48 DAIRYING 



warm days are favorable for a vigorous bacterial growth and when 

 cream is exposed to such weather it should be watched closely in 

 order to prevent the ripening process from going too fast. This 

 may be checked by cooling the cream to 50 F. and lower, but even 

 at this temperature the cream may continue to ripen in muggy, 

 warm weather faster than in bright, dry days. 



This tendency of the cream ripening to be influenced by the 

 weather should receive due consideration from day to day by the 

 buttermaker. 



4. NUMBER OF BACTERIA IN CREAM 



The number of bacteria present in cream at the time ripening 

 begins has an important influence on the rapidity of its ripening. 

 The supply of bacteria in each lot of cream should therefore be 

 controlled by the use of more or less starter depending on the rate 

 at which it is desired to have the cream ripen. This is similar to 

 the growth of vegetation in well prepared soil. The ground may 

 be covered with a luxuriant crop if a liberal amount of seed has 

 been planted, but with a scant seeding very little growth will be 

 seen even if the soil and other conditions are favorable. 



5. THE TEMPERATURE OF RIPENING 



A large number of the bacteria which ripen cream grow rapidly 

 at a temperature between 70 and 90 F. Both the activity and 

 the ripening of cream are hastened at these temperatures. In 

 practice, however, it is not customary to warm cream much above 

 70 F. when one wishes to hasten the ripening; and it progresses 

 so rapidly at this point that a few hours is usually sufficient to 

 bring about the desired effect. 



Checking the ripening is not such an easy matter as hastening 

 it. The growth and development of bacteria may be retarded by 

 cooling the cream to near 50 F., but some changes continue to 

 take place even at this temperature. The ripening goes on ex- 

 tremely slowly, however, and cooling to as low a temperature as 



