50 



Dairy Bacteriology. 



source of contamination than the udder itself, while the 

 small-topped pail receives only that from the udder. 



Milking machines. Where the milk is removed from 

 the udder by machine methods, instead of by hand, it is 

 possible to eliminate nearly all external contamination 

 from the animal and her surroundings. The only oppor- 



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r 'I'l, 



JY,ri 



FIG. 14. USE OF SANITARY MILK PAILS. 



The open pail is fully exposed to the falling dust while the 

 hooded pail excludes much of the dust and dirt coming from 

 the animal. 



tunity for infection is then through the leakage of air 

 around the teat cups. Care should be taken to see that 

 the teats are in a clean condition before applying the suc- 

 tion cups. T.he main problem in the use of a milking 

 machine is to keep the apparatus in an aseptic condition. 

 Immersion of the teat cups and the rubber connections 

 in lime water, brine solution, or other mild antiseptics, 

 prevents bacterial development. Hastings has found 

 that milk having a germ content of less than 10,000 bac- 



