CREAM RIPENING 235 



fall, winter and early spring, when the cows in the central and 

 northern dairy belt are confined to the stable and receive dry 

 feed, there is a marked increase in the group of putrefactive 

 microbes which tend to impair the flavor and shorten the life 

 of the butter, unless their action is retarded by pasteurization 

 or possibly by the addition of lactic acid bacteria to the cream. 



At best, the results from the natural ripening process are 

 uncertain. Where butter of uniformly high quality is desired 

 the natural ripening cannot be recommended and it is justifi- 

 able only, if at all, when butter is made on too small a scale 

 to warrant the extra labor and expense of handling pure culture 

 starters, as is the case on the majority of farms making farm 

 dairy butter and where the milk and cream are produced under 

 highly sanitary conditions. 



While, under favorable conditions, natural ripening may 

 give butter a flavor more attractive to the palate of the consumer 

 than butter made from sweet cream, the keeping quality of 

 such butter is prone to be low and would be materially improved 

 by not ripening such cream at all. 



Artificial Ripening of Cream. By artificial cream ripen- 

 ing is understood the souring of the cream with the aid of a 

 starter. The term starter includes a variety of materials, such 

 as buttermilk, sour cream from the previous churning, sour 

 milk and skim milk ripened by spontaneous souring and sour 

 milk, cream, diluted condensed milk, or redissolved skim milk 

 powder, ripened by the addition of a pure culture of lactic acid 

 bacteria. 



The desirability of the use of buttermilk and sour cream 

 for starter, depends very largely on the degree of purity of the 

 previous batch of cream. If the cream shows a pure, mild acid, 

 the resulting buttermilk may be reasonably safe to use as starter, 

 provided that the cream was not overripe and the churn at the 

 time of churning was in good sanitary condition. Buttermilk 

 from overripe cream and from cream lacking in clean acid flavor 

 is unsafe. Its use is likely to propagate, in the next lot of 

 cream, the very fermentations which are to be avoided. 



Sour cream, if of a clean acid may prove beneficial in the 

 absence of a better starter. In most cases, however, its use is 



