3/0 CHEESE 



obtained two species of anaerobic bacteria, Paraplectrum 

 foetidum and Clostridium licheniforme y from cheese ; they 

 belong to a rod-shaped, spore-bearing class which produce 

 butyric acid, and are supposed to be concerned with the 

 ripening of the cheese and the development of aroma 

 and flavour in it. 



(d) Boekhout and De Vries are inclined to believe that, 

 in the case of Edam cheese at any rate, the cause of 

 ripening is not to be found in the work of bacteria 

 during or after the lactic fermentation has taken place, 

 but is due to the enzymes produced by peptonizing 

 bacteria which get into the milk in the stable and in the 

 dairy. These organisms begin their work when the 

 cheese is made, although their activity is soon checked 

 by the development of the lactic bacteria. However, 

 the proteolytic enzymes already produced by them are 

 not destroyed, and these substances continue to break 

 down the paracasein and ripen the cheese. 



(e) The author is of opinion that the lactic acid 

 organisms are chiefly responsible, in an indirect manner, 

 for the ripening of most cheeses, the proteolytic enzyme 

 upon which the process depends being apparently intra- 

 cellular, only coming into operation at or about the time 

 of death of the bacteria. 



The organisms, of which many millions per gram can 

 be detected in unripe cheese, disappear as ripening 

 proceeds, their bodies being broken down under the 

 influence of their intracellular trypic enzyme ; after this 

 autolytic digestion the enzyme set free from the dead 

 bacteria continues its proteolytic action upon the sur- 

 rounding curd. 



Ex. 160. Take a small piece of cheese, smooth one side with 



