INCIDENCE OF CLOSTRIDIUM-BOTULINUM IN VEGETABLES PACKAGED UNDER VACUUM OR MODIFIED ATMOSPHERE

Because modified atmosphere-packaged (MAP) vegetables may provide an a naerobic environment conducive to Clostridium botulinum growth and tox in production, the incidence of C. botulinum spores in commercially av ailable, precut MAP vegetables was determined. One-pound (454-g) packa ges of MAP vegetables were aseptically opened, added to freshly steame d and cooled sterile trypticase-peptone-glucose-yeast extract broth an d incubated at 35 degrees C for 7 days. Positive and negative controls were included with each sampling. After incubation the broth cultures were tested for toxicity by the standard mouse bioassay. Of the 1,118 MAP vegetable packages examined, one package each of shredded cabbage , chopped green pepper, and Italian salad mix contained C. botulinum t ype A spores. One additional salad mix (main ingredient, escarole) con tained both C. botulinum type A and type B spores. Results indicated a low overall incidence rate (0.36%) of C. botulinum spores in commerci ally available precut MAP vegetables.