CREAM RIPENING 237 



desirable bacteria. Unless the starter added is an active one, 

 and the cream is of relatively good quality the benefits of arti- 

 ficial ripening are prone to be very diminutive. In the case of 

 sour gathered cream, nothing is gained by further ripening un- 

 less possibly here neutralization is resorted to. In this kind 

 of cream the fats and the curd have already been exposed to 

 acid for an excessive length of time and further ripening will 

 tend to weaken their resistance just that much more, invit- 

 ing with greater certainty their partial decomposition. 



If the cream is properly pasteurized before the starter is 

 added the fermentations that occur during the cream ripening 

 period can be controlled most readily, provided, of course, that 

 the operator understands the fundamental requirements for re- 

 lative optimum development of the lactic acid organisms and 

 has proper facilities in the way of temperature control. The 

 artificial ripening of pasteurized cream is, from the bacteriolog- 

 ical point of view, the most nearly ideal method of cream ripen- 

 ing. In pasteurized cream the bacterial count of all bacteria has 

 been reduced to a relatively low figure, approximately to one- 

 tenth of one per cent of their original number. The cream 

 furnishes therefore an ideal seed bed for the lactic acid starter, 

 and the desirable bacteria, added in the form of a pure culture 

 starter, have a free and unhindered field for rapid development. 



Here again it should be understood that the better the 

 quality of the cream, the better and the more uniform will be 

 the results of the ripening process. The ordinary run of gathered 

 cream, such as is received at the centralized creamery, averages 

 possibly about from 50,000,000 to 500,000,000 bacteria per cubic 

 centimeter. Assuming that the pasteurization efficiency, or germ- 

 killing efficiency be 99.9 per cent, which is very good under 

 average commercial conditions, there would still be left in the 

 cream 50,000 to 500,000 bacteria per cubic centimeter. Since 

 a considerable proportion of the micro-organisms which survive 

 belong to the group of undesirable or harmful types, it is 

 obvious that the development of undesirable fermentations dur- 

 ing the ripening process is by no means entirely eliminated, in 

 spite of pasteurization, and that the otherwise beneficial results 

 of artificial ripening are prone to be partly paralyzed. 



