250 Journal of Agricultural Research voi. xiii, no. 4 



from the best quality of raw milk. As in the case of Cheddar, cream 

 cheese made from pasteurized milk is whiter than that made from raw 

 milk. Anyone who has the opportunity to compare cream cheese made 

 according to the different methods learns to distinguish them quite 

 readily by their flavor and color. The texture also differs slightly. 



Experimental soft-cream cheeses have been made from pasteurized 

 milk with the use of Streptococcus X and S. kefir alone or together, in 

 addition to the 5. lacticus starter. The results were definite, showing 

 that flavors in pasteurized-milk cheese can be influenced at will by a 

 choice of streptococci in starters. A cream cheese inoculated with S. 

 lacticus alone has its own peculiar flavor; a cream cheese inoculated with 

 5. lacticus and Streptococcus X has a decidedly different flavor; another 

 inoculated with S. lactictis and 5. kefir has another flavor; and when all 

 three species of streptococci are used together, still another flavor is 

 produced. And as some people prefer their ice cream flavored with 

 vanilla, and others like chocolate flavoring best, so the one cheese flavor 

 is more pleasing to some people, while others prefer another. The pas- 

 teurization of the milk assures a uniform product in cheese making. 

 This is one reason why manufacturers are loath to adopt the pasteuriza- 

 tion of milk for cream-cheese making. They want to develop the cheese 

 flavors which they believe to be peculiar to their own product. It may 

 be that certain strains of streptococci have gained predominance in certain 

 localities, so that season after season a manufacturer of cream cheese 

 can reproduce his own peculiar cheese flavors. The experiments have 

 demonstrated that it will be possible for a manufacturer to choose the 

 flavor which he may want his product to develop in cream cheese made 

 from pasteurized milk. Whether the consuming public will be dis- 

 criminating enough to make the inoculation of soft-cream cheese with 

 cheese streptococci a financial success remains to be demonstrated. 



SUMMARY 



(i) Streptococci that differ from 5. lacticus are common in ripening 

 cheese of various kinds, and in other foods prepared by fermentation. 

 In this paper they are called cheese streptococci. It is probable that a 

 study of the mouth, fecal, and udder types of streptococci will show 

 that cheese streptococci belong to those familiar types. 



(2) 5. lacticus is described culturally and biochemically, and two 

 other species of streptococci, Streptococcus X and 5. kefir, are likewise 

 described. 



(3) The most pronounced biochemical characteristic which distin- 

 guishes 5. lacticus from the other two species of streptococci described 

 is the small quantity of acetic acid which it produces in milk cultures. 



(4) 5. kefir is notable among dairy streptococci because of its vigor- 

 ous production of carbon dioxid when grown in suitable media. 



