154 Dairy Bacteriology. 



diate use, because it lacks a desirable flavor and is not 

 readily digestible. It is nothing but precipitated casein 

 and fat. In the course of a short time, a deep-seated 

 change occurs. Physically this change is demonstrated 

 in the modification that the curd undergoes. Gradually 

 it breaks down and becomes plastic, the elastic, tough 

 curd being changed into a softened mass. This change 

 in texture of the cheese is also accompanied by a marked 

 change in flavor. The green cheese has no distinctively 

 cheese flavor, but in course of time, with the gradual 

 change of texture, the peculiar flavor incident to ripe 

 cheese is developed. 



The characteristic texture and flavor are susceptible of 

 considerable modification that is induced not only by 

 variation in methods of manufacture, but by the condi- 

 tions under which the cheese are cured. The amount of 

 moisture incorporated with the curd materially, affects 

 the physical appearance of the cheese, and the rate of 

 change in the same. The temperature at which the same 

 is ripened, likewise the moisture content of the surround- 

 ing air, also exert a marked influence on the ripening 

 product. To some extent the action of these forces is 

 purely physical, as in the gradual loss by drying, but 

 they also affect the course of the biological changes to a 

 certain extent. 



162. Chemical changes in ripening 1 . The marked 

 physical change that occurs during ripening also records 

 a profound chemical action in the composition of cheese. 

 Coincident with the softening of the curd, comes a change 

 in the condition of the casein. The hitherto insoluble 

 casein is gradually transformed into soluble substances 

 (caseone of Duclaux, or caseogluten of Weigmann) . This 

 chemical phenomonon is a breaking down process that is 

 analogous to the peptonization of proteids, although in 



