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The great Bacterial Contamination of the Milk of Cities. Can it be lessened by the Action of Health Authorities?

Published online by Cambridge University Press:  15 May 2009

Wm. Hallock Park
Wm. Hallock Park
Affiliation:
Professor of Bacteriology and Hygiene in the University and Bellevue Hospital Medical College. Assistant Director of the Research Laboratory of the Department of Health of New York City.
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It will be accepted that milk containing large numbers of bacteria, as well as the products of their growth, is less suitable for food than unpolluted milk. A bacteriological examination of the milk in great cities generally will show that much of it in hot weather, and some of it at all seasons of the year, abounds in bacteria. Clinical experience also teaches that much of the milk in hot weather is unsuitable for food, especially for infants; because in them, owing to the rapidity with which the milk passes through the stomach, gastric digestion is almost no safeguard against the entrance of disturbing microorganisms into the intestines. Even pasteurization of milk charged with bacteria and their products does not restore it to its original condition, for the dead bodies of the bacteria and their toxins still remain. The changes in milk which are most deleterious being now known to be due to bacteria, it is theoretically conceded by all, that commercial cow's milk, the substitute for maternal milk, should be as nearly free as practicable from bacteria.

Type
Research Article
Information
Journal of Hygiene , Volume 1 , Issue 3 , July 1901 , pp. 391 - 406
Copyright
Copyright © Cambridge University Press 1901

References

1 According to Pakes, London milk contains over 3,000,000 bacteria per c.c. (Lancet, Feb. 3, 1900.)Google ScholarPubMed

1 Number of bacteria obtained from development of colonies in nutrient agar in Petri plates. The nutrient medium contained 2% peptone and 1·2% agar, and was faintly alkaline to litmus. One set of plates were usually left four days at about 20°C. and one set 24 hours at 37°C., and then 24 hours at 20°C. From 5 to 30% more colonies developed as a rule in the plates kept at room-temperature than in those kept for 24 hours at 37°C. The milk was diluted as desired with 100 or 10,000 parts of sterile water, and 1 c.c. of the diluted milk was added to 8 c.c of melted nutrient agar. Plates containing over 1,000 colonies were found to be inaccurate, in that they gave too low totals. Apparently a considerable number of bacteria failed to develop colonies when too many were added to the nutrient agar. Nutrient gelatine was found to be more troublesome and not to yield more accurate results than nutrient agar.

1 This circular is to be distributed to all farmers who send milk to New York City.