MILK DEFECTS 67 



bacteria of the coli-aerogenes group give milk a cow-like, 

 salty taste (Weigmann). 



2. " Fishy " Milk. Milk from cows near the end of 

 lactation may have a " fishy " taste. This defect is be- 

 lieved to result also from feeding fish meal and from graz- 

 ing cows on marshes subject to overflow with salt water; 

 but cows have been fed on large quantities of fish meal 

 without affecting the taste of the milk or butter. In one 

 instance, the milk of one cow in a herd had such a pro- 

 nounced " fishy " taste that it tainted the milk from the 

 entire herd, although this cow was fed and stabled in 

 exactly the same manner as the others. The cause in this 

 case could not be determined. Milk may acquire a 

 " fishy " taste from milk vessels which are rusted and 

 also from those which have not been rinsed clean of the 

 soap powder used in washing them. 



3. Rancid Milk. A rancid odor and taste in milk as 

 it comes from the udder may be due to the same condi- 

 tions which give milk a cow-like taste. A rancid odor and 

 taste may appear a short time after the milk is drawn 

 from the udder as a result of the growth of butyric acid 

 bacteria (page 57). On several occasions an unidenti- 

 fied biscuit-shaped organism, growing in pairs, with the 

 flat sides toward each other, has been found to be the 

 cause of a rancid odor and taste. 



4s. Slow-creaming Milk. The milk is thicker and 

 more viscous than usual; the cream separates slowly and 

 in less quantity than normal, sours slowly and does not 

 " butter " readily. This defect has been observed in the 

 milk from cows near the end of lactation and in milk from 

 cows fed on beets, carrots, and turnips. Certain species 

 of bacteria greatly increase the viscosity of milk, pro- 



