8 BULLETIN 148, U. S. DEPARTMENT OF AGRICULTURE. 



Some experiments not recorded in these tables showed very defi- 

 nitely that the temperature of cooking the curd had a very material 

 influence on the effectiveness of Bacillus bulgaricus starters. In a 

 number of tests it was found that cheeses cooked at 125° F. or above 

 were entirely free from gas. It appears probable that the higher 

 cooking temperature served to check the growth of undesirable 

 bacteria for a longer period or until the Bacillus bulgaricus secured 

 a sufficient start to check their growth. 



EXPERIMENTS WITH BACILLUS BULGARICUS STARTERS IN A 

 COMMERCIAL FACTORY. 



The results of our experiments led us to believe that we could 

 demonstrate two points : First, that it was possible to overcome the 

 faults of milk usually delivered to Swiss-cheese factories early in the 

 spring; and, second, that it was possible to secure a normal eye 

 growth with attending characteristic flavors by the use of cultures 

 adapted for that purpose in cheese made early in the spring and in 

 cheese made once a day instead of twice a day, as is the usual custom 

 in summer. In order to study the use of Bacillus bulgaricus starters 

 in a commercial factory, one of the authors spent two weeks, begin- 

 ning the last week in April, 1913, in a factory where cheaper products 

 (brick and Limburger cheese) were made early in the spring, or 

 until the weather conditions became favorable for the making of good 

 Swiss cheese. The value of these cultures should have been demon- 

 strated earlier in the spring, but the factory did not receive milk 

 enough to make one cheese a day until about May 1. The result of 

 this work is compiled in Table -1. 



Table 4. — Results obtained with Bacillus bulgaricus starters in suppressing gas 

 formation in Swiss cheese under commercial conditions. 



Date. 



Cheese 

 No. 



Starter. 



Condi- 

 tion of 

 cheese. 



Amount. 



Acidity. 



May 1 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



Per cent. 

 1 



1.5 

 1.5 

 1.5 

 1.5 

 1 

 1 



1.25 

 1.25 

 1 



1.25 

 1.5 

 1.5 

 1.25 



Per cent. 



1.0 



.7 



.9 



.9 



.8 



.9 



.6 



1.0 



1.1 



1.5 



1.2 



1.1 



1.4 



.9 



Nissler. 



2 



Do. 



3 



Do. 





Do. 





Do. 



6 



Do. 





Do. 



3 



Good. 



9 



Do. 



10 



Do. 



11 



Do. 



12 



Do. 



13 



Do. 



14 



Do. 







The starters used were prepared from pure cultures of Bacillus 

 bulgaricus from the laboratory of the Dairy Division at Washington. 

 As the temperatures were rather low at this time it was necessary to 



