BACTERIA IN MILK. 1 99 



no significance, so far as we know, and they may therefore be 

 omitted from our consideration. 



ABNORMAL FERMENTATIONS. 



The types of milk bacteria included under this head differ 

 from those already considered merely in the fact that they are 

 comparatively rare. Whereas milk will practically always 

 sour through the agency of the lactic bacteria, and will always 

 contain bacteria of the peptonizing class, as well as butyric acid 

 bacteria, the following classes of bacteria are by no means sure 

 to be found. Most of them are occasionally the cause of 

 troublesome dairy infections. When they occur in milk, in 

 numbers sufficient to cause troublesome changes, they may 

 always be regarded as coming from some unusual source of 

 contamination to the milk, which may be prevented. While, 

 as we have seen, the lactic fermentation cannot be prevented 

 by any practical means at the disposal of the dairyman, be- 

 cause of the universal distribution of lactic bacteria, these ab- 

 normal types of troublesome infections may always be pre- 

 vented if sufficient care is taken in regard to cleanliness, and 

 they may be checked if the dairyman simply learns from 

 whence the contamination arises. For these reasons, in prac- 

 tical dairying, it is a matter of special importance to understand 

 their sources. Of the types of dairy infections which follow, 

 the first three are the most important. 



Slimy Milk. A sliminess in milk is not an uncommon oc- 

 currence in the dairy. It is sometimes produced by a diseased 

 condition of the cow, slimy milk being a common characteristic 

 f g ar g et - In the majority of cases, however, and in all cases 

 where a troublesome dairy infection of slimy milk appears, the 

 trouble is due to bacteria. 



In some countries slimy milk is regarded as a delicacy and 

 is actually produced by artificial means. In Norway the people 

 enjoy drinking milk that can be drawn out in long threads 



