Rapid Perfringens Medium (RPM), Perfringens Enrichment Medium (PEM) and Tryptose Sulfite Cycloserine agar medium (TSC) were compared for determination of Clostridium perfringens in spices and herbs. Of 147 samples, 62 (42%) contained C. perfringens when RPM was used; lower percentages of positive isolations were found with PEM (23%), TSC surface plate (19%) and TSC pour plates (26%). Heat-treatment of sample suspensions yielded additional isolates. C. perfringens was isolated by one or more of the techniques from 43 (80%) of 54 different kinds of spices and herbs and from 86 (59%) of 147 samples. Replacing glucose in RPM with raffinose and polymyxin and neomycin with cycloserine did not improve the efficacy of this medium. A good correlation was found between conventional confirmation tests for C. perfringens and tests for acid phosphatase, lecithinase, reverse CAMP test and an antiserum test.
E. de Boer, E. Boot
Journal of food protection