[123] Zeit. f. physiol. Chemie, 10:146; 9 Intern. Hyg. Cong. (London), 1891, p. 118.
[124] Vaughan and Perkins, Arch. f. Hyg., 27:308.
[125] Newton and Wallace (Phila. Med. News, 1887, 50:570) report three outbreaks at Long Branch, N. J., two of which occurred in summer hotels.
CHAPTER VI.
BACTERIA AND MILK SUPPLIES WITH ESPECIAL REFERENCE TO METHODS OF PRESERVATION.
To the milk dealer or distributor, bacteria are more or less of a detriment. None of the organisms that find their way into milk, nor the by-products formed by their growth, improve the quality of milk supplies. It is therefore especially desirable from the milk-dealer's point of view that these changes should be held in abeyance as much as possible. Then too, the possibility that milk may serve as a medium for the dissemination of disease-breeding bacteria makes it advisable to protect this food supply from all possible infection from suspicious sources.
In considering, therefore, the relation of bacteria to general milk supplies, the economic and the hygienic standpoints must be taken into consideration. Ordinarily much more emphasis is laid upon the first requirement. If the supply presents no abnormal feature as to taste, odor and appearance, unfortunately but little attention is paid to the possibility of infection by disease germs. The methods of control which are applicable to general milk supplies are based on the following foundations: (1) the exclusion of all bacterial life, as far as practicable, at the time the milk is drawn, and the subsequent storage of the same at temperatures unfavorable for the growth of the organisms that do gain access; (2) the removal of the bacteria, wholly or in part, after they have once gained access.
Until within comparatively recent years, practically no attention was given to the character of milk supplies, except possibly as to the percentage of butter fat, and sometimes the milk solids which it contained. So long as the product could be placed in the hands of the consumer in such shape as not to be rejected by him as unfit for food, no further attention was likely to be given to its character. At present, however, much more emphasis is being given to the quality of milk, especially as to its germ content; and the milk dealer is beginning to recognize the necessity of a greater degree of control. This control must not merely concern the handling of the product after it reaches him, but should go back to the milk producer on the farm. Here especially, it is necessary to inculcate those methods of cleanliness which will prevent in large measure the wholesale infection that ordinarily occurs.