252 PRACTICAL DAIRY BACTERIOLOGY 



concerned in the ripening. It will be recognized that in the 

 manufacture of a product which requires the proper succession 

 of three or four distinct species of micro-organisms, the problem 

 of their control becomes extremely difficult, and it is not sur- 

 prising that the artificial use of these cultures has not always 



FIG. 66 WORTHLESS CAMEMBERT CHEESE 

 Showing porous texture produced by gas-forming bacteria 



been successful. When we remember, too, that the curd is so 

 full of moisture that it offers the very best medium for bacteria 

 growth we can readily understand the difficulties that the maker 

 of soft cheeses may meet. (Fig. 66.) 



These various troubles must be met by different methods, but 

 there are two general plans of action that help to meet them 

 all. The first is that of pasteurizing the milk. While, as al- 

 ready pointed out, pasteurizing the milk does not seem to be 

 practical with the hard cheeses, since the cheeses do not ripen, 



