Evaluation of Plating Media for Recovery of Heated Clostridium perfringens Spores.

Four selective and eight non-selective plating media were evaluated for their ability to enumerate six strains of heat-activated and heat-injured spores of Clostridium perfringens . Trypticase-sulfite-neomycin (TSN) agar and sulfite-polymyxin-sulfadiazine (SPS) agar gave higher counts of heat-activated spores than non-selective media. In the case of heat-injured spores, wide variation in recovery was obtained depending on strain and medium. Higher counts of heat-injured spores were obtained by incubating plates at 37°C than at 45°C, although, except for one strain, no significant difference between the two temperatures was observed using heat-activated spores.