Ripening of Soft Cheeses 425 



period, but declined towards the end. Peptonizing bac- 

 teria were found in considerable numbers only occasion- 

 ally, such cheeses manifesting a somewhat abnormal 

 ripening, but yielding fairly satisfactory final results. 



The sour curd formed by the lactic-acid bacteria is 

 a favorable medium for the development of molds. Two 

 of these appear to play a predominant role in the ripen- 

 ing of Camembert cheese, namely, Penicillium camem- 

 berti and Oidium lactis. The molds gradually reduce the 

 acidity of the curd until its reaction is markedly modified. 

 Enzymes are produced which gradually diffuse towards 

 the center of the cheese, the curd is digested and becomes, 

 to a marked extent, soluble in water, and the transfor- 

 mation thus proceeds until the ripening process is com- 

 plete. Experiments with pure cultures of the molds 

 showed definitely that they are capable of causing 

 these digestive changes when not associated with 

 bacteria. 



A number of cheeses that were prepared by means of 

 a pure-culture starter and inoculated with Penicillium 

 camemberti ripened properly, but showed no distinct 

 flavor. But when Oidium lactis was also introduced 

 in the cheese, there was developed the characteristic 

 flavor. " Bacteria or other molds," says Thorn, "in 

 many cases modify the flavor of Camembert cheese, 

 but do not seem to produce it independently of the mold. 

 There thus arise characteristic secondary flavors which 

 are associated with the output of certain factories and 

 which command special markets. These varieties are 

 usually more highly flavored than what we have re- 

 garded as typical. The essential relation of the Camerq- 



