Part 10 (1/2)

[122] Duval and Bassett, Studies from the Rockefeller Inst for Med

Research, 2:7, 1904

[123] Zeit f physiol Che (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 anisms that find their way into rowth, improve the quality of milk supplies It is therefore especially desirable froes should be held in abeyance as much as possible Then too, the possibility that milk may serve as abacteria makes it advisable to protect this food supply from all possible infection fro, therefore, the relation of bacteria to general ienic_ 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 gereneralfoundations: (1) the exclusion of all bacterial life, as far as practicable, at the tie of the saanisain access; (2) the removal of the bacteria, wholly or in part, after they have once gained access

Until within coiven to the character of e of butter fat, and so as the product could be placed in the hands of the consumer in such shape as not to be rejected by hiiven to its character At present, however, iven to the quality of ernize the necessity of a greater degree of control

This controlof the product after it reaches hio back to the milk producer on the farm

Here especially, it is necessary to inculcate those e measure the wholesale infection that ordinarily occurs

The tatch words which are of the utmost importance to the milk dealer are _cleanliness_ and _cold_ If the milk is properly drawn frohly chilled, the dealer has little to fear as to his product Whenever serious difficulties do arise, attributable to bacterial changes, it is because negligence has been permitted in one or both directions The influence of cleanliness in di the bacterial life in rowth of those forain access has been fully dealt with in preceding chapters It is of course not practicable to take all of these precautions to which reference has been e supplies ofconditions could be secured if the public would demand a better supervision of this ier cities are awakening to the ily active in the ulations and the enforcement of the same

New York City Board of Health has taken an advanced position in requiring that all milk sold in the city shall be chilled down to 45 F

i and shall be transported to the city in refrigerator cars

Reference has already been e 52) in the inspection of city milk supplies, and it is the opinion of the writer that the curd test (see page 76) could also be used with advantage in deter the sanitary character of milk This test reveals the presence of bacteria usually associated with dirt and pernition of milks that have been carelessly handled

Froe of examinations made of the milk supplies in a number of Wisconsin cities it appears that this test could be utilized with evident advantage

~”Sanitary” or ”certified” er cities, the attempt has been made to improve the quality of the milk supplies by the installation of dairies in which is produced an especially high grade of milk Frequently the inspection of the dairy as well as the examination of the milk at stated intervals is under the control of milk commissions or medical societies and as it is custo board with the product, such milks are frequently known as ”certified” In such dairies the tuberculin test is used at regular intervals, and the herd inspected frequently by courated as to cleanare such as to insure the diminution of the bacteria to the lowest possible point The bacterial lianisms per cc Often it is possible to improve very materially on this standard and not infrequently is the supply produced where it contains only a few thousand organisree of care is exercised, naturally a considerably higher price must be paid for the product,[126] and it should be remembered that the develope centers where the dealer can cater to a selected high-class trade Moreover, it should also be borne in mind that such a method of control is only feasible in dairies that are under individual control The i adequate control with reference to the iven the milk immediately thereafter, when the same is produced on different farms under various auspices is evident

PRESERVATION OF MILK SUPPLIES

While much can be done to ie proportion of the bacteria which norrowth of those that do find their way therein, yet for general municipal purposes, any practical method of preservation[127] that is applicable on a coely upon the destruction of bacteria that are present in the milk

The two possible methods by which bacteria can be destroyed after they have once gained access is (1) by the use of chemical preservatives; (2) by the aid of physical methods

~Chemical preservatives~ Numerous attempts have been made to find some chemical substance that could be added towith its nutritive properties, but as a general rule a substance that is toxic enough to destroy or inhibit the growth of bacterial life exerts a prejudicial effect on the tissues of the body

The use of chemicals, such as carbolic acid, mercury salts and mineral acids, that are able to entirely destroy all life, is of course excluded, except when milk is preserved for analytical purposes; but a number of milder substances are h the statutes of practically all states forbid their use

The substances so used rouped in two classes:

1 Those that unite cherowth to form inert substances Thus bicarbonate of soda neutralizes the acid in souring h it does not destroy the lactic acid bacteria