48 PRACTICAL DAIRY BACTERIOLOGY 



of such infection ; for conditions vary with different dairies ; but 

 generally, when an intelligent dairyman has discovered the 

 source of the infection, the remedy will suggest itself. 



BITTER MILK 



The appearance of a bitter taste in milk is a rare trouble 

 for the milkman, though a common one for the cheese maker. 

 The causes of the bitterness are, at least, three. I. Sometimes 

 it happens that the milk has a bitter taste as soon as it is 

 drawn from the cow. In such a case it must be attributed to 

 some food which the animal has been 

 eating. It is known that if the cattle feed 

 upon lupine or ragweed, a certain amount 

 of bitterness develops in the milk. The 

 remedy is simply to change the food of the 

 cow. 2. Sometimes it happens that milk 

 tastes perfectly sweet when freshly drawn, 

 FIG. 25 coccus k ut m t h e course of a few hours some- 



PRODUCING BITTER . 



MILK (CONN) times not for a day or two a bitter taste 



develops in the milk. Here the taste is due 

 to the growth of bacteria in the milk (B. ligucfacicns amari, M. 

 casei amari), which produce certain bitter products. 1 This 

 type of dairy trouble is quite rare, and only two or three exam- 

 ples of it have been carefully investigated. (Fig. 25.) But 

 bitter tastes in cheese, due to a similar cause, are common. 

 Two different bacteria have been found to give rise to the 

 bitter tastes. The source of the organisms was traced, in one 

 case, to the udders of certain cows, but in other cases the 

 source was not found. One extensive series of bitter milk in- 

 fection was found in a cheese factory in Canada, and produced 

 a great deal of trouble. In this case, the cause of the bitterness 



iConn. Cent. f. Bact., ix., p. 653, 1891. 

 Bleisch. Zeit. f. Hyg., xii., p. 81, 1893. 

 Hugge. Rev. Gen. d'Lait., v., p. 470, 1906. 



