238 CREAM RIPENING 



Temperature of the Cream for Ripening. Bacteriologically, 

 the best temperature for ripening cream is that at which the 

 desirable lactic acid bacteria develop more readily than any other 

 type or species of micro-organisms. The optimum temperature 

 for lactic acid bacteria lies within the range of 90 to 100 F. 

 This temperature, however, is most favorable also to the growth 

 of many species of organisms harmful to the quality of butter, 

 such as those belonging to the Bacillus coli group, the aerogenes 

 group, and certain species of yeast and molds, etc. For this 

 reason these high temperatures, 90 to 100 F., are unsuitable 

 for the ripening of cream. 



On the other hand, experience has shown that a tem- 

 perature of from 60 to 70 F. permits of reasonably rapid develop- 

 ment of the lactic acid bacteria while such temperatures are too 

 low to give most of the harmful species an opportunity to gain 

 the ascendency. Hence this lower range of temperatures, 60 to 

 70 F., has been generally adopted as the proper ripening tem- 

 perature. In summer when the atmospheric temperature is rela- 

 tively high and other conditions are comparatively favorable for 

 rapid acid development, the cream is preferably ripened at 60 

 to 65 F. In winter when the atmospheric temperature is rela- 

 tively low and other conditions present tend to retard lactic acid 

 fermentation, the cream is preferably ripened at 65 to 70 F. 



Aside from the fact that relatively high ripening tempera- 

 tures invite the development and domination of undesirable bac- 

 teria, such as the species of the Bacillus coli and the aerogenes 

 group, etc., at the expense of the pure lactic acid ferments, they 

 may also prove harmful to the texture and body of the butter, 

 causing the butter to be soft and weak in body and of a salvy 

 texture. All of these phenomena indicate unmistakably the 

 danger of ripening the cream at high temperatures. The un- 

 favorable effect of high ripening temperature is more pronounced 

 in the case of cream of a poor quality than with cream of a high 

 degree of purity. 



In more recent years many of the most observant butter 

 makers are leaning towards low-temperature ripening and many 

 creameries have adopted the practice of ripening their cream at 

 temperatures ranging from 48 to 55 F. This practice is rec- 

 ommended especially where a rather sour cream is received, 



