2l8 PRACTICAL DAIRY BACTERIOLOGY 



Turnipy-tasting Butter. It has long been a belief that cows 

 fed upon turnips will produce turnipy-tasting milk and butter. 

 This is true to a certain extent, beyond doubt ; but in some of 

 these cases the turnipy taste has been found due not directly to 

 the food eaten by the cattle, but to a certain kind of bacteria 

 growing in the milk. Two or three bacteriologists have in- 

 dependently investigated infections of turnipy-tasting butter, 

 and have discovered bacteria, which when inoculated into milk 

 produce this undesirable taste. Hence, a turnipy-taste is, in 

 some cases, of bacterial origin. 1 



Cowy Butter. The peculiar odor which is common around 

 the barn, called "cowy odor," is well known. This odor is some- 

 times noticeable in milk, and it has been assumed that this is 

 because the milk absorbs the odors from the barn or the filth 

 that gets into the milk, which is doubtless usually correct. The 

 same odor is sometimes detected in butter, and the interpretation 

 has been that the odors from the barn have been transferred 

 to the butter in this way. But it has been found that certain 

 bacteria are capable of producing exactly this cowy odor, and 

 there seems no doubt that in some cases this peculiar defect in 

 butter is due not to the barn odors primarily, but to bacteria 

 which have been transferred from the barn through the ripening 

 cream to the butter itself. 2 



Putrid Butter. This is a difficulty that is rarely seen, and 

 has only been reported in one or two cases. Jensen found that 

 the defect was due to a certain kind of bacteria growing in the 

 cream and contributing to the ripening. The bacterium in ques- 

 tion is a close ally to certain species found in the intestines 

 (B. putrificus), and the putrid taste is really one of decay. This 

 organism in question is readily killed by heat, and the pasteur- 



1 Gruber. Cent. f. Bact.. II., ix., p. 684, 1902. 

 Jensen. Milchztg., 1892. 



2 Pammel. Bui. 21, Iowa Exper. Sta. 



