DISEASES OF BUTTER. 253 



C. 0. Jensen, who has been very successful in his stud- 

 ies of all kinds of butter diseases, separates these diseases 

 into two different groups. First, diseases caused by the 

 presence of several forms of bacteria, which, each one by 

 itself, is harmless. Second, diseases caused by the presence 

 of a single definite injurious form of bacteria. 



" Off Flavor " in Butter. To Group I the butter disease 

 characterized by the expression an " off " flavor and taste of 

 the butter first of all belong. This disease springs from lack 

 of cleanliness in the treatment of the milk and the cream. 

 Jensen is correct in stating that the fact that a great many 

 forms of bacteria and a multitude of each of them are 

 formed during the ripening of the cream is often in itself 

 a sufficient reason for the poor quality of butter. A sample 

 of butter examined by Jensen, which was described as bitter, 

 unclean, dry, and soft, contained an immense number of 

 forms of bacteria and many of each form. The disease could 

 not be ascribed to any distinct form of bacteria present. 

 The numerous foreign bacteria prevented the normal lac- 

 tic-acid fermentation, and i is also possible that other 

 decompositions arose in the cream by the simultaneous 

 presence of so many different bacteria forms than those 

 produced by the single bacteria forms themselves. 



Among the diseases of Group II the following have 

 been investigated at the present time. 



1. Tallowy Butter. In his investigations and experi- 

 ments as to the ripening of cream Storch found a lactic- 

 acid bacterium to which he ascribed the origin of this dis- 

 ease. This bacterium is not very different from most other 

 lactic-acid bacterium, as^ far as size and form go ; but if al- 

 lowed to grow luxuriantly in cream during its ripening it 

 will produce a most disagreeable tallowy taste in the butter 



