Jw. Austin et al., GROWTH AND TOXIN PRODUCTION BY CLOSTRIDIUM-BOTULINUM ON INOCULATED FRESH-CUT PACKAGED VEGETABLES, Journal of food protection, 61(3), 1998, pp. 324-328
To determine the safety of fresh-cut vegetables packaged in modified a
tmosphere, challenge studies using both nonproteolytic and proteolytic
strains of Clostridium botulinum were performed with a variety of fre
sh-cut packaged salads and vegetables stored at different temperatures
. When vegetables were inoculated with spores of C. botulinum and incu
bated in low-O-2 atmospheres, spore germination and growth and toxin p
roduction were observed. Botulinum toxin was produced by proteolytic t
ypes A and B on onion, butternut squash, rutabaga, salad, and stir-fry
vegetables. Nonproteolytic C. botulinum produced toxin on butternut s
quash and salad. Nonproteolytic C. botulinum was capable of producing
neurotoxin at temperatures as low as 5 degrees C, whereas proteolytic
strains produced neurotoxin at 15 degrees C and higher. Although most
samples were visibly spoiled before detection of botulinum toxin, samp
les of butternut squash and onion remained acceptable after detection
of toxin. The strict maintenance of low temperatures (<5 degrees C) is
recommended in order to control the potential growth of C. botulinum
on fresh-cut vegetables packaged in a modified atmosphere.