242 PRACTICAL DAIRY BACTERIOLOGY 



lines already pointed out, cleaning of the milk vessels, more 

 care in the production of the milk, and the use of larger 

 quantities or more vigorous starters of lactic acid organisms, 

 to check the growth of other bacteria. 



Putrid Cheese. Sometimes milk becomes acted upon by 

 putrefying bacteria; soft spots appear upon the surface, which 

 may become larger and eat their way into the cheese, and 

 produce a more or less slimy appearance upon the cheese, even 

 to the center. The extent of the trouble will depend upon the 

 abundance of the putrefaction. The trouble is undoubtedly 

 due to the growth of putrefying bacteria, but not much is known 

 about the matter at present. 



Fruity or Sweet Cheese. This is a phenomenon which 

 occurs sometimes over widely extended districts, and detracts 

 from the character of the cheese without always ruining it. 

 It is characterized by a peculiar sweet taste, which, although 

 not unpleasant, spoils the flavor of the cheese and thus injures 

 the sale of the product. This trouble has been studied by 

 Harding and found to be due to a yeast, which gets into the 

 milk. 1 



Rusty Spot of Cheese. This is a defect occurring in the 

 cheese during the ripening, characterized by rusty, red spots 

 on the outside and, indeed, not infrequently throughout the 

 whole cheese. The cheese loses its value, and may in the end 

 become quite ruined, if the trouble develops sufficiently. The 

 cause is a bacterium, B. rudensis, which has been studied by 

 Harding and Connell. 2 In all these cases the only remedy 

 is the preventive one of a greater guard placed over the milk 

 supply, a more careful cleaning and steaming of the milk 

 vessels, until the organisms producing the troubles are 

 eliminated. 



1 Harding, Rogers and Smith. Bui. 183, N. Y. Exper. Sta., 1900. 

 - Harding, Rogers and Smith. Bui. 183, N. Y. Exper. Sta., 1900. 

 Harding and Smith. Bui. 225, N. Y. Exper. Sta., 1903. 



