146 Dairy Bacteriology. 



5. Not easily modified in its flavor-producing qualities 

 by artificial cultivation. 



These different conditions are difficult to attain, for the 

 reason that some of them seem to be in part incompatible. 

 Weigmann 1 found that a good aroma was generally an 

 evanescent property, and therefore opposed to good keep- 

 ing quality. Conn has shown that the functions of acid- 

 formation, flavor and aroma production are not necessarily 

 related, and therefore the .chances of finding a single or- 

 ganism that possesses all the desirable attributes are not 

 very good. 



In all probability no one germ possesses all of these de- 

 sirable qualities, but natural ripening is the resultant of 

 the action, of several forms. 8 This idea has led to the at- 

 tempt at mixing selected organisms that have been chosen 

 on account of certain favorable characteristics which they 

 might possess. The difficulty of maintaining such a com- 

 posite culture in its correct proportions when it is propa- 

 gated in the creamery is seemingly well nigh insuperable, 

 as one organism is very apt to develop more or less rapidly 

 than the other. 



A very satisfactory way in which these cultures are mar- 

 keted is to mix the bacterial growth with some sterile, 

 inert, dry substance. This is the method used in most of 

 the Danish cultures. In this country, some of the more 

 prominent cultures employed are marketed in a liquid form. 



Culture vs. home-made starters. One great advantage 

 which has accrued from the use of culture or commercial 

 starters has been that in emphasizing the need of closer 

 control of the ripening process, greater attention has been 



Weigmann, Lamlw. Woch. f. Schl. Hoi., No. 2, 1890. 

 Weigmann, Cent. f. Bakt., II Abt., 3:49 7, 1897. 



