240 BACTERIA IN CHEESE RIPENING. 



ABNORMAL CHEESE RIPENING. 



The close relation of bacteria to cheese is emphasized by 

 certain types of abnormal ripening. Our knowledge in 

 regard to various types of improperly ripened cheeses is 

 somewhat greater than our knowledge of the ordinary ripen- 

 ing. Cheeses that are set to ripen do not, by any means, pro- 

 duce a uniform product. There is always a certain character 

 which is the type desired in the product, but a considerable 

 proportion of the cheeses fail to come up to the proper 

 standard, especially in flavor. It is sometimes stated that 

 half of the cheeses are injured in ripening. This does not 

 mean that this large proportion is so badly ripened that it 

 is not marketable, but that a large proportion of the cheeses 

 fails to come up to the highest grade. Some of the abnormal 

 cheeses are only slightly " off " in flavor, and will sell as 

 palatable cheeses in the market, while others are so decidedly 

 bad that they are valueless. It is, of course, the desire of the 

 cheese-maker to reduce the proportion of these abnormally 

 ripened cheeses as far as possible, and the bacteriologist's 

 endeavor to enable him to control the ripening process so that 

 he may obtain a uniform product. It is not possible to 

 classify all of these types of abnormally ripened cheeses ; 

 even the cheese-maker who is most familiar with them cannot 

 do so. There are, however, some prominent types that are 

 distinct and easily denned, and in regard to quite a number 

 of these the agent which produces the abnormal results is 

 known. Some of these are of sufficient practical importance 

 to require a brief consideration. 



Inflated Cheese. Of the various types of abnormal cheeses 

 there is none better known than that which is called " in- 

 flated " or " swelled " cheese. This is characterized by the 

 development in the cheese of large amounts of gas, and the 

 gas accumulating during the ripening causes the cheese to 



