title: Diversity and distribution of Listeria monocytogenes in meat processing plants.
abstract: Listeria monocytogenes is a major concern for the meat processing industry because many listeriosis outbreaks have been linked to meat product consumption. The aim of this study was to elucidate L. monocytogenes diversity and distribution across different Spanish meat processing plants. L. monocytogenes isolates (N = 106) collected from food contact surfaces of meat processing plants and meat products were serotyped and then characterised by multilocus sequence typing (MLST). The isolates were serotyped as 1/2a (36.8%), 1/2c (34%), 1/2b (17.9%) and 4b (11.3%). MLST identified ST9 as the most predominant allelic profile (33% of isolates) followed by ST121 (16%), both of which were detected from several processing plants and meat products sampled in different years, suggesting that those STs are highly adapted to the meat processing environment. Food contact surfaces during processing were established as an important source of L. monocytogenes in meat products because the same STs were obtained in isolates recovered from surfaces and products. L. monocytogenes was recovered after cleaning and disinfection procedures in two processing plants, highlighting the importance of thorough cleaning and disinfection procedures. Epidemic clone (EC) marker ECI was identified in 8.5%, ECIII was identified in 2.8%, and ECV was identified in 7.5% of the 106 isolates. Furthermore, a selection of presumably unrelated ST9 isolates was analysed by multi-virulence-locus sequence typing (MVLST). Most ST9 isolates had the same virulence type (VT11), confirming the clonal origin of ST9 isolates; however, one ST9 isolate was assigned to a new VT (VT95). Consequently, MLST is a reliable tool for identification of contamination routes and niches in processing plants, and MVLST clearly differentiates EC strains, which both contribute to the improvement of L. monocytogenes control programs in the meat industry.
authors.affiliation: IRTA, Food Safety Program, Finca Camps i Armet, 17121 Monells, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Martín
authors.affiliation: IRTA, Food Safety Program, Finca Camps i Armet, 17121 Monells, Spain.
authors.forename: Adriana
authors.initials: A
authors.lastname: Perich
authors.affiliation: Department of Animal Production and Food Science, Veterinary Faculty, University of Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: Gómez
authors.affiliation: Department of Animal Production and Food Science, Veterinary Faculty, University of Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Yangüela
authors.affiliation: Food Hygiene and Safety, Faculty of Veterinary Science, University of Extremadura, Avda. de la Universidad, s/n, 10003 Caceres, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Rodríguez
authors.affiliation: IRTA, Food Safety Program, Finca Camps i Armet, 17121 Monells, Spain.
authors.forename: Margarita
authors.initials: M
authors.lastname: Garriga
authors.affiliation: IRTA, Food Safety Program, Finca Camps i Armet, 17121 Monells, Spain. Electronic address: teresa.aymerich@irta.cat.
authors.forename: Teresa
authors.initials: T
authors.lastname: Aymerich
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques; D044822:Biodiversity; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling / Q000295:instrumentation*; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D008460:Meat / Q000382:microbiology*; D013030:Spain
keywords: Contamination; Listeria monocytogenes; MLST; MVLST; Meat processing plant