New York Agricultural Experiment Station. 43 



sented, nor have we attempted to establish the relation between 

 slight variations in the flavor of the cheese samples and varia- 

 tions in the yeast flora. 



SWEET FLAVOR PRODUCED BY YEAST STARTERS. ' 



In discussing the causal relation of any organism either to a 

 disease or to a fermentation it was formerly the custom to ignore 

 all other factors than the mere presence of the germ. The fallacy 

 of this method of reasoning has come to be recognized in medical 

 matteris and our experience detailed below, as well as the results 

 of our study of the activity of the organism producing rusty spot, 

 g'hows that the accompanying conditions exert a profound influ- 

 ence upon the activity of fermentative organisms. The fact that 

 sweet flavor ia a factory undergoes seasonal and even daily varia- 

 tions in its activity would suggest the same idea. In beginnin'^, 

 experimental work upon such an untried field as the relation of 

 yea.sts to cheese flavor, it is not surprising that the results have 

 not been uniformly good. By referring to the article on rusty 

 spot it will be seen that, while in a majority of attempts the use 

 of a starter of the causal organism resulted in failure so far as a 

 real reproduction of the typical trouble was concerned, yet when 

 the right conditions were obtained this same organism repro- 

 duced the rusty spot in even more marked form than is met with 

 in the factories. 



The starter used with a majority of the cheeses made in this 

 connection was prepared from a pure culture of a yeast which is 

 designated in the laboratory as 2F. This yeast was isolated 

 from a cheese showing a well-marked case of sweet flavor. In 

 each of these experimental cheeses there was reproduced in a 

 slight degree the characteristic flavor of the original cheese. 

 The determination of this fact rests not only upon the judgment 

 of one of us, but has been subscribed to by a number of expert:, 

 to whom these cheeses have been submitted. However, it must 

 be said in all fairness that the sweet flavor reproduced in these 

 experiments fell short of the intensity often met with in fac- 



