144 



CITY MILK SUPPLY 



between intermediate grades is impossible; so consumers are prone to 

 think that all milk is the same and to be loth to pay more for one dairy- 

 man's than for another's. 



So, while those who have the best interests of dairying at heart fully 

 realize that milk should be produced in a sanitary way, they are keenly 

 alive to the fact that the cost of doing so must be kept at minimum. 

 They are compelled to demand that the protective regulations imposed 

 on the industry by those who are chiefly interested in having the consumer 

 supplied with wholesome uninfected milk shall be such as really accom- 

 plish this purpose, and that they shall not be of such a character as to add 

 materially to the expense of producing and marketing milk, without 

 actually furnishing an equivalent of additional protection. Rational 

 dairy sanitation is not to be secured by adopting preventive measures 

 against every conceivable source of pollution, but by first determining 

 the sources of contamination and infection, and then proceeding to elimi- 

 nate the important ones. 



Sources of Contamination. Observation and experiment point out 

 many sources of contamination. As yet opinion as to their relative im- 

 portance is formed on common sense and on the studies of competent men 

 whose experiments have of necessity been conducted in a somewhat 

 desultory manner. More comprehensive work is under way and no doubt 

 will be helpful in confirming some of our opinions and in modifying others. 



The sources of contamination are: 



1. The cow 



2. Immediate environment. 



3. Man 



Buccal, aural and 

 nasal discharges. 

 Anal and urinary 



discharges. 

 Skin. 

 Clothes. 

 4. Domestic animals, vermin and flies. 



The udder. 



Fecal and urinary discharges. 

 Buccal and nasal discharges. 



Matter from the coat Hair, skin, plants, barn- 

 yard. 



Air, ceiling, ledges, floor, etc. 

 Feed 



Mouldy hay, muddy hay, smutty 



straw, horse manure and sand. 

 Bedding { vs. 



Shavings, corn stalks, sawdust, peat, 



moss, cocoa shells. 



[ Pails, strainers, separators, clarifiers 

 | coolers, piping, bottles, cloths. 

 [ Water and ice. 



Utensils 



