BACTERIA IN CHEESE 257 



cheese, molds cannot grow upon it, for they need a damp, not 

 a wet surface; but a quantity of bacteria grow instead. These 

 ripen the cheese, doubtless by the secretion of chemical fer- 

 ments, although the process has not as yet been fully studied. 

 The resulting cheese contains very high flavors, closely re- 

 sembling those of decay, and the cheeses rapidly putrefy when 

 they become old. If they are marketed at the right stage, the 

 flavors are not strong enough to be disagreeable, and many 

 persons are very fond of them. The Limburger type of cheese 

 includes Bachstein and some others. 



GUARDING THE MILK SUPPLY 



Cheese seems more likely to be injured by unfavorable bac- 

 teria than other milk products. The reason is that it remains 

 for such a long time, during the ripening, in a condition more 

 or less favorable for bacteria growth. Any mischievous organ- 

 isms that get into the milk have, therefore, a great chance for 

 producing trouble before the cheese is ready for market. This 

 is even more true of the making of soft than of hard cheeses. 

 No cheese maker can produce good cheese from milk filled with 

 mischievous bacteria. The cheese maker must, therefore, be 

 on constant guard to protect his milk and all other materials 

 from undesirable bacterial contamination. Several practical 

 suggestions for testing and guarding milk are, therefore, espe- 

 cially appropriate at the close of this discussion on cheese. 



Since a cheese factory is likely to receive milk from many 

 different farms it will happen that the milk from the different 

 sources will not be alike. It may be that while most of the milk 

 is good, that from a single farm contains a quantity of mis- 

 chievous organisms. If this milk is mixed with the rest, it 

 may spoil the whole; but if the infected dairy can be detected, 

 and its milk excluded from the rest until improved, the whole 

 output will benefit. To enable the cheese maker to do this there 

 have been devised the Fermentation and the Curd Tests. 



