86 THE STORY OF GERM LIFE. 



cream ripening, just as yeast is used by house- 

 wives for raising bread, or by brewers for fer- 

 menting malt. These starters will probably in 

 time be furnished by bacteriologists. Bacteriol- 

 ogy, in other words, is offering in the near future 

 to our butter makers a method of controlling the 

 ripening of the cream in such a way as to insure 

 the obtaining of a high and uniform quality of 

 butter, so far, at least, as concerns flavour and 

 aroma. 



BACTERIA IN CHEESE. 



Cheese ripening. The third great product of 

 the dairy industry is cheese, and in connection 

 with this product the dairyman is even more de- 

 pendent upon bacteria than he is in the produc- 

 tion of butter. In the manufacture of cheese the 

 casein of the milk is separated from the other 

 products by the use of rennet, and is collected 

 in large masses and pressed, forming the fresh 

 cheese. This cheese is then set aside for sev- 

 eral weeks, and sometimes for months, to under- 

 go a process that is known as ripening. During 

 the ripening there are developed in the cheese the 

 peculiar flavours which are characteristic of the 

 completed product. The taste of freshly made 

 cheese is extremely unlike that of the ripened 

 product. While butter made from unripened 

 cream has a pleasant flavour, and one which is 

 in many places particularly enjoyed, there is no- 

 where a demand for unripened cheese, for the 

 freshly made cheese has a taste that scarce any 

 one regards as pleasant. Indeed, the whole value 

 of the cheese is dependent upon the flavour of 

 the product, and this flavour is developed during 

 the ripening. 



