A second cheese was. made with a different culture of a gas-produchig- 

 organism, and at the age of seven days was found to contain 15 per cent, 

 of gas-producers. This number gradually declined, and at the age of 45 

 days only 2 per cent, of gas-producing bacteria were present. The cheese 

 was examined at the end of 63 days, and was found to be slightly unpleas- 

 ant in smell and taste, but was judged to be better than that made on 

 the 5th of October, receiving 15 points out of 45 for flavor. On November 

 2nd, two cheeses were made. In the A cheese, ^ per cent, of a 24 hour 

 old milk culture of a gas-producing germ was used, and in the B cheese 

 ^ per cent, of the same culture and i per cent, of the lactic acid bacillus. 

 Both curds were floating about three hours from setting ; the flavor was 

 gassy. The B curd was better than the A, although even B was very 





Growth of gas-producing germs in test 

 tubes containing, sugar gelatin. Noie the gas 

 bubbles. 



Gas-i>rodncing ])acleria ; 

 magnitied_; lUUO diameters. 



gassy. The B cheese was placed in an ordinary curing-room, and the 

 percentage of gas-producing germs at the age of 10 days was .5. The 

 t.lieese was examined at the end of 63 days, and was found to be slightly 

 mottled, with fair flavor. The curd for the A cheese was divided into 

 equal. portions, one of which was placed in an ordinary curing-room at a 

 temperature of 55 degrees to 60 degrees F., and the other put into the re- 

 frigerator curing-room, the average temperature of which was 40 degrees 

 F. The percentage of gas-producing germs in both of these cheeses was 

 very high. They were judg"ed at the end of 63 days, when the taste and 

 , odor of both were found to be bad. The appearance of the one in the 

 ordinary curing-room was very mottled. The one in the refrig"erator 

 curing-room was also mottled, but to a lesser extent. 



These experiments show that gas-producing germs are able to pro- 

 duce a bad odor and flavor in cheese, and cause a mottled appearance, 

 which is probablv brought about by the bleaching action of the gases 

 generated by the organisms introduced in the culture. The good efi"ect of 



[6] 



