134 Dairy Bacteriology. 



which is entitled to most credence on this question 1 , is 

 opposed to this method. 



1 34. Pasteurizing* milk or cream for butter. To 

 pasteurize for butter-making, it is not necessary to 

 carry out the process in the same stringent manner as 

 when it is done to preserve milk or to free it from pos- 

 sible disease-breeding bacteria. A temperature of 140 

 F. for ten minutes is fatal to most of the lactic acid 

 group, but in pasteurizing for butter-making, it is cus- 

 tomary to heat the milk to a higher temperature (155- 

 175 F.). This is done for two purposes. First, the 

 milk is generally heated in a continuous-flow machine; 

 consequently, the maximum temperature is not main- 

 tained for more than part of the time required to go 

 through the machine. Second, the wide- spread preva- 

 lence of tuberculosis, and foot and mouth disease in some 

 of the dairy regions of Europe makes it necessary to heat 

 the skim-milk high enough to destroy the seeds of these 

 diseases. 



In pasteurizing for butter-making, it is also possible 

 to drive off many taints that have been absorbed directly 

 from the cow or through exposure to foul odors 2 . Some 

 states of the Atlantic sea-board are so infested with wild 

 garlic that the milk-supply is rendered practically worth- 

 less for dairy purposes. If this is treated by pasteur- 

 ization, it is often possible to eliminate in part such 

 taints, so that a fairly good product of butter can be 

 made. 



In pasteurizing for butter-making, two methods are in 

 vogue in Denmark where the greatest activity exists in 

 regard to this matter. There, either the whole milk is 



1 99$ of the Danish creameries have pasteurizers, and over 90$ pas- 

 teurize the cream. 



2 McKay, la. Expt. Stat., Bull. 32, p. 477. 



