36 Agricultural Bacteriology. 



milk is much less in a well ventilated stable. Milk should 

 never be strained, aerated or separated in the stable. 



Odors absorbed from the feed. In certain feeds such 

 as turnips, cabbage, rape, and in many weeds are found 

 substances that give to the various plants their charac- 

 teristic taste and odor. If a milch cow is fed on such 

 plants, the peculiar flavoring substance will pass 

 through the system and reappear in the milk, often giv- 

 ing to the milk such a peculiar taste as to render it 

 useless for direct consumption or for butter and cheese 

 making. Such feeds should never be fed except in 

 limited quantities immediately after milking so that 

 the volatile odors may be eliminated from the body be- 

 fore the next milking. Green rye and strong silage 

 should be fed with care or the milk will be injured. 



The milk from cows receiving medicine in any form 

 should be excluded from the supply since many drugs 

 pass from the body tissues to the milk. Such milk 

 may cause illness, especially in children, and injure 

 the quality of butter and cheese. 



The constituent of milk that causes it to absorb odors 

 so readily is the fat. Butter is more easily injured 

 by absorption of "odors than is milk, as is not infre- 

 quently noted when it is kept in an ice-box with fruits, 

 etc. If the milk is tainted, the butter and cheese are 

 very certain to show the same flavor. This can be dem- 

 onstrated by feeding cows on rape and making cheese 

 from the milk. The ripe cheese will possess the flavor 

 of rape to such an extent as to be worthless. 



Contamination under winter and summer conditions. 



It is often thought that the milk produced in summer 

 is much cleaner than the winter milk. This is less true 



