234 DAIRY TECHNOLOGY 



However, this does not apply to dry cultures of B. acidi 

 lactici, because these are in daily use in butter and cheese 

 factories throughout the country, and are known to contain 

 a sufficient number of virile lactic bacteria to insure a 

 desirable fermentation. So-called buttermilk tablets are 

 simply dry cultures pressed into tablet form. 



The germ Bacillus bulgaricus is capable of producing 

 about two per cent of lactic acid in the milk, while the 

 ordinary lactic-acid-producing bacteria in milk produce 

 only a maximum of about one per cent acid. 



Buttermilk. Most common of all fermented milks is 

 the by-product of the butter-making industry. Butter- 

 milk is the milky portion of the cream that remains after 

 the fat has been churned out of the cream. As cream is 

 normally churned sour, the casein of the buttermilk is 

 in a precipitated and very finely divided condition. The 

 casein remains suspended in the liquid for several hours, 

 but gradually settles to the bottom, leaving a transparent 

 whey on top; occasional stirring keeps the buttermilk 

 in its homogeneous milky condition. This universally 

 common beverage needs no further description. When 

 it comes from fresh and properly ripened cream it is a 

 most refreshing and delicious drink. 



Composition. The composition of buttermilk does 

 not differ essentially from that of skim milk. Its fat 

 content is the one variable factor, and this depends upon 

 the completeness with which the fat was churned out. 

 The following is a fair example of the composition of aver- 

 age buttermilk: Percent 



Water 9 39 



Fat o . 50 



Casein and albumen 3 . 60 



Milk sugar 4.06 



Lactic acid o . 80 



Ash 0.75 



