Bacteria in Cheese. 169 



Emmenthaler cheese the development of the specific aroma- 

 producing organism occurs in the superficial layers. Jen- 

 sen has shown, however, that the greatest amount of 

 soluble nitrogenous products are to be found in the inner- 

 most part of the cheese, a condition that is not reconcil- 

 able with the view that the most active ripening is on the 

 exterior. 1 



The course of development of bacteria in cheddar cheese 

 is somewhat influenced by the ripening temperature. In 

 cheese ripened at relatively low temperatures (50-55 F.), 2 

 the bacterial flora retains for a considerable period the 

 same general aspect as in the milk. Under these condi- 

 tions the lactic-acid type does not gain the ascendancy so 

 readily. In cheese cured at high temperatures (80-86 F.), 

 the number of organisms is greatly diminished, and they 

 fail to persist in appreciable numbers for as long a time as 

 in cheese cured at temperatures more frequently employed. 



Influence of temperature on curing. Temperature exerts 

 a most potent influence on the quality of the cheese, as de- 

 termined not only by the rate of ripening but the nature 

 of the process itself. Much of the poor quality of cheese 

 is attributable to the effect of improper curing conditions. 

 Probably in the initial stage of this industry cheese were 

 allowed to ripen without any sort of control, with the 

 inevitable result that during the summer months the tem- 

 perature generally fluctuated so much as to impair seriously 

 the quality. The effect of high temperatures (70 F. and 

 above) is to produce a rapid curing, and, therefore, a short 

 lived cheese; also a sharp, strong flavor, and generally a 



i Freudenreich, Landw. Jahr. d. Schweiz, 1900; Adametz, Oest. Molk. Zeit., 

 1899, No. 7. - 

 Russell, 14 Wis. Expt. Stat., 1897, p. 203. 



