Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 210
Title: Distribution of Dungeness crab meat to retail stores and restaurants in hermetically sealed five pound cans and the risks of Clostridium botulinum toxin production
Author: M. W. Eklund, F. T. Poysky, G. A. Pelroy, M. E. Peterson
Publication Year: 2005
Journal: Journal of Aquatic Food Product Technology
Volume: 14
Issue: 3
Pages: 3-22
Keywords: Clostridium botulinum, type E and A, incidence, toxin production, Dungeness crab meat, spoilage
Abstract: Ready-to-eat picked meat of Dungeness crab (Cancer magister) packaged under vacuum in hermetically sealed (No. 10, five pound) cans, has become a public health concern because the product does not receive a process to inactivate Clostridium botulinum and refrigeration is the only barrier to prevent this bacterium from growing and producing neurotoxins. However, crab meat packaged in this manner has been distributed on ice to retail stores and restaurants for over 50 years without any reported illnesses from C. botulinum. Studies were therefore made to determine conditions that may have contributed to the safety of this product. C. botulinum type E was shown to be present in live Dungeness crab entering the processing facility, but was not detectable after the crabs were cooked in boiling water for ten minutes, nor in picked crab meat. Crab meat samples were inoculated with 10, 100, 1000 and 10,000 type E or type A spores/50 g, packaged in oxygen-permeable or vacuum packaged in oxygen-impermeable bags and stored at either 12¿C or 25¿C to determine whether spoilage occurred before the production of neurotoxins. Crab meat stored at 12¿C in oxygen-impermeable bags were spoiled after 3 days and remained nontoxic for 20 days even when inoculated with 10,000 type E spores. Crab meat was spoiled after 24 hr at a gross abuse temperature of 25¿C. Samples with type E spores became toxic in oxygen-impermeable bags between 6 and 13 days and only when inoculated with 10,000 spores. All samples with type A spores were nontoxic and very spoiled in oxygen-impermeable and permeable bags after 3 days at 25¿C. Type A toxin was produced between 3 and 6 days and only in samples with 1000 and 10,000 spores. The inactivation of C. botulinum type E during the cooking step and rapid spoilage has undoubtedly played an important role in the safety of crab meat. However, to assure the safety from C. botulinum, No. 10 cans of crab meat must be stored and distributed on ice or at refrigeration temperatures below 3¿C.