220 



EFFECT OF PASTEURIZATION 



gives the curd in the sweet cream an opportunity to be acted 

 upon in a normal way by the acid of the sour cream, so that 

 the effect of the subsequent high heat is minimized. 



The pasteurization of very thin sour cream usually causes 

 excessive loss of fat, unless such cream is churned at an exces- 

 sively low temperature. 



Not infrequently, excessive losses of fat in buttermilk 

 from pasteurized cream, while attributed to pasteurization, are 

 due largely to churning factors, such as churning the pasteur- 

 ized cream at too high a temperature, or to not holding the 

 cream at the churning temperature long enough. For most 

 exhaustive churning the cream should be held at the churning 

 temperature not less than two hours and preferably three hours. 

 Attempts to crowd the churns with too large churnings, which 

 are prone to occur during the flush of the season in summer, 

 are a further common cause of excessive loss of fat in the 

 buttermilk. 



Chemical Composition of Butter made from Raw and from 

 Pasteurized Cream. The following table 1 contains averages of 

 the per cent moisture, salt, curd and acid in 76 churnings of fresh 

 butter. 



Table 40. Averages of Composition of 76 Churnings of Butter 

 Made from Raw and Pasteurized Cream. 



As indicated in the above figures, there is very little dif- 

 ference in composition between butter made from raw and 

 from pasteurized cream. The slight differences agree, in direc- 

 tion, with the great bulk of data available on this subject and 

 with the general conception of the effect of pasteurization on 

 the composition of the butter. Thus the moisture, curd and 

 acid are somewhat lower in the pasteurized cream butter than 

 in the raw cream butter and the highest temperature used for 

 pasteurization shows the greatest difference, 



