230 BACTERIA IN CHEESE MAKING. 



digested and assimilated. The high flavors of cheese are a 

 priceless boon to the poorer classes, because they enable them, 

 at a small expense, to furnish the necessary flavor for their 

 plain fare. Even the coarsest bit of dry bread may be made 

 palatable and digestible by a little cheese flavor to give it 

 relish. The source and origin of these flavors is, therefore, 

 a matter of great significance. 



While the chemical changes which concern the digestibility 

 of the casein may be due largely to the enzymes present in 

 the milk there is at present no reason for believing that these 

 enzymes are the primary causes of the flavors. So far as 

 known, these enzymes do not develop flavors, and certainly 

 they are quite incapable of developing the numerous types of 

 flavors that characterize the large variety of cheeses. The 

 flavors in the ripened cheese are probably due, in large 

 degree, to the action of microorganisms. The high flavors 

 and tastes of decomposition products are well known, and 

 decomposition products of the microorganisms growing 

 in the ripening cheese give the cheese its peculiar flavors. 

 We need simply to remember that bacteria are the only 

 known cause of putrefaction, to be perfectly well convinced 

 that the source of the peculiar flavors and odors of the Lim- 

 burger cheese must be due to microorganisms, and, although 

 the putrefactive odor is not so prominent in other cheeses, 

 the same general nature is recognized in the whole series of 

 cheese flavors. 



Soft Cheeses. The relation of microorganisms to the 

 ripening of cheeses is very different in the soft and hard 

 cheeses, although in both they play a part. Other micro- 

 organisms besides bacteria are concerned in the ripening, 

 particularly of the soft cheeses. In some kinds of cheeses 

 molds are more significant than bacteria; in other cases 

 yeasts may be concerned ; while in others bacteria are prob- 

 ably the chief agents. 



