Control of nonproteolytic Clostridium botulinum types B and E in crab analogs by combinations of heat pasteurization and water phase salt.
Water phase sodium chloride (WPS) levels of 1.8 to 3.0% in combination with heat pasteurization for 15 min at temperatures of 75, 80, 85, and 90 degrees C were evaluated as methods for the inactivation or inhibition of nonproteolytic, psychrotrophic Clostridium botulinum types B and E in crab analogs (imitation crab legs) subsequently stored at 10 and 25 degrees C. Samples inoculated with 10(2) type B or E spores per g prior to pasteurization remained nontoxic for 120 days at 10 degrees C and for 15 days at 25 degrees C. With 10(4) type E spores per g and 80 degrees C pasteurization, > or = 2.4 and 2.7% WPS was required for inhibition at 10 and 25 degrees C storage, respectively. Pasteurization at 85 degrees C decreased the inhibitory level of WPS to 2.1% at 10 degrees C and to 2.4% at 25 degrees C. When the inoculum was 10(4) type B spores per g, samples with 2.7% WPS were toxic after 80 days of storage at 10 degrees C. Samples inoculated with 10(3) type B spores per g and processed at 85 degrees C remained nontoxic for 15 days at 25 degrees C with a WPS of > or = 2.4%. When pasteurization was carried out before inoculation and packaging, 1.8% WPS prevented toxin production by 10(2) and 10(4) type E spores per g for 30 days at 10 degrees C, and this time period increased as the WPS concentrations increased. Three percent WPS prevented toxin production by 10(4) type E spores per g in vacuum-packaged analogs stored 110 days at 10 degrees C. Pasteurization processes used in these experiments, however, do not inactivate the heat-resistant proteolytic types of Clostridium botulinum. Therefore, the most important factor controlling the growth of this bacterium is continuous refrigeration below 3.0 degrees C or frozen storage of the finished product.
Peterson
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US Department of Commerce, NOAA, National Marine Fisheries Service, Northwest Fisheries Science Center, Seattle, Washington 98112, USA. mark.e.peterson@noaa.gov
Paranjpye
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Poysky
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Pelroy
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Eklund
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D000818:Animals; D001905:Botulinum Toxins / Q000096:biosynthesis*; D003386:Brachyura; D003014:Clostridium botulinum / Q000187:drug effects / Q000254:growth & development*; D005396:Fish Products / Q000382:microbiology*; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D005519:Food Preservation; D006358:Hot Temperature; D012965:Sodium Chloride / Q000494:pharmacology*; D013171:Spores, Bacterial; D013997:Time Factors
D012965:Sodium Chloride; D001905:Botulinum Toxins