FLAVORS OF BUTTER 



177 



132 , Micro-organisms in butter. There is a certain re- 

 lation between the number and the nature of the organisms 

 in butter and its flavor. The number and types of micro- 

 organisms vary considerably. According to Rosenau, 

 Frost, and Bryant, 1 the number of bacteria in twenty-five 

 samples of butter obtained from the Boston market was 

 as follows : The average number of bacteria to a gram of 

 butter was 5,700,000 ; the lowest number, 8,600; and the 

 highest, 41,000,000. They found that the number of bac- 

 teria diminished markedly with age ; in one sample the 

 reduction was 85.8 per cent in two weeks ; in another, 93.7 

 per cent in four weeks ; and in still another, 95.6 per cent in 

 six weeks. Rogers 2 found that the number of micro-organ- 

 isms in butter decreases very rapidly. The following table 

 shows the results of a study of twelve samples of creamery 

 butter from one churning that were held in one pound tin 

 cans hermetically sealed and stored at 20 C. (68 F.) : 



TABLE XX BACTERIA AND YEASTS PER GRAM OF BUTTER 



(SERIES 5) 



a Sterile. 



1 Rosenau, M. J., Frost, W. D., Bryant, Ruth, A Study of the 

 Market Butter of Boston, Jour, of Med. Research, Vol. 30, N. S., 

 Vol. 25, pp. 69-85, 1914. 



2 Rogers, L. A., Canned Butter, U. S. Dept. of Agri., B. A. I., 

 Bui. 57, pp. 11-13, 1904. 



