THE CAUSE OF EYES AND CHARACTERISTIC 

 FLAVOR IN EMMENTAL OR SWISS CHEESE^ 



JAMES M. SHERMAN 



From the Research Laboratories of the Dairy Division, United States Department of 

 Agriculture, Washington, D. C. 



Received for publication November 22, 1920 

 INTRODUCTION 



Due to a lack of the proper natural inoculation in the mi.k, 

 the Swiss or Emmental cheese industry in the United States has 

 had only a limited success. The peculiar sweetish flavor which 

 is characteristic of the best cheese of this type is very commonly 

 lacking in our American-made cheese. It is also frequently de- 

 ficient in eye development, and in fact in some cases the cheeses 

 are entirely "blind." Swiss cheese is made only during certain 

 seasons in America, because of the uncertainty of obtaining the 

 proper development of eyes and flavor. It would seem that this 

 industry could be put on a sounder as well as a more scientific 

 basis by the use of cultures which would cause proper ripening 

 in the cheese. With such cultures at hand it should be possible 

 to make Swiss cheese of a uniform and high-grade quahty through- 

 out the year; such practice should result in raising very materi- 

 ally the quality, as well as the quantity, of our American-made 

 Swiss cheese. 



Von Freudenrich and Orla- Jensen (1906) in their work in 

 Switzerland have isolated propionic acid-producing bacteria 

 which they consider the cause of eyes in Emmental cheese. The 

 essential organism, called by them Bad. acidi-propiofiici (a), was 

 found to ferment lactates with the production of propionic acid, 

 acetic acid, and carbon dioxide. Other varieties of propionic 



1 Published with the permission of the Secretary of Agriculture. 



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JOUKNAL OF BACTERIOLOGY, VOL. VI, NO. 4 



