BOTULINAL TOXIN PRODUCTION IN VACUUM AND CARBON DIOXIDE PACKAGED MEAT DURING CHILLED STORAGE AT 2 AND 4C

This study was undertaken to determine if carbon dioxide packaging of meat afforded a food safety advantage over vacuum packaging with respect to botulinal toxin production during chilled storage. A cocktail of washed spores from five toxigenic clostridial strains – four reference Clostridium botulinum strains types A, B (2 strains) and E] and a C. butyricum type E strain – was inoculated onto lamb chumps. Of these strains, two were psychrotolerant. The inoculated chumps were individually carbon dioxide packaged and duplicate packs were placed into storage at 10, 8, 6, 4 and 2C. All storage regimens included a weekly defrost cycle when meat surface temperatures increased by up to 6 to 7C during a 2 to 2.5 h period. After 84 days storage, packs were assessed for the presence of botulinal toxin using the mouse bioassay procedure. All packs contained botulinal toxin. To compare toxin production in vacuum and carbon dioxide packs at chill temperatures, the challenge trials were repeated for 4 and 2C storage. Packs were examined at regular intervals for toxin presence. Both pack types contained toxin after 21 and 48 days storage at 4 and 2C, respectively. In the unlikely, but not impossible, event that raw meat would be contaminated with psychrotolerant toxincapable clostridial spores, product safety, with respect to botulinal toxin presence after prolonged chilled storage, requires storage temperatures to be maintained below 2C for both vacuum and carbon dioxide packaged product.