EYES AND FLAVOR IN EMMENTAL CHEESE 389 



to cause a development of eyes in the cheese the resulting flavor 

 is in no way similar to that characteristic of the tj^Dical Swiss 

 cheese. This fact is important, since it shows that the forma- 

 tion of eyes may be due to bacteria other than the one herein 

 described ; it probably explains also the fact that American Swiss 

 cheese is so frequently deficient in flavor even when abundant 

 eye formation takes place. 



In our laboratory work small cheeses of the Emmental type 

 are made from about 200 pounds of milk. These cheeses are 

 then handled in exactly the same way as are the large Swiss 

 cheeses made under factory conditions, and they ripen in an 

 entirely normal manner. From such experiments it has been 

 demonstrated time and again that the organism described in 

 this paper is responsible for the characteristic sweetish flavor 

 of Swiss cheese and that it also causes the development of eyes. 

 Its relation to the eye formation is shown in the photograph 

 reproduced at the end of this paper; its relation to flavor pro- 

 duction has been demonstrated in over 100 laboratory experi- 

 ments in which one cheese in each experiment was inoculated 

 while another cheese made from the same milk was left 

 uninoculated. 



That the use of this bacterium as a ''starter" is practicable 

 under commercial conditions has been demonstrated in a number 

 of different factories. In all cases these factory experiments 

 have shown a marked influence on the ripening of the cheese 

 with respect to both eyes and flavor. The apphcation of these 

 results in cheese-factory practice will be treated more in detail 

 in a future pubhcation. 



ACKNOWLEDGMENT 



Should the work herein reported prove of value to the cheese 

 industry, major credit therefor is due Mr. L. A. Rogers, in 

 charge of the Research Laboratories of the Dairy Division, who 

 recognized the possibilities of pure cultures in the manufacture 

 of Swiss cheese and initiated work toward that end over ten 

 years ago, and who has fostered and directed the work through 



