RELATION OF MICROORGANISMS TO CHEESE. 359 



Colored cheese is produced by chromogenic bacteria. In case the 

 colonies are not numerous and the pigment formed is not soluble in any 

 of the constituents of the cheese, the color will appear as colored specks, 

 such as the rusty spot investigated by Connel and Harding, which is due to 

 red forms of B. rudensis. If the colonies are very numerous, or if the 

 pigment is soluble, the curd may be uniformly colored. 



Putrid cheese is caused by the absence of sufficient acidity to hold 

 the putrefactive bacteria in check. This trouble is rare in cheddar 

 cheese, since such cheese is made from ripened milk. Fruity flavors are 

 asserted to be due to yeasts which form fruit esters. 



Moldy Cheese. In the moist air of the curing-room the cheese forms 

 an excellent substratum for the growth of common molds whose pigmented 

 spores discolor the surface of the cheese and thus impair its value because 

 of the appearance rather than by any effect in the flavor. Cheddar 

 cheese is protected effectively from molds by dipping the cheese, when 

 two or three days old, in melted paraffin which excludes the air from the 

 spores on the surface of the cheese. 



SPECIFIC KINDS OF CHEESE. 



There are cheeses made in this, and especially in foreign countries, 

 which are of great commercial importance. Only a few can be men- 

 tioned. It has been found possible to manufacture a few so-called 

 "foreign cheeses" in this country; however, with some "foreign cheeses" 

 the manufacture has been successful only in such localities where such 

 types originally developed, and where the climate and other conditions 

 are favorable to a normal ripening. 



CHEDDAR CHEESE. Cheddar cheese, treated in much detail in the 

 foregoing considerations because it is the most important American 

 cheese, is made in England and her colonies and in the United States. 

 It appears in many varieties and by the American consumer is often called 

 American cheese in distinction from the foreign cheese. This distinction 

 is not wholly applicable at the present time. 



EMMENTHALER CHEESE. Swiss or Emmenlhaler cheese originated in 

 Switzerland, but is now made in various other countries. A large amount 

 is made in Wisconsin, Ohio and New York (Fig. 84). It is charac 

 terized by its sweetish flavor and by the so-called "eyes," which are 

 holes formed by gas, produced in a fermentation that occurs subsequent 

 to the fermentation of the lactose. The number of eyes is not large and 



