BITTER MILK BACTERIA. 35 



of water tanks and milk vessels will be the efficient remedy 

 in most cases. Slimy milk is a preventable infection and its 

 remedy is simply cleanliness, with, perhaps, disinfection. 



Bitter Milk. There are quite a number of causes which 

 may give a bitter taste to milk. Cows produce bitter milk 

 after eating certain foods, like ragweed or lupine. A bitter 

 taste is found in the milk of late periods of lactation. Cer- 

 tain udder diseases (mastitis) render the milk bitter. These 

 phenomena are none of them very common and are rarely of 

 importance in ordinary dairying. They may in general be 

 distinguished from a bitterness due to bacteria by the fact 

 that they appear at full strength in the milk when freshly 

 drawn. 



A true bitter fermentation of milk is known to be pro- 

 duced by the growth of bacteria. Quite a large num- 

 ber of kinds of bacteria may cause a bitter taste in the 

 milk. Most of them, however, are capable of producing 

 this flavor only after they have grown for a consider- 

 able time in the milk, and the examples that have been 

 studied by bacteriologists are commonly milk that has been 

 imperfectly sterilized, and has subsequently become bitter to 

 taste instead of souring like ordinary milk (81). Such a 

 bitter taste does not interest the ordinary dairyman. Occa- 

 sionally, however, milk develops a bitter taste within a few 

 hours from the time of milking, and in such cases the trouble 

 becomes one of significance to the ordinary dairy (79). The 

 phenomenon is quite rare, but there has been at least one 

 instance of such bitter milk dairy infection studied, and one 

 or two others recorded. A more common occurrence is a 

 bitter taste in cheese and this has been proved also to be due 

 to microorganisms. We have, therefore, at least three kinds 

 of bitter tastes developing in milk products from bacteria 

 growth : ( i ) A dairy infection which affects tolerably fresh 

 milk, and is rare; (2) a bitter taste that develops slowly in 

 sterilized milk as the result of the action of bacteria which 



