690 
Journal of Agricultural Research 
Vol. XXI, No. 9 
It is not definitely known that the souring of beef referred to by 
Ostertag is identical with that which is discussed in this study. 
Certainly the conservation of the interests of the consuming public 
in this regard can be accomplished only by precautions of a far-reaching 
nature, involving vigilance from the abattoir to the platter. 
The common stock of knowledge as to the definite cause of the phe¬ 
nomenon known as sour beef is probably more or less vague. 
A specimen of sour beef was sent to this laboratory from one of the 
large packing establishments with a view to determining definitely the 
cause of the condition in this specific instance, as the meat was very 
decidedly sour. The specimen was assigned the number 1510. 
BACTERIOLOGICAL EXAMINATION OF SOUR BEEF 
An effort was made to isolate any organisms that might be found in 
the interior of the specimen. This was accomplished in the following 
manner: A site was selected favorable to making a deep cut into the 
body of the specimen, and the surface was then scared for a radius of 
several inches with a hot platinum spatula. With a sterile scalpel and 
forceps this surface was removed to a depth of X inch. The newly 
exposed surface was then similarly seared, and with the aid of a fresh 
sterile scalpel and forceps a small cube of meat was aseptically taken out 
and placed into a tube of bouillon medium. 
This bouillon culture showed appreciable growth at the end of 24 
houis incubation at 37 0 C. It was then shaken thoroughly, and a loop¬ 
ful of the suspension of organisms was distributed upon the surface of 
each of three plain agar plates. 
Upon incubation for 24 hours at 37° C. these plates developed three 
types of organisms, which were later transplanted upon plain agar slant* 
and for convenience of identification designated as organism i 5 io-a| 
1510-B, and 1510-C, respectively. Organism 1510-A proved to be 
Staphylococcus albus. Organism 1510-B was a medium short chain¬ 
forming and apparently spore-bearing bacillus. Organism i 5 io-C was a 
fungus. 
An effort was then made to determine whether any one of these three 
organisms or any combinations thereof would artificially produce the 
sour-beef odor in meat as noticed in the original specimen. Sterile nor¬ 
mal beef muscle pieces were placed in sterile plugged test tubes, and the 
following tests were applied. 
Two tubes were inoculated with each organism and two tubes with 
each combination of two organisms. All of the tubes were incubated for 
24 hours at 37 0 C., with the following results: 
Organism 1510-A produced no odor. 
Organism 1510-B produced a distinct sour-beef odor. 
Organism 1510-C produced a musty, fungous odor. 
