The Incidence of Listeria spp., Salmonella spp., and Clostridium botulinum in Smoked Fish and Shellfish

Abstract

The frequency of occurrence of Listeria spp., Salmonella spp., and Clostridium botulinum in samples of smoked finfish and smoked shellfish was analyzed over a 5-year period. Listeria monocytogenes was isolated from 14% of 1,080 samples. For those samples where the smoke process was known, the incidence of L. monocytogenes was higher in cold-smoked than hot-smoked products (51 of 240 cold-smoked compared to 19 of 215 hot-smoked products). Listeria species other than L. monocytogenes were also detected (in 7.2% of cold-smoked and 3.8% of hot-smoked products). The time and temperature smoke processing guidelines are reviewed for a few State authorities. L. monocytogenes was isolated from 15.2% of the 559 samples of foreign origin. There were four countries for which more than 70 samples were analyzed: Canada, Norway, the Philippines, and the United Kingdom. The occurrence of L. monocytogenes in samples from these four countries was 14.3%, 23.7%, 0%, and 16.1%, respectively. The 521 samples originating in the United States were processed by 194 plants. Thirty-seven plants in 13 States produced contaminated product. Salmonella species were isolated from 5 (3.2%) of 156 samples tested for this organism. All positive samples were of foreign origin (4 from the Philippines and 1 from the United Kingdom). No C. botulinum spores were detected in any of the 201 vacuum-packed samples tested for this organism.