CHAPTER X. 



THE BACTERIA IN WATER AND MILK. 



THE BACTERIA IN MILK. 



FROM its appearance and taste little can be known 

 of the bacterial content of milk. It may be teeming 

 with bacteria, yet give no indication of their presence. 

 In fact, ordinary market milk contains from 100,000 

 to 1,000,000 bacteria in every cubic centimeter. 



How do these bacteria get into the milk? In the 

 udder of the healthy cow the milk is practically free 

 from bacteria, but they live in the milk-ducts in the 

 teats, and get into the milk as it is drawn. The chief 

 source of bacteria in milk lies in the uncleanly methods 

 o>f collecting it. Many get in from the dust-laden air of 

 the cow-stable, from the dirt on the hide of the cow, 

 unclean milk-pails, and from the dirty hands of the 

 milkers. It is a true saying that the number of bac- 

 teria in milk is an index of the cleanliness with which 

 it has been collected. Once in the milk, the bacteria 

 multiply with great rapidity, for milk is an excellent 

 medium for the cultivation of bacteria. The tempera- 

 ture of the milk for some time after it is drawn also 

 favors their development. 



To prevent the contamination of milk with ex- 



1 r . tion of 



cessive numbers of bacteria, all that is required is contam- 

 ination 

 cleanliness, clean stables, clean cattle, milkers with 



(105) 



