Bacteria and Cheese Making. 163 



In the making of most kinds of cheese, especially those 

 of the greatest commercial importance, the cheese maker 

 can call to his help no such aids, but must use the milk 

 as it is brought to him. It is possible to prepare certain 

 kinds of soft cheese from pasteurized milk that differ in 

 no essential point from the same cheese made from raw 

 milk. Hard cheese are also made from pasteurized milk, 

 but in most cases such cheese differ, especially in the de- 

 gree of flavor, from that made from unheated milk. It 

 is quite probable that, as the factors concerned in the 

 ripening of cheese become better known, methods will be 

 evolved for the successful production of many kinds of 

 cheese from pasteurized milk. 



It has been shown that the quality of milk is almost 

 wholly dependent upon the number and kinds of bac- 

 teria it contains. These bacteria pass into the cheese, 

 and there produce the same products as they would have 

 done in the milk itself. In butter making, practically 

 all processes are under the control of the maker, until 

 the product is ready for the market; but cheese, on the 

 other hand, passes through a complicated series of 

 changes after it has left the maker's control. During 

 the manipulation of the milk and the curd in the vat, 

 he can exert some influence on the quality of the pro- 

 duct, but he is much more dependent on the quality of 

 the milk than is the case in butter making. 



Every effort should therefore be made to furnish to 

 the cheese maker the quality of milk from which he can 

 prepare fine cheese. In other words, the milk should be 

 produced under clean conditions and carefully cooled 

 and handled until delivered to the maker. Poor milk 

 from a single farm may have such an effect upon the 

 cheese made from the milk of twenty farms as to depre- 



