150 MARKET DAIRYING 
the idea is to get a drink which shall contain practically 
none other than the common lactic acid and the Bul- 
garian bacilli. This requires that the milk be thoroughly 
pasteurized and then inoculated with pure cultures of 
the common lactic acid and Bulgarian bacteria. 
Bacillus Bulgaricus. So far as known, none of 
those who are making a specialty of supplying cultured 
milk have found the Bacillus Bulgaricus entirely satis- 
factory when used by itself. The high acid production 
and the comparatively high temperature at which it must 
be grown, combined with the tendency to produce a 
slimy curd, make milk fermented with this bacillus less 
palatable than that soured with ordinary lactic acid bac- 
teria. The flavor produced by this bacillus is also less 
desirable than that produced by the ordinary lactic acid 
bacteria. ; 
On the other hand, while there are objections to the 
exclusive use of the Bulgarian bacteria, they have a 
use in cultured milk aside from the medicinal value al- 
ready discussed. The slimy curd produced by them 
gives smoothness to body when mixed with the com- 
mon lactic acid cultures and checks or prevents the 
separation of the whey in the finished product. 
Unlike the common lactic acid bacteria, the Bulgarian 
bacteria are extremely sensitive to temperature, develop- 
ing best at about 100° F. At this temperature the 
amount of acid produced may reach three per cent. 
Below 90° F. there is little development and for this 
reason the culture soon deteriorates when attempts are 
made to propogate it at the same temperature at which 
the ordinary lactic acid cultures are prepared. This 
fact has caused many cultured milk manufacturers to 
propogate the Bulgarian and common lactic acid cul- 
