RIPENING OP CHEESE 241 



Geneva, U.S., the fresh cheese, when placed in the 

 cheese-room, had 6—7 per cent, of its albuminoids 

 soluble in water ; at the end of three weeks, at a 

 somewhat high temperature, over 20 per cent, were 

 found to be soluble. In another series of experi- 

 ments the fresh cheese contained 4*2 per cent, of its 

 albuminoids soluble in water, and at the end of five 

 months 35-5 per cent, of the nitrogenous matter was 

 in a soluble state. Of the total nitrogenous matter 

 89 per cent, was still albuminoid, while 11 per cent, 

 had passed into the condition of amides or ammo- 

 niacal compounds. 



The earlier changes which occur in the casein of 

 cheese, before putrefaction sets in, are quite similar 

 to those taking place in the process of animal diges- 

 tion. It was at first supposed that these changes 

 were brought about by bacteria, but it is now believed 

 that they are due to an enzyme naturally present in 

 milk ; the presence of this enzyme was first ascer- 

 tained by Messrs. Babcock and Kussell. It has been 

 shown that cheese will ripen at a temperature near 

 freezing, and in the presence of substances which 

 suspend the action of bacteria. When cheese is in 

 an advanced stage of decomposition, fungi and bacteria 

 become the chief chemical agents, and carbonic acid, 

 water and ammonia the ultimate products. 



The fat of cheese undergoes little change during 

 ripening, but some of the neutral fat is decomposed 

 and butyric and other fatty acids are liberated. It 

 was once believed that fat was produced from albu- 

 minoids during the ripening process; this is not the 

 case. The percentage of fat rises as the cheese gets 

 older, owing to the loss of water and other products oi 

 16 



