498 



MANUAL OF MILK PRODUCTS 



ganisms are always present in the fermented milk. One of 

 these, Bacterium caucasicum, which forms the filament of the 

 grain, is evidently identical with Freudenreich's Bacillus 

 caucasicus. This investigator considers this bacterium, with 

 a torula yeast fermenting lactose, dextrose, and cane-sugar, 

 as essential to the production of kefir. Other bacteria and 

 yeasts are found in the grains and the fermented milk, but they 

 are looked upon as contamination. 



It is probable that kefir is produced under different circum- 

 stances by different organisms. Any combination of bacteria 

 or of bacteria and yeast that will produce a lactic acid and a 

 milk alcoholic fermentation in milk will make kefir, although to 

 secure the most desirable flavor certain organisms may be 

 essential. 



Hammarsten shows in the following table the changes 

 brought about in cow's milk by this fermentation : 



CHEMICAL ANALYSIS OF KEFIR 



It will be observed that the changes were confined almost 

 entirely to the lactose and its by-products. The casein re- 

 mained unchanged and the increase in the peptones was insig- 

 nificant. The lactalbumin decreased slightly. The casein of 

 kefir is ; according to this chemist, not especially soluble, but 



