Gas and Taint in Cheese Curd. 225 



Kxperiment Station.* Before collecting the samples of milk the 

 cows' flanks, udders, teats, and the hands of the milker were 

 washed with a i to 1000 solution of corrosive sublimate. The jars 

 in which the milk was to be collected were sterilized by boiling. 

 The outcome of this series of observations showed the gas and 

 taint producing bacteria to be present more or less constantly in 

 the milk of each animal. In addition to the gas, the curd tests 

 emitted the disagreeable odor. These were invariably present in 

 the test curds made from the milk of certain of the animals while 

 those made from the milk from the other cows were not con- 

 stantly bad, there being occasionally days in which the taints 

 were less marked or absent altogether. 



In the above tests the fore milk was used. The examination 

 was repeated, however, with the milk from several of the cows in 

 which that taken from the middle or latter half of the milking 

 was used. Similar positive results were obtained showing that 

 the rejection of the fore milk from all of the cows would be of 

 little or no use in checking the trouble. 



A study of the results obtained from the daily examinations of 

 the milk from the different animals, gave no assurance that the 

 trouble wonld be eliminated by keeping out the milk from any 

 particular cows. The interesting fact was brought out that the 

 test curds made from the milk of the cows which had suffered 

 from retained placenta were, as a rule, no worse than those made 

 from the cows which had not been so affected. The cows from 

 which the constantly bad curds were obtained were among those 

 which had had a normal delivery. 



The positive results obtained in the test with the fore milk, 

 naturally led to an examination of the dust and filth from the 

 floor of the stable. As in the other examinations this consisted 

 simply of a search for gas producing bacteria. Several varieties 

 or species were isolated and studied, but none of them resembled 



* Samples of milk placed in sterile vessels are allowed to stand in a 

 moderately warm place for several hours after which rennet is added. Gas 

 producing bacteria will, if present, cause the formation of gas bubbles in 

 the curd, similar to those encountered in the cheese vat. The test is fully 

 described in the Twelfth Annual Report of the Agricultural Experiment 

 Station of the University of Wisconsin, page 148 and in Bulletin No. 67 of 

 the same station. 



