Bacteria in Cheese. 171 



tion of this new system of cheese-curing promises much 

 from a practical point of view, and undoubtedly a more 

 complete study of the subject from a scientific point of view 

 will aid materially in unraveling some of the problems as 

 to flavor production. 



Theories of cheese curing. Within the last few years 

 considerable study has been given the subject of cheese cur- 

 ing or ripening, in order to explain how this physical and 

 chemical transformation is brought about. 



Much of the misconception that has arisen relative to 

 the cause of cheese ripening comes from a confusion of 

 terms. In the ordinary use of the word, ripening or cur- 

 ing of cheese is intended to signify the sum total of all 

 the changes that result in converting the green product 

 as it comes from the press into the edible substance that is 

 known as cured cheese. As previously shown, the most 

 marked chemical transformation that occurs is that which 

 has to do with the peptonization or breaking down of the 

 casein. It is true that under ordinary conditions this de- 

 composition process is also accompanied with the forma- 

 tion of certain flavor-producing substances, more or less 

 aromatic in character; but it by no means follows that these 

 two processes are necessarily related to each other. The 

 majority of investigators have failed to consider these two 

 questions of casein decomposition and flavor as independ- 

 ent, or at least as not necessarily related. They are un- 

 doubtedly closely bound together, but it will be shown later 

 that the problems are quite different and possibly suscep- 

 tible of more thorough understanding when considered 

 separately. 



In the earlier theories of cheese ripening it was thought 

 to be purely a chemical change, but, with- the growth of 



