RIPENING AT LOW TEMPERATURES. 239 



ordinary temperatures, although it may be hastened by the 

 use of a large quantity of rennet. The cheeses are of a 

 milder flavor than when ripened at a higher temperature. 

 Apparently this ripening is due chiefly to enzymes. It has 

 been shown by Freudenreich (249) that Emnenthaler cheese, 

 which has a more pronounced flavor of putrefaction, will 

 ripen at these low temperatures well enough so far as con- 

 cerns the changes due to enzymes, but it does not develop 

 into a normal production because of a lack of a typical flavor. 

 This is due to the failure of the bacilli to grow at these low 

 temperatures. That enzyme action should go on under these 

 conditions, although somewhat slowly, is not surprising, and 

 it is certain also that some bacilli grow also at the tempera- 

 ture of freezing water. Both actions may, therefore, be con- 

 cerned. Not enough is known concerning this subject as yet 

 to warrant any positive statements as to ripening under these 

 conditions. It is certain that Cheddar cheese may be ripened 

 at low temperatures, but as yet we are uncertain through 

 what agency, and we do not know whether other types 

 of cheeses can be treated in the same way. If this process 

 should prove to be practical it will be useful in many respects, 

 since it will enable the cheese-maker to have his cheeses ready 

 for market at any season of the year. 



It is even more surprising to find that cheeses may be 

 ripened at temperatures below freezing ; but this has also been 

 demonstrated. The ripening is not normal, however. The 

 texture is soggy and crumbly, and the flavors do not develop. 

 It is difficult to understand how chemical changes can take 

 place at these low temperatures under the influence of either 

 enzymes or bacteria. The whole phenomenon indicates that 

 the physical breaking down of the casein is a phenomenon 

 independent of the production of flavors, the former being, 

 likely, an enzyme action, the latter probably due to micro- 

 organisms, 



