SFP was tested since is commercially available and quite often used. OPSP was selected for its dissimilar composition compared to IS, and DCA was chosen since it is a relatively new and unknown medium. TSN and SPS were not
selected since they mainly differ in the type of antibiotic(s) used compared to TSC and SFP (Table 1).
Furthermore, SPS is known for the frequent failure of C. perfringens to form black colonies and its lack of selectivity (Harmon, 1976; Shahidi and Ferguson, 1971), and TSN is inhibitory to some strains of C.perfringens (Handford and Cavett, 1973; Handford etal., 1971). DCA and IS are not selective for C.perfringens but are used for sulfite-reducing bacteriain general.