Bacteria in Cheese. 187 



to perfectly sweet milk, it is possible to artificially produce 

 the conditions in cheese that so frequently appear in prac- 

 tice. 



Treatment of " pin-holey " curds. When this type of 

 fermentation appears during the manufacture of the cheese, 

 the maker can control it in part within certain limits. 

 These methods of treatment are, as a rule, purely mechan- 

 ical, as when the curds are piled and turned, and subse- 

 quently ground in a curd mill. After the gas has been 

 forced out, the curds are then put to press and the whole 

 mats into a compact mass. 



Another method of treatment based upon bacteriological 

 principles is the addition of a starter to induce the for- 

 mation of acid. Where acid is developed as a result of 

 the growth of the lactic-acid bacteria, the gas-producing 

 species do not readily thrive. Another reason why acid 

 aids in repressing the development of gas is that the curd 

 particles are partially softened or digested by the action of 

 the acid. This causes them to mat together more closely, 

 and there is not left in the cheese the irregular mechan- 

 ical openings in which the developing gas may find lodg- 

 ment. 



Another method that is also useful with these curds is to 

 employ salt. This represses gaseous fermentations, and the 

 use of more salt than usual in making the cheese will very 

 often restrain the production of gas. Tendency to form 

 gas in Edam cheese is controlled by the addition of a starter 

 prepared from slimy whey (lange wei) which is caused by 

 the development of an acid-forming organism. 



Some have recommended the custom of washing the 

 curds to remove the whey and the gas-producing bacteria 

 contained therein. Care must be taken not to carry this 



