Tan., R..- I 670.67af mm=";Iaovaxd&lMuuaBlouxAal THE MILK SUPPLYSUPPLY' OF LARGE TOWNS.TONVNLz. [ML..aoH[KAMM 21, .19030, SO.E BACTERIOLOGICAL CONSIDERATIONS. It would be foreign to our present purpose to go at any length into the subject of the bacteriology of milk. The ON literature is already very extensive, and is growing rapidly. Some general observations are, however, neceseary in order THE MILK SUPPLY OF LARGE TOWNS: that the risks of bacterial contamination to which milk is exposed before it reaches the consumer may be called to ITS DEFECTS AND THEIR REMEDY. mind. The bacteria most characteristic of milk are those which I. produce the lactic and butyric acid fermentations. Of the INTRODUCTORY. lactic organisms which for the most part do not form spores the commropest are the bacillus acidi lactici and the oidium MILK is a delicate and unstable fluid, yet it is the only lactis. Most of the organisms producing butyric acid fer- animal product which is habitually taken raw unless we mentation are sporing species.' According to Klein2 milk -except oysters, a food also under suspicion of being some- received and brought in a sterile vessel from a shop, and kept times a disseminator of disease. It has long been recognized at 370 C., may the next day, or at latest after two days, "1 be that typhoid fever may be disseminated by milk, and more completely clotted and sour, due to the growth and activity of bacillus coli, or it may be decomposed by proteus vulgaris, or ;recently there have been grounds for believing that diph- bacillus mesentericus, or it may be full of gas, clotted with a theria, and perhaps also scarlet fever, may be distributed in large amount of clear whey caused by the growth of the the same way. Recently a great deal of attention has been anaerobic bacillus enteritidis sporogenes." given to the risk of the production of tuberculosis in man- Other microbes producing characteristic effects such as bitter kiind by the consumption of the milk of tuberculous cows, a milk or viscid milk occur, and in milk from cows with inflam- mation of the udder or parts of the udder pyogenic organisms ,risk which, as is well known, Professor Koch considers to be such as the staphylococcus pyogenes aureus, and the strepto- non-existent. The danger, whatever its magnitude, arises in coccus pyogenes, a. brevis and s. longus, may be present. -connexion only with the milk of cows having tuberculous Whether these organisms are ever present in any considerable disease of the udder, and even if it were proved conclusively number except in the milk of- cows with mastitis does not that the bacillus of bovine tuberculosis is seem to have been proved, but they may be present in abun- absolutely dance in purulent matter in milk. A specific microbe innocuous to man, no one will seriously propose that milk has been described as the cause of a specific purulent -should be taken for human consumption from other than inflammation of the udder by Nocard and Mollereau, who healthy cows. applied to it the name "streptococcus mastitidis." Klein But, granted that this condition be observed, there are still has.proposed the name " streptococcus radiatus (pyogenes) " dangers connected with the use of milk as it is now commonly for a microbe associated with a sero-fibrinous massitis in the cow, and producing abscess in guinea-pigs. Many distributed by the trade and consumed in large towns. A otherorganisms frequentlyfound in milkmight be enumerated, large proportion of the fatal cases in the murderous epidemics but it must suffice to refer again to one other, the bacillus -of infantile summer diarrhoea are with good reason attributed enteritidis sporogenes found by Klein in the milk consumed to the consumption of milk in an infective state. by patients who suffered in an epidemic of diarrhoea at St. These dangers are well known, but owing to the supineness Bartholomew's Hospital and in their evacuations, and by Andrewes in other cases of diarrhoea admitted into that of the public are permitted to continue. hospital. It has been found also in water, sewage, manure, Milk may be deliberately adulterated by dishonest traders, and in other samples of milk. Hewlett3 states that it is but the sanitary authorities of the cities and boroughs where generally tq be found in normal dejecta and in dust, and it is distributed have power to deal with such adulterations; that it is probably ubiquitous. It seems probable, however, caumerous prosecutions are, in fact, instituted yearly for the that it is evidence of faecal contamination. It is pathogenic sale of milk which does not reach the official no to guinea-pigs. standard-by We do not propose to enter here upon a discussion of the means exacting. Milk may be " faked" by adding con- occurrence of the infectious agents of tubercle, typhoid fever, -densed unsweetened milk diluted with water to fresh milk cholera, or diphtheria in milk. in such proportions that the final mixture distributed to -customers does not fall below the official standard, a falsifica- CONDITIONS INFLUENCING THE NUMBER OF BACTERIA IN tion MILK. more difficult to detect. But apart from dishonesty and Freshly-drawn milk contains certain germicidal substances the application of " trade secrets," milk from a country farm, which under favourable circumstances, that is to say, when though not adulterated,,may by the time it reaches the con- the milk is kept cool and free from gross contamination, will -sumer's table or the infant's bottle be a highly dangerous check the development of bacteria, and even sometimes- liquid. This is due to want of ordinary cleanliness, and to diminish their numbers. When the temperature of the milk the carelessness with which any and every operation, from is above 5o° F., or when the contamination of the milk is gross, the power of the germicidal substances is quickly ex- the milking of the cow to the delivery of the milk, is too often hausted. -carried out. The cow's udders are soiled and the milker's The whole of the milk drawn at a milking is not sterile, hands are dirty, but neither are washed. The milk pail and but the number of bacteria is small, and- they are contained -churn are inefficiently cleansed. The milk is insufficiently almost exclusively in the part of the milk first drawn. It is cooled or not cooled at all at the farm. The churns are per- probable that, in the intervals between milking, bacteria on the teats grow into the milk ducts, and are washed out at the haps left at a roadside station on the platform for hours in the beginning of milking. Experiments made by Stone for sun. The cans are often not securely closed so that dust can Rotch4 show that milk drawn with minute antiseptic precau.- -enter, and are commonly not sealed, so that they may be tions both as to the milker's hands and as to the cow's teats tampered with by dishonest or careless persons. They may may be absolutely sterile after the udder has been half opened at the railway terminus in a careless way to allow emptied.5 We cannot ask the ordinary milker to dress him- their contents to be measured. Farther for self in a freshly-boiled white suit and cap, to have his hands opportunities and arms thoroughly disinfected with a I in r,ooo mercury contamination occur during the manipulation of the whole- perchloride solution, to wash the cow's udder, teats, flanks, sale dealer and the small retailer. It is not wonderful that sides, groins, and abdomen with the same solution, to dry the milk finally delivered swarms with bacteria indicating for these parts with a freshly-boiled cloth, and to draw the milk the most part excrementitious pollution. into carefully-sterilized bottles, as did Dr. Stone for the All these dangers can be diminished reason- 31anual of Bacteriology, p. 485. London. 1902. enormously by 1H-ewlett, 2 able Journal of Hygiene, vol. i, p. 79. precautions, which experience has proved can be enforced 3 Loc. cit. p. 331. very much to the benefit of the consumer and without unduly 4 Rotch, Pediatric8, the Hygiene and Medical Treatmient of Children, London, the I896. hampering trade. 5 The same rule appears to hold good in the human female. rTX. rmwzux MARCH 21,' 1903.] THE MILK SUPPLY OF LARGE TOWNS. LMmuaAr IovuxNA b79

purpose ot this scientific experiment. But the experiment is Temperature ... 420F. 5o0 F. 55 F. 600 F. 680F. 86° F. worth remembering as proving how little the cow is respons- Bestconditions ... 2,600 II,6oo 18,800 x8o,ooo 450000 1,400,000,C00 ible for the extreme degree of bacterial impurity often to be Usual ,, ... 43,000 8g,ooo I87,000 900,000 4,00,000 14,oo,oo,occ discovered in the milk retailed in large towns. When received the milk taken under the best conditions contained Refinements of this kind and degree are in fact unnecessary. 3,000 bacteria per c.cm., that taken in the usual way 30,000. What we have to aim at is, to quote the words of 'Dr. Rotch,5 Mr. Pakes, then Demonstrator of Sanitary Science and milk "which, while comparatively sterile., has not been steri- Bacteriology at Guy's Hospital, and now Analyst and Bacteri- lized." That this is not an unattainable ideal is now well, ologist to the Transvaal Government, in a paper read before! established.' That it is seldom or never attained is true the Society of Medical Officers of Health in January, Igoo0, that it is commonly departed from so widely that the milk on the application of bacteriology to public health,7 wrote as. actually consumed, especially in the summer months, liter- follows: ally teems with bacteria is a matter of serious consequence to "For the purpose of enumeration, milk must be treated a& the public health. sewage. I have examined many samples of milk, and have ProfessorHallock Park, Assistant Director of the Research found the numbers to vary from 30,000 to 30,o0o,000 per c.cm. Laboratory of the Department of Health of New York City I have examined a few samples which were very carefully3 (the Health Department of London, it may be observed in taken from the cow, and found only scores. Unfortunately passing, has no research laboratory), published recently" a I have never been able to examine milk taken under aseptie very instructive report on the question whether the great precautions direct from a healthy cow. My experience of the bacterial contaminatioh of- the milk of cities can be lessened. ordinary London milk has been very unfortunate, the average His conclusion is that it most certainly can without putting of many samples being between 3,000,ooo and 4,000,000 any undue strain upon the trade. per c.cm." His researches show, as might have been expected and as In commenting on his experiments Dr. Park states that other investigators have shown, that the number of bacteria while the majority of the bacteria met with in milk grew best in any given sample of milk varies with the cleanliness at temperatures above 700, he has found that'42 out of the 6o observed in the cowsheds and during the process of milking, species he isolated from milk multiplied slowly even at 4o0 F. and with the temperature at which, and the length of time Professor Deldpine has made a similar observation, pointing for which the milk has been kept before it is subpmitted to out that the change produced in a few hours in summer might. bacteriological examination. The greater the cleanliness of occur in winter if the milk were kept for a long time. Dr. cow, milker, and vessels, the shorter the time, and the lower Park's general conclusion on this head is that "with only the temperature, the fewer the bacteria present. moderate cleanliness, such as can be employed by any farmer The table given below, constiucted from more detailed sta- without adding appreciably to his expense-namely, cleaD tistics given by Dr. W. H. Park, shows the number of bacteria pails, straining cloths, cans or bottles, and hands, a fairly per c.cm. under various circumstances, and illustrates the clean place for milking, and a decent condition of the cow's effect of the influences justenumerated. All the results are the udder and the adjacent belly, milk when first drawn will not averages of numerous observations. Milk obtained under the' average in hot weather over 30,o0o, and in cold weather not. heading A in the table was from cows which had been roughly over 25,000 bacteria per c.cm. Such milk, if cooled to and cleaned and placed in clean barns before milking. The long kept at 500 F., will not contain at the end of 24 hours over hairs on the udders were clipped and the udders wiped; the 0oo,ooo bacteria per c.cm. If kept at 4O0 F. the number of hands of the milkers were washed and dried, and the pails, bacteria will not be over ioo,ooo after 48 hours. If, however. which had small (6 in.) openings, were thoroughly cleansed the hands, cattle, and barns are filthy, and the pails are not and sterilized before use. In the case of B, the milk was clean, the milk obtained under these conditions will, when taken during winter in well-ventilated, fairly clean, but dusty taken from the pail, contain very large numbers of bacteria, barns. Visible dirt was cleaned off the- hair of the udder even up to a million or more per c.cm." In New York, milk before milking, and the milker's hands were wiped but not purchased in ordinary shops averages in the coldest weather washed. The milkmpails and cans were clean, but the straining over 300,000, in coot weather about i,oon,ooo, and in hot. cloths dusty. In the case of C, the milk was taken from cows weather about 5,ooo,ooo. -in the ordinary way; the ground was covered thickly with manure, and the cows were more or less visibly dirty. The PATHOGENICITY OF BACTERIA IN MILK. teats were cleaned -lightly by running the unwashed hands It will be asked, perhaps, What evidence is there that the over them once before milking. The pails and cans were presence of large numbers of bacteria in milk-even such thoroughly clean, but not sterilized by heat. The railway enormous numbers as are present in hot weather-is injurions samples were taken in March, wben the average air tempera-- to health? People have for generations been drinking milk ture of the previous twenty-four hours-had been 500 F., and obtained without any particular attention to cleanliness, for much of the milk had travelled 200 miles. The milk from the milkmaid in her smart petticoat and apron and milk-white the shops was obtained in the morning. arms is a figment of the imagination of poets and painters, yet In another experiment the rate at which bacteria-developed we survive. Yes, we survive-some of us. The death-rate- at various temperatures in milk obtained under the best con-, from diarrhoea among infants under i year (per million living) ditions and in the ordinary way was studied. The results was, according to the last decennial Supplement to theReport after twenty-four hours were as follows: of the.Registrar. General for England and Wales, i6,044. 5 BRiTiSH MEDICAL JOURNAL, 1902, vol. ii, p. 66o. The mortalityproduced among infants by epidemic diarrhoea 6 Journal of Hygiene, vol. i, p. 39r. 7 Public Health, vol. xii, p. 385. Table showing the number of Bacteria in 1 c.cm. (12 drops) of Milk under variou8 Conditions of Milking and Handling (after W. Ballock Park). Number of Bacteria. Conditions of Milking and Treatment of Milk. A At or shokrtly after IAfter 24 hours. After 48 hours.

A. cleanliness kept at 450 F. 4,333 2,766 zo,583 Scrulpulous 40 F. 5& F. 4,5504,0 B. Cleanliness. Winter. Cooled to 450 F. within two hours. . 5s.500 21,666 76,ooo C. Cows dirty. Milk cooled to 45s F. within two hours SnuiitierI . 30.366 48,ooo000 68o,ono

On arrival at New York Railway Terminus. 450 F. (average) ...... 5,669,85o As retailed. Midwinter{ Tenementohouses .3A77969 September Tenement houses 156360006, September Well-to-do ...... The figures show the number of colonies developing in nutrient peptone agar in Petri plates kept-one set at 20' U. ior iour uays, anu auzuner ay, 3 C. for one day, and at 200 C. for the following day. From 5 to 30 per cent. more colontes developed as a rule in the plates kept at room temperature than in those kept for twenty-four hours at 370 C. Bzmm 68o TM I 6 8o KzDxcALMNIL JOUZXALJoRA]TTHEE MILKML SUPPLYU P Y OFO LARGE& G TOWNS.O N.[ACLMARCH 21,! 1903.93 is so large that the aspect of the vital statistics of that distance were. In both sets of specimens, however, the period of life would be entirely different were it possible to higher the temperature of the air the smaller the percentage eliminate this factor. Moreover, the statistics show only the of milks which could be pronounced good, so that from this direct consequences of this infection, while there can be no point of view the two factors of time and temperature must be doubt that its indirect effect upon the death-rate is very con- taken into account, for " what is produced in a few hours in siderable, since an attack of acute diarrhoea often leaves summer may occur also in winter when the milk has been behind a condition of general debility and impaired nutrition kept a long time." which, if it does not actually favour the development of other These figures, while tending to eliminate disease of the maladies, certainly makes the sufferer more prone to succumb udder in the cow as a cause of a pathogenic condition in milk, ,to them. show that a great deal of the milk which reaches the town The mortality from this cause is highest in warm weather. consumer, especially in warm weather, is already infectious The curve lags a little behind the rise in the temperature of when delivered. A feeding bottle will, if once used for such -the air, but has been shown to follow very closely the rise in milk, perpetuate the infection unless thoroughly sterilized, the temperature of the soil. A continuous period of hot and ordinary washing and rinsing will not do this. weather is requisite to produce the full virulence of the dis- The general conclusion, then, is that with milk obtained by -ease, and it is doubtless for this reason that it is even more the methods which are, unfortunately, those ordinarily fol- fatal in countries with a more constant and continuous lowed a certain proportion of samples will be noxious, and .summer than our own, as, for example, in the Eastern that the longer milk is kept and the higher the temperature American States, where in many of the large cities " summer at which it is permitted to remain, the larger will be the pro- complaint " is a scourge still more serious than in this portion of noxious samples. The result is directly parallel country. to that obtained by Dr. Park in New York, who found that That it is an infective disorder, and that the infection is the number of bacteria present varied directly with these -contained in the food, that is to say in milk, is generally conditions. We are thus justified in drawing the general .admitted, and the conclusion most generally accepted has conclusion, at present, perhaps, rather of the nature of an sbeen that the milk becomes contaminated in transit from the empirical conclusion, that the larger the number of bacteria -dairy to the purchaser, or during storage in the houses of the in a sample of milk the more likely is it to be capable of pro- poor. ducing disease. Bacteriological investigations directed to the examination Professor Deldpine,9 however, takes us a step further, for he -of the organisms present in the alimentary canal in cases of concludes that the changes in milk which give rise to the ,epidemic summer diarrhoea have not yielded concordant or ordinary or common type of epidemic diarrhoea are generally conclusive results. Their general effect has been to make it due to bacilli belonging to the colon group, of which the ,probable that. bacilli of the colon group, but of varying B. coli communis (Escherich) and the B. enteritidis -degrees of virulence, are concerned in the epidemic diarrhoea (Gaertner) are probably two extreme types. He believes ,not only of infants but of adults; that certain outbreaks are that the varieties of most importance are those resembling -associated with the presence of the bacillus enteritidis sporo- the bacillus of Gaertner which do not produce permanent .genes (Klein); and that some cases, probably not very acidity, coagulation, or distinct smell when grown in milk. numerous, and presenting distinct lesions, are due to infec- We are thus brought to the point that the noxious con- tion by pyogenic organisms. dition of milk which is a cause of epidemic diarrhoea, and Professor DehWpine has attacked the question from the other probably the chief cause of the epidemic summer diarrhoea side, and has recently8 brought forward direct evidence of the of infants, is due to the presence of bacteria which are pathogenic properties of some of the bacteria often present in indicative of faecal contamination. Where does this con- milk. He has examined the bacteria present in samples of tamination occur? At the farms and in transit, or in the .nilk shown to possess pathogenic qualities. A similar study houses of the consumers? The answer must be: In both. It of foods other than milk which have caused outbreaks of therefore becomes a duty to guard against both sources of serious diarrhoeal illness has thrown light on the whole contamination. As to their relative importance, there is not problem. at present agreement. But it is abundantly proved that the In the case of milk, if it were assumed to be the source of contamination may attain very serious importance, both as to infection, it was evident that it might be contaminated by quantity and quality, before the milk reaches the consumer's some disease of the cow, or during the various manipulations doorstep. Upon this point the results of Professor Park in -through which it passed between the cow and the consumer. New York ana of Professor DehMpine in Manchester are con- Four stages may be distinguished: (i) milking and treatment cordant and conclusive; the contamination may be, and -in the dairy, (2) transit to the city, (3) collection, manipula- usually is, great, and it may be dangerous to health. -tion, storage and distribution by the wholesale and retail In another article we propose to give some account of the -dealers, (4) storage in the house of the purchaser. Great im- conditions under which milk is obtained and forwarded to portance has been attached to the danger of deterioration large towns, and to point out the numerous opportunities for during the last stage. This view has bad a dlepressing contamination which exist, and might be greatly diminished defect, for the difficulty of-supplying means for the proper or altogether avoided if reasonable cleanliness were ob- -storage of milk, even if the knowledge and intelligence neces- served. sary to use them to the best advantage existed, has been (To be continued.) -obvious to all familiar with the conditions of life in the -crowded poor quarters of great cities. In an early stage of his research, which has been carried on bANITARY BETTERMENT IN V ASHINGTON.-Amerwan Medicine -during the last nine years, Professor Del6pine obtained evi- states that at a recent meeting of the Washington Board of dence that the cause could not be looked for in disease of the Trade a resolution was adopted authorizing its committees on -cow's udder, for of ioo samples of milk taken from such cows public health to co-operate with the Board of Education of none produced in animals an acute infection rapidly fatal the District of Columbia for the improvement of the sanitary (2496 produced tuberculosis), while of 0oo samples of mixed conditions of schools and the diffusion of information con- milk from several cows at a farm, I9 produced such an infec- cerning contagious diseases. The Board recommends that tion. It is true that 38.5 per cent. of the unmixed milks (from Congress should provide for the medical inspection of schools a single cow) produced a chronic, not fatal, infection nearly in the District of Columbia, and appropriate 5,500 dols. for -as often as the mixed milks (40.38), but the milk had in all such purpose. It recommends the establishment in the instances been kept without refrigeration for considerable District of Columbia of proper hospital accommodation for periods before examination, and subsequent investigations persons suffering from tuberculosis. It urges the Board of showed that this was enough to give chance contaminations Health to use its best efforts to obtain the enactment of a law -time to develop. Of specimens of mixed milk coming from prohibiting spitting upon the sidewalks in the District of a short distance, and examined for the most part within ten Columbia. It further invites the Committee on Appropria- hours of milking, 75.68 per cent. were good, whereas of speci- tions in the Senate to include in the amount necessary for maens from a long distance, and generally kept for from twenty- expense in the District of Columbia 35,ooo dols. for the four to sixty hours or even longer before examination, only collection and disposal of ashes and other refuse from 39 per cent. were good; when the mean temperature in the hospitals, apartment houses, restaurants, etc., and also ,shade was 550 to 6o0 not one of the samples from a long dis- 20,000 dols. to provide for collecting like refuse twice a tance was good, whereas 88.8 per cent. of those from a short week during the winter months from private residences instead of once a week as heretofore. * Journal of Hygiene, vol. iii, I o. r, ;o3, abstracted in the BRITISH MEDICAL JOURNAL, 1903, vol. i, P. 457. 9Journal of Hygiene, vol. iii, No.x, 1903.