26 % Agricultural Bacteriology. 



would not be allowed in the kitchen, and yet, in both cases 

 the preparation of human food is in progress. Of neces- 

 sity it is difficult to produce milk in a wholly clean en- 

 vironment; yet every effort should be made to improve 

 the barn conditions as much as possible. 



During the milking, dust, dirt, and manure particles 

 are dislodged from the udder and flanks of the animal 

 by the motions of the milker. These particles inevit- 

 ably fall into the open pail. The amount of dirt and 

 manure thus introduced into the milk depends almost en- 

 tirely on the cleanliness of the animal. If the flanks and 

 udder are coated with manure and dried mud, a very 

 large amount of dirt will enter the milk and nothing 

 can prevent it. 



As has been previously mentioned a prominent source 

 of bacterial life is the intestinal canal of animals. In 

 the manure are found an immense number of bacteria. 

 It requires but a small amount of manure to add many 

 thousands of bacteria to every drop of milk. The fact 

 that the kinds of bacteria derived from the manure pro- 

 duce, in the main, injurious changes in the milk (bad 

 odors and tastes) affecting not only the milk but the 

 butter and cheese as well, makes it highly desirable to 

 reduce the contamination from this source as far as pos- 

 sible. 



The dust from the skin of the animal contains large 

 numbers of bacteria. Esten found in the dust taken 

 from a curry comb 207,000,000 organisms per gram (1-30 

 ounce) . The hairs, even those from the cleanest cows, 

 have large numbers of bacteria on them. 



Prevention of contamination from the animal. In 

 order to prevent the milk from being contaminated with 

 large quantities of mud and manure, the animal must be 



