146 Dairy Bacteriology. 



are able to produce decomposition products 1 , the odor 

 and taste of which strongly recalls these vegetables. 



149. "Cowy" odor in butter. Frequently there is 

 to be noted in milk a peculiar odor that resembles that 

 of the cow stable and sometimes the odor of the animal 

 itself. Usually this defect in milk has been ascribed to 

 the absorption of impure gases by the milk as it cools, 

 although the gases and odors naturally present in fresh 

 milk have this peculiar property that is demonstrable by 

 certain methods of aeration. Occasionally, it is trans- 

 mitted to butter, and recently, Pammel 2 has isolated from 

 butter, a bacillus that produced in milk the same peculiar 

 odor so commonly present in stables. 



150. Lardy and tallowy butter. The presence of 

 this unpleasant taste in butter may be due to a variety of 

 causes. In some instances, improper food seems to be 

 the source of the trouble; then again, butter exposed to 

 direct sunlight bleaches in color and develops a lardy 

 flavor. 3 In addition to these, cases have been found in 

 which the defect has been traced to the action of bacteria. 

 S torch 4 has described a lactic acid form in a sample of 

 tallowy butter that was able to produce this disagreeable 

 odor. 



151. Oily butter. Jensen has isolated one of the 

 causes of the dreaded oily butter that is reported quite 

 frequently in Denmark. The specific organism that he 

 found belongs to the sour-milk bacteria. In twenty-four 

 hours it curdles milk, the curd being solid like that of 

 ordinary sour milk. There is produced, however, in ad- 

 dition to this, an unpleasant odor and taste resembling 



1 Jensen, Molk. Ztg., 6: Nos. 5 and 6, 1892. 



8 Pammel, Bull. 21, Iowa Expt. Stat., p. 803. 



3 Fischer, Hyg. Rund, 5: 573. 



4 Storch, 18th Kept. Danish Agric. Expt. Stat., 1890. 



