Outgrowth and Toxin Production by Clostridium botulinum in Bottled Chopped Garlic

The ability of Clostridium botulinum types A and B spores to grow and produce toxin in commercially bottled chopped garlic in soybean oil was investigated. Eight type A and seven type B strains of C. botulinum , mostly of vegetable origin, were used as inocula. Various numbers of spores were inoculated directly into the jars containing garlic, incubated at 35°C and sampled for organoleptic acceptance and presence of toxin every 5th d. In parallel studies conducted at room temperature, jars were sampled at 15-d intervals. At 35°C, when 1 spore/g of garlic was used as inoculum, toxin was produced in 15 d by type A and in 20 d by type B strains. At room temperature, five spores of type A or B per g of garlic produced toxin throughout 75 d. Even when highly toxic, garlic looked and smelled acceptable. Five strains of C. botulinum type A were isolated from 115 bulbs of fresh garlic.