Outgrowth of Clostridium botulinum in Shredded Cabbage at Room Temperature Under a Modified Atmosphere

The ability of Clostridium botulinum types A and B spores to grow and produce toxin in shredded cabbage at room temperature under a modified atmosphere was investigated. Seven type A and seven type B strains of C. botulinum , mostly of vegetable origin, were used as inocula. Shredded cabbage in high barrier bags, 250 g/bag, was inoculated with various numbers of spores, sealed under a modified atmosphere of 70% CO₂ and 30% N₂ and incubated at room temperature. Duplicate bags were examined for organoleptic acceptability and the presence of toxin from day 3 by blending the entire contents of each bag and injecting mice with dilutions of the extracts. Toxic extracts were typed with appropriate antitoxins. Only type A spores grew and produced toxin in the cabbage. An inoculum of approximately 100-200 type A spores/g of cabbage, whether in single strains or in various combinations, produced toxin on days 4, 5, and 6, while the cabbage was still organoleptically acceptable, as determined by appearance, odor, and texture.