Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 2/10/2008
Publication Date: 8/4/2008
Citation: Pagadala, S., Parveen, S., Rippen, T., Tamplin, M.L., Luchansky, J.B., Porto Fett, A.C., Wiedman, M. Isolation and Characterization of Listeria monocytogenes from Blue Crab Meat (Callinectus sapidus) and Blue Crab Processing Plants. Meeting Abstract. P5-63 DSC. page 173. Interpretive Summary:
Technical Abstract: Listeria monocytogenes is a Gram positive, intracellular food borne pathogen which causes a severe disease called listeriosis in high risk groups. However, there is limited information about the prevalence and sources of L. monocytogenes in blue crab and blue crab processing plants in Maryland. The purpose of this study was to address this data gap. For this study, samples were collected from seven processing plants in Maryland from May through November 2006. A total of 272 raw crabs,344 finished product samples, and 344 environmental sponge samples were analyzed by the US Food and Drug Administration bacteriological analytical method. Presumptive L. monocytogenes was confirmed by the BAX Polymerase Chain Reaction and API Listeria Kit. L. monocytogenes was isolated from 6.3% of raw crabs, 0.3% of finished products and 3.5% of environmental samples. Among the environmental sites, the most contaminated were raw crab coolers (11.6%) and receiving docks (6.8%). To track the origin and spread of L. monocytogenes, one isolate from each positive sample was subtyped by Ribotyping and Pulsed-Field Gel Electrophoresis (PFGE). Automated EcoRI Ribotyping differentiated 7 ribotypes among the 30 L. monocytogenes isolates. For each of the four plants with L. monocytogenes positive environmental samples, one or two ribotypes appeared to persist in the plant environment during the study period. In one plant, a specific ribotype persisted in raw crab and in an environmental site, and may also be responsible for contamination of one of the finished products. Twenty six different pulsotypes were recovered from among the 30 L. monocytogenes isolates. Fifteen and 11 pulsotypes were recovered from raw crabs and environmental samples, respectively. Indistinguishable pulsotypes were observed both in raw crabs and in several environmental sites. These results indicate that raw crabs are an important initial source of L. monocytogenes contamination in blue crab processing plants.