Gas and Taint in Cheese Curd. 231 



The cows were then given daily in their drinking water from one 

 to two quarts of a bouillon culture oi d^ Bacillus pro dig iosus.^o^w^ the 

 milk carefully examined but this organism did not appear in the 

 milk although the feeding and examinations were continued daily 

 for nearly two weeks. The experiment was repeated with cul- 

 tures of the gas-producing bacillus with similar negative results. 



From the known facts it is highly probable that the cause of 

 the " gassy " curd made from the milk of cows allowed to drink 

 from stagnant pools is not that any bacteria in such water pass 

 through the animal tissues into the udder , but that the cows wallow- 

 ing in this water or other unw^iolesome places, smear the teats and 

 udder with the dirt and filth containing the obnoxious organisms. 

 These bacteria are then either carried directly into the milk on the 

 dried particles which drop into the pail at the time of milking, or 

 else they infect the milk ducts and udder as in the case herein 

 described. There is always left on the end of the teat a small 

 drop of milk in which the bacteria can multiph', and from which 

 they can gradually grow up into the milk passages. In such an 

 infection we have a condition quite similar to the one under 

 consideration. 



In the case where the "gassy " curd follows the drinking of 

 stagnant water, it is presumable that a different species of bacteria 

 is the cause. There are a number of bacteria which produce gas 

 and which are found to be widely distributed in nature. How 

 many of these are capable of producing the taint in question is 

 not known, but it is highly probable that several of them could 

 do so. We do not presume the organism we have isolated and 

 studied is the only one to be feared or guarded against. The 

 facts elicited suggest that all bacteria capable of producing a 

 gaseous fermentation in milk, might, if the fermentation process 

 was continued for a sufficient length of time, give rise to 

 objectionable taints and flavors. In our experimental work with 

 the bacillus in question, a considerable variety of taints were 

 detected in the milk and curds. The difference in them 

 depended for their cause upon the length of time the fermentation 

 had been going on. It is not unlikel}' that this explains in part 



*This organism was chosen as it is easily detected, if present, by the deep 

 red color of its growth on culture media. 



