title: Prevalence and genetic diversity of Listeria monocytogenes in vacuum-packaged ready-to-eat meat products at retail markets in Latvia.
abstract: Nine groups of different retail ready-to-eat vacuum-packaged meat products from 10 Baltic meat processing plants were analyzed for presence and numbers of Listeria monocytogenes at the end of shelf life. A total of 38 (18%) of 211 samples tested positive for L. monocytogenes serotype 1/2a (88%) or 1/2c (12%). The prevalence of L. monocytogenes in cold-smoked, sliced, vacuum-packaged beef and pork products (42%) was significantly higher than in cooked, sliced, vacuum-packaged meat products (0.8%) (P < 0.001). Enumeration of L. monocytogenes showed that 84% of the positive samples contained <100 CFU/g upon expiry of product shelf life. The numbers of L. monocytogenes exceeded 100 CFU/g only in cold-smoked, sliced, vacuum-packaged beef products. Identical pulsed-field gel electrophoresis types were recovered from different production lots of cold-smoked vacuum-packaged beef and pork products produced by the same meat processing plant, demonstrating L. monocytogenes contamination as a recurrent problem within one meat processing plant.
authors.affiliation: Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, FI-00014 Helsinki, Finland. aivars.berzins@helsinki.fi
authors.forename: Aivars
authors.initials: A
authors.lastname: Bĕrziņs
authors.forename: Margarita
authors.initials: M
authors.lastname: Terentjeva
authors.forename: Hannu
authors.initials: H
authors.lastname: Korkeala
mesh_terms: D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004269:DNA, Bacterial / Q000032:analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D005506:Food Contamination / Q000032:analysis*; D018857:Food Packaging; D005525:Food-Processing Industry / Q000592:standards*; D014644:Genetic Variation; D006801:Humans; D007844:Latvia / Q000453:epidemiology; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D008461:Meat Products / Q000382:microbiology*; D012703:Serotyping; D013045:Species Specificity; D014618:Vacuum
chemical_list: D004269:DNA, Bacterial