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care bestowed upon handling the milk in most farms. Even in case the milk should be carefully cooled during transportation and distribution it would be impossible especially in the hot season to prevent large quantities of milk from getting unfit for consumption.
The Pasteurization of milk for consumption is of far greater importance for public health.
Statistics amply show how beneficial an influence Pasteurization has had with regard to lowering the percentage of infant mortality. Well substantiated data in support of this fact are to be found anywhere in literature.
There are numerous instances of the spread of typhoid fever and other contagious diseases whose germs may be transmitted through the consumption of non-Pasteurized milk. It is a fact that the majority of housekeepers seem to be unwilling to realize the great danger for the health of their families which may result from the consumption of raw bulk milk, even though experts seize every opportunity to sound a warning against it.
In connection with the above we must be aware of the fact that the greater part of Pasteurized milk sold to consumers is consumed as such. Most people have not the faintest notion that this milk, too, might be exposed to risks if not heated again before consumption.
Therefore, from the standpoint of public health, it must be considered of the highest importance that measures should be taken to give full guaranty to the consumers that the milk sold as Pasteurized has actually been submitted to operations that would render it perfect from an hygienic point of view.
In the designation “Pasteurized” the public reads a guaranty for the efficiency of the procedure to which the milk has been submitted ; they repose a certain confidence in Pasteurized milk, as to its fitness for being consumed as delivered by the milk plants. Hence it is expedient, that the designation “ Pasteurized” should not be used in
iscriminately for all milk that has been submitted to heating, but that this term should be exclusively reserved for heated milk that has been treated in such a way that it can not imperil the health of the consumer.
Pasteurized milk must be milk that has been heated in such a manner that it may be fairly taken for granted that it contains no living pathogenic germs. Measures must be taken that such milk, after heating, can not again be contaminated with deleterious organisms. After Pasteurization the milk must be refrigerated and kept at so low a temperature that the remaining spores can not develop.
A regulation by law of the sale of Pasteurized milk must enact. in the first place, the prohibition of selling milk by the name of Pasteurized milk, if the seller can not show a license from some competent authority. Such a license can be withdrawn at any time.
A dairy can be granted a license for selling Pasteurized milk only provided it meets certain requirements both as regards building and equipment, and the responsible manager will have to pledge himself in writing to follow the instructions that will be given with regard to the handling of milk in his plant.
It is not my object to give full details as to the conditions that will have to be satisfied previous to granting a license for supplying Pasteurized milk. I shall restrict myself to the essential points and only mark out the main outlines.
(a.) The building. The building in which the business is conducted will have to meet sanitary specifications. Therefore certain demands shall be made as to the construction of walls, floors, and ceiling, lighting, ventilation, and premises of the building, and the absence of undesirable works and trades in the environment of the dairy. The building will have to afford ample room for a spacious mounting of the required machinery.
(6.) I'he mechanical features. The machinery required for working the milk will have to be constructed so as to guarantee sanitary handling of the milk. The cleansing and upkeep of the machinery will be under permanent control. The plant will comprise steam boilers of a capacity sufficient to insure a careful sterilization of apparatus and containers.
(c.) The milk. For milk to be labeled “Pasteurized,” the milk plant under control will have to use, exclusively, such milk as is unadulterated, hygienically produced, and carefully handled; it should be perfectly fresh the moment it is Pasteurized, and its bacteria count must not exceed a fixed norm. The dairy under control will have to make certain, by means of prescribed reactions, that the milk shows no abnormal properties.
The milk that is to be Pasteurized will have to be shipped in well-cleansed vessels and will have to meet certain specifications as to cleanliness.
Pasteurization must always be preceded by mechanical clarification of the milk.
(d.) Pasteurization.-In connection with the machinery employed, the minimum temperature and the minimum duration must be fixed for every milk plant separately. The period of Pasteurizing must be increased in proportion to the lowering of the temperature.
In Pasteurization according to the Danish method (see above) neither temperature nor period of heating can be accurately regulated. In order to make sure that the pathogenic organisms are actually destroyed, care should be taken that the temperature should always be kept rather too high than too low and that the apparatus should have a large capacity in order to make the average (computed) time of flow as long as possible. In case this method of Pasteurizing should be permitted, it will be necessary to require that milk treated according to this system should show a negative Storch reaction (said reaction to be executed at room temperature during an observation period of five minutes, at the least).
In Pasteurizing at low temperature by the continuous or flash method (the milk flowing uninterruptedly through the wholder" or “retarder”) we are able to regulate the temperature pretty accurately, but, on the other hand, we can not definitely fix the proper period of heating. It could only be done in case there was no mixing up in the apparatus of milk entering first and milk flowing in at a later period. However, this mixing can not be prevented in any apparatus of the continuous process. Therefore, the computed average flowing period is not identical with the exact heating period; so it will also be found necessary in this case to re
quire a wide margin of safety. It will be desirable, before putting an apparatus into use, to examine the extent to which the milk that flows into the apparatus in successive intervals is mixed.
The absolute or positive “holding” process is preferable to the others inasmuch as it allows us to regulate both temperature and time with great accuracy.
The most commendable equipment is that which works quite automatically, inasmuch as it will prevent such errors as, for instance, the untimely opening and shutting of taps by attendants.
Care must be taken that all the taps should fit perfectly, lest there should be a mixture of Pasteurized milk with that which is not suliciently heated.
The different investigators are not of one mind concerning the temperature at which milk should be Pasteurized in order to make sure that the pathogenic organisms are destroyed. It is, however, pretty generally admitted that heating up to 61° C. during 20 minutes will be effective, provided the milk is kept moving during the heating period, and provided the formation of foam or membranes is avoided.
As for temperature, practice has fixed certain limits in the countries where the public positively requires such milk as will cream in a normal way. In fact, a heating above 63° C. will reduce the creaming ability of milk. Seeing that a certain allowance must be made for temperature, say from 1 to 11° C., one is likely to fix the lowest limit somewhat below 63° C., say, at 61! or 620 C., and to fix the minimum duration at 30 minutes.
Several American States have issued conformable regulations.
(e) Control of Pasteurization.-Dairies wishing to bring Pasteurized milk upon the market will have to fit their apparatus with selfregistering thermometers (thermographs, “recorders”), which are to be sealed up during the time of Pasteurization. The dated and certified registrations are to be kept for inspection.
The officials, having charge of the inspection, will have to be admitted to the dairy at any time and, on demand, they are to be furnished with all data relative to the technical part of the business; they are empowered to take milk samples necessary for inspection and to collect all data they might think expedient for efficient verification.
(1) The handling of Pasteurized milk.-Pasteurized milk must be transported and distributed in closed vessels exclusively so as to render it impossible to open the container without breaking up a seal or label.
This measure is necessary for preventing Pasteurized milk from being contaminated or polluted during distribution.
In the case of milk which is sold in the street or in a shop from out a can or a vat, the risk of its being contaminated is so great that such milk can not be allowed to be delivered as Pasteurized milk, even in case it should be drawn by means of a tap.
The container will have to bear the date of the day on which the milk was Pasteurized.
(9) Cooling the Pasteurized milk.--After Pasteurization, the milk will have to be thoroughly cooled and kept at low temperature. At the time of delivery the temperature must not exceed 8° C.
(h) Staff of the dairy.—The staff of the dairy, so far as they handle the milk or the utensils in any way whatever, will have to be placed under medical control.
(i) Control of Pasteurized milk.-At any time Pasteurized milk will have to meet certain bacteriological requirements, to be stipulated later on. Among others, one might insist that the investigation as to coli-bacteria count must yield a negative result. This
. again, is a question of details that can be further elaborated after the main principles will have been laid down in their general outlines.
Wilson H. LEE, president, Certified Milk Producers' Association, New Haven,
Certified milk is clean, unprocessed milk of uniform composition from healthy cows, and carefully guarded against disease or contamination. Dr. M. J. Rosenau says:
It represents one of those high ideals which at first seems visionary and unattainable, but is, in reality, an accomplished fact.
In 1891, Dr. Henry Leber Coit, of Newark, N. J., conceived the idea of having a representative commission of physicians establish correct clinical standards of purity for milk, and undertake the control and supervision of the dairy farm producing it; and when all requirements were fully met, to certify to the high quality of the product. Mr. Stephen Francisco, of Montclair, N. J., who was at that time producing a high-grade milk on his Fairfield dairy farm, volunteered to place that farm and its little herd of 13 cows under the proposed commission. In April, 1893, physicians of Newark, Orange, and Montclair, N. J., joined Doctor Coit in incorporating the Medical Milk Commission of Essex County, N. J. Standards. rules, and regulations were formulated, and a contract was made with Mr. Francisco. This initial effort was so successful that Mr. Francisco soon had to increase his herd—it now contains about 1,000 cows-and certified milk became an established fact.
The term “ certified milk” originated with Doctor Coit, and with the approval of the Essex County Milk Commission it was registered by Mr. Francisco in the United States Patent Office in 1904. This was done solely to protect the term against possible abuse, and with the definite understanding that any properly qualified medical milk commission should be free to use it.
Between 1891 and 1896, 11 other medical milk commissions were formed in different parts of the country, and of course as many different certified-milk farms developed. Little progress was made. , however, until after the organization of the American Association of Medical Milk Commissions in 1907, and of the Certified Milk Producers' Association of America the year following.
The medical milk commissions did not always appreciate the difficulties and problems of the producers; and except for the general desire to secure a milk of the highest quality there was too often a distinct absence of the sympathetic and helpful cooperation that the producer felt was his due. As a consequence the associations grew
apart rather than together. However, as is usually the case, when each understood the other's point of view better feeling began to develop. Then followed joint meetings wherein the good faith and even the intelligence of the producers received recognition. This mutual understanding grew stronger, as did the realization that neither organization could function without the other, and that the interests of both could best be served by establishing one national headquarters. This was accomplished last year when Dr. Ralph R. Ferguson consented to accept election as executive secretary of both the medical and producers' associations. More than 100 per cent increase of members in both organizations shows the well-deserved appreciation of Doctor Ferguson's efficiency.
Practically all medical milk commissions are appointed by a county or State medical society, although there are a few such commissions that have been created in other ways, notably the one that supervises the Walker-Gordon laboratories and farms.
Many States now recognize and protect certified milk by statute, and in at least one State the law requires that the standards approved by the American Association of Medical Milk Commissions and the Certified Milk Producers' Association of America shall be complied with in the production of milk before it may be labeled * certified."
In 1912 the American Association of Medical Milk Commissions first published The Methods and Standards for the Production and Distribution of Certified Milk. While there have been no fundamental alterations in the content, some changes have been found desirable, and these have been made in the recently approved revision.i
The certified-milk movement is unquestionably the outstanding effort and the only nation-wide one organized to secure and maintain the production of the highest possible quality of milk; but we should not forget that to no one man, organization, or even country belongs all the credit for the advances that have been made in the production of pure milk. Primarily we are indebted to the scientists, but their work would still be merely interesting scientific knowledge without practical results had not the altruistic spirit of Mr. Francisco been shared by other producers who were encouraged by the medical profession to apply this knowledge. An outstanding example of this is the work of George Ede Gordon, who with the scientific cooperation of Dr. Thomas Morgan Rotch, developed the Walker-Gordon Laboratories and their farms for the percentage feeding of infants and invalids under physicians' prescriptions. It is to Mr. Gordon that we are indebted for many of the practical methods in use to-day in the production of clean milk, among them the use of steam for sterilizing all dairy utensils and putting into use Doctor Freeman's idea of a covered milking pail.
No objection has been raised to the use of any of the different dairy breeds for the production of certified milk; but the prime requisite being perfect health and condition, many producers prefer to use good grades, not because the grade is more resistant to dis
1 Copies of the revised Methods and Standards for the Production and Distribution of Certified Milk may be obtained from R. R. Ferguson, J. D., secretary, 4175 Irving Park Boulevard, Chicago, m.