CREAM-RIPENING. 191 
butter, it is very essential that the undesirable germs be ex- 
cluded or suppressed and that the conditions for the develop- 
ment of the desirable typical acid ferments in the cream be 
made as favorable as possible. The undesirable ferments may, 
as a whole, be said to be those which act upon the nitrogenous 
matter, or those which cause ordinary decay. They very likely 
come from filth in the barn, milking utensils, unclean milkers, 
Fig. 125.—The new Jensen cream-ripening vat. (Peerless.) 
and unclean and dusty barns. Abnormal fermentations of 
cream, such as ropy, bitter, chromogenic fermentations, etc., 
are of course undesirable ferments. For kinds and classifica- 
tion of germs in milk, see Chapter IV on Bacteria, and Chapter V 
on Abnormal Milk. 
(2) To Increase Churnability of Cream.—Cream-ripening 
is not essential in order to complete the churning process, but 
ripened cream will churn more easily and more completely than 
unripened cream, under the same conditions. This is due to a 
