Report of the Medical Officer of Health for the years 1922-23 and 1923-24, and review (1902-25) of the public health conditions and progess of Johannesburg.

  • Johannesburg (South Africa)
Date:
1925
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Licence: Public Domain Mark

Credit: Report of the Medical Officer of Health for the years 1922-23 and 1923-24, and review (1902-25) of the public health conditions and progess of Johannesburg. Source: Wellcome Collection.

    52/70 (page 44)
    M.O.IT Milk. . 1922-3-4. Pure Untreated Milk vs. Pasteurised Milk. This very important question arose in most interesting form in February, 1924, from a request by i he Superintendent of the General Hospital to advise as to the respective merits of a tender by a first-class milk supply company (Messrs. “ Y ”) to supply the Hospital with pasteurised milk at Is. 8d. per gallon, and that of a very progressive dairy farmer (Mr. “X ’) in the vicinity of Johannesburg to supply fresh, untreated milk at 2s. per gallon. The contract conditions specified milk “ fresh, sweet, whole and unseparated, “ containing not less than 3 per cent of fat and not less than 8'5 per cent., of “ solids-not-f'at.” The bacterial standard required was:—“Total blood heat organisms per c.c. not to exceed 100,000 in winter and 250,000 in summer: “ and B. Welchii test to be negative in 5*0 c.c.” It may be stated that in February, 1924, Mr. “ X ” held the existing con¬ tract on the foregoing conditions. Samples for chemical and bacterial examina- iion by the Government Analyst’s Department and the S.A. Institute for Medical Research were taken, usually monthly, but on irregular dates, by representatives of these Institutions. The results were somewhat surprising. The average “ fat content ’’ for the 11 occasions between January, 1923, to January, 1924, was no less than 4*49 per cent., that for “ solids-not-fat being 8‘8 per cent. The presence of B. Welchii was not once detected in 5 c-c. in the 11 samples, and the counts for organisms per c.c. at 37° C. were as follows:—25,550, 9,100, 9,900, 7,000, 13.100, 60,000, 62,000, 15,200, 1,200, 319,000, 128,000. The Medical Officer of Health’s reply to the Hospital inquiry was as follows: — My opinion is, as I -understand, invited upon A. _The’ herds, and presumably also the premises and methods, of the dairy farms specified by Messrs. “ Y ” and also upon those of Mr. “ X’s ” farm. B. —The Nielsen Process of Sterilisation. C. —The relative value of Nielsenised milk compared with Mr. “ X’s ” milk as an article of hospital diet, especially for children. A,—Herds, Premises and, Methods. (1) Of the dairy farms specified by Messrs. “ Y.” all four possess good milk- producing herds, but in no one of them are the animals subjected to periodic tuberculin testing, which is a very important matter. In only one case are the buildings first class. In all of them the methods of handling are good. In none of them are the employees subjected to the very necessary Widal Test for enteric carriers. The score-card aggregate of these farms would vary from 70 per cent, to 75 per cent'. The distance over which the milk has to he brought in by train varies from 27 to 35 miles. (2) Mr. “ X’s ” farm possesses a good milk-producing herd of some 300 “ mixed ” or “ grade ” Frieslands, and. incidentally, the notably high average fat-content (4-49^pcr cent.) of their yield is a most remarkable answer to the defence so often put up that Frieslands necessarily produce thin milk. All his animals are tested every 12 months for tuberculosis, and all his employees undergo the test for enteric carriers. His cow-stables are built in concrete to the model plans of this Department, his methods are excellent in every respect, and his score-card aggregate would be between 95 per cent, and 100 ‘per cent. The distance over which “ X's ” milk is brought in by motor is 12 miles. 7T—The Nielsen Process of Sterilisation. The validity of the claim that this process produces a sterile milk without chemical change greater than that resulting from ordinary pasteurising is admitted for the purposes of this Report. But apart from chemical change, there is what may be termed a vital change, for there is in milk a constituent known at ^ itamine C, which is of essential nutritive importance, especially as regards the prevention of scurvy and rickets. Now, as the value of Vitamine 0 commences to be impaired at a temperature of 125° F., it is fair to assume that this value is materially affected )>y exposure to a temperature of “ 263° F. for a few seconds,” which forms part of the Nielsen process, and which is 100° F. above the maximum temperature (150° F.) permitted by the 1923 Regulations of the Hnglish ^Ministry ol Healtfqfoi pasteuiising milk. At the same time, it should he understood that Messrs. “ Y offer an alter¬ native system (the Holder) of sterilisation at 14oJ 1*. for 30 minutes. But, if it can be avoided, it is very undesirable that the milk which forms so large a part of the diet of children and other invalids in hospital should have the value of its important Vitamine C impaired. It is also very inconvenient, and costs something, to have to rectify that impairment by adding fresh lemon juice or anything else Lastly, milk sterilised by any heat process becomes less palatable, especially to invalids. It is true that pasteurised milk is supplied to our Child Welfare Centre by Messrs. “ Y,” but this is because the total quantity of milk required W insufficient as a business proposition to obtain “ certified ” unpastenrisod milk (seO next page).