Evaluation of unacidified products bottled in oil for outgrowth and toxin production by Clostridium botulinum

A variety of unacidified products bottled in oil or water were investigated for their ability to support growth and toxin production by Clostridium botulinum. The products were inoculated with a mixture of five strains of C. botulinum type A spores (about 50 spores/g or ml) and incubated at room temperature (23°C). At monthly intervals the organoleptic acceptability of the products, as determined by appearance, odor, and texture, was evaluated and a portion of each sample was removed, diluted 1:2 in gel-phosphate buffer, and injected intraperitoneally into mice. At the end of 4 months the drained solids of each sample were macerated with a minimal amount of buffer and centrifuged; the clear extracts were then injected into mice. None of the products tested supported growth and toxin production by C. botulinum.