Contamination of Milk. 43 



latent organisms, like spores, in a condition where germi- 

 nation will not occur. 



To hasten this lowering of temperature, artifical cool- 

 ing is a necessity. Coolers using cold running water or 

 ice water are efficient in reducing the temperature to a 

 point where development is much checked. 



44. Tainted milks. Not all taints in milk can be 

 traced to the development of bacterial causes. In many 

 cases they are produced by the direct absorption of 

 odors in a purely physical way or to some unusual condi- 

 tion of the system of the animal. In some cases with 

 animals old in lactation, the milk becomes abnormal in 

 that the cream does not rise readily. Such milks are 

 known as "lazy n or "dead" milks. Then again, the 

 dairyman may experience difficulty in churning, but 

 more often these difficulties are attributable to the non- 

 performance of important manufacturing details rather 

 than to a perverted condition of the milk itself. Milk is 

 very prone to absorb volatile odors, the fat especially 

 having a great affinity for many of these substances. 



45. Direct absorption from animal. Odors of this 

 sort may be absorbed by the milk previous to or after 

 the milking has occurred. The peculiar "cowy" or "an- 

 imal odor 7 ' of fresh milk is an illustration of an inherent 

 peculiarity of the milk. If certain strong flavored sub- 

 stances as onions, certain root crops, or other vegetables- 

 are consumed by the cow, the odor-yielding substances 

 in the same may reappear in the milk, especially if the 

 animal partakes of these a short time before milking. 

 According to Kober and Busey, the milk of swill-fed cows 

 has a peculiar taste, and is said to produce a highly 

 acid urine and eczema. Brewers' grains and distil- 

 lery slops when fed in large quantities frequently in- 

 duce an abnormal chemical reaction of the milk. Taints 



