The most favorable medium for the growth of the organism was found
to be the modified egg-meat mixture of Rettger, which has been
previously described. In this medium the organism develops rapidly
at a temperature of 20° to 25° C., giving rise to the characteristic
sour-meat odor. Like the bacillus described by Klein, it also grows
readily on pork-agar and pork-bouillon containing glucose, but differs
from Klein’s bacillus in that it will grow, though less luxuriantly,
on ordinary nutrient media—agar, gelatin, and bouillon—without the
addition of glucose.
The optimum temperature for growth is 20° to 25° C. The organism does
not grow at incubator temperature (37.5° C.). At ice-box temperature
(8° to 10° C.) it develops readily, although the growth is less rapid
than at 20° to 25° C. That the organism will develop at even lower
temperatures was shown in the inoculation experiments with hams, where
it developed and multiplied extensively in the bodies of the hams at
the temperature of the pickling cellars, which are held usually at 34°
to 36° F. (1° to 2° C.).
The organism develops best in a neutral or slightly alkaline medium.