Enumeration of Clostridium botulinum spores in meats by a pour-plate procedure.

Colonies of Clostridium botulinum could be easily distinguished from meat particles by supplementing Wynne agar with 0.4% egg yolk. The pour-plate method was suitable for enumeration of C. botulinum, provided the medium was covered with a layer of agar containing 0.01% dithiothreitol. Viable counts of heat-treated spores were consistently higher in Wynne agar supplemented with egg yolk (Wynne-EY agar) than in Wynne agar alone.