ABNORMAL CHEESE RIPENING. 245 



putrefaction of the soft cheeses is more likely to occur if the 

 cheese is ripened at a low temperature ; but why it occurs in 

 some cheeses and not in others, and to what distinct micro- 

 organism it is due, have not yet been ascertained. 



Some forms of abnormal cheese ripening are characterized 

 by the appearance of colored spots in the cheese. Red spots 

 or rusty spots are quite common, occurring chiefly upon' the 

 surface of the cheese. Black spots and blue spots are also 

 sometimes found. The red and blue spots are produced by 

 bacteria which are known; the black spots are caused by a 

 mold-like organism. 



Certain forms of cheeses sometimes develop a sweet, 

 sugary taste, which is foreign to their normal flavor and 

 injures their marketable product. This is especially true of 

 Neufchatel cheese, and it has been proved to be due to the 

 development of a yeast in the cheese. Other foreign flavors 

 are occasionally developed, as well as various odors ; but little 

 is known in regard to them, and the cause of the particular 

 flavors has not yet been demonstrated (271). 



It is not our purpose to proceed further into the considera- 

 tion of the various abnormal forms of cheese ripening. The 

 list is a long one, but beyond the few that have been men- 

 tioned, hardly any of them have been sufficiently studied to 

 enable us with accuracy to state their cause, and in a few 

 cases only has it been possible to suggest any remedy. The 

 general remedy for all dairy troubles may be recommended 

 for any cheese factory that has any trouble of any of these 

 kinds. Cleanliness in cheese-making is apparently as requisite 

 as cleanliness in dairying in general. In actual practice it has 

 been found that some of these troubles may be 'quite allayed 

 by careful disinfection of the cheese factory and all the 

 utensils used therein, and then by giving attention to methods 

 of cleanliness in the dairies that furnish the milk. The im- 

 proper ripening of cheeses is probably, in most, if not in all 

 cases, due to the presence of improper species of microorgan- 



