Sometimes one and sometimes all of these bacteria were present in a
given ham. They were encountered most frequently in hams which had
been pumped in both body and shank, and were probably ordinary pickle
bacteria. They were not strict anaerobes, but belonged to the class of
facultative or optional anaerobes; that is, organisms which will grow
either with or without free oxygen. These bacteria were isolated and
grown on the egg-pork medium, but failed to give any characteristic
sour or putrefactive odors, and were therefore discarded.
A series of sound hams, all of them of mild cure—that is, hams which
had been pumped in the shank only—were also examined bacteriologically.
In examining these hams cultures were taken at varying depths,
beginning at the skinned surface and going backward toward the fat.
Cultures were also taken from the bone marrow of the femur. In the
cultures taken near the skinned surfaces the ordinary pickle bacteria
were obtained, but these did not, as a rule, extend beyond a depth of
3 centimeters below the skinned surface. The cultures taken from the
deeper portions of the hams and from the bone marrow of the femur were
entirely negative—that is, failed to show any growth—and the anaerobic
bacillus noted in the sour hams was not encountered in any of the
cultures made from these hams.
The anaerobic bacillus isolated from the sour hams was found to
correspond in morphology with the organism noted in the microscopic
sections made from the muscular tissue. In view of this fact and the
fact that it was constantly present in the sour hams examined, and was
capable of producing in egg-pork cultures a sour-meat odor of the same
nature as that obtained from sour hams, this organism was subjected to
further study and experimentation.