PASTEVRIZ'A'TIO'N , 



101 



continuously maintaining the higher temperatures as 

 required in the above laws : 1 . There will be no doubt 

 about the proper temperature being reached to kill the 

 bacteria ; 2. The Storch test l may be applied to deter- 

 mine whether the temperature has been raised to at least 

 178 F. 



73. Other effects. It is generally considered that the 

 pasteurization of the cream causes the buttermilk to whey- 

 off, 2 which is a detriment to its sale. 



Pasteurization of sour cream causes a greater loss of 

 fat in the buttermilk than if the cream were not pasteur- 

 ized. On the other hand, the pasteurization of sweet 

 cream increases its churning properties. Farrington 

 and Russell 3 state : " A richer buttermilk was obtained 

 from the pasteurized than from the unpasteurized churn- 

 ings in hot weather, when the pasteurized cream, as a 

 rule, was not so easily and thoroughly cooled as the un- 

 pasteurized. At other seasons, when both churnings were 

 made at about the same temperature, there was not much 

 difference in the amount of fat left in the two buttermilks." 

 Mortensen, Gaessler, and Cooper 4 report the following : 

 ' The percentage of milk-fat lost in the buttermilk when 

 churning raw cream is slightly greater than with cream 

 pasteurized while sweet. Reversed results were obtained 



1 Ross, H. E., Explanation of Boiled Milk Test, A Dairy 

 Laboratory Guide, p. 18, 1910. 



2 Lee, Carl E., Pasteurization as a Factor in Making Butter 

 from Cream Skimmed on the Farm, Univ. of 111. Agri. Exp. Sta., 

 Bui. 138, p. 368, 1909. 



3 Farrington, E. H., and Russell, H. L., Pasteurization as 

 Applied to Buttermaking, Univ. of Wis. Agri. Exp. Sta., Bui. 69, 

 p. 39, 1898. 



4 Mortensen, M., Gaessler, W. G., and Cooper, W. H., The 

 Pasteurization of Cream for Buttermaking, Agri. Exp. Sta. 

 Iowa State Col., Bui. 156, p. 15, 1914. 



