Study on food contamination with L. monocytogenes and their drug resistance in Jiangmen City Center

Objective This study was conducted to understand the status of food contamination with L. monocytogenes and their drug resistance in Jiangmen City Center. Methods The national standard detection methods were used with reference to the handbook on the national detection of food-borne diseases for the detection. 9 kinds of foods including non-standardized packaged cooked meat, raw meat, raw milk, aquatic products, ice cream and raw edible vegetables, etc. were collected from trade markets, supermarkets and individual sales stands of cooked food for L. monocytogenes and drug resistance tests were conducted for the isolated bacteria. Results 40 strains were isolated from 550 samples of 9 kinds of foods with an average positive rate of 7.27%. The positive rate of L. monocytogenes was the highest(14.81%) in non-standardized packaged cooked meat, with the rate in raw chicken, raw pork, raw mutton and raw beef being 13.33 %, 8.33%, 6.00% and 3.64% respectively, and in aquatic products and raw edible vegetables 2.00% and 1.40%. No L. monocytogenes were isolated from raw milk and ice cream. Sensitivity tests showed that the bacteria were resistant to 12 of the 20 antibiotics to a different degree. Conclusion There is a potential risk for L.M poisoning from the 9 kinds of foods in Jiangmen City Center. Management of food hygiene, especially the non-standardized packaged cooked and raw meat should be strengthened. It's necessary to control the addition of antibiotics to animal feedstaffs with strict observation of withdrawal time.