Clostridium botulinum toxin formation in romaine lettuce and shredded cabbage: Effect of storage and packaging conditions

Abstract

The potential for growth and toxin production by Clostridium botulinum spores was investigated in samples of fresh-cut romaine lettuce and shredded cabbage packaged in vented and nonvented flexible pouches at storage temperatures of 4.4, 12.7, and 21 °C for up to 28 days. One hundred grams of cut, washed romaine lettuce and cabbage were placed in polyester bags. Approximately 104 heat-shocked spores were added per package. Before sealing, half the packages were vented. No toxin was detected with either storage method at 4.4 and 12.7°C. In nonvented pouches of romaine lettuce at 21°C, spores grew and produced toxin after 14 days. Romaine samples at 21°C in vented pouches became toxic after 21 days, indicating formation of anaerobic microenvironments within the pouches. In nonvented packages of cabbage at 21°C, toxin was detected after 7 days. All toxin-positive samples were judged to be inedible prior to toxin detection. Copyright © International Association of Milk, Food and Environmental Sanitarians.