MILK 29 



astringent taste in rusted vessels in consequence of the 

 formation of iron lactate. A "fishy" taste may also be 

 present when the milk vessels are rusty or when they 

 have not been rinsed free of soap powder. 



Certain aromatic feeds impart a characteristic odor 

 and taste to the milk. Among these are ensilage, rape, 

 cabbage, and beets, turnips, rutabagas, carrots, and their 

 tops. This is not ordinarily due to the ingestion with the 

 feed of substances responsible for the taste and odor and 

 their elimination with the milk through the udder, but 

 to the absorption by the milk of the odor of the feed from 

 the air of the stable. This is demonstrated by the fact 

 that when these feeds are fed in ordinary quantity and 

 after milking, and not immediately before or during 

 milking, the odor and taste of the milk are not affected. 

 If these feeds are given in large quantity, it is probable 

 that some of the aromatic substances may be excreted 

 through the udder. In the case of garlic, however, the 

 volatile oil to which the odor of that substance is due is 

 eliminated through the udder in the milk. Odors are 

 readily absorbed by milk, especially when it is warm. 

 Milk drawn and allowed to stand in an unclean or poorly 

 ventilated stable will acquire a stable-like odor and taste. 

 It has been demonstrated experimentally that if milk 

 at a temperature of 14 to 22 C. (57 to 72 F.) is ex- 

 posed to the odor of ensilage or horse manure for a half 

 hour to an hour and a half it will acquire an odor and 

 taste resembling these substances (Russell). 



Abnormal odors and tastes result also from the 

 growth of bacteria in milk. The activity of the pepton- 

 izing bacteria may produce first a bitter taste, due to 

 the production of peptone, and later a foul and unpleas- 

 ant odor and taste, the result of decomposition processes. 



