The dissemination of disease by dairy products, and methods for prevention.

Date:
1910
Catalogue details

Licence: Public Domain Mark

Credit: The dissemination of disease by dairy products, and methods for prevention. Source: Wellcome Collection.

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    The bacteriological examinations of the water supplies of the first 60 dairy farms showed that only 25 per cent were under the danger line—that is, if we take 500 bacteria to the cubic centimeter of water as the limit of safety; 30 per cent were suspicious, having above 500 bacteria to the cubic centimeter, and 45 per cent were positively unfit for use, as they showed the presence of sewage bacteria. The bacterial counts in some instances were as high as 27,000, though they were made in November and December—that is, in comparatively cold weather. Since these bacteriological examinations were made similar exami- nations have followed in other cities and States, with almost identical Fig. 8.—Milk sediment magnified. This sediment consists of cow dung, hair, bacteria, etc. results. Up to August, 1908, 386 such examinations had been made on the dairy farms around Chicago. Doctor Evans, the health officer, was so impressed with the bad conditions that he decided to continue the investigations. Professor Prescott, associated with Professor Sedgwick, reported upon 240 farms in Massachusetts. While the tests showed far better conditions than those in other States, enough information as to bad conditions was obtained to warrant Professor Prescott in recommending these examinations to be made annually. Bulletin 154 of the Bureau of Plant Industry, United States Depart- ment of Agriculture, by Kellerman and Whittaker, issued November 6, 1909, gives the results of the examination of the water supplies of 79 farms in Minnesota. Twenty were found to be good, and 59 were
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