ON MILK AND MILK-TESTING I3 



This tends to prevent the entrance of bacteria into 

 milk. 



2. By keeping milk cold. This checks the 

 growth of bacteria. The lower the temperature, the 

 more their growth is prevented and the longer will 

 milk keep sweet. 



3. By high temperatures. High temperatures 

 are used to destroy bacterial life in milk. This is 

 the principle of pasteurization. 



4. Preservatives are used to kill bacteria or to 

 prevent their growth. The use of preservatives in 

 milk is prevented by most pure food laws. 



5. Electricity has been used to destroy bacteria 

 in milk. 



6. The use of carbonic acid gas is used to car- 

 bonate milk and prevent the growth of bacteria. 



What methods are used to keep bacteria out of 

 milk? 

 I. The health of the cows is considered. The 

 tuberculin test is used to diagnose tuberculosis. 

 Milk from diseased animals is not used. 



• 2. Cows* udders, flanks, and legs are shorn of 

 hair to make cleaning easy. 



3. These parts are washed or wiped with a 

 damp cloth before milking. 



4. Stables are properly ventilated, made free 

 from dust, whitewashed, or otherwise made sani- 

 tary by cleanly methods. 



5. The health, clothing, hands, and person of the 

 milkers are regulated in sanitary requirements. 



6. Small-top milking pails are used. 



7. Milk is strained or filtered in a clean place. 



