BACTERIA OF MILK 65 
The kind of bacteria which will predominate in milk of 
this kind when it reaches the consumer will depend upon 
the temperature at which it is kept (see above). The 
fermentation test offers a rapid and convenient method 
of determining the kind of bacteria which predominates 
in a sample of milk (see page 278). 
A large percentage of the bacteria present in market 
milk belongs to the inert group. This is shown by the 
following table compiled from examinations reported by 
Ayers and Johnson’: 
No. samples Average Percent? Percent. Percent. Percent. Percent. 
examined. number bac- peptonizing. Alkali- inert. Acid, coag- Acid, non- 
teria per c.c. forming. ulating. coagulating. 
12 382,950,000 17.31 6.47 29.381 386.17 10.71 
17 3,451,000 14.10 19.66 43.51 12.98 9.74 
24,700 12.81 3.383 43.13 383.85 6.85 
1B. A. I. Bull. 161, pp.20—-27. 
