Submitted to: Food Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/29/2012
Publication Date: 4/7/2012
Citation: Pagadala, S., Parveen, S., Rippen, T., Luchansky, J.B., Porto Fett, A.C., Bowers, J., Tamplin, M.L., Wiedmann, M., Call, J.E. 2012. Prevalence and sources of Listeria monocytogenes in blue crab (Callinectus sapidus) meat and blue crab processing plants. Food Microbiology. 31:263-270. Interpretive Summary: Information on the prevalence of Listeria species in crab processing plants is minimal, especially for L. monocytogenes, a foodborne pathogen isolated from many foods and food processing environments. This lack of information about prevalence and sources of L. monocytogenes in ready-to-eat (RTE) products including crab meat makes it difficult to design effective science-based intervention technologies and to conduct risk assessment to reduce human exposure to this pathogen. In addition, little information is available about the application of molecular methods for tracking the sources of L. monocytogenes in crab meat and crab processing plants. Thus, we determined the prevalence of Listeria spp. and L. monocytogenes in blue crab meat and crab processing plants and identified the contamination sources for L. monocytogenes isolated therefrom based on their phenotypes and genotypes. Our findings established that the prevalence of Listeria species and L. monocytogenes in raw crabs, crab meat, and crab processing plant environments ranged from 0.2% to 69.5%. In addition, our results also demonstrated that molecular methods can provide critical information for understanding L. monocytogenes persistence in the blue crab processing industry. These findings will be useful to develop and evaluate effective interventions for L. monocytogenes and to enhance the safety of the crab processing industry.
Technical Abstract: Seven blue crab processing plants were sampled to determine the prevalence and sources of Listeria spp. and L. monocytogenes for two years (2006-2007). A total of 488 raw crab, 624 crab meat, and 624 environmental samples were tested by molecular and culture-based standard methods. Presumptive Listeria spp. were isolated from 19.5% of raw crabs, 10.8% of crab meat, and 69.5 % of environmental samples. L. monoctyogenes was isolated from 4.5% of raw crabs, 0.2% of crab meat and 2.1% of environmental samples. Ninety-seven percent of the isolates were resistant to at least one antimicrobial agents tested. Eight different serotypes were found among the 76 L. monocytogenes isolates, with the most common being 4b, 1/2b and 1/2a. Automated EcoRI ribotyping differentiated 11 ribotypes among the 106 L. monocytogenes isolates. For each of the six plants testing positive for L. monocytogenes, two or three ribotypes persisted in the plant environment during the study period. A total of 92 ApaI and 88 AscI pulsotypes were found, and distinct pulsotypes were observed in raw crabs and environmental samples. Our findings suggest that use of molecular methods can provide critical information about the sources of L. monocytogenes in a food processing plant, and such information can assist in the implementation of improved control strategies.