Abstract
In our laboratory, a simple method is used for adding agar to thioglycolate medium (Eiken) as a culture medium for the detection of the Clostridium and the spore number assay. However, the method appears to be inconsistent, resulting in inaccurate spore counts. The clostridia assay (the official method) and a substitution method are described in the manual, “Microorganism Test Methods in Food” (K. MISE and F. INOUE, ed.). In the official method, the anaerobic pouch is impractical for examining a lot of tested samples at one time. In the substitution method, it is necessary to add 15 ml of culture medium after pouring 10ml of well emulsified sample solution in petri dish. In this method, however, there is a hazard that the culture media will rapidly cool and partially solidify before mixing. Therefore, we changed the mixing ratio of the sample solution and the culture media in the official method, and examined the effectiveness of this modified method . We found that this modified method gave satisfactory results, and report our results herein.
