Abstract:Objective The aim of this study was to determine the prevalence of Listeria species in food products in Maanshan, Anhui Province. Methods From January 2009 to December 2014, a total of 2 372 food products, including meat, poultry, fishes, shrimps, animal viscera, cooked food, vegetables, flour products, bean products, eggs, juice, dairy products and ice creams, were randomly collected from restaurants, supermarkets and retail markets in Maanshan. Listeria spp. strains were isolated according to GB 4789.30-2010 method. Furthermore, all the Listeria monocytogenes were examined for the presence of virulence genes. Results Out of 2 372 tested samples, 332 (14.00%) were contaminated with Listeria spp., of which 25.15% (82/326) were isolated from meats, 23.98% (82/342) from poultry meats, 16.20% (104/642) from fishes and shrimps, 11.66% (26/223) from animal viscera, 8.49% (31/365) from cooked food, 2.88% (4/139) from vegetables, 2.20% (2/91) from flour products and 1.33% (1/75) from bean products. There was no Listeria spp. isolated in eggs, juice, dairy products and ice creams. The highest prevalence of Listeria spp. occurred in 2009 (23.97%, 70/292), followed by 2011 (15.62%, 67/429), 2012 (15.36%, 49/319), 2014 (11.65%, 48/412), 2013 (11.11%, 47/423) and 2010 (10.26%, 51/497). The difference of the prevalence rates of Listeria for different years were statistically significant (χ2=26.80, P<0.05). Six virulence genes, including hly, prfA, plcB, inlA, actA and iap, were observed in all of the L.monocytogenes isolates. Conclusion There were different contamination levels of Listeria in different food and years in Maanshan. This study revealed the potential risk of foodborne disease outbreak caused by L.monocytogenes. Persistent surveillance on the contamination of Listeria spp. in food products should be strengthened to prevent foodborne listeriosis.
