Isolation and Characterization of a Bacterium Producing the Conditioned Raw Beef Aroma
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In our previous paper, a desirable odor generated in raw beef by conditioning, i. e., the conditioned raw beef aroma, was suggested to be produced by some kinds of bacteria at the site containing both leans and fats in the presence of oxygen. Thus, we isolated such a bacterium and examined some of its features. Bacterial isolates from beef loins were screened on sterile lean extract with floating sterile adipose tissue or sterile fat to obtain the bacterium producing the conditioned raw beef aroma. Of 89 isolates, one isolate (H 25W) producing this odor apparently was obtained. H 25W was gram-positive and catalase-positive, and occurred as unbranched rods in short chains. It was nonmotile and grew on the streptomycin-thallous acetate-actidione medium. These features implied that H 25W was Brochothrix thermosphacta, a very common bacterium in market meats. Some other features (oxygen-requirement, etc.) of H 25W coincided with those of Brochothrix thermosphacta. Furthermore, the type culture strain of Brochothrix thermosphacta ATCC 11509 demonstrated to have produced the conditioned raw beef aroma. Thus, H 25W which produced the conditioned raw beef aroma was strongly suggested to be Brochothrix thermosphacta.
- Nihon Chikusan Gakkaiho
Nihon Chikusan Gakkaiho 71(4), 409-415, 2000-07-25
Japanese Society of Animal Science