the connective-tissue framework. Micro- photograph. FIG. 3. Colostrum.—The udder secretion of a cow that has recently calved. Stained lightly with osmic acid, causing the fat globules to become dark. Shows several colostrum bodies and fat globules. Microphotograph. Milk.- The fat globules are shown as light circles on a dark background. Micro- photograph. THE MILK GLANDS 13 Some cells are seen that have a distinct amæboid movement; these are leucocytes that have wandered through the epithelium into the glandular pockets and have taken up some globules of fat. Besides these, there are to be found some epithelial cells that have undergone more or less degeneration. The chemical examination of colostrum ows its principal constituents to be: water, proteids (especially globulin and albumin, and also casein and nuclein com- pounds), sugar, fats and cholesterin, and, besides these, lecithin, various salts and other substances in smaller quantities. Colostrum differs from norma] milk in its higher percentage of solids and especially in its higher content of globulin, albumin, nuclein compounds and lecithin. The chemical composition of colostrum differs slightly among animals of different species. In the course of a few days, the secretion of colostrum passes into milk secretion so that at the expiration of about one week, the secretion possesses the characteristic ap- pearance and composition of milk. The microscopic picture of milk is quite different from that described above. has collected some reports on this subject: of 210 typhoid patients not less than 45 (more than 20%) exereted bacilli with the urine, and Petruschky 7° found that the number of bacilli in the urine exceeded 170,000,000 per e.c. It will be evident to every one who is familiar with existing conditions and customs, especially in the country, that under these circumstances no extreme or unusual carelessness or 25 Deutches med. Wochenschr., 1890, p. 824. 26 Zentralbl. f. Bakteriologie, XXIII, 1898, No. 14. TYPHOID FEVER 111 accident is necessary to afford an indirect or direct means of carrying typhoid bacilli into the water or milk. The typhoid bacillus can multiply rapidly in milk and greatly increase in number in the course of a short time, it resists the commencement of acid formation but its growth is checked and, later, it is killed by great acidity; yet it is not certainly killed by the degree of scouring to which cream is subjected before churning. Bolley and Field have found that typhoid bacilli will live at least ten days in butter [and Bruck has shown that they were virulent after 27 days]. Hence, not only milk and cream but also buttermilk (epidemic in Ham- burg; Frankel and Koster), newly made butter and fresh cheese may be bearers of virulent typhoid bacilli. The typhoid bacillus is destroyed by pasteurization at 80° C. (176° F.) and heating for a few minutes at 70° to 75° C. (158° to 167° F.) will kill it. Care must be taken to heat the whole volume of milk to this tem- perature. (See ‘‘Pasteurization.’’) In pure culture, the typhoid bacillus does not change the appearance of milk and alters its reaction but little. It is very difficult to detect it in milk, as it is in drinking water, for its colonies in gelatin are very similar to those of the colon bacilli. To detect it, the milk must be sown in the usual method in gelatin plates and then as great a number as possible of suspicious colonies iso- lated. These are then implanted in fermentation bulbs in bouillon, some of which contain grape sugar and some sugar of milk. Those forms which cause an acid reac- tion in the milk sugar bouillon or those which ferment the grape sugar with the formation of gas or which do not change the reaction of the grape sugar bouillon are to be rejected. Only those cultures which give a strong acid reaction without producing gas in the grape sugar bouillon, are really suspicious and these must be sub- 112 MILK HYGIENE jected to a far more searching examination before they can be identified as typhoid bacilli.27 It is unnecessary to pursue this subject further, since the demonstration of the typhoid bacillus in market milk is not, as yet, a prac- ticable procedure in milk inspection. Jensen’s investigations have shown that there are several kinds of typhoid bacilli, distinguished from each other by a somewhat different fermentative power. It appears to be possible that by means of cultures from different patients one may determine what cases of typhoid belong to one and the same epidemice. b. Diphtheria. Diphtheria not infrequently appears to be spread by milk from milk shops or by that deliv- ered from cooperative dairies, but less frequently than typhoid fever. N. Flindt?° has given a detailed account of such an epidemic in the neighborhood of Holbeak in which the disease was being spread for a long time by milk from a cooperative dairy. He states: The epidemic occurred in June, 1889, and soon became violent. Fifty-one per- sons were sick at the end of the month, 16 cases occurred the following month and in August and September 6 more; 3 patients died. Everything tended to prove that milk delivered from the cooperative dairy had contained the contagion and this belief was strengthened by the fact that two persons from the dairy were affected. The exact mode of entrance of the infectious material into the milk was not traced. The case is remarkable in that the milk appears to have been contaminated for quite a long period. ~ 27 C. O. Jensen: On Vanskelighederne ved Typhusbacillens Diag- nose og om Racer af Typhusbacillen. (On the Difficulties of Diag- nosing Typhoid bacilli and on the Races of Typhoid bacilli) Hospitalstidende, 1901, p. 1193. ?S Ugeskrift for Laeger, 1890, p. 405. DIPHTHERIA | 113 A large epidemic of diphtheria?? which broke out ~ among the inhabitants of the villages along the coast north of Copenhagen, in 1881, offered conditions of prop- agation which strongly signified that milk was the means of spreading the contagion. In 1893 a small epidemic was noted in Lund, Sweden, when eight persons in different families were sick with diphtheria. These cases were traced to the use of milk from a farm near Lund which was infected with diph- theria.°° Quite an extended epidemic occurred in 1886 in F'rim- ley, England; in the course of a few days 70 cases of diphtheria occurred, distributed in more than 30 fam- ilies, 15 cases being fatal. All the sick had received milk from the same dairy. Not one case of diphtheria oc- curred during this time among those using milk from other dairies.*! [The medical literature of recent years contains many reports of milk-borne outbreaks of diphtheria, a number of which are gathered and summarized by Swithinbank and Newman.*? The following case, cited in their summary, is instructive. At Ashtabula, Ohio, 100 persons became affected with diphtheria in Decem- ber, 1894. The houses in which the disease occurred were widely separated but milk was taken at all of them from the same dairyman. On the farm of this dairyman, a workman had a very sore throat, probably diphthe- ritic. This person had assisted in the work of the dairy while suffering acutely from sore throat. Of 44 house- holds investigated, it was found that 32 had received 29 Ugeskrift for Laeger, 1881. 30 Hospitalstidende, 1893. 31 Ref. in Milchzeitung, 1886, p. 835. 32 Bacteriology of Milk. 8 114 MILK HYGIENE milk directly from this sick person; the other 12 had received milk from the same dairy but it had been deliv- ered by another man. In this outbreak there were 24 deaths. L.P.] A great many other reported cases might be quoted. As yet the diphtheria bacillus has rarely been iso- lated from market milk but, notwithstanding this, there ean be no doubt of its occurrence in milk and that it may causeepidemics like those mentioned above. Thebacillus must come directly or indirectly from the oral cavity of people who are or have been recently attacked by diph- theria. Just as the typhoid bacillus is maintained in many cases in the urine of convalescents, it is also very common for diphtheria bacilli to retain life for months, even for a whole year, in the oral cavity and on the mu- cous membrane of the nose in persons who have been af- fected, but who apparently have entirely recovered from the disease. It is on this account that it was possible in only a few epidemics of milk-borne diphtheria to dis- cover the original source of infection and it is difficult, not to say impossible, to wholly guard against the occa- sional infection of milk by diphtheria bacilli. Fortun- ately, these bacilli are frequently of low virulence. The opinion, that was held formerly by some, that diphtheria in man could come from a disease of milch cows, 1s entirely erroneous. It has been stated that diphtheria bacilli grow readily in raw milk and that they thrive less well in boiled milk (Schottelius) ; but from the experiments made by Meyer, it appears that diphtheria bacilli act as other bacilli; that is, that they are checked by the germicidal power of fresh raw milk and grow best in boiled milk. Diphtheria bacilli withstand acidity and may there- fore be present in the different dairy products, but the infectivity of the latter has not yet been determined. SCARLET FEVER 115 It is certainly very difficult to prove the presence of diphtheria bacilli in market milk because even if the milk has been the cause of the epidemic, they are pres- ent in only very small quantity and, usually, but for a limited time. If one wishes to experiment in this direc- tion the best method of proceeding is to make a culture on blood serum (Loffler”s) in a manner similar to that employed in the examination of the throat of a diph- theritic patient. If the culture tubes are brought to body heat for 24 hours, the conditions will be more favorable for the increase of the diphtheria bacilli than for the greater number of milk bacteria. One must then make a careful study of the colonies that have developed. c. Scarlet fever. Reports of scarlet fever epidemics that are presumably to be attributed to the spread of infection through the milk, come chiefly from England and America. The infectious material must come from affected persons and may enter the milk directly through their contact with it when it is being drawn, in the sales- places, etc., or it may reach the milk in an indirect way. Since the organism of this disease is unknown, it is diffi- cult to form a well founded opinion concerning these possibilities, and one cannot ascertain whether there is an increase of the infectious material in milk. About 18 years ago some scarlet fever epidemics aroused great attention in England because it was thought that, without doubt, they could be traced to an infection through milk and to a peculiar new eruptive disease upon the teats and udders of cows. From the evidence that is now available, one is justified in regard- ing it as established that the outbreaks of scarlet fever referred to had no relation to the disease of cows, which was in reality only a somewhat unusual form of cow pox. 116 MILK HYGIENE Malet ** cites an example of a milk epidemic wherein from August 21st to the 2d of September, 18 persons be- longing to 11 households were attacked with scarlet fever after drinking milk from a farm where there was a scarlet fever patient. [The cases next following are selected from among those cited by Swithinbank and Newman."4 Buffalo, New York (reported by Wende). ‘‘ Two outbreaks of scarlet fever occurring in 1899 in Buffalo were traced to an infected milk supply. The first out- break was that of 57 children, the second was less severe and numbered only 20 cases. The channel of infection was well traced out in the former, and it was found that on the implicated dairy premises there were two cases of desquamating scarlet fever. One was a child, aged 9, the other a young man aged 19 who did the milking and in other ways assisted in the dairy during his illness. The 57 cases were almost simultaneous in occurrence, and the severity of the attack appeared to depend upon the quantity of the implicated milk consumed.’’ London, 1901. The total number of cases was 293, all resulting from one polluted milk source. ‘‘ The out- break occurred on the delivery course of a certain con- tractor in London. He obtained milk from 38 farms. On one of these farms there were four cases of scarlet fever, the farmer, his wife, son and daughter. The cows were healthy.’’ The cases were widely scattered in Lon- don but were all directly traceable to milk from the im- plicated farm. ‘‘ The large number of adults attacked differentiated this outbreak from those of ordinary type. After the regular distribution had been stopped the con- 33 Reference in Recueil de méd. vétr., 1895. 34 Bacteriology of Milk. For original references to eases cited, see this work. ASIATIC CHOLERA LILY tractor then sent his milk to other consumers, who then contracted scarlet fever.” Beverly and Salem, Massachusetts, 1901. The num- ber of cases was 60, all resulting from one polluted source. ‘‘ The dairyman in this outbreak produced 5 eans of milk daily and obtained 14 other cans from 3 neighbors. On one of these 3 farms, 3 children had been ill; a girl of 16 had sore throat, another girl of 12 anda boy of 14 followed a few days later with a similar affec- tion, namely, swelling of the glands in the neck, and gen- eral malaise. One of them had a shght rash. After the recovery from acute condition they assisted in handling the milk. The outbreak was very sudden, and promptly declined from a time dating a few days after the milk supply from the farm was stopped. The fatality was high, as many as 11 deaths occurring. The distribution of the cases of scarlet fever was localized to the distri- bution of the milk in question.’’ L. P.] d. Asiatic cholera. From what we now know of the epidemiology of cholera it cannot be doubted that the spread of the germs of cholera is due chiefly to drinking water; nevertheless the possibility of its spread through milk and other foods cannot be left out of consideration. Examples of transmission through milk are certainly not numerous; one of the best established is the follow- ing reported by Simpson: On board a ship in the harbor of Calcutta, 10 persons fell victims to cholera after drinking milk sold by a native. Four patients died, 5 others were seriously ill, and one who drank but little of the milk was shghtly affected. It was learned that the milk had been diluted with water from a tank into | which the excrement of a cholera patient had been thrown a few days before. Among those pe did not drink the milk there was no illness. Simpson was able also to trace a small cholera epi- 118 MILK HYGIENE demic in a prison in Calcutta, with considerable cer- tainty, to the distribution of the cholera bacilli through the milk, and it was probable that the milk was already infected before delivery. Gaffky also reported an epi- demic caused by infection through milk. In quite fresh milk, cholera bacilli appear to succumb readily to its bactericidal action, but they increase rapidly in older milk but are again checked and, at last, killed, as the acidity increases. €. Tuberculosis. ‘Tubercle bacilli may enter milk not only from tuberculous cows and infected stables but also, without doubt, from tuberculous people. Of course there is no definite illustration—for obvious reasons—of transmission of tuberculosis in this way; but if one con- siders what a quantity of tubercle bacilli may be ex- ereted daily by a consumptive, the possibility of such transmission can scarcely be disputed, although the dan- ger is considerably lessened by the fact that the number of tubercle bacilli will not increase while the milk is kept. It is justifiable, therefore, to forbid tuberculous people working with market milk. f. Other diseases. It is stated in text books that there are instances of the transmission of syphilis, and there are reports in English journals of epidemics of sore throat and of erysipelas which are said to have come from infection through milk. In these latter cases, how- ever, it is doubtful if the infectious material came di- rectly from sick people, for the microbes concerned (chiefly streptococci) may gain access to milk from other sources. [As illustrations of such outbreaks of sore throat, the three following cases are taken from among those summarized by Swithinbank and Newman.*® 35 Bacteriology of Milk. SEPTIC SORE THROAT 19 In Anglesey, in 1897, 15 people who took milk of one dairy, became affected at about the same time with sore throat. Several persons in the affected families who consumed milk from the same source but in a boiled state escaped the sore throat, the chief evidence of which was tonsilitis. The bacteriological examination of the milk revealed the presence of Streptococcus pyogenes and Staphylococcus pyogenes, but no Bacterium diphtheria. Bacteriological examination of the patients’ throats yielded precisely similar results. ‘In May, 1902, an outbreak occurred in Lincoln, affecting a large number of persons. Dr. Brook had seventy-five cases in his own practice. The chief symp- toms were erythema of the face, and sore throat. In many cases a drab colored fur covered the tonsils. A roseolous, papular eruption, in some cases appearing to be urticarial, occurred in two-thirds of the cases. There was no marked fever, except in cases having complica- tions. The pulse rate was not increased, and no albu- minuria occurred. The onset was sudden, and in no ease out of the seventy-five investigated by Dr. Brook was infection communicated to others by contact. Nearly all of the patients were adults, and well advanced in years. The complication most commonly met with was swelling and tenderness of the cervical glands. With one doubtful exception, all the patients had had milk from the same dairy. Boiling the milk appeared to prevent persons from taking the complaint. The poison seemed to be present particularly in the cream. The differences between the disease and scarlet fever were very marked. £ A sudden outbreak of a severe form of ‘septic sore throat ’ occurred at Bedford at the end of June, 1902. On 27th June, the first case occurred; on 29th June, 4 cases occurred; 30th June, 15 cases occurred; Ist 120 MILK HYGIENE July, 13 cases; 2nd July, 3 cases; 3rd July, 2 cases; and 4th July to 8th July, 4 cases—making a total of 42 cases in 22 families. The symptoms included redness, swell- ing of the throat, fauces, palate, and uvula, with numer- ous spots, patches of exudation, and in some cases ulcers. The general symptoms consisted of severe head- aches, giddiness, backache, and pains in the limbs, very much like an attack of influenza. The temperature was about 102° to 103° F., but in a few cases was higher. In some cases there was gastric and intestinal disturbance. Great weakness was also present. In every case the milk supply was obtained from the same dairy. On Sunday, 30th June, many persons consumed cream with fruit, and these included nearly all the worst cases. In some families children who drank boiled milk escaped, whilst parents who consumed unboiled milk or cream were attacked. One man took cream in the form of ice- cream, and had a severe attack.”’ It must, however, be regarded as possible that these cases of sore throat were caused not by contamination of the milk from a human source but to the presence of organisms of suppuration eliminated by cows with dis- eased udders. L. P.] The transmission of measles, small-pox, pest, dysen- tery, or cerebro-spinal meningitis by milk has not been observed, but the possibility of such transmission can scarcely be doubted. VI. CONTAMINATION WITH OTHER BACTERIA Milk becomes infected with bacteria during the act of milking. These contaminating organisms come partly from the teat canal, partly from dirt, hairs, and dandruff on the skin of the cow, partly from the hands and cloth- ing of the milkers, partly from the dust of the stable. Still more are added when the milk is collected and CONTAMINATION WITH BACTERIA 121 stored in unsterilized vessels or when it is exposed to the air. It is evident that the number of bacteria found in freshly drawn milk varies greatly according to the conditions of cleanliness of the stable and the cows, and as to the cleanliness and carefulness observed during milking. Freshly drawn milk possesses a certain bactericidal action which, however, does not seem to affect all forms of bacteria. The number of living bacteria in milk may be lessened appreciably in the course of a few hours as > a result of this activity, but the action does not last and, under appropriate temperature conditions, bacteria soon begin to increase and their number, at times, be- comes enormous. The rapidity with which the bacteria increase after milking is dependent entirely upon the temperature at which the milk is kept. If the milk is cooled immediately after being drawn and is kept at a temperature not higher than 10° C. (50° F.) there is no material increase of bacteria during the first 24 to 36 hours; even at 14° to 15° C. (57.2° to 59° F.) the increase is relatively slight. But as the temperature rises, the number of bacteria increases rapidly and bacteria are very numerous in milk that has stood at 20° to 25° C. (68° to 77° F.) for 12 hours. In order to illustrate the importance of cleanliness in the stable and during milking, the following figures determined by Grotenfeld may be of use. In one c.c. of milk from cows particularly well cared for, he found 106 bacteria, while the freshly drawn milk of cows in a dirty stable contained 617,000 bacteria per c.c. Therefore, one cannot generalize as to the number of bacteria in freshly drawn milk, but milk from well-cared-for and carefully milked cows will, as a rule, contain hardly more than 1000 to 6000 bacteria per c.c. The following results show the potent effect of cold in checking the increase of bac- 122 MILK HYGIENE teria. The milk used contained about 9300 bacteria in one c.c. and was kept at 15°, 25°, and 35° C.: AT 159 C. (59° F.) | Av 25°C. (77° F.) | AT 35° C. (95° F.) Beginning of the test. 9,300 9,300 9,300 After 3 hours 10,000 18,000 30,000 After 6 hours 20,000 172,000 12,000,000 After 9 hours 46,000 1,000,000 35,280,000 After 24 hours 5,700,000 50,000,000 577,500,000 At the low temperature, it is seen that the increase is at first very slight. Moore found that the number of bacteria in milk kept at 21° C. (70° F.) did not increase during the first 6 to 9 hours but then increased rapidly ; he also found that in the course of from 36 to 48 hours, no appreciable increase in the number took place, if the temperature did not rise above 12° to 138° C. (53.6? to 55.4? F.) and that a still lower temperature, as 4° to 5° C. (39.29 to 41° F.), could prevent the increase of bacteria for a longer period. Meyer found, through experiments carried on in Jensen’s laboratory, that cooling the milk to 10° to 12° C. (50° to 53.6° F.) checks the growth of bacteria for a long time. It is evident, from all of this, that the quick and per- manent cooling of the milk to 10° to 12° C. (50° to 53.6° F.) is most important in preserving it. Of course the number of bacteria in market milk varies greatly according to its age and care and to the temperature of the air. Experience gained in most of the larger cities shows the bacterial content of market milk to be seldom below 50,000 to 100,000 per e.c. but it is often greater, varying between 1,000,000 to 30,000,000 ; indeed, not infrequently, even from 100,000,000 to 150,- 000,000 have been found. And such milk may not be noticeably tainted. SPONTANEOUS CHANGES IN MILK 123 If the question be asked: What is the sanitary signifi- cance of the existence of this mass of bacteria? we must consider the changes which bacteria in pure culture may cause in milk, and which were mentioned above, for it is evident that these same changes occur, although often very much less clearly marked, in market milk rich in bacteria. When milk is kept a long time it may become altered in one of several ways, of which the following are the most common: 1. The well known coagulation (curdling), following the formation of acid, is the most frequent. 2. Less often, a more or less disagreeable (putrid) odor and taste occur without much acid formation and without coagulation. 3. Still less frequently, the milk becomes slimy or <£ stringy,’’ either without souring, or accompanying the process of souring. Sour milk. Itis known that sour milk has no harmful effect on healthy people. But it is different with those suffering with catarrh of the stomach, and with small children. In these cases a degree of acidity not be- trayed by coagulation or appreciable sour taste appar- ently may cause vomiting and indigestion, possibly be- cause the numerous lactic acid bacteria rapidly increase with the warming of the milk in the stomach, and cause coagulation before the gastric juice can check their growth. Milk in which the lactic acid fermentation is so far advanced that it will not stand boiling, or the taste of which is slightly sour, must therefore be regarded as unfit for food for small children. The number of bac- teria in milk does not give us a safe criterion for judging it in this connection, but the degree of acidity furnishes a reliable guide. (See below.) Putrid milk. Even though the taste is not yet decid- edly foul, but is only bitter (formation of peptone) 124 … MILK HYGIENE nausea and vomiting may be caused, even in adults, and there are many instances of the poisoning of large num- bers of people by such milk. This alteration is most fre- quently observed in summer when the milk is not prop- erly cooled, and occurs especially in milk that has been warmed or even boiled for a short time [pasteurized], without sufficient cooling afterward. Slimy milk. According to information at hand, the slimy change seems to have no harmful effect, although it may make the milk most unappetizing. In Sweden, however, this change is produced and ‘‘ langmjolk ” is prepared for food, as sour milk (curds and whey) is prepared in other countries. Milk that is inclined to the slimy change should not, at any rate, be fed to small children. | Some bacteria that occur in milk but which, on ac- count of their properties or small number, do not have any noticeable effect upon the appearance or changes of the milk, may still be harmful. These are sporulat- ing forms, as the hay bacilli or members of the group of butyric acid bacilli, which may break up the casein with the formation of albumoses, peptones and amid- and am- monia compounds. Sometimes there are bacteria which generate special poisons that go into solution in the milk or that remain attached to the bacteria cells. Little is known of these forms, although the opinion has been frequently expressed that these very bacteria play an important part in the etiology of diarrhcea in children. Finally, there may be bacteria which are pathogenic for animals and for man and that are capable of causing inflammation. Such bacteria are very common in mar- ket milk. In the examination of 56 samples of market milk in Berlin, Beck found streptococci in 34, which caused fatal enteritis when fed to rabbits and guinea pigs. In injecting milk in the abdominal cavity of rab- SPONTANHOUS CHANGES IN MILK 125 bits (in order to test it for tubercle bacilli) Friis discov- ered that 15 of the 28 samples contained bacteria which caused either peritonitis or abscesses or pyemia. Guinea pigs were generally useless for his experiments because they all died of peritonitis. Similar results have been obtained by many others. The forms of bacteria considered in this connection are chiefly streptococci, staphylococci and members of the colon group, some of which are generally present, although, perhaps, in quite- small amounts, in market milk; besides these, there are still many other kinds, some of them occurring regularly, in small numbers, and some are only met with now and then. Where do these bacteria come from? Primarily from the dirt that gets into the milk when it is drawn,—it is a well-known fact that the excrement contains numerous, and sometimes pathogenic, bacteria. They may also come from cases of mastitis and metritis in the stable; moreover these forms of bacteria are widespread and probably they very often occur in cow stables, as is shown by the fre- quent occurrence of calf cholera. ‘‘ Calf cholera’’ isa common name for a group of fatal diseases of new-born calves among which the most usual forms are navel infection (most frequently caused by streptococci, colon bacilli and pseudo-colon bacilli) and diarrhcea or dysen- tery of calves (in most cases caused by colon bacilli). It does not follow that all milk containing strepto- cocci or the other bacteria referred to above is harmful or dangerous. But if these are present in large num- bers, they make the milk suspicious and there are many evidences that such milk has been most injurious. It is highly probable that a very great part of the gastro- enteritis, so harmful to small children, is traceable di- rectly to these bacteria. The fact that the mortality among small children in general has decreased to a great 126 MILK HYGIENE extent where the milk is bacteriologically clean or has been sterilized according to Soxhlet’s method, is one of the arguments in favor of this view. Heubner is of the opinion that infant mortality has been diminished in this way to the extent of 27 per cent. In order to prevent too great contamination by such bacteria—it is difficult to wholly exclude them—there is no other way than strictly to guard the health of the herds, as well as the cleanliness of the stable [of the utensils and receptacles] and of the attendants. The eventual danger may be partly removed by pasteurizing or boiling the milk. VII. ADMIXTURE OF DIRT As has already been stated, it is customary for milk to become more or less contaminated with particles of dirt and their adherent bacteria during milking. The dirt consists, principally, of bits of manure and, besides this, hairs, dandruff, particles of food, earth and dust. Usually, after milking each cow, the milk is passed through a strainer which retains particles of dirt; but if the strainer is not cleaned very frequently, the particles of dung and dirt are softened in the milk, bacteria are washed through and substances that carry abnormal odors and tastes are set free in the milk. By straining, then, one accomplishes only the removal of the larger and more solid particles of dirt that are quite harmless in themselves, such as hairs, cellulose, sand, ete. When unclean milk is permitted to stand, a distinct sediment is formed and its presence signifies lack of cleanliness in respect to production. The importance of dirt contamination is due chiefly to the addition of bacteria with the dirt and to the solu- tion of fecal matter; the visible dirt is important only as it makes the milk unappetizing. It follows that a ADMIXTURE OF DIRT 127 greater or less dirt content has a great influence upon the healthfulness and keeping quality of the milk; this is emphasized by a study of the bacterial content of cow dung. Wuthrich and Freudenreich found this to vary according to the kind of feed; the bacteria in the dung of cows fed with hay appeared to be most numerous; 1 gramme of such excrement contained 375,000,000 bacteria. Of course the quantity of dirt in market milk differs very greatly. An investigation in Hamburg showed that the quantity varied from 0.0 to 183.5 milligrams per liter; on the average, there were 13.5 milligrams of dry dirt in a liter of milk. In other experiments, Schmelk in Christiania found an average of 11 milligrams in a liter, von Hellens (Helsingfors) found only 1.79; in Berlin, | Renk showed the average to be 10.3; in Halle, 14.92; in Leipsig, 3.8 and in Munich, 9.0. The maximum quan- tity in each case was much greater than the averages mentioned, although it never reached the maximum for Hamburg milk. In Dresden the standard regarding market milk states that it must not contain more than 8 milligrams of dirt per liter. In Denmark there are no general regulations con- cerning the dirt content of milk; *° there, too, it varies considerably, it is great in the milk from distillery fed herds and less in milk delivered by the large companies. 36 In 1895, the Copenhagen health commission had 39 samples of milk tested for dirt, which was found in small quantity, varying be- tween 1 and 13 milligrams per liter. BAIA ay: PASTEURIZATION AND STERILIZATION In the household, milk is boiled to make it keep longer and this process serves also to kill any pathogenic bacteria that may be present. Little by little, the public has learned that milk often contains disease producing germs and that small children are especially exposed to their harmful effects, so the custom has become more or less general of sterilizing milk intended for infants. Quite naturally, the idea developed to sterilize market milk, by heating before it was offered for sale. By this means, the following desired results have been ob- tained: the milk keeps for a longer time, it loses its capacity for infection, and the annoying process of ster- lization in the home is avoided. In most large cities there are one or more companies engaged in the sale of sterilized or pasteurized milk. The difference between pasteurization and steriliza- tion consists, essentially, in the greater degree of heat applied during the latter process. I. PASTEURIZATION By pasteurizing a fluid is generally understood heat- ing it to a temperature below boiling which is sufficient to increase its keeping qualities. It is sometimes used to indicate heating to 50° to 60° C. (122° to 140° F.) and sometimes the use of a higher temperature. In ref- erence to milk and dairy products, the term ‘‘pasteur- ization’? is used in a more definite sense. In butter- 128 PASTEURIZATION 129 making pasteurization is understood to mean a brief heating of the cream and whole milk to 80° to 85° C. (176° to 185° F.), the purpose of which is to kill most of the existing bacteria, in order to prevent those fer- mentations of the cream which might cause the butter to be of inferior quality. At the same time, pathogenic micro-organisms (particularly tubercle bacilli) are made harmless. In some places, ‘‘pasteurized butter’’ is made solely for the latter purpose. In Denmark, on account of the danger of spreading tuberculosis among animals, it is provided by law that skim milk and buttermilk delivered from creameries to be used as food for animals must have been heated to 85° C. (185° F.). In this connection, however, the law does not mention pasteurization but, in practice, pasteurized separator milk (or buttermilk) is understood to be milk that has been subjected approximately to the above men- tioned temperature and that does not react to Storch’s or to the guaiac tests. Since market milk is pasteurized especially in order to render harmless any disease producing germs that may possibly be present, and since the majority of con- sumers are, doubtless, of the opinion that pasteurized milk may be used with perfect safety without further heating, it should be strictly required that market milk sold as ‘‘ pasteurized ’’ shall have been subjected to a sufficient degree of heat to kill with certainty all of the pathogenic micro-organisms that are present. The pathogenic bacteria that are of importance in this connection are the germs of tuberculosis, typhoid fever, diphtheria, cholera and pest and pyogenic cocci and the virus of foot-and-mouth disease. These have been shown by recent investigations to be killed by mo- mentary heating to 70° to 80° C. (158° to 176° F.) and they die at a temperature of 65° C. (150° F.), if this 9 130 MILK HYGIENE degree of heat is maintained long enough. This is also true of many bacteria occurring in milk which may be injurious, yet which cause no specific disease. There- fore, milk may be pasteurized either by a brief heating at a higher temperature or a longer heating at a lower temperature. But the spores of bacteria and the thermo- philie forms that are specially capable of resisting heat, are not destroyed by these methods, so pasteurization does not have the same effect as sterilization. Milk may be pasteurized in different ways. The following three methods are those most commonly used: 1. The milk is heated during one-quarter to one hour at from 80° to 85° (176° to 185° F.) while it is flowing through an appropriate pasteurizing apparatus; then it is cooled immediately. 2. The milk is heated from one quarter to one hour at about 65° C. (150° FF.) in-a tank or vate) vetoes flows directly from this vessel into the one in which it is to be sold, or it is first passed through a cooler. 3. The milk is poured into well cleansed or sterilized bottles or metal vessels, is then heated for a consid- erable time at 65° to 80° C. (190° to 176° F.), then the bottles or vessels are sealed and quickly cooled. For sanitary reasons the last of these methods is unquestionably to be preferred, but it has not been adopted extensively on account of its cost. Heating many small vessels requires a great amount of heat and causes great loss in bottles, if such are used. The initial cost, also, and the amount of labor required are con- siderable. If one of the first two methods is employed, the pas- teurized milk must be drawn into vessels (bottles or metal cans) which have previously been properly sterilized. Pasteurizing milk and then placing it in unsterilized PASTEURIZATION 131 vessels has no effect. Indeed, if bottles are used, this is to be forbidden as injurious to health. Very often the milk is drunk directly from the bottle, which may be infected by this means and, in spite of washing, fresh milk may be infected as it is poured out. In this connec- tion, what is to be understood by sterilization? The aim is, so far as possible, to kill all microbes. The task is not difficult with metal vessels because, after thorough mechanical cleansing, these can be subjected to very hot steam or can be scalded. With glass bottles, the task is more difficult, because strong heat causes much break- age, and if the price of the milk is not such as to cover this loss, another method must be used. Thorough me- chanical cleansing, scouring the outside as well as the inside, followed by long soaking, in a strong, warm solu- tion of washing soda at 70° C. (158° F.) and rinsing in pure, lukewarm water, is believed to kill with reasonable certainty all pathogenic forms and also the majority of other milk bacteria. ' A very large number of machines for the quick pas- teurization of milk have been built, chiefly for use in ecreameries. The principle of these machines is dif- ferent. One of the first pasteurizers was that made by Fjord; it consists, as the diagrams (Figs. 5 and 6, pp. 132 and 133) show, of a tinned copper tank provided with an insulated steam jacket. The tank contains rotating arms by which the milk is thrown against the heated walls. The milk is admitted at the bottom through pipe H and leaves the apparatus at the top. By regulating the quantity of milk admitted, the rapidity of the revolving arms and the amount of steam, the milk may be heated as desired. Many other pasteur- izing machines are built according to the same principle. In other pasteurizers, the milk is heated while it flows in thin layers over heated metal surfaces, or while 132 MILK HYGIENE forced between two surfaces lying close to each other, or while it is being passed through a system of heated pipes. In some pasteurizers hot water serves as the source of heat for the metal surfaces or pipes, while steam is used in others. ‘i 7 ml iia) - 1) I il ih fl 4 || Oi Hel TH mi ll HU a) aH Wl | | Mine ii | == = NÆR i ON Fjord's pasteurizing apparatus. Since one can hardly be sure that every particle of the whole volume of milk is heated to a given tempera- ture by this method of pasteurization, it should be re- quired that the temperature of the milk, when it leaves the apparatus, shall be at least 80° C. (176° FJ) ie ths PASTEURIZATION 133 is not done, it cannot be regarded as certain that the milk has been freed from pathogenic micro-organisms. Moreover, a pasteurizer which is to prepare milk for use as food must fulfil the following requirements: 1. The entire quantity of milk, mecluding the froth formed during heating, must be heated equally to the desired temperature. FIG. 6. ——!:?»= a fs 20 soem ar evn TTT my mT apll ats ua mj [mm FN S | em ell! = i 3S & ae Stam ÅL os Fjord’s pasteurizing apparatus. 2. The apparatus must work reliably, in order that there shall be no danger that at times the milk is not sufficiently heated. 3. The machine must be easy to clean. 134 MILK HYGIENE All pasteurizing apparatus must be under the con- stant inspection of a reliable man, or must be provided with a self regulator. A regulator which shuts off the milk automatically if the temperature of the contents of the machine falls below the given standard, was de- vised by Henriques and Stribolt. Up to the present time, this principle is not widely applied, but doubtless it deserves to be introduced into the better plants which prepare and sell pasteurized milk. Fig. 6 shows a Fjord pasteurizer with a self regulator; the latter con- sists of a metal thermometer (see Fig. 7) whose free arm (mn) is attached to a horizontal rod (r y) which may move a valve placed in the entrance pipe to the pasteur- 1zer. FIG. 7. = ZILA LALERL ERA Chee INATE aR NANA SAADNNNNN NN ERNN OUNANNANNNNCU CLL LLL LLL ag Automatic temperature-regulator, as devised by Henriques and Stribolt. The construction is shown by Fig. 7. As the temperature of the milk in the machine rises, the two arms of the thermometer approach each other and the valve m d c is thus pressed back by the horizontal rod r u, which presses against m so that the opening at b k is free PASTEURIZATION 135 and the milk can pass from o to p. If the temperature falls, the pressure of the horizontal rod is withdrawn from the valve, which is then caused to close the opening by means of a spring, s, so that the milk cannot flow to the pasteurizer; thereupon the discharge of milk immediately ceases, and not until the milk has been sufficiently heated will the valve open again, so that fresh milk may enter and expel that already heated from the apparatus. Fie. 8. SSS < Schmidt’s milk-cooler; a, entrance for cold water ; b, exit for cold water. From the pasteurizer, the milk must be passed over or through a cooler in order to lower the temperature as much as possible, for otherwise it would soon spoil. From the cooler, the milk should be drawn directly into the container from which it is to be sold. Fig. 8 represents a cooler which consists of a spirally fluted 136 MILK HYGIENE metal tank, through which cold water or, better, ice water is passed and over the surface of which milk slowly flows. For pasteurizing milk in bottles or in cans an appa- ratus of different construction is used. Some consist simply of a water bath; a large shallow metal tank is partly filled with water and the bottles are so placed in this that they are submerged as close as possible to the neck, then the tank is closed by a cover and the water is heated with steam. Other pasteurizers are built according to the follow- ing principle: there is a perforated drawer in a large metal tank upon which the filled bottles are placed close together (Fig. 9); after the tank has been tightly closed by means of a cover or door, steam is admitted until the desired temperature is reached. Of course these ma- chines are also adapted to sterilizing at a higher tem- perature (100° to. 110° ©. 212° to 2307 semen from one-half to one hour’s heating, the bottles are allowed to cool a little before the tank is opened, then they are immediately sealed. In some machines, all of the bottles are sealed before the tank is opened, by means of a specially arranged mechanism. The further cooling of the bottles is attended with certain difficulties, as they crack easily. This may be accomplished by passing the bottles through several tanks of water of progressively lower temperature, or by slowly lowering the temperature of the water surrounding them. While the fact of the previous heating of milk to not less than 80° C. (176° F.) may be established with cer- tainty by the Storch or guaiac tests, it is not possible to determine whether or not the milk has been subjected to a less degree of heat; moreover, since a brief heating at 80° C. (176° F.) is cheaper and far more convenient than a longer heating at, for instance, 65° C. (150° F.), there PASTEURIZATION 137 is much to be said in favor of the establishment of a fixed rule that all milk designated as pasteurized shall be heated to at least 80° C. (176? F.), that is, a temperature that can be determined by the Storch or guaiac test. But there is another side to the question. In the medical Flaack’s apparatus for sterilizing bottled milk. world the sentiment against pasteurizing at high tem- peratures has been growing during recent years, for it has been claimed that this causes a change in the pro- teids which makes them less digestible. In many places, therefore, the longer heating at a lower temperature, has 138 MILK HYGIENE been adopted. All milk from Bolles’ great .establish- ment in Berlin, is handled in this way. Under these conditions, such a requirement as that mentioned above could scarcely be maintained but, with- out doubt, regulations with regard to the sale of pas- teurized milk should be laid down, and the following appear to be appropriate: 1. Milk sold as ‘** pasteurized ” without a more ea- plicit statement must have been heated to at least 80° C. (7%6 EF). 2. Milk that has been pasteurized by heating at a lower temperature, shall be sold as ‘‘ pasteurized ” only if at is marked with a label giving the degree of heat ap- plied, and not until after the health authorities are con- vinced that the establishment in question is prepared to pasteurize in an approved and effective way. The advantages derived from pasteurizing market milk, from a hygienic standpoint, are as follows: 1. The specific pathogenic bacteria are destroyed. 2. Most of the other bacteria are likewise killed and, therefore, the milk keeps better. 3. Pasteurization necessitates a better method of de- livering milk than that commonly employed in many places. By means of pasteurization, as has been said, the pathogenic bacteria and the larger part of the other bacteria are killed. Since the bacterial content of ordi- nary milk is most variable, and since the forms are by no means always alike, the number of bacteria that live through pasteurization—even after heating to the same temperature—is not even approximately the same. In other words, the average bacterial content of milk that has been pasteurized a short time cannot be stated. There are usually only very few bacteria per c.c. in pas- teurized milk that was freshly drawn and handled in a PASTEURIZATION 139 cleanly way; while under other conditions hundreds, even thousands of bacteria are to be found in every c.c. of pasteurized milk. Lactic acid forming bacteria in milk are killed by pasteurizing, while certain harmless bacteria, many bacteria of putrefaction and spore form- ing bacilli survive; for this reason pasteur wed milk sel- dom sours but Hen putrefies. No absolute conclusions can be drawn concerning the effectiveness of pasteurization from the bacterial con- tent of pasteurized milk sold in the retail market, for one does not know the nature of the milk before pas- teurization, the length of time the miik has been kept since pasteurization or the temperature at which it has been kept, and these factors are largely LE pon ble for an abundance of bacteria. The objections to pasteurization are: 1. Even by the use of a self-regulating pasteurizer, it is difficult to provide absolute guarantee that all milk has been heated to the required temperature. 2. Pasteurization incurs expense, therefore the milk costs more. 3. To a certain degree, pasteurization may conceal a tainted condition which exists before heating. Quite an abundance of bacteria of putrefaction and other bacteria | may be present, or the lactic acid fermentation may have begun to. take place; these bacteria are killed by pas- teurization, consequently the fermentations and changes that were under way are interrupted. Under such cir- cumstances, one cannot tell by the appearance or taste of milk that it 1s damaged and that it contains the products of decomposition of the albumen, or, possibly, even toxic substances. On the whole, there is no way, at the present time, of determining whether or not pas- teurized milk was damaged before it was heated, while, with respect to raw milk, the keeping quality and bac- 140 MILK HYGIENE terial content furnish sufficient evidence regarding its true condition. 4. The bacteria surviving pasteurization are, for the most part, the quick growing bacteria of putrefaction which are inhibited in raw milk by the lactic acid bac- teria, but in pasteurized milk they multiply very fast and undoubtedly they are capable of generating poisonous substances. It has been suggested, therefore, that a pure culture of lactic acid bacteria be added to milk after pasteurization in order to check the bacteria of putrefaction. 5. In purchasing pasteurized milk, one cannot tell if NUMBER OF SAMPLES NUMBER OF BACTERIA IN 1 C.C. ana Ordinary whole milk |Pasteuriz’d whole milk 0-10 = 2 10-50 - ~ 100-500 - 2 500-1,000 - 4 1,000-5,000 - i 5,000—10,000 - 10 10,000-20,000 — 6 20,000-50,000 - 12 50,000—100,000 — 7 100,000—1,000,000 7 66 1,000,000—5,000,000 1 20 5,000,000—10,000,000 ~ 9 Above 10,000,000 1 3 Total number of samples...) 9 142 it be fresh or old and cannot determine, from its appear- ance, if putrefaction has begun or if only a few bacteria are present. That this objection to the sale of pasteur- ized milk is valid, is shown by the Copenhagen health PASTEURIZATION 141 Commission, in its report, especially that for 1899, on the number of bacteria in pasteurized milk, as compared with the number in unpasteurized milk. It is evident that these figures do not seem to favor pasteurized milk, and the situation is still less favorable if one considers that the bacteria in raw whole milk are chiefly lactic acid bacteria, while in pasteurized milk the greater part consist of bacteria of putrefaction. The figures above cited for the year 1899 are especially high, but the summary given below is made from examina- tions of pasteurized milk extending through a period of several years: *7 NUMBER OF COLONIES IN | 1 cc 1896 1897 1898 1899 1900 Below 100,000 22 26 il 44 40 100,000-1,000,000 1 5 19 66 39 Above 1,000,000 : 1 17 32 26 Total number of samples! 23 32 48 142 105 This increase in the number of strongly infected sam- ples occurs coincidently with the equipment of many milk establishments for the production of ‘‘ pasteur- ized ”” milk and apparently without such careful direc- tion as to make it certain that the whole quantity of milk was really heated to the required temperature; that this was the case is indicated by the result of investiga- tions of the health commission in the year 1899, which show that of 36 samples of pasteurized cream 2, and of 389 samples of pasteurized milk 23 could not stand the 7 Stadslaegens Aarsberetninger (Annual Report of the City Phy- sician). Copenhagen. 142 MILK HYGIENE Storch test, which showed that they had not been heated vorso CM RD When we compare the advantages and disadvantages it will be found that there is serious doubt as to whether it is advisable to endeavor to obtain general pasteuriza- tion of market milk, as has been suggested by many. A well organized and well conducted large milk business may be in position to carry out pasteurization with safety and to obtain all the various advantages that result from this process but, undoubtedly, it would be necessary for the great majority of establishments to be kept under comprehensive, strict and expensive con- trol by the health authorities which, even then, could scarcely be effective. [It has been shown by Rosenau that heating milk to 60° C. for 20 minutes is sufficient to render harmless the specific micro-organisms of tuberculosis, typhoid fever, diphtheria, dysentery and cholera. His conclu- sion is based on his own careful laboratory experiments. Whether any system of commercial pasteurization may be depended on to give safe results at this low tempera- ture has not been shown. In the absence of experiments to determine this question and until the management of commercial pasteurization can be confined to technically trained and competent men and until there can be such official supervision of the equipment, method and prac- tice of milk pasteurizing plants as to insure thorough work and reliable results, it would appear to be unsafe to accept, for the purposes of pubhe control, such a small margin of safety as is indicated by these figures. In any case, the labeling of all so called pasteurized milk should be insisted upon and the label should show the degree of heat to which the milk has been subjected, the period of heating, the day and hour of the treatment and the place. L. P.] STERILIZATION _ 143 II. STERILIZATION By sterilization of milk is understood a long contin- ued boiling, or heating to a temperature above the boil- me pomt asel05° to 110° C: (220° to,230°: F.). "The superiority that is claimed for sterilization over pasteur- ization is that all of the bacteria are killed and the milk, FIG. 10. Kleemann's high-pressure pasteurizer and regenerative heater. a, water of condensation b, to the cooler. consequently, will keep for an unlimited time. But nearly all the examinations of ‘‘sterilized milk’’ bought in the market, that have been made, up to the present time, have shown that the milk is not sterile but con- tains the spores of bacteria. On the whole, sterilization offers no special advantage over pasteurization, on ac- count of the unpleasant taste of sterilized milk, due to changes in the albumen and lactose, and on account of the greater expense connected with it. Sterilization has 144 MILK HYGIENE the advantage only when it is a question of keeping the milk a long time or transporting it a long distance, and in this case the principle followed is essentially the He iW Section, to show construction of apparatus shown in Fig. 10. a, entrance for milk; 5, exit for milk; c, steam-chamber; d,steam-opening ; e, safety-valve. same as that followed in the preparation of preserves in hermetically sealed cans. Considerable advance has been made in recent years in regard to the preparation STERILIZATION 145 of such preserved, canned, milk, in that the boiled and burnt taste has been prevented by pumping the air out of the milk before heating it and by the exclusion of oxygen during heating, so that a high temperature is possible and a safer sterilization is accomplished with- out seriously affecting the taste. Another difficulty FIG. 12. Mor's regenerative milk-heater. which it has been necessary to contend with, the separa- tion of cream, and of butter formation during storage, seems by degrees to have been overcome. For the purpose of sterilizing milk, instead of the usual apparatus built according to the Fjord system, tightly closed machines are used, so that the tempera- 10 146 | MILK HYGIENE ture of the milk can be raised above the boiling point, and through these the milk is forced by means of a small pump. There is a large number of such machines. In Germany they are commonly used for simple pasteuriza- tion. Of the machines most used in recent years, the so-called ‘‘regenerative heater’’ is to be commended be- cause it saves much steam. It is built according to the principle that the hot milk flows past the entering cold milk (only a thin metal plate separating them) so that both streams of milk have opposite directions; by this means, there is the advantage that the hot milk, even before it leaves the sterilizer, 1s somewhat cooled with- out expense, while the cold milk gains quite a little heat before it is heated by the action of the steam. In this way steam, as well as ice, is saved. Machines built in accordance with this principle differ much in appear- ance. Some, for example the apparatus shown in Fig. 10, which is one of the newest, consists really of two parts, the sterilizer proper (the ‘‘high pressure pasteur- izer’’) and an apparatus quite similar (‘‘the regenera- tive heater’’) in which the stream of warm milk works upon the incoming cold milk. Both parts have the same construction, which is easily seen from Figs. 10 and 11. Other machines of this kind (for example, Mor’s re- generative milk heater, Fig. 12), are simpler in that both processes take place in the same machine. For sterilizing milk measured into bottles, machines which are described and figured on pages 136 and 137 (Fig. 9) are used. ARSEN THE USE OF MILK FOR INFANTS THE advantages of milk as a general food for man are so well known that no further discussion is neces- sary; but the special use of milk for infants, as a sub- stitute for mother’s milk, offers certain points of inter- est which merit further consideration. It is logical first to review the behavior of milk and the changes that occur in it during digestion. Under the influence of the gastric juice, the proteids undergo a process of splitting up in the stomach. The albumin and globulin are first changed into syn- tonin and then separated into albumoses and, probably, peptone. Casein behaves somewhat differently. It is transformed by the hydrochloric acid of the gastric juice into an acid calcium salt and then, under the influence of rennin, it undergoes a change, during which whey albu- min is formed, into calcic paracasein, which separates as acurd. The calcic paracasein is then split by pepsin into albumin and paranuclein (pseudoneuclein) which is pre- eipitated but-which is afterwards dissolved by the pro- longed action of the gastric juice, being broken up into an albumin-like material and phosphoric acid. The albu- mins that are formed by splitting of the casein are later changed into albumoses (caseoses) and peptone. Ac- cording to recent investigations it appears that these substances may undergo still other changes before they are absorbed. Through the action of rennin, an albu- min-like substance (plastein) is formed and through the 147 148 MILK HYGIENE action of an intestinal ferment (erepsin) the splitting of peptone is continued into di- and mon-amido acids. Little is known as to the resorption and use of these substances. There is a difference of opinion regarding the fate of the milk sugar; some think it is absorbed from the intestines unchanged, but others are convinced that it is first inverted into dextrose and galactose. The absorp- tion takes place more slowly than is the case with glu- cose, maltose and cane sugar. The absorption of milk-fat takes place as that of other fats, with a preceding saponification. It is well known that cow's milk is being used more and more as food for infants and for small children. As a substitute for mother’s milk, there are some objections to it, however, and if used for nursing babes, it must receive especial treatment. This is on account of the fact that it differs materially in chemical composition from human milk and that it constantly contains micro- organisms, and, sometimes, even pathogenic forms. The differences in composition of human milk and cow’s milk are shown by the averages given below: Water. Casein. Albumin. Fats. Lactose. Salts. Woman’s milk... 87.92 0.58 0.52 3.43 Ted 0.2 Cow’s milk 87.75 3.00 0.50 3.40 4.60 075 [Human milk appears to vary more in composition than cow’s milk. This may be due in part to the greater difficulty in obtaining a fair sample than is the case with cow's milk. It is known, for example, that the compo- sition of the fore milk and the strippings differ consid- erably, and if small samples of milk are drawn from a ecow’s udder at irregular times during the day, before and after regular milkings, the samples will be of very different composition. Besides this, the less regular life MILK FOR INFANTS 149 of the woman and the nervous influences to which she is subject may tend to make her milk more variable than that of the even-going cow. The figures, however, that are given in the above table show less proteids than were found by most of the leading authorities. The average composition of woman's milk, as determined by a large number of analyses, is given by Richmond as follows: Water. Proteids. Fat. Lactose. Ash. RVers WK. HE ee Sa seg 88.2 1.5 3:3 8.8 02. Johanssen, however, found but 1.1 per cent. of pro- teids, as an average for 25 samples, thus agreeing, in this respect, with the figures given on page 148 which are from Gottlieb. L. P.] The first thing to be considered is that the quantity of total proteids in cow’s milk is more than three times [or more than twice] the quantity in human milk, so that a child nourished with cow’s milk has apparently a considerably greater nitrogen assimilation than a child nourished in the natural way. It is not known with cer- tainty what significance this has for the health of the child, but it is not safe, off hand, to conclude that the highly nitrogenous diet is advantageous. Moreover, the chief part of the protein of cow’s milk consists of a casein, which, in contrast with the casein of human milk (the proteids of human milk do not give a curd with ren- net), 1s precipitated in the stomach as large curds and in a form that apparently makes it less digestible. Great importance has been attributed by some to the fact that human milk often contains more fat than cow’s milk and, it is affirmed, on this account the nutritive value of human milk is greater than cow’s milk. But since we know that the fat content of human milk is sub- ject to great variation (for individual peculiarities see page 24) no particular importance can be attributed, in 150 MILK HYGIENE general, to this difference. On the other hand, the fact must be considered that the fats in the two kinds of milk differ somewhat chemically, and that cow’s milk contains much more volatile fat (butyric acid) than human milk. These other important conditions should be mentioned: the decided different proportions of lactose which, doubtless, is of value in the nourishment of the child, and the small quantity of lecithin in cow’s milk, to which great importance is now ascribed in metabolism. It is doubtful if the greater quantity of citric acid and of morganic salts in cow’s milk has an unfavorable influ- ence:on the nourishment of the child. Many attempts have been made to correct the defects of cow’s milk and to make it a more appropriate food for infants. 7 By diluting cow’s milk with water, the percentage of salt is proportionately decreased so that the casein coagulates in the stomach in flakes, just as the casein of human milk, and at the same time there is a proportion- ate diminution in the percentage of the total proteids. But there is also a decrease in the quantity of albumin as well as of the other ingredients of great nutri- tive importance—lecithin, lactose and fat—which is decidedly disadvantageous. In order to remedy this, the milk is often diluted with barley- or oat-water or the proper quantity of milk- or grape-sugar is added. Others have used cream diluted with water; by this means an appropriate quantity of protein and fat can be had, and since fat may be substituted for lactose, the deficiency of the latter makes little difference. To make cow’s milk approach human milk more closely, and to make it more easy of digestion many methods of preparation, some of them rather complex, have been proposed, and some have been used commer- cially. The following are examples of such preparations: MILK FOR INFANTS 151 *‘Gartner’s fat milk ” is prepared in the following way: cow’s milk is diluted with water to such an extent that the casein content corresponds to human milk, then it is so centrifuged that the milk flowing from the cream tube has a fat content which agrees with that of human milk. . The milk is put into bottles and sterilized. The composition of the ‘‘ fat milk’’ may, of course, be changed at will; the average composition of such a prep- aration made in Germany is: fat, 3.7 per cent.; proteids, 1.5 per cent.; lactose, 2.2 per cent. ‘* Voltmer’s mother’s milk ” is the name given to a milk preparation that is sometimes marketed in the form of ‘‘ milk,’’ and sometimes is condensed and sold in eans. The preparation is somewhat complicated; fresh centrifuged cow’s milk is heated to 100° C. (212° F.) and distilled water, cream and sugar are added to it in such quantity that the content of proteids, fat and sugar correspond to human milk; the mixture is now exposed to the action of pancreas ferment which process changes the casein into albumoses. : The preparation is sterilized sue. to. 105°C. (215.6° to 221° F:)>or evaporated and poured into cans which are sterilized after solder- ing. According to several analyses, the composition of the commercial product is, approximately: fat, 2.3 per cent.; proteids, 1.8 per cent. (about three-fourths of this is albumose); sugar, 6.2 per cent.; and salt, 0.4 per cent. » ‘“Backhaus’s infants’ milk’’ is similarly prepared. The cream is separated by the centrifuge; the skimmed milk is heated to 40° C. (104° F.) and rennet and trypsin are added. In the course of half an hour the precipi- tated cheesy mass is filtered out; by this means a part of the casein can be taken out, while the rest is trans- formed into easily digestible albumoses. The action of the ferments is stopped by heating, and cream and sugar 152 MILK HYGIENE of milk are now added. The preparation, which is mar- keted in a sterilized condition, has been widely recog- nized. Its composition may easily be varied. For small children a preparation of about the following composi- tion is made: fat, 3.1 ver cent.; casein, 0.6 per cent.; albumin, 1.0 per cent.; lactose, 6 per cent.; ash, 0.4 per cent. Gottlieb has proposed that sweet whey, cream, sugar of milk and lime water may be mixed together in such proportions that the composition of the mixture will closely resemble human milk. [‘‘ Modified milk ” as developed and prepared by the Walker-Gordon Laboratory Company, with the scientific aid of Dr. T, M. Roach, has been in use in the larger cities of America and in London for a number of years; it was first prepared and sold in Boston in 1891. Such milk is dispensed upon physicians” preserip- tions, and is prepared by mixing whole milk, cream, whey, skim milk, lactose and water or other substances, if ordered, as lime water, starch, barley-water. etc., in the proportions required to give accurately the desired per- centages of protein, fat, sugar, etc. It is dispensed in round bottles (‘‘ tubes ””) each of which contains suffi- cient milk for a single feeding. The bottles are plugged with cotton-wool. The milk is produced on farms be- longing to or under the control of the company and most exacting precautions are taken to protect it from con- tamination. The milk is served raw, pasteurized or sterilized, as ordered. Usually it is pasteurized and if the proteids consist chiefly of those present in whey, the tempera- ture reached during pasteurization is not permitted to exceed 155° F. By means of modified milk the nutritive requirements of the individual child can be supplied. EPA MILK FOR INFANTS 153 Many special preparations similar to the above have been used abroad and have received the approval of pediatrists. In Denmark, however, they are used but little and they will never have a very broad field on ac- count of their high price. In France, asses” milk is quite commonly used as a substitute for human milk and in Dresden an establish- ment has been started for the production of asses” milk, which is desired partly because of its great similarity to human milk and partly because of its favorable effect in indigestion of children. On account of the small milk yield of the donkey, this milk is much too expensive to be used generally. For the same reason, mare's milk has been used in some places, but only to a limited extent. Goat’s milk has been suggested as food for infants, and large herds of goats have been maintained in some places for this purpose—principally on account of fear of tuberculous infection from cow’s milk. The prevalent opinion of the infrequency of tuberculosis in goats is untenable, since they are very easily infected and may suffer, just as cows do, with udder tuberculosis. There- fore, there is no reason to prefer goat’s milk to cow’s milk. In by far the majority of cases in which the mother has not enough milk, or her child will not nurse, cow’s milk is used as a substitute. The question has often been discussed as to whether and, if so, what special require- ments should be made for milk intended for infants, and different answers are given. It was formerly thought that the composition of the cow’s food had a marked influence on the chemical composition of her milk, and upon its character, and on account of this opinion it was formerly required in Germany that cows kept for this purpose must be fed nothing but dry food the entire year. The price of such milk has been considerably in- 154 — MILK HYGIENE creased on this account. In Denmark also, similar, though less strict, requirements were made for the pro- duction of milk for infants. During recent years, how- ever, views concerning the effect of the forage on the quality of the milk have changed materially, and it has been observed by many that babies have been fed with- out discoverable detriment on milk from cows fed with green fodder, turnips, oil cakes, etc., and, indeed, in some instances, with brewery grains. There does not appear to be adequate ground for the requirement that cows kept to produce nursery milk should be restricted to this one sided diet. On the other hand, there is need for an active control of the sanitary conditions of the produc- ing herd, for the public must be assured that milk sold at a high price especially for the use of infants may be fed to them without danger of a grave infection of some kind. The nature of the requirements which, in our judgment, should be made concerning the production, handling and sale of ‘‘ nursery milk ’’ are considered later. | The mortality among children during the first year of life is very significant. In Norway and Sweden, from 1891 to 1895, on the average, 10 per cent. died each year ; in Denmark, 14 per cent.; in Finland and Switzerland, 15 per cent.; in Prussia, 20.5 per cent.; in Baden, 22 per cent.; in Wurtemberg, 25 per cent.; in Bavaria, 27 per cent.; and in Saxony, 28 per cent., while the mortality in Austria and Hungary is 25 to 28 per cent. The mor- tality is greatest in large cites, somewhat less in small cities and least in the country. Different cities show different death rates; for ex- ample, from 1886 to 1895, on an average, each year 13 per cent. of the children less than one year old died in Lyons, 15 per cent. in Christiania, 16 per cent. in Paris and London, and the death rate in Berlin reached 295.3 MILK FOR INFANTS 155 per cent., in Budapest 28 per cent., in Munich 31.4 per cent. and in Ingolstadt even 40.9 per cent.** In Copenhagen, the mortality, during the first year of life, has decreased significantly; 1877 to 1886, 20.83 per cent. died each year; in the next decade 19.04 per eent., during 1897 to 1899, 17.87 per cent., while only 15.55 per cent. died in 1900. Infant mortality is also on the decrease in the provincial cities, and this is certainly true of many large cities abroad. A comparison of normally fed children with chil- dren fed on raw or prepared cow’s milk, shows a far greater death rate among the latter. If the cases of dis- eases and death are arranged according to the separate months, it is noticed that in most cities there is a marked increase of deaths in July and August and a propor- tionate decrease in September, and this increased mor- tality pertains almost exclusively to children fed arti- ficially. By far the greater part of the fatal diseases are af- fections of the stomach and the intestines as catarrh, colics and cholera infantum. Although the causal con- ditions are not fully explained, it may be stated that cow’s milk appears to induce a predisposition to intes- tinal infections, on account of its varying and hetero- geneous composition. The diseases are to be attributed to the action of microbes; possibly in some cases to bac- teria that have formed toxic substances during their development in the milk, but in the greater number of cases it is, doubtless, a question of the presence of patho- genic microbes in milk (streptococci, proteus- and colon forms). Therefore, milk intended for infants should be sterilized. Opinions differ as to whether heating with steam for an hour (Soxhlet’s method) is to be preferred 38 These figures are taken from Ohlens’ Die Milch und ihre Beden- tung, 1903. 156 "MILK HYGIENE to brief boiling or to pasteurization, since it is thought that long cooking affects the digestibility of the casein. Through the zealous efforts of physicians, it has been possible, during recent years, to cause the general ac- ceptance of the practice of sterilizing milk for infants and the reports show that this has had a favorable influ- ence in preventing disease and death. There are, however, some children with whom cooked cow’s milk does not agree, as it causes continual indiges- tion and loss of weight so that, indeed, when six months old they may weigh less than at birth (infantile atro- phy). This condition is often improved at once if a wet nurseis procured for the child or if asses’ milk is used; or a change to raw cow’s milk may lead to quick recovery. An explanation of these different effects of cooked or raw cow’s milk cannot be given here, since there is no convincing reason for the opinion that cooked milk is harder to digest than raw. Possibly the favorable effect of raw milk can be attributed to the presence of sub- stances antitoxic to some of the poisons absorbed from the intestinal canal, which antitoxins are destroyed by heating the milk. [In America, the balance of opinion among pediatrists appears to be in favor of clean, raw milk, specially produced, of low bacterial content and from a reliable source (‘‘ certified milk ’’) ; or milk that has been pasteurized at a moderate temperature (155° to 185° F..) and that has not been boiled. L. P.] PARA VE PUBLIC CONTROL OF THE PRODUCTION AND HANDLING OF MILK NATURALLY there are great differences in different countries in the way cities are supplied with milk and in the manner in which it is handled after it reaches the cities. In general, it may be said that there is no diffi- culty in supplying small towns, as herds are sometimes to be found within their limits and usually enough milk is brought in from the immediately outlying districts. It is different with the larger cities and, with respect to them, the milk business has been greatly changed dur- ing the last 20 to 30 years. The conditions in Copenha- gen may serve as an example, as they do not differ mate- rially from those found in other large European cities. Copenhagen was once supphed with milk chiefly from the brewery herds and other herds within the city, and by farmers from the adjoining country, who delivered milk to their own regular customers in the city; now the conditions are wholly changed. The continual growth of the city and the constantly increasing hygienic demands have caused the almost complete discontinuance of cattle keeping within the city, and proximity to the large city has greatly affected the character of the farming nearby, so that the breed- ing of cattle and dairying have fallen off. On the other hand, on account of easy transportation by railroad, farmers living at quite a distance can deliver their milk to advantage in Copenhagen, and at this time the city is 157 158 MILK HYGIENE supplied with milk not only from the island upon which it is situated but also from the surrounding islands. This facility of transportation by railroad and boat has led to the establishment of milk depots that receive the milk from the farms, handle it appropriately and deliver it to their customers, selling it either from established sales places, or from wagons. This evolution in the handling of milk, which has occurred in most of the large cities of other countries as well, marks an important advance in hygienic methods. The milch herds in the cities and the retail shops con- nected with them were very often the source of grave epidemics; the uncontrolled sale of milk by small farm- ers has had the same unfortunate result, and there is danger, too, inthe small shops, as the limited space makes it difficult to prevent the various members of the family from coming into too close contact with the milk contain- ers and with the milk itself. Large companies are better able to bear the expense resulting from the observance of hygienic requirements, and the sanitary control of these may be much more easily effected than in the case of numerous small con- cerns. It is to be observed also that many of the large milk establishments have voluntarily adopted standards for the production and handling of milk that are in ad- vance of requirements of the health authorities. There are no proven cases of milk epidemics traced to infec- tion through milk from well conducted large concerns; no doubt the mixing of a large quantity of milk lessens the danger of infection, since usually a certain amount of infectious material 1s necessary to produce infec- tion. On the other hand, however, the mixing together of a great quantity of milk, under unfavorable condi- tions, may be particularly dangerous because if a milk epidemic were caused it would be very widely spread. HANDLING OF MILK 159 A strictly enforced control is, therefore, no less neces- sary for large establishments than for small. The first large milk company established in Co- penhagen was the Copenhagen Milk Supply Company which, more than 25 years ago, at a time when milk hygiene was still on a low plane in Denmark, as it was abroad, established, voluntarily, a comprehensive stand- ard covering the condition of health, the cleanliness and the feeding of the herd, the health of the milkers and other employees and the proper handling of the milk. This company rapidly developed a very important busi- ness and has been imitated in Denmark and in other countries. Several new companies have made even greater advances in the adoption and enforcement of hygienic requirements. Moreover, the large, well organ- ized milk companies have had a very great influence in forcing the small concerns to handle their milk with much greater cleanliness and care. The most familiar ways of retailing milk in cities, are: the milk is drawn and sold in established shops or it is drawn or dipped from tanks carried on wagons, or, thirdly, the milk is first bottled, or is placed in cans that are closed and sealed. The last method is decidedly the best and it is now rapidly displacing the other methods. When milk is measured out on the street, it may easily be contaminated by dust and dirt blown about by the wind, and as the delivery buckets are carried from one kitchen to another, there is a possibility that they may carry contagion. This. method of delivery is also at- tended by the possibility of defective measuring, etc., by the deliveryman. The hygienic requirements that should be established with relation to the milk supplies of cities, will doubtless lead to a further change in the milk business as this is apparently going more and more into the hands of a 160 MILK HYGIENE few large companies while the number of small con- cerns is steadily decreasing. [In America this tendency toward centralization of the business is very marked in most large cities, and especially in New York and Boston. The reason, how- ever, is economic and is similar to the causes for con- Solidaond in other lines of trade. L. P.] Since milk, as has been said, can acquire hare properties in pervert ways, since its composition may vary considerably, and since it may be adulterated in many ways, the milk business must be supervised by public authority, under appropriate laws or ordinances. Formerly, in most large cities, the occasional examina- tions had reference only to the fat content of the milk (transparency test, determination of the specific gravity, etc.), and in many places, even at the present time, no further progress has been made. But our present knowledge makes it obvious that such an examination, in comparison with the standard that should be estab- lished to guard against dangerous milk, has relatively little importance. The public control, therefore, is not to be limited to an examination for adulteration and souring or ‘‘ spoiling ’’ of milk on the market, but must extend to the production and the care and treatment of the milk (including the condition of health of those per- sons who come into direct or indirect contact with it). The enforcement of complete regulations for this pur- pose, of course, is accompanied with great difficulties, and there is no city in the world whose measures in this respect can be said to be ideal. A point to be avoided in such a control is a great increase in expense which would raise the price of milk. This would be a hardship for the public, the importance of which from the economic and hygienic view points, must not be underrated. In the inauguration of a thorough-going supervision it may HANDLING OF MILK 161 be necessary to interfere considerably with the methods of producing and handling milk as these have gradually developed. Local conditions will have an important in- fluence on the establishment of a system of control and will determine the rapidity with which the various re- quirements can be fulfilled. General laws governing the production and handling of milk, are lacking in most countries. Only a few coun- tries (7.e., Portugal in 1900) have enacted such laws and there is not much evidence as to the practical success of these requirements for a whole country. Ina large num- ber of the cities of Europe somewhat detailed regula- tions have been adopted in regard to the milk trade; but these regulations, even in the same country, differ very much. Dresden may be mentioned as an example of a large city with excellent modern regulations for the handling of milk. (Published July 31st, 1900, with amendments of February 26th, 1901.) In order to estab- lish a uniform system in Prussia, the Prussian govern- ment in 1899 published a circular of information to mu- nicipalities with detailed instructions for a judicious regulation and supervision of the milk trade. In many of the small cities there is either no control at all or a very defective one. [The following table from a report by H. E. Alvord and R. A. Pearson on the milk supply of 200 cities and towns in the United States shows the subjects of most frequent legislation in connection with market milk in 126 cities, the milk ordinances and regulations of which were examined with especial care. The most popular subjects for legislation are readily seen. ild! 162 SUBJECTS. EEE OF CITIES Dairies: License or permitrequired| 12 Special authority for in- SPECUIONS sameeren 58 Pure water supply....... 8 Drainage of barnyards...| 12 Stables : Proximity to other build- MES Se cre ouput) Se eee 6 i aKa OY bests ete ba RA YES SDR 15 Wentilationye ns EDER ERR 32 Is Oor Spacer a see 15 IAI SACO aoe Fos eel eee: 10 Cleamllamess ys ysis ... cere 24 Source of supply to be posted 2. oe eae eae 14 Generalinspectionin cities} 75 Signs on wagons ......... 79 Unsanitary milk prohib- ited AES ae 109: Confiscation of impure milk. o2) Ao eee 30: Definite standard for com- Position 2. 5/1 SØNS SEER 67 Skimmed milk prohibited | 12 Skimmed milk permitted conditionally. eee 61 Bottling at farmere 8. Storage of milk for sale...| 23. Milk tickets to be used but ONCE! in... Si ee eee 16 Milk wagons to becovered| 12 Milk wagons not to carry PAL OAS... clei 5 Sellers to register custom- ETS sm TE Sr 7 HANDLING OF MILK 163 While the establishment of milk control on the part of the public leaves much to be desired, private initia- tive, as mentioned before, has led to significant sanitary improvement, in that large stock companies have been formed in many cities to provide sanitary milk and have voluntarily subjected themselves to extra expense for guaranteeing and controlling it. In some respects, this voluntary control far surpasses what the public could impose at this time. Appendix I gives the require- ments of the youngest company in Copenhagen (‘‘ Tri- folium ’’), which shows how far a private company may carry this sanitary control, and these regulations may well serve as a model for other places. While the companies referred to established their own requirements and determined the extent of the con- trol to which they submitted, another very successful plan has been inaugurated in Stockholm, which consisted in the establishment, in 1885, by private initiative, of a milk commission of 9 members, including 4 physicians, 1 veterinarian and 1 chemist. The members of this com- mission are chosen in part by the Board of Health and in part by the Medical Society. This commission has outlined a comprehensive control, which includes all who desire it and who are ready to bear the expense con- nected with it. The business advantages of this control are such that a higher price than usual is obtained for the milk produced under it. Since the legal requirements in the different cities vary and are adapted to the local conditions, it is not possible to give a concise, epitomized view of existing regulations; *® the following, however, is an 39 For a review of the local milk inspection laws of the United States and recommendations, see “ The Milk Supply of Two Hundred Cities and Towns,” by H. E. Alvord and R. A. Pearson. U. S. Dept. of Agr., B. A. I. Bulletin No. 46, Washington, 1903. 164 MILK HYGIENE attempt to define the requirements which, from a sani- tary standpoint, are to be considered necessary or desirable. In order to be effective, the legal or police require- ments covering the milk trade, must contain detailed regulations concerning: The production of milk. The care and handling of milk. The prevention of adulteration. The prevention of the sale of tainted or damaged milk. In respect to the enforcement of these regulations in cities, the supervision will rest—at least in Denmark— with the local health authorities, and preferably with a veterinarian appointed by this authority, who will con- duct the inspection of the milk establishments with the cooperation of the police, and take the necessary sam- ples for further examination. In small cities, the inspec- tion of the production of the milk may also be under- taken by the same veterinarian; but in the larger cities, as a rule, this is left to the local veterinarians in the coun- try, and the various dealers or herd owners are required to furnish certificates, that should be drawn up on a prepared blank and be submitted to the health office con- cerned. I. REGULATIONS REGARDING THE PRODUCTION OF MILK Public supervision of the production of milk presents great difficulties and has been carried out in but a few places. In the ordinances of most cities, there are cer- tain requirements pertaining to the production of milk, but their enforcement is not always provided for. In several cities every owner of cattle who delivers milk in the city, either directly or indirectly, is obliged to appear before a public authority and pledge himself to observe REGULATION OF PRODUCTION 165 the existing legal requirements or those that may be made later, and especially to report every change in the make up of his herd. This is a good arrangement. The actual observance of these requirements should be con- trolled by frequent visits of a veterinarian appointed by a central authority or by occasional visits of the local veterinarian, but the latter plan is not so satisfac- tory. Such a regulation would, of course, be particularly difficult in large cities as, for example, Copenhagen, which receives milk not only from a very large number of large and small herds, the cows in which are often changed, but is supplied with milk from a large part of the country. On the other hand, the regulations men- tioned can be adopted without great difficulty in small cities, although they might cause dissatisfaction at first among the dairy farmers. In most of the larger cities, up to the present time, little has been done except to publish notices in regard to the regulations respecting the -production of milk, but no reports have been de- manded of producers and no special control has been provided to enforce these regulations. The local boards of health have the right to investigate cases which are reported and if necessary to forbid the sale of milk from the premises involved. [In the United States, there is a certain amount of dairy farm inspection under the authority of the states. In Massachusetts, herds are inspected by the Cattle Bu- reau of the Board of Agriculture, in Pennsylvania by the State Livestock Sanitary Board, on request from local boards of health that their milk supplies be exam- ined into; in several states, herds and premises are in- spected under authority of the State Dairy and Food Commissioner, the Commissioner of Agriculture or the State Board of Health. In no state, however, is there a 166 MILK HYGIENE systematic inspection of all dairy herds, excepting in Massachusetts, where the inspection is made for the pur- pose of controlling bovine tuberculosis. A number of cities, on the other hand, require periodical inspection of the herds from which they obtain their milk supply. Te. es) The control to which a number of large milk com- panies have submitted voluntarily, either from philan- thropic motives or because driven to it by competition, consists chiefly in frequent, regular visits from vet- erinarians to the milk producing herds, during which not only the conditions of health of the cows but also their food, the cleanliness of the stables, the handling of the milk, and the health of the milkers are the objects of a more or less effective supervision. Some establish- ments have provided a separate organization for super- vising the health of the employees. It is self-evident that the methods of such companies, however good their private supervision may be, must be subject to the supe- rior control of health officers. [It will be observed that the author dwells not so much on the importance of the recognition of infective organisms in milk as on their exclusion. Unquestion- ably it is infinitely better, from the standpoint of the public health, to prevent the contamination of miik than, by means of laboratory examination, to discover evi- dences of contamination in a sample representing a quantity of milk that has already been consumed. Milk is not a food that is kept long; it cannot be put away in storage until a sanitary examination has been made, and then released for consumption, or destroyed, according to the result of the examination. Only the briefest inspections can be made while the milk is en route from the producer to the consumer. The supply continues as a flowing stream, and is REGULATION OF PRODUCTION 16% never just alike at different times or places. The lab- oratory examination of a milk sample gives some infor- mation as to the condition of that sample and, by infer- ence, as to the conditions under which a certain quantity of milk was produced and handled on a given day. But some of the contaminations of milk that are most dan- gerous cannot be detected by routine examinations in the laboratory, if at all, excepting by their effects on the consumer; among such contaminations are those caused by the specific organisms of tuberculosis, typhoid fever, diphtheria, scarlet fever and the materies morbi of many diseases of cows. Therefore, so far as the pre- vention of the infection or pollution of milk is concerned, it is more important that the milk be produced under such conditions that contamination is well guarded against than to know the condition of a certain quantity that has already been used. The laboratory examination of milk is, however, of much value in checking and controlling the accuracy of ‘farm and herd inspections, which inspections are de- signed to prevent infection and pollution, while the lab- oratory discovers contaminations that have already occurred. The author’s position on this general subject is quite analogous to the opinion that is now held by sanitarians in regard to the way in which the purity of the water supply should be obtained and insured; that is, by clean- ing and guarding the source. It is well to lock the stable door before the horse is stolen. But it has, thus far, been impossible in America, excepting in a few isolated instances, to impress the public sufficiently to lead to the establishment of a sys- tematic inspection of the sources and methods of hand- ling and transporting milk. Reasons for this condition are, the paucity of specially trained men for this ser- 168 … MILK HYGIENE vice and, on this account, the difficulty health officers have experienced in securing inspectors to do such work in a satisfactory way and, secondly, the expense. A properly equipped dairy farm inspector must have had special training, and must be familiar with, and be able to apply, facts from pathology, bacteriology, zodtechnics and dairy husbandry. Dr. William T. Sedgwick has emphasized the impor- tance of control of the source of the milk supply, to pre- vent pollution, as follows: *° ‘* It should never be forgotten that if water were to be drawn, as milk is, from the body of a cow standing in a stable, by the hands of workmen of questionable clean- liness, and then stored and transported over long dis- tances in imperfectly cleaned, closed cans, being further manipulated more or less, and finally left at the doors at an uncertain hour of the day, few would care to drink it, because its pollution and staleness would be obvious. It is clear, moreover, that it requires and deserves more careful treatment than water, for it is more valuble, more trusted and more readily falsified or decomposed.’” Dr. Rowland G. Freeman has stated his opinion as to the importance of controlling the source of the milk sup- ply, rather than to attempt to determine its character by bacteria counts, in these words: ‘‘ It seems to me that while the counts of bacteria are exceedingly valuable as an exponent of cleanliness and proper handling of milk, they should be used only to prevent carelessness at the dairy and to stimulate better methods and discipline. ‘¢'The opinion of a milk commission of representa- tive men (experts) based on an actual knowledge of the management of the dairy is of vastly more value to the 40 Sedgwick, Principles of Sanitary Science and the Public Health. New York and London, 1902, page 279. REGULATION OF PRODUCTION 169 medical profession and to the public than any statement regarding the precise number of bacteria in the milk upon any given day or days. The most important things, after all, are such a régime as shall make con- tamination by pathogenic organisms improbable, and at the same time insure that the milk is produced under such conditions of cleanliness that other bacterial con- taminations will be reduced to the minimum.’’ L. P.] a. The condition of health of the herd. The ideal requirement that only milk from a perfectly healthy herd may be marketed, cannot be maintained. The pub- lic, therefore, must be satisfied to demand that the health condition of the herd is such that its milk does not pos- Sess injurious qualities. If infectious diseases which are transmissible, through milk, to man, break out in the herd, the sale of the milk should be forbidden as long as danger of infection be present. If individual cases of infectious or other diseases occur which may lead to the contamination of the milk of the affected cows by patho- genic bacteria or toxins, it must be the duty of the owner to prevent this milk being mixed with the other milk, and, indeed, wholly to prevent its use as food for man. Such regulations as the following may be regarded as necessary: The use of the milk from the whole herd is to be dis- continued if foot-and-mouth disease, lung plague or anthrax occur, also in the case of extended outbreaks of transmissible infections of the udder, septic enteritis, cowpox, or of any toxic disease of a large part of the herd. The milk of individual cows should not be used, and affected animals are immediately to be removed from the stable, in cases of tuberculosis affecting the udder, the uterus or the intestines and when the lungs are so affected as to occasion physical symptoms; also, milk 170 MILK HYGIENE from cows suffering from anthrax or rabies (bitten by affected animals), and that from cows with mastitis, with inflammation of the uterus and retention of the afterbirth, inflammation of the intestines or severe diarrhæa, and with severe cellulitis or abscesses and suppurating wounds. ; Milk should not be used from cows suffering from any sort of febrile disease or intoxication, with pox or suppurating sores on the teats, with inflammation or other disease of the udder, constipation or diarrhea. Moreover, it should not be used from cows that are being treated with medicines that have a strong odor (volatile oils, ether, asafcetida and the like), with alkaloids or potent glycosides, with preparations of iodine, arsenic, mereury, antimony or lead. | A very proper requirement is that milk from cows that have recently calved is not to be mixed with the rest of the milk, for the beast milk (colostrum) differs greatly in composition from normal milk and may have a harmful effect on small children. For 6 to 8 days after calving, the milk should not be mixed with the other milk. Also, milk from cows approaching the — end of the period of gestation and which are only giving a little milk, should not be mixed with that mtended for sale, because it is often quite alkaline and may differ a good deal in its composition from normal milk. The complete observance of these requirements is, evidently, very difficult to control. In part, one must rely on the honesty of the owner, who should be held responsible for failure to comply with the legal require- ments. When a dairyman is under contract to furnish milk to a company having its own conditions and regula- tions, he may be held accountable for failure to fulfil the obligations he has undertaken. In general, it can be REGULATION OF PRODUCTION 171 said that the observance of the conditions that are out- lined above, as well as those that will be mentioned later, can be expected only when the dairy farm is under the inspection of a veterinarian who is entirely independent of the owner. Therefore, when it is possible, one should endeavor strongly to arrange for such veterinary supervision. Naturally, it is of some advantage to make inspections now and then, at irregular times, but if the control is to be really effective, the visits must take place frequently, and with some degree of regularity. Preferably, the visits should not be more than fourteen days apart be- cause, in that time, tuberculosis may attain such develop- ment that bacilli may be excreted with the milk, and dis- eases of the udder often develop acutely and follow a short and rapid course, thus making frequent examina- tions necessary. Only in cases in which the milk is sub- jected to a really safe process of pasteurization before it is sold, should a less frequent inspection be considered sufficient. [This amount of supervision, a visit to each produc- ing farm every two weeks, is not attainable with relation to the milk supply of the large cities of the United States, nor is it to be regarded, in the present provi- sional state of the sanitary development of the country, as necessary. That producing farms should be under some supervision, all agree. The amount of supervision that is necessary varies with the conditions. If a given herd is known to be infected with tuberculosis and infested with other diseases, if the premises are bad and the owner careless, then frequent inspections should be made until there is decided improvement; on the other hand, if a certain herd is known to be clear of tuber- culosis, calf cholera, infectious gargets, etc., if the prem- ises are good and well kept and the owner intelligent and 172 MILK HYGIENE careful, longer intervals may safely be permitted to elapse between visits. After an inspector has gone over his ground and has become acquainted with local condi- tions, and the individuals, the question of frequency of visits should be left to a larger extent to him. The number of inspectors required is of course in direct proportion to the frequency of inspections. If a single inspector could visit all of the dairy farms sup- plying a given city in one year, about twelve inspectors. would be required to visit these farms each month. It is estimated that the number of inspectors that would be required to carry out an adequate system of dairy farm inspection for the city of Philadelphia is about 20. About 60 to 80 country inspectors would be required for the city of New York. L. P.] For herds supplying “‘ nursery milk ’’ or “‘ infants” milk,’’ decidedly rigid requirements must be made be- cause, so far as possible, this milk must be so produced that it can be used in its raw state by children and invalids without any danger whatever. Therefore, dealers should not be permitted to sell milk under these names if the herds are not under the inspection of a public veterinary officer; and the inspec- tions should take place at least every fourteen days, preferably every week. It must be required that ‘‘ nurs- ery milk ’’ shall come only from herds absolutely free from tuberculosis (7.e., herds that are tested with tuber- culin at least once every year, and to which only abso- lutely healthy animals are allowed to be added), be- cause the diagnosis of some dangerous forms of tuber- culosis is often very difficult and, in the earlier stages, even impossible, and because it has been proven impossi- ble to prevent the occurrence of the dangerous forms merely by the removal of animals in which tuberculosis is clinically apparent. Besides, the definite requirement REGULATION OF PRODUCTION 173 must be made that the delivery of milk must cease in- stantly if numerous cases of septic enteritis or strepto- coccus mastitis appear and also if ‘‘ calf cholera ”” occurs malignantly or endemically. Moreover, the prompt removal from the herd is de- sired of every animal that has fever, or any kind of infectious disease. It is the duty of the owner himself to discontinue the delivery of the milk and to undertake the necessary isolation, when occasion may arise be- tween the visits of the veterinarian, and he should call the veterinarian as soon as any suspicious disease may appear. These requirements are already enforced by private companies and so there can be no question as to whether it is possible to carry them into effect but, up to the pres- ent time, they are enforced by the public in only a few cities. | b. Feeding the herd. As has already been stated, it is now the belief that the composition of the milk does not depend in any material degree on the composition of the food, and that injurious substances are not ex- ereted through the udder to the extent that was formerly supposed. Therefore, one is not justified in forbidding the use of such a number of foods as has been done and is still done by some large cities. Only such foods should be prohibited as are decomposed (mouldy, putrid or fermenting), or materials containing great numbers of resistant bacteria of fermentation (creamery refuse, frozen forage, the offal of root crops, ete.), or excessive quantities of unnatural food materials (the refuse of some manufactories, distillers’ slops, malt, molasses ete.), and strongly smelling vegetable matter (turnip tops, cabbage, green forage containing poisonous plants, etc.). The use of other food stuffs should be forbidden in such quantities as are injurious to the cow (turnips 174 MILK HYGIENE causing diarrhæa, concentrated feed causing indigestion, poisoning by cotton-seed and nut-cake, etc.). It has been required in some cases that cows supply- ing ‘‘ nursery milk ’’ shall be fed only upon dried fod- der, and the use of oil meals has been restricted. By this means, milk has been obtained which is good and uniform, but it is so very expensive that its use is re- stricted. Our present knowledge of the effect of food upon milk does not sustain this requirement. But, it should be observed, the stable and cows can be kept clean much more easily if the cows are fed exclusively upon dry foods than when they are fed in part upon turnips or other green food. Therefore, if this one-sided method of feeding is not demanded, great emphasis must be placed on cleanliness with respect to herds supplying nursery milk. It is not inappropriate, however, to make some extra requirements in regard to feeding cows pro- ducing nursery milk. For example, food stuffs, such as distillers’ slops, malt and molasses, as well as all fodder which, fed in large quantities, may be injurious to cows, should not be used (buckwheat, lupine, mustard, rape, cakes mixed with mustard, cotton-seed meal, nut-cakes, potatoes, ete.). Of course it is difficult to prove that a ration containing a small quantity of these materials would impart injurious properties to the milk; but it is safest, when it concerns milk for small children, to avoid any possible danger connected with the use of such foods; the more so, as this prohibition would have no influence at all upon the cost of production of the milk. Nor should one be allowed to give so great a quantity of turnips or green fodder to cows that are stabled that they suffer from diarrhea, even to a slight degree. [There has been much discussion and, in the past, much difference of opinion, as to the propriety of using REGULATION OF PRODUCTION 175 silage as a food for milch cows, and especially as food for cows producing nursery or certified milk. The building of silos and the ensiloing of crops are new procedures in America, as elsewhere, and methods both of construction and filling have undergone rapid development. Only a few years ago, when square, poorly built silos were used, some of them built as pits, below ground, and before silage cutters and elevators had been developed, and when it was the practice in some cases to ensilo green maize stalks without cutting, and in bundles, there was much decomposed, putrid and mouldy silage, which had a very offensive odor and which was decidedly objectionable as food for dairy cows or, indeed, for any animals. In these days, however, silos are better made and better filled; they are usually round or octagonal, thus facilitating even filling and settling, machinery for cut- ting has been perfected, so that the silage is divided into short lengths of from one-half to one inch, and Indian corn, the chief silage crop, is no longer used in the soft, immature state, but is permitted to come al- most to maturity. Putrefaction does not occur in prop- erly handled silage. The fermentation that takes place is caused partly by bacteria and partly by enzymes in the maize plant. Good silage is a wholesome, nutritious food that is appetizing and comparatively easy of di- gestion. Silage is fed to cows on nearly, if not quite, all of the large farms in America devoted to the production of certified and nursery milk. It is not known to be subject to any objection other than if fed in too large quantity it produces an undesirable degree of laxativeness, and if fed just before or during milking, if it is not first class, the odor of the silage may be eliminated with or ab- sorbed by the milk. This is avoided by feeding it after 176 MILK HYGIENE milking and by not allowing the residues to accumulate in or about the stable. Frasier *1 has shown by some tests made with milk from cows fed silage of good quality that no objection- able flavor or odor was imparted to the milk either when the silage was fed before, during, or after milking. In- deed, in 372 tests made, silage milk was preferred in 233, or 60 per cent. L. P.] A further demand in reference to herds supplying nursery milk should be established—that frequent and sudden changes in food should be forbidden, as the com- position of the milk immediately after such a change is often materially altered, and it is more probable that when the udder is ‘‘ surprised’’ by such a sudden change the secretory function is thrown out of equilib- rium and abnormal, and possibly injurious, substances are secreted with the milk. c. Cleanliness in the stable and during milking. In order to guard, so far as possible, during milking, against pollution with dirt and, at the same time, with bacteria, the most thorough cleanliness of the cows and the stable, and care on the part of the milkers, is to be desired. However, it is very difficult to establish detailed regulations in this respect, and no less difficult to en- force them. We usually find that the regulations under this heading are confined to the concisely stated orders that cows and stables must be kept clean; that, at milk- ing, the greatest possible cleanliness must be observed and that, just before milking, the udder and teats are to be washed. However, where the conditions permit the establish- ment of more detailed regulations, as in the larger milk 41 Wilber J. Frasier, Bulletin No. 101, Agricultural Experiment Station, University of Illinois, Urbana, 1905. REGULATION OF PRODUCTION 177 companies, which are under private control, this should be done. In this connection, the following regulations which, first, the Copenhagen Milk Supply Company and, afterward, other companies in Copenhagen, have fur- nished to their producers stand as an example to be imitated : 1. The stable must be so built that the urime has an unobstructed exit and the floor must be of such nature that it may easily be kept clean. The cows must be well bedded and, for this purpose, no spoiled or rotten straw or hay can be used, nor straw or hay that has previously been used for packing. The stable must be kept as clean as possible. In the morning, the manure must not be removed until after milking; in the afternoon, at least one hour should pass after mucking out before milking. After cleaning the stable, it should be thoroughly aired, unless the ventilating system is particularly good, so as to render this unnecessary. 2. In order to prevent the hind quarters of the cow from. becoming too dirty, the hair of the tail, on the udder, the flanks and on the outer side and the rear of the thighs should be clipped before the cow is stabled in the fall. Besides this, the cow should be cleaned with a curry comb and brushed every day. Definite and more stringent regulations concerning the cleanliness of the stable and the cows should be made in summer, if they are fed in the stable, and in winter if green (laxative) fodder is used. 3. When the cows are kept in the stable, their teats are to be washed with clean water and dried with a clean cloth. If the udder is dirty, this, also, must be washed and dried. If the cows are milked in pasture, this cleansing cannot be done so satisfactorily [and there is less occasion for it], so it is usually best to confine the washing of the teats and udder to such of the cows 12 178 MILK HYGIENE as are apparently soiled with manure or earth. If there are sores upon the teats these must be carefully washed off. Instead of washing, one may rub the udder with a dry cloth or brush it and then rub in a little neutral fat. [as vaseline ].?? 4, The milkers must have a special dress to be used. only during milking, and this must be washed as often as necessary. The milkers must wash their hands be- fore milking, and during milking they must have plenty of clean water and clean cloths at hand with which to wash not only the teats but also their own hands, as often as is necessary. 5. Milk pails, milk strainers and milk cans must be carefully cleaned in the dairy house. If it be necessary to rinse out the pails or strainers when milking in the pasture, only clean water which has been carried to the place must be used and not that from a reservoir in the pasture. d. The health of the attendants. A very important point in milk hygiene is the condition of health among the workers in the dairy and of the milkers and, indeed, among all persons who are connected with milk produc- tion. As has already been emphasized, there are a num- ber of infectious diseases of man which can easily be transmitted through milk and which have appeared in many instances as extended ‘‘ milk epidemies.’’ Fre- quent inspection by a physician of all persons connected 42 [This reference to milking cows at pasture, which has now become unusual in most parts of America, is explained by the Danish custom of keeping cows tethered out of doors the entire summer. During this season, the cows are allowed to graze on grass and especially planted forage crops, which are harvested by the cows without waste, as the tether pin to which the tie rope is attached is moved but a few feet at a time and is not moved again until the forage within reach has been consumed. Water is carried to the cows in tanks on wagons. L. P.] REGULATION OF PRODUCTION 179 with the business is scarcely feasible, both because it would be an expensive procedure and because, in most cases, it would meet with great opposition and tend to increase labor difficulties. | But the following regulations are regarded as neces- sary and they should be incorporated in public ordi- nances: | The sale of milk shall cease immediately if typhoid fever, scarlet fever, diphtheria, or other malignant in- fectious disease breaks out among people living in the farmstead ; ** the sale shall not be resumed until a physi- cian’s certificate has been received showing that all dan- ger of infection is over." Care must be taken that the milk does not come in contact in any way with persons in whose household one of the above-mentioned diseases exists, nor those who have discharging sores or skin diseases of the arms, hands or face. In addition, the local authorities should have the right to forbid the sale of milk if this is known, or be- lieved, to be the cause of an epidemic, even though no source of infection be proven on the farms in question. Several of the large milk companies of Copenhagen have established even more rigid regulations in regard to the health of the personnel and they insure the en- forcement of these rules by allowing the producer full value for his milk, when he holds it back on account of the occurrence of disease. The value of such a provision is obvious. e. The water supply. Since typhoid bacteria (and 43 |The farmer’s residence and the cow stable adjoin, so that they are, practically, parts of the same building, on most of the small farms of Denmark.|] 44 [The danger of infection from persons recovering from typhoid fever and diphtheria continues for a long time. | 180 MILK HYGIENE other pathogenic bacteria) may gain access to milk through water used to wash the milk vessels, care must be taken that pure water be provided on the farms from which market milk is sold, and that polluted or infected water is not used for cleansing the dairy utensils, nor the udder, nor shall it be used for the cows. [Contam- mated water has also done harm when used for cooling milk and it is believed to have led to the infection of milk, indirectly, through the soiling of the skin of the cow, as when wading through a foul stream. L. P.] f. The care of the milk. Immediately after milking each cow, the milk must be run through a fine metal strainer into a container. The strainer holds back only the larger pieces of dirt and some of these are dissolved by the continuous pouring of the milk, and bacteria are washed through, so it is advisable, so far as possible, to prevent the dirt that has been removed from coming into contact with the milk that is to follow. But it cannot be said that a strainer has yet been made that solves this problem in a satisfactory way; therefore one must get along by frequently cleansing the strainer from the par- ticles of dirt. Of course, it is very difficult to insure the observance of such a stipulation. Sufficiently rigid re- quirements in regard to the cleanliness of the milk sold and the seizure of impure milk, followed, perhaps, by the imposition of a fine would aid in enforcing the regula- tion. After the milk is drawn, it must be carried to a place prepared for this use and which must be used for no other purpose. This room must be well ventilated, clean and have an impervious floor. The milk must be cooled as soon as possible by pass- ing it over a cooler or by putting the cans into tanks containing ice water. If it is nursery milk, the cooling must be very carefully done, so that the temperature REGULATION OF PRODUCTION 181 may not exceed 10° C. (50° F.). Milk should be kept chilled until it is ready to be shipped and then it must be guarded carefully against high temperature by protect- ing it from the sun, transportation by night, ete. If the transportation of milk requires a long time, it must be cooled to a low point, and, while it is not well to allow the whole quantity to freeze, in recent years a partly frozen milk (the outside layer frozen in the cans) or the addition of frozen milk to the other milk have been successfully used. [Milk shipped long distances in America is sent in refrigerator cars. Some milk is on the railroad 10 hours before it reaches market. Milk shipped short distances is usually not sent in refrigerator cars because, on the short runs, the cars have to be opened so often at local stations that there would be a great consumption of ice. If such milk is thoroughly chilled by the use of ice before it is shipped, it usually arrives in good condition; but if it is cooled only by the use of well or spring water it is an uncertain commodity in the hottest weather. Bot- tled milk is shipped in wooden boxes with broken ice packed around the bottles. Helm ££ has proposed that milk shall be shipped in square, instead of round, cans, so that they may be packed more closely and thus make a solid block, of low temperature, which may be covered over if neces- sary, and which will remain cold much longer than a loose collection of round cans, between which the warm air may freely circulate. This style of can is shown in figure 14. L. P.] Only well-tinned metal cans which are easily cleaned should be used for keeping milk (Fig. 13) ; these should be closed and sealed when transported by rail or boat. 45 Wilhelm Helm, Die Milchbehandlung, Liepzig, 1903. 182 MILK HYGIENE Il. REGULATIONS CONCERNING THE SALE AND DELIVERY OF MILK Just as supervision is necessary of the herds which produce the milk, and in regard to the care of milk at its source, so also is supervision necessary after it comes into the hands of the wholesale and retail dealers. This supervision is much easier to carry out than that with relation to production. The regulations governing sale and delivery must embrace not only the methods of handling the milk and Fie. 13. (ee Cn eae Mio Oi 1m N Mere el] FREJ | | I li i" wy MOM i th. ! im ul ls Whe | m SO = Olin SMT | Nie Danish milk-eans. Helm’s milk-eans. the health of the attendants, but there should also be rules concerning the place in which the milk is sold, the manner of selling it and the labelling of the goods. a. Preparing the milk for delivery. Although small concerns subject the milk to no especial treatment from the time it is received until it is sold, this is not the ease with the large companies. These have considerable work to perform in the handling of milk and its delivery to eustomers. The milk [under the Danish system] is received from the stations in a more or less cool condi- REGULATION OF SALE 183 tion and the cans are put into ice water in order to chill the milk sufficiently. It is then poured into a tank and mixed, thus making its composition uniform. Then fol- lows a process of cleansing, wherein the milk is either passed through a centrifuge, so constructed that the cream and the milk are not separated, but only particles of dirt are thrown out, or it is passed through a filtering apparatus which holds back some of these particles. A gravel filter is frequently used for filtering. This is a tank which is filled with layers of gravel of different degrees of fineness, through which the milk is slowly forced. The gravel is cleansed daily by washing and roasting. Only the particles of dirt are removed by this process; the number of bacteria is not appre- ciably reduced. A filter made of numerous layers of fine linen, tightly stretched, has been used successfully in- stead of the gravel filter. The cloth part is renewed after each use. This method has, among others, the ad- vantage that the filtering may take place directly into the can from which the milk is drawn off for sale, or the apparatus may be so arranged that while the milk is being filtered and run off, it is at the same time cooled. The ‘‘ clarified ”” milk is put into metal cans or glass bottles in which it is to be sold. This filling is sometimes done automatically, so that incorrect measuring is not possible, and sometimes by means of a machine similar in construction to those used in filling beer bottles. If the milk is to be pasteurized, it is first filtered, then run through the pasteurizer and over the cooler, into the delivery can; or it is placed in the clean bottles or eans that go into the pasteurizer or sterilizer (see page 29): The public will scarcely require ordinances contain- ing exactly detailed regulations in regard to these differ- ent processes. Generally it is required only that the 184 MILK HYGIENE vessels and apparatus used shall be entirely clean, that the milk be handled with the greatest cleanliness and be kept in well-tinned metal cans or in glass or earthenware vessels with perfect glazing, containing no lead, and that all vessels shall be so constructed that they will not be difficult to clean. Special regulations should be established for the pas- teurization of milk. If the heating is of short duration, it is desirable that the milk be heated to 80° C. (176° F.) and cooled immediately afterward. The following re- quirements should be established for heating at a lower temperature: Milk should be raised to a temperature of 65° to 70° C. (149° to 158° F.) and held there for one- fourth hour or it should be kept for one-half hour at a temperature of 60° to 65° C. (140° to 149° F.). The pasteurizer should be known to act accurately enough to attain the required temperature with certainty. b. The places for keeping and selling milk. The places in which milk is handled must be light, airy and easy to keep clean; therefore, they must be provided with an impervious floor and a good drain, and good, pure water must be easily accessible. The salesplaces must likewise be bright, airy and clean and, in addition, there are a number of special -ognol Reese: Milk shame not be allowed to be sold in the same shop with other goods, with the exception of certain foods (as bread, honey, flour, butter, margarin and eggs), which cannot, either by their odor or in any other way, have a deleterious influence on the flavor and the keeping quality of the milk. Conducting a laundry, or a similar business, in the same place in which milk is kept or handled, should not be permitted. Of course, the apartment must not be used as a dwelling or a sleep- ing room, and it should not be in direct communication with sleeping rooms. If the place used for keeping and REGULATION OF SALE 185 selling milk is in communication with living rooms, as happens in small premises, then it is positively neces- sary to have the apartments separated by a thick door, which shall be kept closed. c. The condition of health of the attendants. The same rules that apply to attendants in the places of production should be binding upon those at the salesplaces. How- ever, as the enforcement of these rules naturally meets very great difficulties, im most cities action has been limited to making the regulation and then punishing those guilty of offences that are, by chance, discovered. Several large concerns (e.g., some in Copenhagen) have voluntarily enforced strict regulations in regard to the health of attendants. In order to be sure that no suspicious disease among them or in their households shall escape being reported, they provide free medical services and also pay full wages to every employee who is temporarily absent from his work on account of illness in his family. (Compare regulations governing the producers for this society, page 178, and Appendix I, page 241.) Moreover, the publie health department of the gov- ernment must be authorized—possibly upon the pay- ment of indemnity—to close milk businesses for a longer or shorter time, which are known to spread contagion, even though it cannot be shown just where the infection comes from. This authority must also apply to milk shops, when cases of typhoid fever, scarlet fever or diphtheria exist among people who work with the milk. If it is proven that the infection did not occur in the shop, the milk and the cream may be sold after steriliza- tion, if care is taken to see that this is thoroughly done. A milk shop is to be kept closed as long as there is dan- ger that it may distribute infection. d. Marking and packing the milk. The requirements 186 MILK HYGIENE in respect to marking milk for sale form quite an impor- tant part of the regulations on the handling of milk, be- cause these have a very important bearing on the pre- vention of adulteration. The kinds of milk and milk products which are of importance are whole milk, ‘‘ half milk,’’ skim milk, cream and buttermilk. Whole milk is the usual name for normal cow’s milk which has not been deprived of any of its fat or other ingredients. As the fat content of milk is far from being uniform, and as partial skimming, or the addition of skimmed milk, is, therefore, not easily detected, many attempts are made to deceive by these falsifications. In order to prevent the sale of milk that may be unadulter- ated but which is too poor in fats, and in order to lessen the number of adulterations, a minimum content of fat and solids has been established in many cities, as well as the limits of the specific gravity. Milk which does not contain the required amount of fat cannot be sold as whole milk; if it is so sold it is considered adulterated. Reinsch £? has made a comparison of these require- ments in the German cities. Among 63 ordinances, 60 contain such a minimum limit for fat; 37 of these place the limit at 2.7 per cent., 5 at 2.4 per cent. to 2.5 per cent., 7 at 2.8 per cent., 9 at 3 per cent. and only 2 have established a higher minimum at 3.2 per cent. to 3.3 per cent. In 19 ordinances, the minimum content of solids varies between 10.5 per cent. and 12 per cent.; most require 11 per cent. to 11.5 per cent. Twenty- five place the limits of specific gravity; 10 of these as 1.028 to 1.034, 8 as 1.029 to 1.033 and 5 as 1.029 to 1.034, while a single one provides 1.027 to 1.034. [The German standards are low because the fat con- tent of the milk of some of the breeds of dairy cows 46 Die gesetzliche Regelung des Milchverkehrs in Deutschland, Hamburg, 1903. REGULATION OF SALE 187 in Germany is very low. It would be quite impracti- cable to enforce higher standards under such circum- stances. In 26 states of the United States there are laws estab- lishing milk standards.” The limits for fat are from 3 per cent. (in one state only is the limit below 3 per cent. ; in Rhode Island it is 2.5 per cent.) to 3.5 per cent. (in one state, Massachusetts, for half the year, the limit is 3.7 per cent.). For total solids, the limits are from 12 per cent. (in one state only is the standard lower: Ohio, during May and June, it is 11.5 per cent.) to 13 per cent. The standards for cities and towns vary within the same limits; some are established by the state standard and some by the cities themselves. L. P.] : It is evident from the above requirements that it is difficult to agree on percentages and standards which may be considered perfectly just and reasonable. If the requirements are placed too high, the owners of a num- ber of herds (especially those made up of purchased cows) soon find it impossible to deliver milk in the cities; if the requirements are placed too low, the object of reg- ulation is attained only to a very limited extent. There- fore, it has been suggested that different grades of whole milk be established. Leipzig and Dresden have such a provision, under which only milk with a minimum fat content of 2.8 per cent. to 3 per cent. is permitted to be sold as ‘‘whole milk I quality,’’ while unadulterated cow's milk of less fat content can be sold under the name ‘‘whole milk II quality’’; in Leipzig, however, this can be marketed only with the designation of the fat content. Several other Saxon cities have similar 47 H. E. Alvord and R. A. Pearson, The Milk Supply of 200 Cities and Towns, U. S. Dept. of Agr., B. A. I., Bulletin No. 46, Washington, 1903. 188 MILK HYGIENE provisions, under which milk containing less than 2.8 per cent. fat can be sold only with a definite statement of the fat content. It must depend upon local conditions whether such a provision is desirable or not, and also whether it is re- garded as wise to establish a minimum fat (and solid) content, and at what point these should be placed. [Legal standards for milk are, by some, objected to on two grounds; first, that it is unfair to establish a mini- mum standard so high that it will exclude the milk from some cows, and, second, that if the standard is low it will encourage dealers to dilute rich milk to a point just above the standard. As to the first objection, it does not appear to be un- reasonable that an article of food sold as milk shall be required to contain a certain minimum amount of nutri- ment. Entirely aside from the adulteration of milk, which such standards are established to check, it is pos- sible to select and develop herds of cows of certain breeds that will furnish milk of very low fat and solids— not fat content. What has occurred in this direction is shown by reports on the weekly analyses of the milk of a herd of cows at Jaschkowitz,*® where the milk ran down to 2.47 per cent. fats and 7.88 per cent. solids not fat. The lowest average for the herd for a month was: fat, 2.60 per cent.; solids not fat, 8.06 per cent.; total solids, 10.66 per cent. The official records of Holstein cows 7? show that many individuals yield milk contain- ing less than 3.0 per cent. of fat, and some as little, for a time at least, as 2.6 per cent. This tendency could, undoubtedly, be intensified if the absence of milk stand- 48 Bericht uber die Tatigkeit des Milechwirtschaftlichen Instituts zu Proskau fiir das Jahr 1905-1906. 49 C. B. Lane, Record of Dairy Cows in the United States, U. S. Dept. of Agr., B. A. I., Bulletin No. 75, Washington, 1905. REGULATION OF SALE 189 ards favored it. In other words, the milk could be wa- tered through the cow. The tendency among breeders of Netherland cattle in America (and largely on account of milk standards) is to increase the fat content of their milk, and many such cows yield milk containing 4 per eent. to 4.5 per cent., and, exceptionally, even 5 per cent. of fat. In regard to the second objection, the dilution of rich milk is scarcely more likely to be practiced if there is a minimum standard than if there is none, and it can be prevented quite as effectively by law, inspection and penalty with a minimum standard, as without one. All of the existing standards in the United States are much below the average quality of the milk sold in the cities to which the standards apply. It is proposed by Wing?" that no special standard be established, but that each dealer be required to guarantee his own stand- ard, and that he be held responsible if his milk be found below this guarantee. Some dealers now sell bottled milk of different grades, containing either 4 per cent. or 5 per cent. of fat, but all of it is above the minimum standard. L. P.] Special rules must be made for milk sold under the name “‘ infants’ milk’’ or “nursery milk,’’ and it must be required that this shall come absolutely from herds that are under constant veterinary inspection and whose condition of health and cleanliness and feed are gov- erned by special requirements (see page 174). In a number of German ordinances, in addition to these re- quirements, the minimum fat content is placed at 3.0 per cent., which is considered fair. [In the United States ““Certified milk’’ is usually required to contain 4 per cent. fat.] Another regulation which is justly put upon 50H. H. Wing, Milk and its Products, New York and London, 1899. 190 MILK HYGIENE the dealer in nursery milk is that the milk shall be sold only in clear glass bottles and that the bottles shall be cleansed or sterilized before they are filled. It should be required that milk sold as ‘‘ controlled ” (‘‘certified’’ or ‘‘guaranteed’’) shall come from herds that are under constant and competent veterinary in- spection. Half skimmed or ‘‘ half milk ” is milk from which a part of the fat has been removed. It is well to estab- lish a minimum fat content of 1 to 1.5 per cent., as already has been done in some German cities. [In most cities in America, milk that is below the minimum standard, as half skimmed milk is, can be sold legally only as skimmed milk. There is no grade for milk between whole milk and skimmed milk. The desira- bility of establishing such a grade may well receive care- ful consideration. The same end could be gained by the adoption of Wing’s suggestion, but its enforcement would entail administrative difficulties. L. P.] [Skummed milk is milk from which the cream has been removed by hand skimming or from which the but- ter-fat has been extracted by means of a centrifugal sep- arator. The former kind may contain from 0.5 per cent. to 1.5 per cent. fat, while the latter rarely con- tains more than 0.3 per cent. fat and sometimes as little as 0.01 per cent. The sale of skimmed milk is wholly prohibited in some American cities, as in New York. This prohibition is placed on account of the great in- clination on the part of some dealers to sell skimmed milk as whole milk and the difficulty of detecting and preventing this practice. It is possible, however, to secure a proper observance of the law on this subject, as is proven by the experience of cities in all countries, and it would be far better for the rich City of New York to employ more inspectors, if necessary, to prevent fraud REGULATION OF SALE 1 in the sale of skim milk than to deprive the poor of this wholesome, nutritious and cheap food. It should be required in every case that vessels con- taining skim milk shall be permanently and conspicu- ously marked. To deliver or to store skimmed milk in an unmarked container on the premises or wagon of a dealer should be regarded as evidence of intent to de- fraud and should subject the violator to penalty. Skimmed milk should contain not less than 9.25 per cent. of milk solids. L. P.] Cream, for the production of which the same sani- tary requirements are necessary as for milk, should be sold with the fat content designated, if there is no local regulation to grade it or establish fat percentages. [The percentage of fat in cream varies from 8 per cent. to 50 per cent., or more. The usual quality, as sold in the market, contains about 15 per cent. to 20 per cent. fat. The standard for cream, as established by the U. S. Department of Agriculture, is 18 per cent. Heavy, rich cream contains from 30 per cent. to 40 per cent. fat. L. P.] [Buttermilk requires no special standard except that it be made from clean milk, and in a cleanly way. It is largely used as a summer beverage and, as typhoid bacilli and other pathogenic forms will live in it for some time, it is important that it be protected from con- tamination. An imitation of buttermilk is sometimes made in city milk shops by churning sour skimmed milk. ds ea Pasteurized milk. The following regulations are proposed for milk that has been heated and that is to be sold as ‘‘ pasteurized ’’: Under this name, and without a more detailed statement, should be understood milk that has been heated to at least 80° C. (176° F.); if the milk is pasteurized at a lower temperature, this must be 192 MILK HYGIENE distinctly marked upon the bottle or can, and the milk must not be permitted to go upon the market until the method has received official sanction. Sterilized milk should be sold only with a statement of the way in which sterilization has been done, and not until after the method has been inspected and approved. But it is not enough merely to establish such requirements; the sani- tary officers must see to their enforcement, partly by vis- iting the pasteurizing and sterilizing establishments, partly by taking samples and examining the milk sold. Fortunately, it is possible to determine by chemical means whether milk has been heated to 80° C. (176° IF.) or not. These tests are based on an observation by Arnold and have been developed by Babcock, Storch and others“! The principles are the following: Storch’s method: 5 c.c. of milk are poured into a test tube; a drop of weak solution of hydrogen dioxide (about 0.2 per cent.), which contains about 0.1 per cent. sulphuric acid, is added, and 2 drops of a 2 per cent. solution of paraphenylendiamin, then the fluid is shaken. If the milk or the cream becomes, at once, indigo blue, or the whey violet or reddish brown, then this has not been heated or, at all events, it has not been heated higher than 78° C. (172.5° F.); if the milk becomes a light bluish gray immediately or in the course of half a minute, then it has been heated to 79° to 80° C. (174.2° to 176° F.). If the color remains white, the milk has been heated at least to 80° C. (176° F.). In the examination of sour milk or sour buttermilk, lime water must be added, as the color reaction is not shown in acid solution. Arnold’s guaiac method: a little milk is poured into a test tube and a little tincture of guaiae is added, drop by drop. If the milk has not been heated to 80° C. (176° F.), a blue zone is formed between the two fluids; heated milk gives no reaction, but remains 51 Heating milk to a high temperature coagulates the albumin and globulin and the milk loses its property of ecurdling by the action of rennet. By this change one may discover that it has been heated, but not determine whether the milk has been heated to 80° C. (176°F.), that is, if it has been pasteurized. REGULATION OF SALE 193 white. The guaiac tincture should not be used perfectly fresh but should have stood a few days and its potency have been determined. According to the observations by Glage, the guaiac-wood tincture appears to be more reliable than the harz tincture. Zink recommends the addition of a few drops of weak solution of hydrogen dioxide, as this causes the reaction to be much surer and sharper. Of the two methods, the guaiac method is preferable in that the tineture is very lasting and may be kept a year without becoming ineffective, while the paraphenylendiamin solution must be renewed quite often; on the other hand, the guaiac method is, perhaps, hardly so accurate as the Storch method. Other substances are useful as reagents in combination with hydrogen dioxide, as solution of potassium iodide with starch (Storeh, du Roi, Kohler and others) and ursol (Utz); besides these, a methylene-blue-formalin solution (Schardinger) has been suggested for this purpose. [Storch’s test may also be used for the purpose of detecting the adulteration of fresh milk with diluted condensed milk. In this ease it is well to make the test comparative by running a parallel sample of milk known not to have been heated. L. P.] The sale of milk preparations which are made either by using foreign additions or by some special manipula- tion of the milk should be permitted only when the milk has been produced under the requirements above stated and only on declaration of the composition of the prep- aration. Milk containers. In case the milk is retailed in containers, there should be some _ stipulation in regard to these. Metal cans should be of tinned iron; for tinning, no tin should be used that has more lead than is absolutely necessary; the form must be such that they can be easily cleaned. Bottles are to be made of clear glass so that every impurity is noticeable; their form must, likewise, make satisfactory cleansing possible. In recent years, the large milk companies have en- 13 194 MILK HYGIENE deavored in their own interest, as well as in that of the public, to provide sealed stoppers or covers for delivery bottles and cans, which more surely prevents their being opened before delivery and which makes it impossible for an unscrupulous person to fill anew, with milk or cream, the vessel which, from accident or improper rea- sons, was partly or wholly emptied. With metal cans, this security is most easily effected by the use of a simple lead and wire seal, applied after filling. A per- fectly reliable closure for the bottles, on the other hand, offers some difficulty, because it is so expensive. The accompanying illustrations show some of the methods used. Fig. 15 shows a method of closing which corre- sponds to that used on mineral-water bottles. After closing, a label is pasted over the top; this method is somewhat expensive and does not furnish a satisfactory guarantee as the label is easily loosened. Fig. 17 shows FIG. 15. Ul the method used by the ‘‘ Trifolium ”” milk company in Copenhagen. The upper part of the neck is perforated, and after the bottle has been closed by the insertion of the stopper, a wire is drawn through the holes and se- cured with a lead seal; this method gives efficient pro- tection but is somewhat expensive. Fig. 16 shows a method used during recent years in Germany, which is cheap and quite satisfactory. In the inside of the neck REGULATION OF SALE 195 there is a small groove; after the bottle is filled, it is closed with a paraffined pulpboard cap which is pressed down into the neck of the bottle by means of a stamp, with its edges in the groove; at the same time, the cap is marked, and it cannot be taken out without being torn. A similar cover, a pasteboard cap which is pressed a little way into the bottle (without the groove), is used by many milk concerns, but this gives little security, as the cap can easily be taken out and a new one substituted. [Paper or wood-pulp discs (sterilized) used as stop- pers may be sealed by pouring on top of them a little melted paraffine. This method is used by some dairies that produce certified milk. The customary method, however, among the best dairymen, is to cover the top of the bottle, after it is closed with the usual disc, with a cap of parchment paper, held around the neck of ‘the bottle with a wire, cord or rubber band; or a cap of heavy tin foil is used, which is pressed down around the shoulder at the mouth of the bottle, and this holds its position quite well. Both of these methods have the ad- vantage of thoroughly guarding the mouth of the bottle and the disc that confines the milk. The lip of the bottle, over which the milk must be poured, is prevented from becoming soiled. These methods, however, do not afford. such complete protection against tampering with the contents of the package as is furnished by a lead seal. clowever, if the box in which the bottles of milk are shipped from the farm to the distributing point, or to the customer, is sealed with a lead seal, as is done by some producers, the protection is sufficient. The usual practice among average dairymen is to depend on unparaffined and unsterilized wood-pulp discs, upon which is often printed the name of the dealer. Small dealers (and some large ones as well) some- times indulge in the most vicious and unsanitary prac- 196 0 MILK HYGIENE tices in regard to bottling milk. They pour milk into ‘bottles from cans in their wagons or hand carts on the street, exposing it to dirt, and, worst of all, they some- times fill bottles that have not been cleaned, or that have not been properly cleansed. Milkmen have been known to take a soiled bottle from the house of a customer, fill it with milk on a dirty wagon, while the wind is blowing dust about, close it with a dise taken from a coat pocket, perhaps from alongside a handkerchief, and then deliver it in the next house. It is not surprising that it has been seriously proposed to prohibit the use of milk bottles. But the bottling of milk marks a distinct sanitary ad- ‘vance, where it is carried out in a proper manner. It ehould be provided by public regulation that milk shall be delivered in bottles only under the following conditions: 1. Before they are filled, bottles shall be washed and sterilized, or they shall be Clea ccu by the use of some method that has the approval of the sanitary authorities. 2. Stoppers for the bottles shall be clean (preferably sterilized) and shall be kept only in sterile packages or in a clean metal or glass receptacle provided exclusively for this use. 3. Bottles shall be filled with milk only in a clean room provided for this purpose, and they shall not be removed from this room until they are stoppered. L. P.] III. PUBLIC SUPERVISION TO PREVENT ADULTERATION Just as many foods can be adulterated, so also can milk and cream. As the fat is the most valuable ingredi- ent of milk, a common adulteration consists in partial skimming, or in the addition of skimmed milk or water; less frequently, foreign material is added to the milk in order to give it a better appearance. It can be only excessively rarely that gross adulterations occur, such as the one reported by Sullivan, wherein a sample of PUBLIC SUPERVISION 197 ‘“milk ’’ was found to consist of a mixture of water, white pigment, common salt.and a little skimmed milk. There is no general rule as to the frequency of adul- teration. In some cities, it does not appear to be partic- ularly frequent, while in others it is very common. Besides the adulterations found upon official exam- inations of the market milk in cities, the question of fraud sometimes arises in connection with the milk deliv- ered to creameries. In the creameries, it is customary to use some quick method for determining the approx- imate fat content of the milk that is delivered by the various patrons. In the official control of milk in cities two provisional or preliminary tests have long been used and these are still depended on to some extent; they consist in the de- termination of the specific gravity and in a test of the transparency. Even when used in conjunction, these tests are not to be relied upon very far, but they can be used, if with sufficient caution, to determine whether a more thorough examination be necessary. If it is de- cided that a laboratory examination is required, a sam- ple should be taken with great care, and sealed and delivered to the appropriate expert for analysis. The specific gravity of cow’s milk varies between about 1.027 and 1.040 at 15° C. (60° F.) ; but such differ- ences are to be found only in the milk of certain indi- vidual cows. The specific gravity of mixed-herd milk usually falls between 1.028 and 1.034. If the specific gravity is either above or below these limits it is always suspicious. [The average specific gravity is 1.032.] Many different forms of apparatus have been pro- posed for measuring the transparency of milk, to deter- mine if it is or is not diluted. However, these instru- ments are all defective and the results obtained by their use are not to be regarded as of any value except to indi- 198 MILK HYGIENE cate whether a sample of the milk should be taken for analysis. The transparency of milk is dependent partly on the size and number of the fat globules, and partly on the casein in solution. As milk with fewer, but large, fat globules has not the same transparency as milk with more, but smaller, ones, even if the fat per cent. be the same, it is evident that these methods of examination may give misleading results. Feser’s lactoscope is the simplest and best instru- ment made for this purpose. As Fig. 18 shows, it con- sists of a glass tube which narrows toward the bottom and is closed with a metal cap which supports a short vertical glass column on which are six black lines; the upper part of the glass has divisions marked with a double row of figures. Four c.c. of milk to be examined are poured into the tube, then enough water is added so that it will reach figure 40 (that is, 36 c.c. of water); the fluid is now mixed by shaking. If it is not possible to see the lines on the glass column inside the tube, a little water is added and the tube is again shaken; this is continued until the lines become visible. When they can be seen through the diluted milk, the fat per cent. can be read from the scale. For example, if so much water has been added that the fluid reaches figure 60 (60 e.c. water and milk), then the milk has 3 per cent. fat. As already stated, this result cannot be relied upon; in the examination of skimmed milk, quite too high a per- centage of fat is always indicated and, in regard to whole milk, the test may show from 0.5 per cent. to 1 per cent. too much or too little. On account of the unreliability of this method in many places this preliminary test is no longer used and the inspectors take samples, without preliminary inspec- tion, for examination in the laboratory. [In the use of the lactoscope, the individual coeff- TRANSPARENCY TEST 199 cient is of great moment. Different inspectors will in- terpret the same result quite differently. When one is experienced in examining with the lactoscope the milk of a given breed of cows, he may become so proficient that he can make a fair estimate of the fat content, but Feser's Lactoscope. Quevenne's Lactodensimeter. when another kind of milk is examined the result may not be so accurate. If milk tests normally, both in re- spect to specific gravity and lactoscopically, it is not apt to be much skimmed or watered. The following is from Leach: >? 52 A. E. Leach, Food Inspection and Analysis. New York, 1905. 200 MILK HYGIENE “As in the case of the lactometer, the purity of a milk sample cannot be positively established by the lactoscope alone. For instance, a watered milk abnormally high in fat would often be found to read within the limits of pure milk, when as a matter of fact its solids would be below standard. By a careful comparison of the readings of both the lactoscope and the lactometer, however, it is rare that a skimmed or watered sample could escape detection. “Thus, if the specific gravity by the lactometer is well within the limits of pure milk, and the fat, as shown by the lactoscope, is above 34 per cent., the sample may be safely passed as pure, or as conforming to the standard. £ A normal lactometer reading in connection with an abnormally low lactoscope reading shows both watering and skimming, and with an abnormally high lactoscope reading shows a milk high in fat, or a cream. With the lactoscope reading below three, and a low lactometer reading, watering is indicated. A lactometer reading above thirty-three, and a low lactoscope reading, indicate skim- nm 108 1225] IV. METHODS OF EXAMINATION In order to determine whether adulteration has taken place or not, the examination should cover the follow- ing: The specific gravity of the milk and of the whey, the fat content of the milk, the amount of milk solids, the amount of solids not fat, the specific gravity of the solids, the quantity of fat [and the percentage of ash]. Sometimes, the examination is extended to include the taking of a herd sample under special conditions in order to make a comparison between the sample officially collected and the milk offered for sale. Finally, foreign ingredients are tested for, as ni- trates, starch, [preservatives, artificial color, ‘‘ visco- gen,’’ gelatin, etc. ]. a. Taking samples for laboratory examination must be conducted with great care. Upon standing, the cream quickly rises to the top, so that the upper part of the milk contains more fat, even though no definite layer of cream has yet been formed. Therefore, before the test METHODS OF EXAMINATION 201 is made, the milk should be well mixed. In milk that has been thoroughly chilled, it is difficult to again mix the cream equally, so one must be very exact in taking the sample. It often happens, in the milk shops, that the milk is not well mixed when sold and an examination of what is left may show so low a percentage of fat that one immediately becomes suspicious that adulteration has taken place, although it may not be so. b. Preserving the sample for analysis. If the milk sam- ple is to be kept or shipped, it is necessary to add a pre- servative. For this, potassium dichromate (1 grm. to 1 hter) is used, which keeps the milk fluid for a long time; this addition causes an increase in the specific gravity and the result of the chemical examination is also af- fected. This must be taken into consideration at the final test. It is generally better to add 20 drops of forma- lin to every liter, yet in this case it is possible that the specific gravity of the whey may be affected, on account of a partial splitting of the casein. It is still better to boil the filled bottle and then close it with a sterilized cork. In taking the sample, it is also necessary to avoid adding water even in the slightest quantity (rinse the bottles with milk), in order that no nitrate shall be added. c. The herd sample. In cases in which adulteration is suspected, comparison may be made of the milk under suspicion with that of the herd milked under super- vision. The importance of the stable, or herd test has been much overestimated. The great variations in the composition of the milk of individual animals, leads one to be careful in putting confidence in a comparison of the fat content of milk on different days; but comparisons may fairly be made between the quantities of solids not fat and the specific gravity of the whey, which are fairly regular. The stable or herd test is very uncertain, therefore, for individual cows, or small herds, but it may 202 i MILK HYGIENE sometimes be used with advantage for large herds, al- though there is seldom cause, even in this case, to apply it. In taking a herd sample, the feeding and the care of the animals should not be varied in any respect, the milking should be conducted by the usual persons at the usual times and in the usual way; less thorough milking gives lower fat content, while particularly thorough milking raises the percentage of fat. The quantity of milk for the day must be mixed together and the sample taken from the whole. Ås transitory changes occur in the composition of the milk, surer results will be gained from daily examinations for several days than from but one examination. d. Determining the specific gravity of milk and whey. Various instruments are used for this purpose: different areometers, the pycnometer or the hydrostatic scale. The areometer method is the simplest and, at the same time, it is sufficiently accurate, so there is no occasion to describe more in detail the other methods, which require weighings. Quevenne’s lactodensvmeter, in some one of its sev- eral modifications, is the areometer in common use. This is made like an ordinary areometer and divided into degrees which correspond to a specific gravity from 1.014 to 1.040, or only from 1.022 to 1.038, since, by the latter division, a greater space is gained between the different degrees, without unduly lengthening the in- strument. From such a lactodensimeter one can easily read off four decimal places. The milk whose specific gravity is to be determined is well shaken and poured into a high glass cylinder of suitable diameter; the areometer is dropped in slowly, in order to prevent its bobbing up and down. [The bulb should be free from adhering air bubbles.] The figures LACTOMETER TESTS 203 on the stem are the second and third decimals of the numbers of the specific gravity, so that 34 is to be read 1.034. For this examination, the temperature of the milk must be 15° C. (60° F.); if it is not, the specific gravity of the milk at 15° C. must be calculated from the specific gravity found and from the temperature, for in milk inspection and analysis this is the standard. With the aid of the tables on pages 204 and 205, one of which is valid for whole milk and the other for skimmed milk, one can easily compute specific gravity for 15° C. from that found at another temperature. If the temperature of the whole milk is 18° C., and the lactodensimeter reads 29, one finds in the table, at the intersection of the perpendicular column 18° C. and the horizontal line 1.029, the number 29.6; the specific gravity is therefore equal to 1.0296 at 15° C. (See tables, pages 204 and 205.) In several of the lactodensimeters (e.g., Soxhlet’s) there is a thermometer in the instrument, whose scale does not show the degree of heat but gives directly the decimal to be added to or subtracted from the reading on the stem of the lactodensimeter, as the specific grav- ity. If the latter number is, for example, 29, and if the thermometer registers 3.5 above zero, the specific grav- ik kor CS 1s 102935: | [The so-called New York Board of Health lactometer has an arbitrary scale divided into 120 equal parts. One hundred on this scale corresponds with a specific gravity of 1.029, which was supposed to represent the lowest specific gravity of pure milk, and 0 represents 1.000, the specific gravity of water. If the specific gravity of a sample of milk fell to 90 it was supposed to be 90 per cent. pure, that is, to contain 10 per cent. of added water. But the specific gravity of milk varies so that this cannot be relied on and there is no single advantage MILK HYGIENE 204 NTOUUOIUPYA soimjerod uo, 00°89 | 06°99 | oF F9 | 09°S9 | 08'°0G | .0°6G | OG LG | oF GG | o9°EG | o8'TG | .0°0G | o0'8F | oF IP | 9 FP | 08 GP fog | O98 | 268 | PGE | ogg | OSE | 2ZHS | FHS | SHE | OFS | BSE | MEE | VES | oe | TEE Ge0'T ees | O¢S | LHS | THE | SE | OFE | VES | GEE | SSS | TEE | 6S | AGE | GCE | GCE | Gas veo T ESPE | OFS | MES | PES | SES | OS | SCE | OE | HS | oes | OVE | SIE | STE | VIE | STE €e0'T CROC ENIS GER RTE siGGel GCG NOG a |nSilG | Glen | VIS ole | OS | 38084) 90S" | SOS) 10s ce0'T €cs | OCS | LIS | PIE | STE | OTS | SOS | 9OE | POS | GOS | OOS | 86e | 46e | 96e | S6e TEO'T GIS | 60 | 908 | FOE | ZOE | 0:0 | 862 | 96Z | F6S | G6S | 06S | 88S | 486 | 98S | 86 0€0'T GOS | 662 | 962 | 16S | 262 | 06S | 88S | 986 | V8S | 8S | [8s | 626 | BLS | LL] | VLE 620°T 666 | 68S | 98S | F83 | 8S | O8S | 843 | 943 | HLS | SLE | TLS | WLe | 69 | 89S | 19% 820'T G86 | 616 | OLE | HLS | S16 | OLS | 89S | 99S | GOS | F9S | 9S | 19S | OV | 6Se | Bes LG0'T TLZ | 693 | 9°92 | #96 | 79S | O96 | BSS | OES | Gas | Soe | age | TSe | OFS | GFE | 8a 920'°T 096 | 89 | OES | HES | Tes | OFS | 82 | OFS | GTS | SHS | SHS | THs | OFS | GEE | SES GZ0'T OSS | ShS | OFZ | HHS | SHS | OFS | BES | OES | GES | VES | SES | GES | LEG | OSS | 62S 60 T OFS | 883 | HES | HES | SES | OFS | 873 | HV | GES | VSS | FSS | GGG | Tas | OGE | 616 €60'T O§Z | 82S | OSS | HSS | 332 | OVS | SIZ | 9IS | GIS | WIS | SIS | Sle | TIG | OTs | 6/06 G60'T O'ge | SIZ | 9TZ | FIZ | SIS | OTS | 8703 | 90% | GOG | FOS | FOS | &0G | TOS | 00] | GEL T60'T G06 | 403 | $0g | 802 | 10e | 0'02 | 8'6T | 96T | $6T | F'6I | &6T | G6T | T6I | OGL | 0'61 0G0'T GEGEN GER | GEL | GOL | WOE | OGL | eRe) Ate) Ge qc FASTE RSS IEEE GESTEN HIT RS TE Is net 610 T 006 | o6T | 281 | oLLT | 9L | GT | oPT | ST | ST | ofl | OF 06 08 ob o9 “APIABIDH OYTOOdY ‘OpBISIUDD soinjviod ua, AMALVANdNAL OL DNIGHMOOOV MITA DIOHM HO ALIAVYS OIHIOHdS AHL ONILDTHUAUOOV JOH Wav 205 SPECIFIC GRAVITY DETERMINATION eS OS EE EE EE eee a 00°89 | 06°99 | oF ¥9 GIv | 6'0r | 90P GOV | 668 | 96 G6E | 68E | 98E G8E | BLE | OLE TE | 698 | 99& O9€ | 8Ss | OSE OGE | SPE | OPE OPE | SEE | OE OSE | SCE | OE OcE | SIE | OTE 6:08 | 20E | GOES 666 | L266 | $'66 686 | L286 | G'86 616 | L146 | GL] 696 | 296 | 96 sae | 946 | FG SPE | OFS | FFG BEG | OES | FES ‘qIoyuoIyRy samerddwoal 0969 | 08°09 | .0°6S | OG LG | oF GG | o9°EG | 81S | 0°0G | BBP | OP IP | 9 FP | 8 BP Or | 20h | OOF | 868 | 968 | HEE | G6E | T6E | 68E | 88s | 48E | OE 0r0'T V6E | J6§ | O6E | V8E | 98E | VSS | S8E | o8E | OBS | BLE | SLE | ALE 6€0°T V8E | @8E | O8S | SZE | 9L4E EPS | SZE | o2s | TZE | OLE | 69S | 89E 8E0T Ve Gece OG. | S98 eG MOG ee. leaoe. | Los a O08 OSs 4) 8cs LE0'T POS | S98 | O9E | SEE | OEE | HEE | Ses | oss | TSS | OSS | BE | STE 9€0'T PCS | Sos | OG | SPE | OVE | HHE | EVE | SHE | THE | OVE | GEE | BEE GE0'T VPS | GPS | OE | SES-| OSE | GES | HEE | SSE | SSE | Les | OSS | Gcé veo rss | oes | OS | Sos | PSE | SSE | Fes | ESE | SS | TSE | OE | NSE €e0'T Pee eas |] Os | Gas OWS | CS NAPS |W GIS es PRS | Wks |) Oks cE0'T VIS | ats | OT8& | SCs | 908 cs | 70s | GOs | GUS | IOs OOS Os TE0'T €0E | TOE | OOS | 86% | 966 | 6S | F'62 | S6S | 62 | 16s | 066 | 062 0£0'T &'6G | 16% | 0'6 | 883 | 986 | 983 | F8S | &'82. | 8s | T8G | 18S | T'86 620°T 8c | 18s | O82 | S46 | 922 | GAS | HLS | GAS. | ole | Le | Vs] | 122 820°T $12 | VL4S | OLB | 89S | 99S | G9 | H9S | €9S_.| G9S | T9S | L9G | 19 LG0°T 92 | 19S | O92 | 8'Se | 9ES | Gee | FEs | Eee | age | Tse | Ve | Se 960'1 Go | 1&6 | OGG | SPS | 9S | GE | Tr | St | She | Lee | Lhe | Lhe G20'T GS | LPS |. OPS | BES | LES | OES | SES | VES | SES | SES | GES | GES ¥G0'T SSS | VSS | OSS | 62S | VSS | LS | YS | GEC | HVS | FSS | FCS | GCs €20'T oLT | o9f | oGT | OPTI | o&T | SL | oft | OL 06 08 ol o9 mm "Ayraviy) oyroadg ‘OpPVISIUIO soinyBiod ula, HAUAALVAHdWÆL OL SNIGMOOOV MTIW CIWWINSS JO ALIAVED OIdIOHdS AHL ONILOMAMOD WON ATAVL 206 MILK HYGIENE in this arbitrary scale, which is very confusing. Un- fortunately, however, it has come into rather general use among milk inspectors, especially in the Eastern States. To convert readings of this lactometer into corre- sponding readings of the Quevenne scale, they must be multiplied by 0.29, or, the following table may be used: QUEVENNE LACTOMETER DEGREES CORRESPONDING TO NEW YORK BOARD OF HEALTH LACTOMETER DEGREES. Board of 4 Board of Board of See | | ee | ee 8 AR 61 17-7 81 23-5 101 29-3 62 18-0 82 23-8 102 29-6 63 18-3 83 24-1 103 29-9 64 18-6 84 24-4 104 30-2 65 18-8 85 24-6 105 30-5 66 19-1 86 24-9 106 30-7. 67 19-4 87 25-2 107 31-0 68 19-7 88 25-5 108 31-3 69 20-0 89 25-8 109 31-6 70 20-3 90 26-1 110 31-9 71 20-6 Sl 26—4 111 32-2 72 20-9 92 26-7 112 32-9 om 21-2 93 27-0 113 32—8 74 21-5 94 27-3 114 33-1 75 21-7 95 27-6 115 30-4 76 22-0 96 27-8 116 33-6 aa 22-3 97 28-1 15187 33—9 78 22—6 98 28—4 118 34—2 79 22—9 99 28—7 119 34-5 80 23-2 100 29-0 120 34-8 Te] Specific gravity of the whey. In many eases it is of value to determine the specific gravity of the whey be- cause this is much more constant than that of milk, for the reason that the lactose and salt vary less than the fat. SPECIFIC GRAVITY OF WHEY 207 Lescoeur warms the milk to 45° C. (113° F.) and adds rennet; after about one-half hour the whey is pressed out and filtered, then it is cooled to exactly 15° C.; the specific gravity may then vary between 1.029 and 1.031, but if water has been added it decreases significantly, as shown below: Whey of pure milk = 1.0300 Whey of milk +10 per cent. water 1.0275 Whey of milk +20 per cent. water = 1.0251 Whey of milk + 30 per cent. water 1.0230 Reich recommends that 20 c.c. glacial acetic acid be added to 500 ee. milk, that the mixture be well shaken and heated for 5 to 6 minutes to 60° to 65° C. (140° to 150° F-.) in a closed flask, then cooled and filtered; the filtrate is to be heated in a flask until the albu- min coagulates, then filtered again and the specific gravity determined after cooling to 15° C. According to his results, this varies between 1.027 and 1.029; a specific gravity of 1.026 is always a sign of the addition of water. If one wishes to apply the determination of specific gravity of whey to milk inspection, it is necessary to develop a definite method, which must be followed out exactly, for, otherwise, the result is uncertain; and be- fore basing a prosecution on the results of this method, one must have made careful comparisons, with the same method, of normal and watered milks. From investigations that were undertaken in Copen- hagen under Jensen’s direction, it appears that these two methods do not give uniform results. From 35 milk samples the following results were obtained: Rennet method Acid method Specific gravity Specific gravity 7 samples 1.0270 to 1.0274 2 samples 1.0257 to 1.0259 7 rf 1.0275 to 1.0279 10 a 1.0260 to 1.0264 Hi ef 1.0280 to 1.0284 15 vg 1.0265 to 1.0269 5) 6 ae 1.0285 to 1.0290 8 = 1.0270 to 1.0276 208 MILK HYGIENE The addition of water causes a lower specific gravity of the whey. In the examination of adulterated skimmed milk, he found the figures to be 1.0256, 1.0246, 1.0254 and 1.0257 (rennet method) and 1.0242, 1.0234, 1.0238 and 1.0241 (acid method). e. The determination of the fat content of milk. There are many methods for determining the fat content of milk; some of these are too inexact to be considered (e.g., the above mentioned transparency test by means of the lactoscope, and the like), others give very good results but require rather expensive apparatus, still others require exact weighings and work that can be done only in chemical laboratories. Some simple tests are, however, so accurate and so practical that they are available for the work of milk inspection. Among the methods used, besides the transparency test already mentioned, the creamometer should be named, that is, the measurement of the layer of cream which rises when the milk is allowed to stand. Since, however, the thickness of the layer of cream furnishes no reliable gauge as to the fat content, this method can- not be used if there is to be a prosecution. The separa- tion of the cream by a centrifuge of high velocity (Fjord’s test), and subsequently measuring the layer of cream, gives better results and is often used in cream- eries for comparing milks. For general use, however, it is impractical, and not sufficiently accurate. The available methods are, principally, Soxhlet’s method, which was formerly used to a greater extent than it is now; Gerber’s method, [the Leffmann-Beam and the Babcock methods] and methods of chemical analysis. Soxhlet’s method is founded upon the following prin- ciple: the solution of the fat in ether and the determina- tion of the specific gravity of this solution. GERBER’S FAT DETERMINATION 209 The following appliances are necessary for this examination (see Fig. 20): (1) three pipettes of 200, 60 and 10 c.c.; (2) several half liter bottles; (3) two delicate areometers with thermometer, one for whole milk and the other for skimmed milk; (4) one large glass tube (A) adjusted for flowing water; (5) a smaller glass tube (B) enclosed in A; (6) a rubber bulb with a tube; (7) a larger container filled with water heated to 17° to 18° C. Besides these, the following chemicals are necessary: (8) potassium hydroxide solution, of specific gravity 1.27 (400 gr. potassium hydroxide is dissolved in water and after the solution has cooled it is made up to 1 liter); (9) ether, shaken with one-fifth its volume of water and decanted off; (10) ordinary ether. The milk to be examined is warmed in a water bath to 18° C. and is well shaken. By means of a pipette, 200 ¢.c. of this are drawn off and mixed in a bottle with 10 c.c. of the potassium hydroxide solution. Then, 60 c.c. of ether are added. The bottle is immediately closed by a perfectly tight stopper, is violently shaken and allowed to stand one-fourth hour in water at 18° C., during which time it must be shaken frequently. Gradually, the ether dissolves the fat and a transparent layer is formed on the surface. Now the stopper of the bottle is replaced by another (D) and, by means of a bulb, the transparent fat-containing ether is driven up into the tube B which is surrounded in tube A by water warmed to 18° C. The areometer (C) is in the inner tube, and after the fluid rises so high that it ean float, the flow is checked by means of a valve q, then the specific gravity is read. The quantity of fat dissolved is shown, and from this the fat content of the milk can be ecaleulated. Soxhlet’s apparatus is accompanied by tables from which the fat content of the milk can easily be read, if one has determined the specific gravity of the fat-ether, and has read its temperature. Gerber’s acidobutyrometer affords a very convenient and accurate way of determining fat, that is widely used. The method consists in measuring the quantity of fat in an accurately measured quantity of milk, after the fat has been separated and dissolved in amyl-alco- hol. Gerber’s instrument (see figs. 21 and 22), consists of a centrifuge, bottles (G) of special shape, and 3 pipettes, i.e.: 1 acid pipette to hold 10 ¢.c.(H) and 2 small pipettes (I, K) of 1 and 11 ce. capacity. These chem- 14 210 MILK HYGIENE icals are required: crude sulphurie acid of a specific gravity at 15° C. (60° F.) of 1.825, and amyl-aleohol. The examination is made in the following way: 10 e.c. Fia. 20. Soxhlet’s apparatus for fat-determination. of sulphuric acid are measured out by the acid pipette, this is permitted to flow slowly into the bottle G; 1 c.c. of amyl-aleohol is measured and poured carefully into GERBER’S FAT DETERMINATION 211 the glass so that it forms a layer upon the surface of the sulphuric acid. Now, exactly 11 c.c. of well mixed milk that has been heated to 15° C. (60° F.) are measured and poured into the bottle, which is closed by a rubber stopper and then it is well shaken. The milk dissolves with the generation of considerable heat. The stopper is driven in so far that in the inverted bottle, the fluid FIG. 21. ==! Tm =e El Gerber's apparatus for fat-determination. reaches the mark 0 on the scale; the bottle is put into the centrifuge and this is set in motion, after it has been well balanced. If the sample is not to be centrifuged at once, the bottle should be placed in a water bath at 60? to 65° C. (140° to 150° F.). The process of centrifuging lasts 10 minutes with such a machine as shown in figure 21; and in order to keep up speed it is necessary to ac- 212 MILK HYGIENE celerate the motion three times, by drawing the strap. [With some patterns of centrifuge, those that have a velocity of 800 to 1000 per minute, the whirling is com- pleted in 3 to 4 minutes.] After centrifuging, the bottle is taken out and placed in a water bath at 60° C. (140° F.). The fat forms a clear layer in the top of the tube. Through shifting the stopper, the lower border of the Fig. 22. Test bottles and pipettes used in connection with Gerber s method for fat-determination. fat layer can be brought into the same plane with one of the division lines and the thickness of the layer of fat ean be read off. One should read from the lower part of the curved upper line. The upper, narrow part of the tube is divided in 90 parts, each line corresponds to 0.1 per cent. fat; for example, if the fat layer reaches line 35, then the fat content of the milk is 3.5 per cent. LEFFMANN’S FAT DETERMINATION 213 [The Leffmann-Beam method (sometimes, improp- erly, called the Beimling test) was worked out in ad- vance of the Gerber test, which resembles it. The fol- lowing description is from Leffmann:*? ‘‘ The dis- tinctive feature is the use of fusel oil, the effect of which is to produce a greater difference in surface tension between the fat and the liquid in which it is suspended, and thus promote its readier separation. This effect has been found to be heightened by the presence of a small amount of hydrochloric acid. ‘‘' The test bottles have a capacity of about 30 c.c. and are provided with a graduated neck, each division. of which represents 0.1 per cent., by weight, of butter fat. ‘* Fifteen c.c. of the milk are measured into the bot- tle, 3 ec. of a mixture of equal parts of amyl-alcohol and strong hydrochloric acid added, mixed, the bottle filled nearly to the neck with concentrated sulphuric acid, and the liquids mixed by holding the bottle by the neck and giving it a gyratory motion. The neck is now filled to about the zero point with a mixture of sulphuric acid and water prepared at the time. It is then placed in the centrifugal machine, which is so arranged that when at rest the bottles are in a vertical position. If only one test is to be made, the equilibrium of the machine is maintained by means of a test bottle, or bottles, filled with a mixture of equal parts of sulphuric acid and water. After rotation for from one to two minutes, the fat will collect in the neck of the bottle and the percent- age may be read off. It is convenient to use a pair of dividers in making the reading. The legs of these are placed at the upper and lower limits respectively of the fat, allowance being made for the meniscus; one leg is 53 Henry Leffmann, Analysis of Milk and Milk Products. Phila- delphia, 1905. 214 MILK HYGIENE then placed at the zero point and the reading made with the other. Experience by analysts in various parts of the world has shown that with properly graduated bottles the results are reliable. As a rule, they do not differ more than 0.1 per cent. from those obtained by the Adam’s process, and are generally even closer. € The mixture of fusel oil and hydrochloric acid seems to become less satisfactory when lorg kept. It should be clear and not very dark in color. It is best ‘kept in a bottle provided with a pipette, which can be filled to the mark by dipping. Rigid accuracy in the measurement is not needed.” The Babcock method or ‘‘ test ”” is, in America, by far the best known and most used centrifugal test for fat in milk. The Leffmann-Beam and the Gerber tests are, however, being used more and more, on account of the shorter time required. In careful hands, the Babcock test is very accurate. Small or large outfits, the centrifuges to be driven by hand or power, may be purchased from any dairy sup- ply establishment. The test is made by placing in the special test bottle 18 grams (17.6 cc.) of milk. To this is added, from a pipette, burette or measuring bottle, 17.5 ce. commercial sulphuric acid of a specific gravity of 1.82 to 1.83. The contents of the bottle are carefully and thoroughly mixed by a rotary motion. The mixture becomes brown and heat is generated. The test bottle is now placed in a properly balanced centrifuge and whirled for five minutes at a speed of from 800 to 1200 revolutions per minute. Hot water is then added to fill the bottle to the lower part of the neck, after which it is again whirled for two minutes. Now, enough hot water is added to float the column of fat into the grad- uated portion of the neck of the bottle, and the whirling is repeated for a minute. BABCOCK’S FAT DETERMINATION = 215 The amount of fat is read while the neck of the bottle is still hot. The reading is from the upper limits of the mensicus instead of the lower, as with the Gerber and the Leffmann-Beam tests. A pair of calipers is of as- sistance in measuring the column of fat. L. P.] The chemical methods consist in accurately weighing the fat separated from a definite quantity of milk. The FIG. 23. ul im ==—= | hh I | = | | FEE — ss mining —— —— “AU NT MA / ‘| I an Hey an | ——— Ss HIT nT jin”! 1] EN) Nill Sil gwd One form of Babcock's apparatus for fat-determination.* most exact result is gained by the evaporation of a defi- nite amount of milk (see below) and by the extraction of the fat from the evaporated mass by ether or benzine, which is then evaporated. Quite accurate results are also gained without evaporating the milk, by separating * From “ Principles and Practice of Butter-Making,” by McKay and Larsen, by permission of Messrs. John Wiley & Sons, the publishers. 216 MILK HYGIENE the fats from the other ingredients and ascertaining their weight. Gottleib’s method gives results sufficiently accurate for our use. For this method one requires, as apparatus, only a cylinder of 40 e.c. capacity, divided to measure quantities of 0.5 c.c., some glass flasks and a long, thin glass syphon. 10 grm. of milk are accurately weighed into one of the small flasks and poured into the glass cylinder; the amount of milk left adhering to the walls of the flask is determined by a second weighing, so that one may know exactly how much has been poured into the cylinder. 1 c.c. of 10 per cent. ammonia water (specific gravity 0.96) is mixed with the milk and shaken, then 10 ¢.c. alcohol (95 per cent.) are added and it is shaken again, after which 25 c.c. ether are added. The cylinder is well closed with a cork that has been moistened in water, and shaken hard. 25 ec. petroleum benzine are added and, after repeated shaking, the bottle should be allowed to stand undisturbed at least 6 hours. By that time, the fluid 1s separated into two sharply marked layers; the upper one is the ether-benzine-fat mixture, the under one contains the water, the lactose and proteids; a whitish sediment consists of phosphates. The volume of the upper layer of the fluid is read off and a determined quantity of it is syphoned off into a small weighed flask. The ether and benzine are now evaporated by mild heat. Thereupon, the flask is allowed to stand a couple of hours in a drying chamber at 100° C., is cooled in an exsiceator and, finally, weighed. From the total volume of the mixture of ether, benzine and fat, and from the quantity of fat in the portion evaporated, the weight of the total fat content of the milk sample can be calculated, and thus the percentage is determined. f. Determination of the total solids in milk. The total solids in milk are determined chemically in the following way: Exactly 10 c.c. of milk are measured into a plat- inum or porcelain vessel, the weight of which is already known; the vessel is heated in a water bath to 100° C. until all the water is evaporated. After cooling in an exsiceator, the vessel and its contents are weighed. The difference between the weight found and the original weight of the dish gives the total amount of solids in the milk. If the amount of fat, found in another way, is DETERMINATION OF SOLIDS 217 subtracted, one gets the quantity of solids not fat. By incinerating the contents of the vessel, in a muffle oven, and again weighing, the amount of salts, or ash, is deter- mined. If it is desired to extract the fat from the other solids, to determine the fat percentage, it is necessary before drying the milk to mix with it a weighed quantity of roasted pumice stone; then, after evaporation, the fat is removed by means of ether (or benzine) in an ordi- nary fat extraction apparatus, and is determined by weighing, after evaporating the ether. This work is quite particular and requires a well appointed labora- tory. Moreover, in practical milk control, gravimetric analyses are not indispensable, for one can easily cal- culate the quantity of solids from the specific gravity and the fat, according to the formula derived by Fleisch- mann. If total solids are represented by t, the fat per cent. by f and the specific gravity by s, one has: fee ate zs IE That is, if we say f = 3.55 and s = 1.0327, we get 100 X 1.0327 — 100 1.0327 7 ) = 4.260 -+ 2.665 X 3.27 — 12.697 — 1.2 .55 2 t=1. x 8.55 + ( 665 X 1.0327 Another formula proposed by Bertschinger gives quite accurate results: 5f + 100s USSR TEE + 0.07 Moreover, tables have been worked out from which the total solids can be read off, if both the other factors are known. Ackermann has constructed an ‘‘ automatic reckoner ’’ from which one can read off one of the fac- tors when both of the others are known, by simply turn- ing circular dises. [Richmond has devised a sliding rule for the same purpose. | The computation of the solids not fat is very easy. 218 MILK HYGIENE One has only to subtract the fat percentage found from the computed percentage of total solids. The percent- age of fat (p) in the total solids is easily computed according to the formula: p=. 100 To use the above illustration: p= Soe, X 100 = 27.95 Likewise, it is quite easy to determine the specific gravity (m) of the dry milk solids by a simple computa- tion, according to this formula: nt st ~ st — (100s — 100) m Using the same illustration again: 1.0327 12.697 13.112 ie 10827 2169703272100), =e Teas m The specific gravity of the dry solids of whole milk varies, according to the fat content, between about 1.31 and 1.36. V. ADULTERATION AND ITS DETECTION. The most frequent adulterations of whole milk con- sist in partial skimming, dilution with skimmed milk, dilution with water or a combination of these. Skimmed milk is adulterated by the addition of water, and cream by starch, flour, ete. a. Partial skimming of whole milk or dilution with skimmed milk produce the same result; in both cases the fat content is lessened, while the percentage of solids not fat is increased very slightly, and the specific gravity is increased. If the skimming is not so great as to cause the fat percentage to fall below the minimum limit for DETECTION OF ADULTERATION 219 mixed milk and the specific gravity to rise above its Inaximum (1.034), this adulteration is difficult to dis- cover, as the considerable variations in normal milk | would lead one to expect. It is in these cases that com- parison was formerly made with the stable or herd sam- ples, but, as stated before, these are worth but little in relation to small herds, and even in the case of large ones they are not entirely trustworthy. When it is pos- sible to compare the figures of inspected milk with the results of the herd test, an opinion can be formed as to how great a percentage of the fat content is lacking, from this formula: x = 100 x #4 in which F shows the fat percentage in the herd sample and f the fat percentage of the sample under suspicion. Where there is reason for suspicion, the best method for proving the existence of such adulteration is, in many cases, furnished by the judicial hearing of the persons charged, and the witnesses. In many places, as has already been stated, to prevent such adulterations a minimum standard has been established for the fat con- tent of whole milk. [In America, where there are legal standards calling for 3 to 3.5 per cent. of fat in whole milk, prosecutions for partial skimming or dilution with skimmed milk are not often brought if the sample comes up to this estab- lished standard, although such adulteration may be suspected from a marked disproportion between the fat and the solids not fat. But this proportion is, at best, so variable that it furnishes no definite guide. ESP: b. The dilution of whole milk with water causes an increase of volume and, therefore, a decrease in the per- centage of fat, of solids and of the specific gravity of the 220 MILK HYGIENE milk, as well as of the whey. Feser gives the following example: Start with 9 liters of milk of the composition: 3.95 per cent., fat; 8.9 per cent., solids not fat; 1.031, specific gravity. To this add hk liter of water of this soap RER 0 per cent., fat; 0 per cent., solids not fat; 1.000, specific gravity. This gives 10 liters of adulterated milk of the com- position: 3.55 per cent., fat; about 8.0 per cent., solids not fat; 1.028, specific gravity. Further evidence of this adulteration is found in the lower specific gravity of the whey and in the fact that the specific gravity of the dry solids (m) and the fat content (p) of the solids are, practically, normal; in the above example, then: &? ee ST så 1.031 X 12.85 BIDE ene — ST — (1008 — 100) 1.031 X 12.85 — (100 X 1.031 — 100) 1014 ~ ae st et 1.028 11.55 oe SS a ag FEE) i ERE) TT IE NE 3.95 a Fe eae OX 200 pas X 100 = 30.738 p= X 100 = = x 100 = 30.736 If milk samples are available which may be justly com- pared with the milk under suspicion (herd samples taken under fixed conditions; milk from the same large herd; other milk sent by the same shipper or from the same can in the dealer’s possession), then the percent- age of water added can be computed according to Vo- gel’s formula: x= X 100+ 100 541M and P represent the specific gravity of the total solids and the percentage of fat in the total solids of whole milk, and m and p the same factors in adulterated milk.] DETECTION OF ADULTERATION rapa In the example just. given we have F = 3.95 and f == 5.00, then 3.95 X= Gar X 100 — 100 % that is, exactly 1 part to 9 parts. On account of the great variations in the percentage of fat, one must be very careful with this computation. In detecting this adulteration, the herd sample is of some value, since the solids not fat are subject only to shght variations. In drawing conclusions, therefore, these other factors must have full consideration (esti- mated solids not fat, specific gravity of the whey), and are of more value as a guide than the percentage of fat. [The percentage of solids not fat should not be less than 8.5 or 9. The percentage of ash is of considerable value in detecting adulteration by adding water. This factor is rather constant, and in pure milk is usually between 0.70 and 0.75 per cent. L.P.] It has been suggested that use be made of the deter- mination of the freezing point of milk and of its conduct- ibility for electricity, since these qualities are consid- erably changed by the addition of water. But these methods are not yet sufficiently developed to be avail- able. On the other hand, there may be some advantage in determining the acidity of the milk, since this is less- ened by dilution (see page 227), yet the lessened acidity may come from other causes. The addition of lactose or cane sugar to milk diluted with water, renders judgment more difficult, since, by this means, the specific gravity of the milk as well as that of the whey, and also the amount of solids not fat, is increased. While milk is always free of nitrates and nitrites, even if the animals have taken such substances with 299 NIGER HYGIENE their food, these are frequently present in water in small quantity. The presence of nitrates or nitrites in the milk, therefore, shows, with certainty, that water has been added. However, the lack of nitrates does not ex- clude this, as all water does not contain nitrates. Even a very small quantity of nitrates and nitrites can be detected as follows: 1.5 c.c. of a 20 per cent. calcium chloride solution is added to 100 ¢.c. of milk; the mixture is boiled and filtered. Og Se | Se (6. | se | S382 | S22 eee Sa | 8. | 2s | 8S | Bas | Sas | o@ | Bes ° oe 72) On mn 3 Ds SN a |e Ben sø AE HD | 1.029 to NG ra ae At 1.034 | 1.029 to , | 8.5to |1.30to | 20to | 0.7 to | armen, rose 2-10 24 sigi5) Faroe Horne NER 0 (| 1.032 Skimmed or diluted 2 no very : with skimmed milk 4 | higher change lower jslightly) higher | lower | higher 0 | higher Water added ........ | | lower | lower | lower | lower | nee lchanee| lower | + or0 Skimmed and Seah DE water added....... | Face lower | lower | lower | higher | lower | lower | + or0 Although each form of adulteration has its own char- acteristics yet, in practice, it is often very hard to deter- mine whether a shght adulteration has occurred, be- cause the composition of milk, as explained above, dif- fers so much physiologically—and with the same animal from day to day. Unless there is a distinct departure from the normal, one should be careful in expressing his opinion, especially if he does not know the herd con- * This table is changed somewhat from the one prepared by Jensen [L. P.] DETECTION OF ADULTERATION 225 cerned. Usually, the presence of nitrates is positive, still it must not be forgotten that when the milk can is rinsed a little water may be left, which, if it is rich in nitrates, may cause the milk to show a slight reaction, so that it might appear that water has been intentionally added. Usually water does not contain such a quantity of nitrates as to cause a suspicious reaction when the milk has not really been adulterated. d. Adulteration of partly skimmed and skimmed milk. In most cities no minimum limit is fixed for the fat content of the half skimmed and the skimmed milk, and the only form of adulteration to be considered in this connection is the addition of water. This causes a lowering of the specific gravity of the milk (from 1.030 to 1.036 to from 1.032 to 1.040) and whey, as well as a diminution in the amount of solids. 40,000 fe 450,000 RÅ 2,500,000 i 50,000 ig 500,000 23 3,000,000 ss 60,000 = 600,000 oe 3,500,000 of 70,000 S 700,000 4 4,000,000 gf 80,000 sg 800,000 IS 4,500,000 ud 90,000 Sy 900,000 = 5,000,000 så 100,000 ** 1,000,000 DS 6,000,000 150000 = 1,200,000 etc., by millions. SEE2. 001000 Counts on ‘‘certified’’ or ‘‘inspected’’ milk shall be expressed as closely as the dilution factor will allow. The whole number of colonies on the plate shall be counted, the practice of counting a fractional part being resorted to only in case of necessity, such as partial spreading. Various counting devices have been recommended by different workers. The more simple ones, where the whole plate can be seen at once, are more desirable on account of there being less likelihood of recounting . colonies. Colonies too small to be seen with the naked eye or with slight magnification shall not be considered in the count. Examination of cellular content of milk. Examination of milk sediment reveals certain cellular constituents which when present in abnormal quantities are often regarded as indicating a pathological condition in the 248 | MILK HYGIENE animal producing the milk. Microscopical examination of these elements shows a majority of them to be poly- morphonuclear cells, and these are generally considered as indicative of suppurative changes. There seems to be absolutely no relation between the number of these leucocytes in the milk and the general leucocyte content of the blood, thus indicating that a large number of leucocytes in the milk points to a local condition only. Cattle not infrequently suffer from udder troubles,— gargets of various types in which inflammatory pro- cesses of varying degrees of severity may occur. In some cases these may be so slight as apparently not to affect the nature of the milk. Often, however, the milk becomes viscous, sometimes clotty or stringy, and may even be of a bloody nature. Occasionally such troubles as these develop into a stage in which pus is actually present in such quantities as to be easily recognizable. Milks of this character should of course be excluded from food supplies. In these cases where a physical examination reveals an abnormal condition a microscopical study naturally presents a far different picture from that which one obtains in apparently normal milk, and the increase in the number of leucocytes is especially noticeable. In contrast to these cases where the physical exam- ination and the microscopic findings are in harmony, there are many instances where, although there are an abnormal number of leucocytes present, no physical changes can be demonstrated. Boards of health have adopted arbitrary standards in a number of instances and rejected supplies with abnormal leucocyte content on the ground that the milk was unwholesome. Where the numerical standard set is a high one this proceeding must be commended, since there are not lacking unscrupulous people who will put on the market milk from ‘‘gargety’’ cows which cannot be detected by the ordinary chemical tests. The numerical leucocyte test has been the means of detecting such milk, and trac- ing it back to cows with manifest physical lesions in many instances. BACTERIAL MILK ANALYSIS 249 Since, however, evidence already collected warrants, beyond all question, the general statement that these cells frequently do not have the significance that has been attached to them by many observers, it would per- haps be more fair to all parties concerned to use this test at present as a means of detection only, and not condemn the supply unless physical lesions are demonstrated. We are not prepared at this time to recommend a numerical standard to serve as a basis for such in- spection. Milk having a high cell content should, how- ever, be regarded with suspicion. Such milk should be traced to its source and the cow yielding it excluded or kept under close observation if not showing definite physical lesions. The two methods for the determination of leucocytes in vogue, (1) smeared sediment, (2) volumetric, have each their advocates according to the view point of the worker, and each possesses in its distinctive sphere points of advantage which cannot be ignored. The volumetric method may be further subdivided, some of the methods devised being quantitative only, while others are qualitative as well. The standards so far chosen have been more or less arbitrarily selected on what appears as rather inade- quate data, and from a comparison of results it is apparent that much more comparative work needs to be done. So much has been published descriptive of these various methods that references only can be given here. The smeared sediment method has been most used for city inspection work or work of that character where, through examination of many specimens, undesirable sources of supply may be cut off. Its advantages along this line are: 1. Smallness of sample seized, 10 c.c. being ample for all necessary tests, including bacterial count, leu- cocyte and streptococci estimations. 2. Rapidity of operation, exact counting being un- necessary in routine work, and as has been proved through thousands of tests, nine out of every ten samples being practically free from suspicion. 250 MILK HYGIENE 3. Since in city inspection work a smear of the sedi- ment is often made and examined for estimation of the number of bacteria present, it is profitable to make both tests at the same time. 4. The operation for many samples is much more simple than the volumetric, and less trying on the eyes. 5. This method has been shown to give consistently lower results than the volumetric. If therefore, for example, 500,000 leucocytes to a c.c. are estimated by this method, it can safely be said that the milk contains greatly in excess of that number, and to that degree is much more suspicious than would be a volumetric de- termination indicating 500,000. The volumetric method has been most used for care- ful research work where exact leucocyte content was to be determined as nearly as possible. It is hoped during the coming year comparison of volumetric and smeared sediment technique may give us a more exact relation between the two, and that further work by those who have herds at their command may place these examinations upon a more satisfactory basis. Determination of streptococci. Although by careful searching a few streptococci will be found in most sedi- ments from pus milk, they are seldom found to any great extent by direct microscopical examination. Occasion- ally a sample will be found crowded with long chains; more often streptococci, if present, are in the form of diplococci or very short chains. Where streptococci, diplococci or cocci are found in the sediment and the plate from the same sample con- tains colonies resembling streptococci colonies, these colonies may be grown in bouillon to see if chains will develop. First make and record an estimate of the number of such colonies present, then transfer from ten to fifty of them to bouillon and grow for twenty-four hours at 37° C. To examine the bouillon culture spread a loop- ful on a glass slide, fix with heat, fix with alcohol while slide is still quite hot, stain with methylene blue, wash immediately, dry and examine. BACTERIAL MILK ANALYSIS 201 Streptococci in small numbers are present in most market milk as shown by Heinemann, and many of the short chain varieties are undoubtedly at the time harmless, though by passing through animals their pathogenicity may become marked. Long chain streptococci are considered more apt to indicate inflammatory reactions, and milk containing these in large numbers is certainly not a safe article of diet. A milk should not be condemned because a few chains are found together with large numbers of other micro- scopic organisms in a bouillon culture but it is safer to exclude a milk from the market when these three tests agree: 1. Microscopical examination of the sediment shows streptococci, diplococci or cocci. 2. The plate from the same samples shows colonies resembling streptococci colonies exceeding a count of 100,000 to a cubic centimeter. 3. The bouillon culture from these colonies shows long-chain streptococci alone or in great excess as com- pared with the other bacteria present. Milk showing in the stained sediment both abundance of long-chain streptococci and a high leucocyte content should be condemned as unsafe. Microscopic estimate of bacteria. A milk sediment properly prepared and examined under the microscope with a one-twelfth oil immersion lens gives a very fair idea as to the number of bacteria present. It is also fairly easy to determine through the micro- scopic examination what dilution will be necessary for plating in order to ascertain as correctly as possible the number of bacteria present. Detection of gas-producing organisms in milk: Wis- consin curd test. The Wisconsin curd test is conducted as follows: 1. Sterilize milk containers so as to destroy all bac- teria in vessels. This step is very important and can be done by heating cans in boiling water or steam for not less than one-half hour. 2. Place about one pint of milk in a covered jar and heat to about 98° F. 252 MILK HYGIENE 3. Add ten drops of commercial rennet extract and mix thoroughly with the milk to quickly coagulate. 4. After coagulation cut curd fine with case knife to facilitate separation of whey; leave curd in whey one- half hour to an hour; then drain off whey at frequent intervals until curd is well matted. 0. Incubate curd at 98° to 102° F. by immersing jar in warm water. Keep jars covered to retain odors. 6. After six to nine hours’ incubation open jars and observe odor; examine curds by cutting same with sharp knife and observe texture as to presence of pin holes or gas holes. Observe odor. 7. Very bad milks will betray the presence of gas- producing bacteria by the spongy texture of the curd and will have an off flavor. 8. If more than one sample is tested at the same time, dip knife and thermometer in hot water before each time used. | Milks showing the presence of gas or bad odors in any considerable degree are milks that have been more or less polluted with extraneous organisms or carelessly handled, and as a consequence such milks show a curd filled with small pin holes due to gas. Itis not intended that this test should be used for absolute indication of the presence of gas-producing organisms, but rather it has been of service in the detection of the condition of market milk. Other methods of detecting gas-producing organisms in milk. Gas-producing organisms in milk may be tested for, as in water, with glucose or lactose broth in fermentation tubes. Tests similar to presumptive tests for B. coliin water analysis may be made by inoculating into these broth fermentation tubes a c.c. each of the 1-100, 1-1,000 and 1-10,000 dilutions, or if B. coli or- ganisms are to be numerically determined the milk may be plated in lactose litmus agar, red colonies counted and species tests worked out. Lactose-bile medium has also been used for the determination of B. coli in milk. The presence of these gas-producing organisms in abundance usually indicates dirty condition of stables, cows or vessels. In small quantities they may be found in most milks. BACTERIAL MILK ANALYSIS 233 A rough test is to place five tubes of the milk to be tested at 20° C., 27° C. and 374° C., observing time and character of the coagulation and the odor. This test does not require extra apparatus, uses but little milk, does not require rennet and in the hands of one familiar with the fermentation of milk gives good results. Determination of acidity. While milk is still fresh, 1.e., before it has begun to undergo lactic fermentation, it will show an acid reaction which is sometimes ex- pressed in terms of lactic acid. In view of the fact that the acidity of ‘‘sweet’’ milk is due partly to the presence of acid phosphates and partly to dissolved carbonic acid in milk and not to lactic acid, which is probably absent, a better plan is to express the acidity in terms of the number of cubic centimeters of tenth normal alkali necessary to neutralize a given quantity of the milk, either 25 or 50 ce, using phenolphthalein as an indicator. If it is desirable to calculate the acidity in terms of lactic acid, multiply the number of cubic centimeters of tenth normal alkali used by 0.897 and divide by the number of cubic centimeters of milk titrated, the result being the percentage of lactic acid. For all practical purposes the factor 0.9 instead of 0.897 may be used. For field work acidity of milk may be measured quite accurately by the alkaline tablet method. Records. A card catalogue is far superior to any other method of keeping records. A series of working cards may be kept in order of the date and duplicates entered in another series in order of the place obtained, thus making it easy to refer to any day’s work or to any special dairy. Cards of different colors may be used to distinguish the different sources, such as samples taken from stores, teams, ete. The collector may take cards with him and enter details as he takes his samples, or the sample number may be written on the test tube and the details opposite the same number in a notebook, cards being copied from the notebook on return to the laboratory. 254 … MILK HYGIENE Sterilization: Dry sterilization. Petri dishes, pi- pettes, empty test tubes, etc., are usually sterilized by dry heat. A common gas-stove oven of large size may be used. Empty test tubes are sterilized when the heat causes the cotton plugs to turn slightly brown; petri dishes and pipettes should be exposed to the full heat for at least one-half hour, and are best sterilized in dust-proof copper boxes in which they may be kept sterile for a long time. Such a petri dish box may be made 45x41x 10 inches with a hinged cover on one side closing over the edges and a ring handle on top. A convenient pipette box is one 11x2x2 inches, square in section rather than round to prevent rolling, with a ring handle on the end cover. These boxes must be made without solder, on ac- count of the heat to which they are to be exposed in dry sterilization. Autoclave sterilization. Media, dilution water, and the rubber stoppers used in the centrifugal apparatus should be sterilized in the autoclave. They should be kept under fifteen pounds steam pressure, which gives a temperature of about 250° F. for at least half an hour. PART VE THE REGULATIONS GOVERNING THE TRI- EOREFUM MILK SUPPLY COMPANY IN COPENHAGEN, DENMARK. I TARE WORK OF THE COMPANY SHALL BE UNDER THE SUPER- VISION OF A COMMITTEE OF CONTROL CONSISTING OF A PHYSICIAN AND A VETERINARIAN. II. THE OBLIGATIONS OF THE COMPANY TO THE COMMITTEE OF CONTROL SHALL BE AS FOLLOWS. 1. Milk may be taken only from herds that have been ap- proved by the committee, and that furnish milk containing at least 3 per cent. fat. 2. Nursery (children’s) milk shall come only from herds that are proven to be entirely free from tuberculosis by the use of the tuberculin test, and these herds shall be retested at least once a year. Milk may be received from a tuberculosis- free part of a herd only after the committee has investigated the conditions, and has given its approval. In this case, the healthy part of the herd is to be kept entirely apart from the reacting section, it is to be retested at least once a year, and the reacting animals are gradually to be disposed of. If a calf plague (calf cholera, contagious pneumonia, pyæmia, etc.) occurs in the herd the committee may require shipments of milk to be discontinued until further notice. 3. The company pays one or more veterinarians, who are ap- pointed by and are responsible to the committee of control. Farms that supply the regular whole milk, skimmed milk and cream are to be inspected by the veterinarian twice a month, unless in summer the cows are kept stabled, in which ease four visits per month are to be made. Herds that supply nursery milk are to be inspected the year through four times a month. Travelling expenses are paid by the company. 4. Nursery milk is to be shipped only in containers that 255 256 MILK HYGIENE are easily distinguished by their shape and color from the containers used for the regular milk. 5. The company shall not employ any weakly persons, nor any that are afflicted with an infectious disease or with any repulsive skin disease, as tuberculosis or syphilis. Any em- ployee so affected is to be dismissed. If any one of the employees shall contract typhoid fever, gastric fever, diphtheria, scarlet fever, erysipelas or any other virulent infectious disease, the affected person shall not come upon the premises of the company or resume his work until .he shall present a certificate from a physician to the effect that he is no longer capable of conveying infection. The same applies to employees in whose dwelling any one of the above named diseases may occur. If any one of the employees shall be afflicted with discharg- ing or suppurating wounds on the face, hands or arms or with any transmissible or repulsive disease or with severe diarrhæa, the affected person shall not be employed, during the continuance of the condition, in any work in which he would come into direct or indirect contact with milk, nor shall he be permitted to wash bottles. Every employee who may not work on account of illness, or on account of disease in his family, is fo receive his full pay as though working. A physician is appointed with whom the employees and the members of their families may consult and who shall make frequent visits to the dairy premises and keep an oversight of the employees as to their health. The company shall keep a special record showing the em- ployees that are ill, when they are laid off, and the nature of the illness. 6. The milk shall be cooled to 5° C. (41° F.) as it is re- ceived from the producers and shall be kept at this or a lower temperature. 7. All containers®® are to be thoroughly cleaned by a method approved by the committee. The bottles for nursery 58 The milk is delivered to customers only in sealed cans or, in the ease of nursery milk, in bottles. COMPANY REGULATIONS 2057 milk are to be cleaned and heated in accordance with the instructions of the committee. 8. The herds and all of the premises connected with the business are to be open to the members of the committee at all times. All necessary travelling expenses are to be paid. 9. All announcements and communications regarding the business, so far as these relate to the technical matters under the supervision of the committee, are to be approved by the committee before they are published. 10. A member of the committee of control shall be privi- leged to resign (a) at any time when in his opinion the hygienic regulations relating to the conduct of the business are not properly observed and, similarly, if later regulations made by order of the committee are not complied with, or (6) [under other circumstances] he may resign after three months’ notice. III. REGULATIONS CONCERNING THE PRODUCTION AND CARE OF MILK A. THE HEALTH OF THE HERDS 1. The producer must agree to permit the veterinarian of the company to examine his herd as often as may be con- sidered by the company to be necessary and he must give the veterinarian such information as he may desire in regard to the herd, the feeding and the milk. The producer must agree to observe the instructions of the veterinarian. 2. The cattle that are designated by the veterinarian as tuberculous are to be removed from the herd at once, and, as soon as possible, they are to be sold or killed. Cattle that for any other cause are picked out by the veterinarian are, as he directs, to be removed from the stable or placed apart at one end; the milk may not be used and the cows may not be restored to their places with the herd until permission is given. 3. In ease disease occurs between the visits of the veter- inarian. and especially any of the following,—tuberculosis, in- flammation of the udder, inflammation of the uterus, severe diarrhcea,—the affected animal or animals are to be isolated 16 258 MILK HYGIENE and their milk must not be used. The company will con- tinue to pay for this milk until the veterinarian makes an in- spection. If a number of cows become diseased in such a way as to suggest the outbreak of an epizootic or poisoning the veterinarian and the business manager of the company are 10 be notified at once by telegraph or telephone. 4. The milk of newly purchased cows may not be used until these cows have been examined by the veterinarian and ap- proved. 5. The producers of nursery milk are obligated to add no cows to their herds until they have been tested with tuberculin and are declared by the veterinarian for the company to be healthy. All of the cows of the herd are to be tagged by the veter- inarian. The producer is required to have his herd tested with tuberculin at least once a year. The records of test are to be submitted by the veterinarian of the company to the com- mittee. If there is maintained on a farm a herd of reacting cows, the producer is required to dispose of these gradually and to take care that there is no contact between the healthy and the reacting cattle. B. THE HEALTH OF THE PERSONNEL 1. The producer is required to observe the following rules in relation to the health of the persons who work in the stable or with the milk: a. No one may be employed who is affected with tubereu- Josis or syphilis. b. Persons who have discharging or suppurating sores or wounds on the face, hands or arms, or a disease of the skin of these regions, or that have severe diarrhcea are not under any circumstances to be permitted to come in contact with the milk. c. Persons who live in a house where there is typhoid fever, gastric fever, diphtheria, scarlet fever or any other virulent infectious diseases are, likewise, positively prohibited from coming in contact with the milk until the local physician COMPANY REGULATIONS 259 certifies that they are no longer infectious. If, nevertheless, such persons should by accident come in contact with the milk, it is to be held back (not shipped) and the company will pay the usual price for it, unless the contamination was the result of connivance on the part of the producers. d. The producer is required to use all possible care in keeping informed as to the condition of health of his employees so that every case of infectious disease may be discovered and isolated as soon as possible. e. Once a year—soon after the “‘moving days’’—a state- ment is to be submitted from the local physician to show the state of health of the persons on the farm and all cases of in- fectious diseases that he treated [on the farm]| during the pre- ceding half year. 2. If a case of typhoid fever, gastric fever, diphtheria, scarlet fever or any other virulent infectious disease occurs among the people living at the farmstead or among the people employed on the farm, the producer is obligated immediately to notify the manager of the company by telegraph or tele- phone. The milk shall be held back and shipments may not be resumed until the committee of control has given permis- sion. For all milk that is held back under these circumstances the company will pay full price. C, FEEDING AND CARE OF THE COWS 1. All food must be quite fresh [frisch—not deteriorated]. Mouldy or otherwise damaged food must not be in the stable, or in the immediate vicinity. The veterinarian of the com- pany has the right to inspect the food. 2. In summer, so far as possible, the cows are to be fed in the pasture. If it is necessary to feed them in the stable, the company is to be notified and then the producer is re- quired to use care that the stable and the cows are kept as © clean as possible. The company reserves the right to forbid, if it is considered necessary, the stable feeding of cows that produce nursery milk. 260 MILK HYGIENE 3. The veterinarian shall be advised as to the composition of the feed. The following rules apply: a. No roots may be fed to cows producing nursery milk except carrots and sugar beets, and of these not more than 20 kilos [40 Ibs.] per day. b. Cows producing regular milk may receive as much as 30 kilos [60 lbs.| per day, provided this amount does not cause diarrhea. c. Beet tops, beet trimmings, cabbage, distillers’ slops, malt, ete., may not be fed. d. For cows producing nursery milk, the following foods are prohibited: molasses, cotton-seed meal, green or dry buck- wheat and mustard. These feeds may be given to other cows, but only in small quantities. Molasses must not be used if it produces any undesirable effect. e. If rape seed is used, it must not contain any consider- able quantity of oil of mustard, and before it is used it must be shown to the official veterinarian. 4. The producer is required, so far as possible, to forbid frequent and sudden changes of food. 5. Before the cows are stabled in the fall, the hair is to be clipped from the udder, tail and thighs. 6. The use of beast milk is forbidden until ten days after ealving. The milk shall not be used from cows that have daily less than 3 kilos [3 quarts]. D. THE CARE OF THE MILK 1. Milking must be conducted with the highest degree of cleanliness and care. The following specific rules shall apply: a. Each milker must always wear a milking suit and must be supplied with a towel. Clean water must be supplied in ample amount, so that the hands may be washed as often as necessary. b. The stable must be so well hghted, and especially behind the cows, that those who do the work ean see clearly enough to perform their work in an orderly and clean manner. c. Immediately after milking, the milk is to be passed COMPANY REGULATIONS . 261 through a fine metal strainer, which must be cleaned fre- quently. d. The milk is to be cooled before it is shipped, at all sea- sons, and just after milking, by the use of a cooler, to at least Bc. (464° ff .). e. Mucking out shall not take place until after the morn- ing milking, and in the afternoon it must be completed at least one hour before milking. f. Fresh cows [those giving beast milk], cows which give less than 3 kilos [8 quarts] a day, and cows that have been separated from the herd by the veterinarian shall have places in the end of the stable, so that it will not be possible for the milkers to mix their milk with that of the cows producing milk for the use of the company. 2. A sufficient supply of ice shall be available. For cool- ing, an apparatus is to be used that is set up in a light, clean room, that is used for no other purpose, and each time, before used, it is to be rinsed off with clean water. 3. The producer agrees to follow the instructions regard- ing cleanliness in the stable and the care of the milk that may be given him by the company or by their veterinarian. E. DELIVERY 1. In the summer the transport wagons must be supplied with a cover to protect the milk cans from the sun. Feed, fertilizer, etc., must not be carried on the same wagon with milk or with the cleaned milk containers. 2. The company furnishes the cans used for transporting the milk. Those used for nursery milk must not be used for other milk. Under no circumstances shall the cans be used for any purpose other than to send milk to the milk station. The cans are cleaned by the company before they are returned. 3. The producers are to rinse the cans in clean, cold water, and, if soiled during transportation, they are to be cleaned. 4. The producer is required to furnish a supply of good water for the cows and for cleaning the vessels and utensils that come in contact with the milk. Any suspected defect of 262 " MILK HYGIENE the water supply is to be reported at once to the committee on control. F. OTHER PROVISIONS 1. The producer agrees to answer truthfully and honestly all questions from the company in regard to the milk supply. 2. It is agreed that the herds and premises where the milk is handled and cared for shall be open at all times to the mem- bers of the committee on control. IV. INSTRUCTIONS TO THE VETERINARIANS The veterinarians are appointed and can only be dismissed by the committee on control, and all instructions come from this committee. A report is to be rendered to the committee on every visit to a herd, and this shall contain information in regard to: the total number of cows, the cows in milk, all cases of disease, whether cows have been sold or killed that were isolated as suspicious or diseased, the condition of the whole establish- ment in respect to cleanliness, the method of feeding and re- marks on any pertinent subject. [It is especially to be noted, in respect to the above regula- tions, that they are planned not for the purpose of measuring, by means of a laboratory examination, the extent to which milk has become contaminated, but for the purpose of preventing contamination. The most injurious bacteria in milk are the pathogenic forms that come from diseased persons or cattle and the putre- factive organisms that come from diseased cows, dirty prem- ises or utensils or faulty methods of milking or handling milk. The most important pathogenic forms cannot be detected in milk by the usual routine methods in use in milk laboratories, if at all. And if these organisms are detected by laboratory examination it is not until long after the milk has been con- sumed. Nor can the injurious saprophytes be identified in the laberatory until too late to prevent the use of milk con- COMPANY REGULATIONS 263 - taining them. Hence, it must be clear that the truest protec- tion to the consumer consists in guarding the source of the milk and the milk itself, from. conditions that are known to be accompanied by danger of injurious contamination. The value of laboratory examinations as to the number and kind of bacteria, pus cells ard solid dirt is not under-esti- mated; it is very great as a measure of the thoroughness of the precautions taken on the dairy farm, and during shipping. But the value of this examination should not be exaggerated, as appears to he the tendency in some quarters, and it should not be thought that any laboratory examination can, with safety, be permitted to take the place of regular, expert veter- inary inspections of the cattle, methods and premises. The bacteriologic and microscopic examinations of milk that are made in public health laboratories keep contaminated milk from entering the market only in so far as they point out the necessity for the veterinary and sanitary control of dairy farms. (See quotation from Freeman on page 168.) L. P.] ARPENDPESETE GERMAN INSTRUCTIONS FOR PRODUCING NURSERY MILK. The following instructions in regard to the production of nursery milk are taken from a circular letter of May 27th, 1899, from the central government of Germany to the local governments. NURSERY MILK ‘* The special establishments for producing and selling nursery milk, which have greatly increased in number in re- cent times, and which use special designations, as sanitary dary, health milk, children’s milk, superior milk, ete., are to be looked after with special care by the sanitary authorities. The general methods, the cleanliness of the stable, the store- room, the utensils, the condition of health of the cows and their feeding and care are to be placed under veterinary oversight. ‘“ The stables shall be roomy, light and airy, and they shall have impervious floors and mangers of such description that they can be easily cleaned. Running water shall be provided for. cleansing and the drainage shall be good. Only cows for the production of nursery milk shall be kept in such special stables and these cows shall be marked in some permanent way. ‘* It is not necessary to lay down special regulations for feed- ing such cows, but attention should be called to the known facts as to injurious effects of certain cattle foods on milk used for infant feeding. ‘* In general, the feeding of creamery refuse should be for- bidden on account of the danger of spreading tuberculosis. ‘“ The condition of health of cows designed for producing nursery milk is to be determined before they are placed in the empire. This examination is to be repeated at intervals of three months. 265 266 MILK HYGIENE < A careful book record is to be kept of these examinations. The official who is charged with this oversight shall make an appropriate entry for each visit. The occurrence of any one of the following named diseases among the cows is to be reported at once to the official veter- inarian: anthrax, contagious pleuro-pneumonia, foot-and- mouth disease, black quarter, rabies, cowpox, icterus, dysentery, inflammations of the udder, blood poisonings, especially pyemia and septicemia, putrid inflammation of the uterus or other febrile conditions, retention of the after-birth and con- ditions that result in the occurrence of discolored milk. ‘“ Cows which show evidence of disturbance of digestion, of diarrhcea or pica, or cows that are suspected of being afflicted with tuberculosis shall at once be removed from the stable, until the animal is examined and the condition determined by the official veterinarian. It is not permitted to use as bedding soiled or refuse straw or other waste material. ‘* Cows for producing nursery milk shall E kept particularly clean. Before milking, the udder is to be carefully cleaned. The milkers must keep themselves thoroughly clean. They must wash their hands and arms with soap before milking, and wear a clean frock. Any person suffering with a contagious or eruptive disease must not be permitted to milk.” APPENDESG FH: THE MILK COMMISSION OF PHILADELPHIA. Certified milk in Philadelphia is produced under a com- mission organized in 1899 upon the following plan: 1. There shall be a Milk Commission of the Philadelphia Pediatric Society, whose duty it shall be to have examined milk submitted to them by dairymen and certify as to the result of such examination. 2. The actions of the Commission shall be reported from time to time to the Society and shall be subject to its approval. 3. The Commission shall consist of four members besides the President of the Society, who shall be a member ex officio. The members shall be appointed yearly by the President as soon as possible after his election. The Commission shall elect a ehairman and a secretary from their number. 4. No statement for publication or information to any dairyman shall be given by a member, but only after considera- tion by the Commission and in the name of ‘‘The Milk Com- mission of the Philadelphia Pediatric Society.’’ 5. The Commission will hold itself in readiness to examine milk from dairies desiring this examination, and to certify to the good quality of milk which comes up to the standards fixed by it. It is understood that only the milk of dairies, and not that of milkmen who merely serve milk bought by them, will be examined by the Commission. 6. The method of examination and certification to which the dairyman shall agree to submit shall be as follows: 7. The Commission shall select a bacteriologist, a chemist, and a veterinary inspector. The bacteriologist shall procure a specimen of milk from the dairy, or, preferably, from de- livery wagons, at intervals to be arranged between the Com- mission and the dairy, but in no case at a longer interval than 267 268 MILK HYGIENE one month. The exact time of the procuring shall be with- out previous notice to the dairy. He shall test this milk for the number and nature of bacteria present in it, to the extent which the needs of safe milk demand. He shall also make a microscopic examination of the milk for pus cells. Milk free from pus and injurious germs and having not more than 10,000 germs of any kind or kinds to the cubic centimeter, shall be considered to be up to the required standard of purity. 8. The chemist shall in a similar manner procure and ex- amine the milk for the percentages of proteids, fat, sugar, mineral matter, and water present. He shall also test its chemical reaction and specific gravity, and shall examine it for the presence of foreign coloring or other matters or chem- icals added as preservatives. Standard milk shall range from 1.029 to 1.034 specific gravity, be neutral or very faintly acid in reaction, contain not less than from 3.5 per cent. to 4.5 per cent. proteid; from 4 per cent. to 5 per cent. sugar, and not | less than 3.5 per cent. to 4.5 per cent. fat in the case of 4 per cent. fat milk, and shall be free from all contaminating foreign matter and from all addition of chemical substances or color- ing matters. Richness of cream in fat shall be specified and shall vary not more than 1 per cent. above or below the figure named in selling. Neither milk nor cream shall have been subjected to heat before the examination has been made, nor at any time, unless so announced to the consumer. 9. The veterinary inspector shall, at intervals equal to those of the bacteriologist and chemist, and without previous warning to the dairy, inspect the cleanliness of the dairy in general, the care and cleanliness observed in milking, the care of the various utensils employed, the nature and quality of the food used, and all other matters of a hygienic nature bearing upon the health of the cows and the cleanliness of the milk, including also as far as possible the inquiry into the health of the employees on their farms. He shall also see that the cows are free from tuberculosis or other disease. 10. The charges made by the experts shall be—for the veterinarian $10.00, and $5.00 for each of the others for each examination; this amount to be paid by the dairy at the time PLAN FOR COMMISSION 269 of the examination and without regard to whether the report is favorable or unfavorable. The experts shall make their examinations when, and only when, notified to do so by the Commission. Any dairy the milk of which shall be found by the examiners to be up to the standard of the Commission shall receive a certificate from the Commission, which shall read as follows: MILK COMMISSION OF THE PHILADELPHIA PEDIATRIC SOCIETY ee The Veterinary Inspector of the Commission has examined khedarry Ob MP oo. oes. and reports it to be well kept and clean, and the cows to be in a healthy condition. The Bacteriologist reports that the milk does not contain germs beyond the limits of the standards of the Commission. The Chemist reports that the milk is of standard richness, and that he has discovered in it no impurities, coloring mat- ters, chemical preservatives, or harmful substances. The Commission certifies to these statements of the examiners. It is understood and agreed to by the said Le, 875. that this certificate is good for not more 021 {or from date, when another examination is to be made [Signed by the Commission. ] 11. In ease an examination shows the milk not to be up to the standard the dairy may have a re-examination made within a week or within a short time, at the discretion of the Commis- sion. 12. Milk furnished by the dealers to whom certificates have been issued shall be furnished to consumers in glass bottles hermetically sealed in a manner satisfactory to the Com- mission. In addition to the sealing, and as a guarantee to the consumer that the examination has been regularly conducted, there shall be pasted over the mouth of the jar, or handed to the consumer with every jar, according to the discretion of the Commission, a certificate slip which shall read as follows: 270 MILK HYGIENE PHILADELPHIA PEDIATRIC SOCIETY. MILK COMMISSION CERTIFICATE. Milk from the dåalmy (Of Mir sa ee ae a EG even een ae nee has been recently examined by the experts of the Milk Commission and found to be up to the required standards. Another examination is to be made within a month, and, if satisfactory, new labels for the bottles will be issued, dated NOTICE THE DATES. The blanks used by the experts of the Commission in re- porting to the secretary are as follows: | REPORT OF VETERINARIAN. Philadelphia; |... ..:)-c)0 oe aoe eee 190... Secretary of the Commission, DEAR SIR:—I have examined, as requested by the Commission, the Claire y elles. pine GES SES ect Sens LE TERRE Abia. ERE RE 3 and find the following conditions:— JES DE noah utente milking cows. URE Re es DE SE hospital cows. ET ania cows sick since last report. ALS KENDTE FAR dry cows. ALE ae as cows recently calved. SAREEN RER cows added since last report. Did they pass veterinary inspection and the tuberculin test before eaters Ane cows now in quarantine. Total number of cows in herd.......... of whichy see have been tested with tuberculin in the past year. II. Food employed. Oe eee IV. Condition of Stables: Ventilation a ase. Ane > TET Anah Cleanliness eter SEN rl ee ee Ce ae BIOORS ey ren inten ees a Droughs.7 2255 2 ete ; Conditionfof other buldimgs He rer V. Health of employees and their families, as far as ascertained, IK ENA ee a ' VI. The general precautions of cleanliness in milking and the care of the milk are ....... eerie Ass ; I therefore recommend that milk from this dairy be submitted to the Bacteriologist and Chemist of the Commission for their examinations. Bot kant bes ERE cate sic area ER BENE re Veterinarian. ESTIMATION OF QUALITY gel REPORT OF BACTERIOLOGIST. Philadelphia ESSENS wis soles es ate, were 190... Secretary of the Commission, DEAR SIR: At the request of the Commission, received on.......... milk BA cere vo SOEs Cream stroma the dar sOfs chee sic ae aise wie ous See oe [ly aka ON Soni SS gra anlar Poi Lene was obtained by me on............ Lal ear Tipe’ Big, Ae ea ane gree Pere RRS SOMES a Al) fae ek o’clock, ..-M., and examined at-...... o’clock, ....M., with the following results— milk Number of bacteria. per c.c. of cream. :...:.0......:. I have been unable to detect any pathogenic organisms or evidence of purulent inflammation of the udder. milk I therefore recommend the cream as coming up to the bacteriologic standards adopted by the Commission. I find the bottles to be sealed in the manner prescribed by the Commission. Yours truly, SAMUS ES ce cee se te Eee RENT OM KEDE PN Bacteriologist. REPORT OF CHEMIST. nila elo nits cats: swcqoral steres lel atetoeletie Gre ese! sy LOE 5 Secretary of the Commission, DEAR SIR: At the request of the Commission, received on.......... milk SS See POOR ereamstrom (ie Galry Ol) tis. tracts ele ass) eha« eee er es “ATR EC| SMU OO aT gs ee eee VEL SE was obtained by meon............ 190.., and examined with the following results: Hat uetman=beam method.) Wo eel ee he Total proteids, (Kjeldahl-Gunning method, factor 6.25), Ae oe Preservatives, added color and heat, none. LNG TYRAN ENE at sere on SEERE pe PT Oe te ia BSClacrerNMuie wee Ty i i Me te he) ae milk I therefore recommend the cream as coming up to the chemical standards adopted by the Commission. __ I find the bottles to be sealed in the manner prescribed by the Com- mission. Yours truly, ss ud wale SR RGS A iota an ela PN ETEER Chemist. APPENDIX III. A SCORE CARD FOR DAIRY FARMS. The following plan for estimating the quality of dairy farm conditions, and for making it possible to compare farms, was originated and arranged by R. A. Pearson, Professor of Dairy Industry at Cornell University. The score card idea has been extensively employed in judging animals, plants, seeds, ete., but this is the first adapta- tion of this principle to the judging of such a complex object as a dairy farm, including all of the factors that enter into the production of sanitary milk. A special feature of this scheme is the division into groups; a low score in any group renders the whole inferior, no matter how excellent the other groups may be. The general idea is an excellent one; it enables the in- spector to record in convenient form a summary of the result of his inspection and, by this means, a comparison can readily be made between the conditions of a farm at different times. Some practice is required to obtain the best results from the use of this method. 273 274 MILK HYGIENE Department of Dairy Industry, College of Agriculture, Cornell University. Score Card for Production of Sanitary Milk. Date rye ESSEN donee Dairy Of e/s\e 70's lee ojatese la 47s o srayernve ER ER EEN Perfect Health and comfort of the cows and their isola- I. Health of the tion when sick or at calving time............. 45 herd and its pro- Location, lighting and ventilation of the stable..| 35 tection Moodand water sce. scuste tcl ae eee eee 20 10) 21] ea Oni Ne PION AOA LACM Ia REED 100 COWES an aco eae acto Siem te Nee Eee 30 TT, Cleanliness of Stable... 6506. ee ee 20 the cows and their) Barnyard and pasture...................0ceeceeee 20 surroundings Stable air (freedom from dust and odors) ........ 30 Oba cere set is eb PEER se cee sane eee 100 Construction of utensils and their cleaning and | TTT, Construction SCOTUIUZ TIO. i Meson ENE phic eee 40 and care of the Water supply for cleaning and location and pro- tensil tectronofitsisoureer I I ee eee 25 utensils Care of utensils after cleaning... 20 Use of small-top milking pail...…................... 15 TOCA oral Sipe levaleis che eens eee cotta REE nn 100 Health ofiemployeesincs sascen aces cca eee 45 IV. Health of em-) Clean over-all milking suits and milking with ployees and clean, dry Hands SAS ENES Oy a nS on ee ADESER 30 “1.| Quiet milking, attention to cleanliness of the manner of milk udder and discarding fore milk............... 25 ing Sas TOGA che cisloen cna ien eae er eee eee 100 Prompt and efficient cooling..................-.-: 35 V. Handling the Handling milk in a sanitary room and holding it milk atia low temperature ss concrete 35 Protection during transportation to market...... 30 TOCA BESES AS BES cinvcasi acouseronaiensie siete erentaeete 100 porre > ==) NODAL OR Ann SCORHS9. RENE 500 If the total of all scores is And each division is The sanitary conditions are: ASNORIRDOV CH os nee occ cass we eta QOORADOV Elsie eens ech eee EXCELLENT AHOIOLIADONVE Noasis seit oats eo onibes sores SOOM A DOVE. ja nsec aan eee GOOD AQOFOR AVONS rater elser ere ae eter GOFOT AbOVE ites lesa ER EEN ERR MEDIUM Below 40 DRE RS EL e de Or any division is below 60............... POOR The sanitary (COIN MONE) AWKD> oon dodoAaonocoonoLs SCOPE Dy o)0 sie Siete taie whayAie Oane Een = Pelee tN OX TV: THE MILK COMMISSION OF ESSEX COUNTY, NEW JERSEY. On account of its historic value, the following agreement, which was the first provision for the production of ‘‘certified milk’? in America, is reproduced. The plan of the agreement originated with Dr. Henry L. Coit, of Newark, N. J., and the ‘*“ party of the first party,’’ of the contract is the Medical Milk Commission of Essex County, New Jersey. The date of this agreement was May 9th, 1893. It is still in force. i. The party of the second part doth hereby agree to con- duct such parts of his dairy as may be hereafter named, collect and handle its products in conformity with the following code of requirements, for and in consideration of the promised endorsement of the parties of the first part, as hereinafter indicated. The milk thus produced shall be known as certified milk; shall be designed especially for clinical purposes, and when at any time the demand shall be greater than the supply, and it is required by a physician, either for infant feeding or the diet of the sick, it is hereby agreed that such shall be the preferred purchaser. 2. The party of the second part further agrees to pay for chemical and bacteriological examinations of the aforesaid certified milk, at such time as in the Judgment of the party of the first part is desirable. 3. He also agrees to defray the cost of a bi-monthly in- spection of his dairy stock, or oftener, if necessary, by a competent and approved veterinarian, all of which persons, namely: the chemist, the bacteriologist, the veterinary surgeon, shall be chosen by the parties of the first part, to whom they shall render their reports in writing. 4. It is expressly understood and agreed, that the party of the second part shall not pay more than the sum of five hundred dollars in any one year, for the services of chemist, bacteriologist and veterinary surgeon, and the party of the 275 276 MILK HYGIENE first part shall limit the expense of such service to that amount. It is furthermore agreed that the party of the second part, on receipt of a certified copy of the reports of the experts, shall mail to the persons indicated by the parties of the first part, and not to others, a duplicate printed copy of the aforesaid reports, bearing the signatures of the experts and the names of the physicians. The same to be issued at such intervals as in the judgment of the parties of the first part is desirable; also that the necessary expenditures for printing and circula- tion be met in the same way as herein provided for expert examinations, LOCATION OF LANDS 5. It is hereby understood and agreed, that the lands used by the owners, agents or assigns of the dairy, conducted by the party of the second part, and employed for pasturage, or any lands that may hereafter be acquired for such purpose, or such lands as may be used for the cultivation of hay or fodder, shall be subject to the approval of the parties of the first part. BUILDINGS 6. It is also understood and agreed, that the buildings, such as stables, creamery, dairv house and spring house, shall be constructed after the most approved style of architecture, in so far as construction may affect the health of the dairy stock, or the character and conditions of the milk. 7. The buildings, used for the housing of the animals, shall be situated on elevated ground, and capable of being properly drained. 8. Said buildings to be sheltered from cold winds, lighted and ventilated according to approved hygienic methods. The buildings shall be constructed so as to favor the prompt and easy removal of waste products. 9. The apartments used for the storage of either feed or fodder shall be removed from possible contamination by stable waste or animal odors. 10. All buildings shall, in addition to healthy location, ap- proved construction and proper ventilation, be kept free from animal or vegetable matter in a state or process of decomposi- FIRST AMERICAN AGREEMENT BT tion or decay, and always free from accumulations of ater or mould. THE WATER SUPPLY 11. The dairy shall be supplied with an abundance of pure water. 12. No water from shallow wells or springs holding sur- face drainage, shall be used for watering stock, cooling milk or cleaning vessels. 18. Nor shall any well or spring be located within three hundred feet of the stable. SURROUNDINGS 14. It is further understood and agreed that the immedi- ate surroundings of the buildings shall be kept in a condition of cleanliness and order. There shall not be allowed to ac- cumulate in the vicinity any loose dirt, rubbish or decayed vegetable or animal matter, or animal waste. 15. Nor shall there be within three hundred yards of any building, any constantly wet or marshy ground, or stagnant pools of water. | 16. Nor shall there be kept within three hundred yards of-any building used for dairy purposes any fowls, hogs, horses or other live stock. THE COWS 17. It is hereby understcod and agreed that the following unhealthy conditions shall be a sufficient reason to exclude any animal from the herd used for any purpose in the aforesaid dairy: Any animal that is judged by a competent observer to suffer from tuberculosis, even though the disease be localized ina part distant from the vital organs. 18. Any animal with fever. Any animal suffering from septic absorption or other disease, following or associated with parturition. 19. Any animal suffering from mammitis or mammary abscess. 20. Any animal with persistent diarrhcea or any other ab- normal physical condition, which could in any way be detri- mental to the character of the milk. 218 MILK HYGIENE 21. It is furthermore agreed that when an animal shall be found by a competent observer to be in a state of ill health, prejudicial either to the other animals in the herd or to human health, the same shall be removed immediately, and if neces- sary. shall be killed. 22. It is also understood and agreed that the party of the second part shall exclude from the herd used for produc- ing certified milk, immediately after discovery, any animal subject to the following conditions: Any animal that was bred through consanguinity within a period of three gener- ations. 23. And from this time forth, any animal of those bred by the party of the second part, used for producing certified milk, that was not, as a heifer, kept sterile during its first twenty- seven months. 24. Any phenomenal milker, except that glandular disease or tuberculosis has first been excluded for a competent ob- server. 25. It is furthermore agreed that if at any time it is de- sired by the parties of the first part, that a different breed of milch cows should be substituted for the one in use, in order that the standards of quality in the milk may be raised, the party of the second part will endeavor to carry the same into effect. HOUSING AND CARE 26. It is furthermore agreed, that the dairy stock employed in the production of certified milk, shall be properly sheltered from the influences of weather and climate prejudicial to their health; also that the animals shall be kept clean, groomed every day. and treated kindly at all times. 27. The waste products of the stable shall be removed so frequently, and the stable floor so thoroughly cleaned, that the same shall be as free as possible from animal odors. 28. It is also agreed that no milch cow shall be used for dairy purposes while in a state of excitement, either as a result, or during the period of estrux, or which has been made nervous either by heating, whipping, kicking, prodding or running. FIRST AMERICAN AGREEMENT 2 Qc] CO FEEDING 29. It is hereby understood and agreed that the methods of feeding the cows furnishing the certified milk, shall be sub- ject to the approval of the parties of the first part. The feed and fodder shall consist only of nutritious and wholesome ma- terials; such as grass, clover and timothy hay, whole grain, or the entire result of the grist. No materials shall be employed which are or may become injurious to the health of the ani- mals. There shall not be fed at any time, or in any quantity, either alone or mixed with other feed or fodder, hulls, screen- ings, wet or dry brewers’ grains, oil cake, sour ensilage, the refuse from distilleries, glucose or starch factories, any waste by-product in the treatment of grain, low marsh grass, or any of the questionable or exhausted feeds or fodders employed either to increase the milking capacity of the animal, or that will produce an impoverished milk, or that will impart to it unnatural odors or flavors. Nor shall the cows be allowed to eat green or worm-eaten fruit, poisonous weeds or to drink poisonous or stagnant water. COLLECTING AND HANDLING 30. It is furthermore understood and agreed, that the cows from which is obtained certified milk shall be milked only in a clean building, and not an illy-ventilated stable containing foul odors and bad air. 31. No animal furnishing certified milk shall be milked until the udder shall first have been cleaned in a manner ap- proved by the parties of the first part. 32. No person shall be allowed to draw the milk that has not within fifteen minutes of the milking first washed his or her hands, using soap and nail brush, and afterward thor- oughly rinsing the hands in clean water. 33. The person or persons engaged in milking shall also be dressed in clean over-clothes. 34. No person shall be allowed to draw the milk who has been engaged with the care of horses in the same clothing or without first washing his hands. 30. No milk shall be represented as certified milk that is not 2800 MILK HYGIENE received from the udder into vessels, and from these into cool- ing cans, both of which are perfectly clean and dry, having been cleansed and heated, at a temperature adequate to effect com- plete sterilization, since the last milking; and have been kept inverted in a clean, dry and odorless atmosphere. 36. No milk shall be represented as certified milk that has not been passed through a sieve of wire or other cloth, either while milking or immediately thereafter, having not less than one hundred meshes to the linear inch. 37. No milk shall be represented as certified milk that does not consist of the entire contents of the udder at each milking, including the fore-milk, middlings and strippings. 38. No milk shall be represented as certified milk that has been drawn from the animal at abnormal hours, such as mid- night or noon; nor from any animal for a period of nine weeks before calving, or that has not been separated for nine days after parturition. 39. No milk shall be represented as certified milk, which has been exposed to the emanation or infection of any form of communicable disease, either in the person or persons hand- ling the milk, or by accidental contamination in cleaning milk containers, or by the association of any person engaged in handling the milk, with person or persons sick of contagious disease. PREPARATION FOR SHIPMENT 40. It is hereby understood and agreed, that all milk repre- sented as certified milk shall receive every known detail of care that will promote its keeping qualities, and favor its safe transportation. 41. That the milk on being drawn from the cow, shall be treated by ice, or clean, cold water in motion and proper aera- tion, in order, first, to remove its animal heat, and second, to reduce its temperature to a point not above fifty degrees, nor below forty degrees Fahrenheit; said temperature to be ac- quired within forty-five minutes after milking, and maintained within the above limits while held for shipment, during its transportation and until it is delivered to the purchaser. FIRST AMERICAN AGREEMENT Zou 42. That the cooling of the milk shall not be conducted in the same building in which it is drawn, nor in an atmosphere containing dust or tainted with animal odors. 43. That all the foregoing provisions concerning the cleans- ing and condition of vessels or utensils shall be complied with in the said cooling process. 44. It is furthermore agreed, that no milk shall be repre- sented as certified milk, that has been changed or reduced in any way, by the addition of water or any solid or liquid sub- stance, in or out of solution, or the subtraction or removal, in any manner, of any part thereof. 45. It is hereby understood and agreed, that all milk to be represented as certified milk, shall be packed in flint glass quart jars immediately after it is cooled. 46. Said jars to be of a pattern approved by the parties of the first part. 47. It is furthermore agreed that the bottles or jars, before being used, shall be cleaned by hand, separately, with the aid of hot water, alkaline soaps, rotating brush and steam, and that they shall be rinsed in two separate baths of. clean, hot water and then thoroughly dried and kept inverted until used, without covers, in a clean, dry atmosphere free from odors. 48. It is agreed that the jars shall be filled by a method approved by the parties of the first part. 49. That they shall be sealed after all air has been excluded, by the most approved device for closing them. 50. The bottles after being filled, shall be labeled across the cap, bearing the words ‘‘Certified Milk,’’ with the name of the dairyman, together with the date of milking. ol. It is furthermore agreed, that no milk shall be sold as certified milk, that is more than three hours old when bottled, nor more than twenty-four hours old when delivered. TRANSPORTATION AND DELIVERY. 52. It is hereby understood and agreed, that the transporta- tion and distribution of all milk represented as certified milk, shall be conducted by the party of the second part, either in person or by persons employed by him. 282 MILK HYGIENE 53. That in transit, the milk shall not be exposed to any of the foregoing prohibitory conditions. 54. That it shall not be subjected to agitation. dd. That it shall not be exposed to the heat of the sun. 56. That the delivery wagons shall be so constructed that the required temperature of the milk may be maintained dur- ing transit. o7. That before the wagons are filled for shipment, the body, the trays and compartments shall be flushed with boiling water. 98. It is furthermore agreed that the distributing agents shall, during the transfer of the milk from the dairy to the purchaser, be subject to the following restrictions, namely : 59. That they shall use no tobacco or intoxicating drinks. 60. That they shall not collect the empty containers, nor receive money or milk checks from houses in which an infec- tious or contagious disease is known to exist. 61. It is also hereby agreed that the collection of empty bottles, from places where infectious or contagious disease is known to exist, shall be made by other persons that those em- ployed to deliver the milk. 62. That these collections be made with wagons not em- ployed in the distribution of the milk. 63. That before these empty bottles shall be returned to the dairy, they shall be carried to a separate building and first be subjected to the process of cleaning bottles indicated in a former clause of this contract. 64. It is hereby understood and agreed, that if any further precautions or changes in method, calculated to improve the quality of milk, or guard the same from impurities or dangers, are desired, that the party of the second part will cheerfully be governed by such additional rules and regulations as may be laid down by the parties of the first part. 65. It is understood and agreed by the party of the second part, the same binding the owners, agents or assigns of the aforesaid dairy, that the product known as certified milk shall be under the following restrictions in its sale, namely: That until the amount required within the boundaries of Essex FIRST AMERICAN AGREEMENT 283 county shall first be supplied, it shall not be sold beyond these limits, except that the parties of the first part shall give their consent. 66. It is furthermore agreed by the party of the second part, the same binding the owners, agents or assigns of the aforesaid dairy, that in the event of a failure to comply with any or all of the requirements of the foregoing contract, the party of the first part shall reserve the right to withdraw from the contract, and publish the fact in such manner as they deem best. 67. Finally, it is understood and agreed that nothing in this contract shall prevent the obrogation of any of the pro- visions of the same, by the parties of the first part, provided that it shall be done for the purpose of substituting other provisions, designed to promote the objects of their organiza- tion. 68. It is further understood and agreed by and between the parties hereto, that the party of the second part shall be at liberty to cancel this agreement by giving two months’ notice in writing, of his desire to do so, in case of inability for any reason, to comply with the terms of the same. ARBEND REV ESSERAGCT FROM THE REPORT OF THE BRITISH ROYAL COMMISSION ON TUBERCULOSIS. The Second Interim Report of the Royal Commission on Human and Animal Tuberculosis was issued in January, 1907. It presents the conclusions of the commission after thorough and extensive investigations covering more than five years. The report is signed by Sir Michael Foster, Prof. G. Sims Woodhead, Prof. Sidney Martin, Sir John McFadyean and Prof. Rubert Boyee. The following is an extract: CONCLUSION ‘‘ We may briefly sum up the. bearings of the results at which we have already arrived as follows: ‘* There can be no doubt but that in a certain number of cases the tuberculosis occurring in the human subject, es- pecially in children, is the direct result of the introduction into the human body of the bacillus of bovine tuberculosis; and there also can be no doubt that in the majority at least of these cases the bacillus is introduced through cows’ milk. Cows’ milk containing bovine tubercle bacilli is clearly a cause of tuberculosis and of fatal tuberculosis in man.” £ Of the sixty cases of human tuberculosis investigated by us, fourteen of the viruses belonged to Group I, that is to say contained the bovine bacillus. If, instead of taking all these sixty cases, we confine ourselves to cases of tuberculosis in which the bacilli were apparently introduced into the body by way of the alimentary canal, the proportion of Group I becomes very much larger. Of the total sixty cases investigated by us, * Original not italicized. 285 286 MILK HYGIENE twenty-eight possessed clinical histories indicating that in them the bacillus was introduced through the alimentary canal. Of these, thirteen belong to Group I. Of the nine cases in which cervical glands were studied by us three, and of the nineteen cases in which the lesions of abdominal tuberculosis were studied by us, ten belong to Group I. These facts indicate that a very large proportion of tuber- culosis contracted by ingestion is due to tubercle bacilli of bovine source. £ A very considerable amount of disease and loss of life, especially among the young, must be attributed to the consump- tion of cows’ milk containing tubercle bacilli. The presence of tubercle bacilli in cows’ milk can be detected, though with some difficulty, if the proper means be adopted, and such ought never to be used as food. There is far less difficulty in recog- nizing clinically that a cow is distinctly suffering from tuber- culosis, in which case she may be yielding tuberculosis milk. The milk coming from such a cow ought not to form part of human food, and indeed ought not to be used as food at all. “Our results clearly point to the necessity of measures more stringent than those at present enforced being taken to prevent the sale or the consumption of such milk.” INDEX. Abdominal tuberculosis, 78 Abnormal coloration, 56 odors and tastes, 55 Abortion, 41 Absorption of odors, 68, 69 Acid, benzoic, 64 boric, 62 eitric, 150 lactic, 52 reaction, 227 salicylic, 63 Acid-fast bacteria, 81 Acidity, determination of, 253 Acidobutyrometer, Gerber’s, 209 Actinomyeosis, 92 and tumors, 48 Addition of lactose or cane sugar, 221 Admixture of dirt, 126, 127 Advantages derived from pasteur- izing market milk, 138 Adulteration, frequency of, 197 of cream, 225 partly skimmed and skimmed milk, 225 Adulterations, effects of, 224 Age of the cow, 29 Albumin, 14 Aleohol test, 229 Alkalies, 68 Alkaline reaction, 227 Alkaloids, 49 Alpine eattle, milk of, 40 Amphoterie reaction, 227 Anthrax, 90 Antisepties, 61, 68 Appearance of milk, 226 Arnold’s guaiae method, 192 Arsenic, 60 Asiatic cholera, 117 Ass’s milk, 24 Attendants, health of, 178, 185 Automatic temperature-regulator, 134 Babeock’s method, 214 . Backhaus’s infants’ milk, 151 Bacteria, acid-fast, 81 in dung of cows, 127 market milk, 122 milk, 120 microscopic estimate of, 251 of putrefaction, 61, 229 pathogenic, 129 Bacterial milk analysis, standard method for, 237 Bacteriological examinations, 231 Beast milk, 12 Beet taste, 40 Benzoie acid, 64 Biteh’s milk, 25 Blue milk, 56 Board of Health lactometer, 203 Boiled taste, 59 Borie acid, 62 Breed peculiarities, 27 Buffalo’s milk, 23 Burnt taste, 40 Buttermilk, 191 Calf cholera, 101, 125 Carbohydrates, 18 Carbolie odor, 69 Casein, 14, 16 Catarrh, mucous, 46 purulent, 46 Cat’s milk, 25 Cell protoplasm, 14 Cells, degenerated, 13 Cellular content of milk, 247, 291 Certified milk in America, 275 Philadelphia, 267 Changes in milk, 51-58 at high temperatures, 58, 59 the secretion, 46-48 Cholera, Asiatic, 117 Callie l(t Citric acid, 150 Cleanliness, 176 288 Colostrum, 12, 29, 30 bodies, 12 Composition of milk, 21—26 Constituents of milk, 15—21 Contamination with bacteria, 120— 126 organisms, 104—120 Control of milk in cities, 197 Contusions of the udder and teats, Cooler, 135 i Copenhagen Milk Supply Com pany, 159 Counting, 246 Cow, disease of, 42 Cowpox, 89 Cow’s milk, 21 Cream, 191 adulteration of, 225 Curd fermentation, 230 Daily variations, 34 Dairy farm inspector, 167, 168 Degenerated cells, 13 Determination of fat content of | milk, 208 of bacteria, numerical, 238 of streptococci, 250 Digestion, 147 Dilution of whole milk with water, 219 Diphtheria, 112 baeilli, 114 Dict AG Disease of the cow, 42 Effects of various adulterations, 224 of acidity, 253 Embolism and thrombosis, 45 Enteritis, 98 Examinations, bacteriological, 231 HOT inte pus, 234 of cellular contents, 247 Excretion of foreign matter, 48-50 of poisonous substances with milk, 60, 61 Exercise and work, 42 INDEX. Farm conditions, 273 Fats, 19 Fatty degeneration, 14 Feeding the herd, 173 iermentation, curd, 230 test, 229 | Feser's lactoscope, 198 Fjord pasteurizer, 132, 133 Food, influence of, 37 Foot-and-mouth disease, 87 virus of 89 Foreign matter, excretion of, 48 Formaldehyde, 66 Formalin, 66 Formol, 66 Galactase, 20 Gangrenous mastitis, 47 Gartner's fat milk, 151 Gases, 20 gas-producing organisms, tection of, 251 | Gerber’s acidobutyrometer, 209 German instructions for producing nursey milk, 265 Globulin, 14 Goat’s milk, 23 de- Half milk, 190 skimmed milk, 190 Harmful properties of milk, 60 Health of the attendants, 178 Herd, attendants of, 178 feeding the, 173 health of, 169 sample, 201 sudden changes in food of, 176 Ineubation, 246 Indigestion, 101 Individual peculiarities, 28 Infant mortality, 126 Infection by milk, 70-104 Infectious diseases, 103 Influence of food, 37 Inorganic salts, 20 Inspection of the milk, 10 Intestinal tuberculosis, 72 Todine, 60 Laetalbumin, 18 Lactation period, 29 Lactic acid, 52 Lactodensimeter, Quevenne's, 202 Lactoglobulin, 18 Lactometer, Board of Health, 203 Lactoscope, Feser's, 198 Lactose, 14, 18, 221 Lecithin, 150 Leffmann-Beam method, 213 Legal standards, 187, 188 Lung plague, 92 Mare's milk, 23 Mastitis, 46, 93, 125 gangrenous, 47 parenchymatous, 47 Media, 243 Medicines, 43 Mereury, 60 Method, Arnold’s guaiac, 192 Babcock, 214 Leffmann-Beam, 213 Soxhlet’s, 208 standard, 237 Storch’s, 192 Metritis, 125 Milk, acidity of, 228 analysis of, 237 appearance of, 226 ass’s, 24 Backhaus’s infants’, 151 bacteria in, 120 market, 122 beast, 12 bitch’s, 25 blue, 56 bottling of, 196 buffalo’s, 23 eare of, 180 certified, 251 changes in, 51-59 collections of samples, 239 commission, 163 composition of, 21-26 constituents, 15-21 containers, 193 control, 9, 10 of in cities, 197 cow’s, 21 INDEX. 289 Milk, determination of fat con- tent of, 208 of bacteria, numerical, 238 dilution of whole with water, 219 elephant’s, 26 epidemics, 104 fat, 19 for infants, 147 Gartner’s fat, 151 glands, 12-15 goat’s, 23 half, 190 skimmed, 190 harmful properties of, 60 infection by, 70-104 inspection of, 10 keeping and selling, 184 legal standards for, 188 mare’s, 23 modified, 152 . nursery, 265, 266 odor of, 226 of the Alpine eattle, 40 of the cat, 25 packing of, 185 pasteurized, 191 pasteurizing market, 138 preparations, 193 preparing for delivery, 182 publie control of, 157, 158 publie supervision of, 196, 226 putrid, 123 rabbit’s, 26 red, 56 regulation of production of, 164-181 regulation of sale of, 182-196 reindeer’s, 26 retailing in cities, 159 sale and delivery of, 182 secretion, 12-15 sheep’s, 23 sickness, 103 skimmed, 190 slimy, 124 specific gravity of, 197, 202 sterilization of, 143 sterilized, 192 sour, 123 290 Milk, sow's, 25 taste of, 226 transparency of, 197 tubercle bacilli in, 73 mixed, 81 unclean or dirty, 235 variations in, 24-26 Voltmer’s mother’s, 151 voluntary control of, 163 whole, 186 woman’s, 24 yellow, 57 zebu’s, 22 Milking, method of, 31 time of, 31 Miliary tuberculosis, 73 Modified milk, 152 Mortality among children, 154 Mucous eatarrh, 46 Nitrate and nitrites, 221 Nursery milk, 265, 266 Nymphomania, 41 Odor, carbolie, 69 of milk, 227 Odors, 69 abnormal, 55 absorption of, 68, 69, 70 (strum, 41 Oily taste, 56 Ovariotomy, 41 Paracasein, 17 Parenchymatous mastitis, 47 Partial skimming, 218 Partly skimmed, adulteration of, 225 Pasteurization, 128-142 objections to, 139 quick, 131 Pasteurized milk, 191 Pasteurizer, Fjord, 131 Pasteurizing a fluid, 128 market milk, 138 Pathogenic bacteria, 129 Pepsin digestion, 17 Peptone, 123 Plating, 244 Potassium bichromate, 65 INDEX. Preparing for delivery, 182 Preservatives, 61-68 Preserving samples for analysis, 201 Proteids, 16 Pseudo-tubercle bacilli, 81 Public supervision, 196, 226 Purulent catarrh, 46 Putrid milk, 123 Quevenne’s lactodensimeter, 202 Rabbit’s milk, 26 Rabies, 91 Rapid method for determining acidity of milk, 228 Reaction, 227 acid, 227 alkaline, 227 amphoteric, 227 Red milk, 56 Regenerative heater, 145 Regulation of production, 164- 181 sale, 182-196 Reindeer’s milk, 26 Retailing milk in cities, 159 Sale and delivery, 182 Salicylic acid, 63 © Salts, 20 Sample, herd, 201 Samples, preserving, 201 taking, 200 collection of, 239 Searlet fever, 115 Sediment, 126 Septie metritis, 101 Sexual conditions, significance of, Sheep’s milk, 23 Skimmed milk, 190 Skimmed milk, adulteration of, 225 Skimming of whole milk in con- junetion with addition of water, 222 partial, 218 Slimy milk, 124 Soapy taste, 56 INDEX. Sore throat, 119 Sour milk, 123 Sow’s milk, 25 Soxhlet’s method, 208 Specifie gravity, 197 of milk and whey, 202 whey, 206 Stage of the lactation period, 29 Sterilization, 130, 143-146 Sterilized milk, 192 Storch’s method, 192 Streptococci, determination of, 250 Sudden changes in food of herd, 176 Suppurative processes, 102 Tabes mesenterica, 78 Taking samples, 200 Taste, beet, 40 boiled, 59 burnt, 40 of milk, 229 oily, 57 soapy, 57 Tastes, abnormal, 55 Temporary changes, 38 Test, aleohol, 229 fermentation, 229 Transparency of milk, 197 Toxie substances, 60 Tubercle bacilli in milk, 72 mixed milk, 81 separation of, 85 temperature at which killed, 86 Tuberculosis, 71-78 abdominal, 78 291 Tuberculosis, broncho-pneumonia, in eattle, 71 intestinal, 72 miliary, 73 udder, 48, 71 Tumors, 48 Typhoid bacillus, 110 fever, 106 Unelean or dirty milk, 235 Udder and teats, contusion of, 45 inflammation of (mastitis), 93 oedema, 46 tuberculosis, 48, 71 Unsanitary practices in bottling, 195, 196 Variations in cow’s milk, 26-45 Viseogen, 226 Viscosity, 58 Volatile oils, 60 Voltmer’s mother’s milk, 151 Voluntary control of milk, 163 Water, 16 supply, 179 Whey proteid, 17 specific gravity of, 202, 206 Whole milk, 186 dilution of with water, 219 skimming of in conjunction with water, 222 Woman’s milk, 24 Yellow milk, 57 Zebu’s milk, 22 i SØN, cet HON pir F ch N ; bh ue . th ae G . y i ~ = 4 | i Es ie 4 == . : | . É É i i åg JR É 4 ? mn > — “ = * : vd dj r t é A oF ie 2 Så Øg v K a nd i ' 24 easy ” ; ry X i i i 4 8 ? 4 7 i \ ' 4 Å a srt rå (ae. | | = v oa tL r c i ‘ bs ‘ ¢ 4 > . 34 - 7 i X r a i sj + J" t Ed E : . Oe i 3 ‘awk =~ if 4 É . i mn ~ i, ra f 4 = i ng 4 dé +: v. 2 v le = X i) + ” rr a ESS [ETUI 00008958798