Contamination status and characteristics of food-borne pathogenic bacteria in retail meat products in Taiyuan

Objective To investigate the contamination status of Salmonella, Vibrio parahaemolyticus and Staphylococcus aureus and bacterial resistance in retail meat products in Taiyuan, Shanxi Province. Methods In the epidemic season of diarrhea in 2017, poultry and meat product specimens were randomly collected from the farmer′s markets and supermarkets of 10 districts and counties of Taiyuan. Salmonella, Vibrio parahaemolyticus and Staphylococcus aureus were isolated form these specimens. Serotypes of Salmonella strains were analyzed. ELSIA was used to detect Staphylococcus aureus enterotoxin (A-E). Vibrio parahaemolyticus isolates were tested for the virulence genes encoding direct hemolysin (tdh) and indirect hemolysin (trh). Antibiotic resistance of the three food-borne pathogens were analyzed using microdilution methods. Results A total of 38 food-borne pathogens were isolated from 123 poultry and livestock meat product specimens with a positive rate of 30.9%, of which mainly were Salmonella (26 strains, 21.1%), followed by Vibrio parahaemolyticus (8 strains, 6.5%) and Staphylococcus aureus (4 strains, 3.3%). The 26 strains of Salmonella belonged to 10 serotypes. The Salmonella strains isolated from pork specimens had diverse serotypes. Salmonella serovar Derby, Salmonella serovar Gold-coast and Salmonella serovar Liverpool were isolated from raw and cooked pork food for the first time in Taiyuan. All Salmonella strains isolated form chicken products were Salmonella enteritis. The enterotoxin types of the four Staphylococcus aureus strains were three E-type and one complex type (A/E). All Vibrio parahaemolyticus isolates were negative for tdh or trh gene. Ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracyclines (ACSSuT) resistance was prevalent in multi-drug resistant (MDR) Salmonella strains, but there was high sensitivity to fluoroquinolones and cephalosporins. MDR Staphylococcus aureus accounted for 75%. No third-generation cephalosporin- or fluoroquinolone-resistant or MDR Vibrio parahaemolyticus strains were isolated. Conclusions There were food-borne multi-pathogenic bacteria contamination in retail raw and cooked meat products in Taiyuan. Salmonella strains had diverse serotypes and high MDR rate. It was suggested that the regulatory authorities should strengthen the management of antibiotic use in aquaculture and specialized laboratory-based monitoring of meat supply chain. Key words: Meat products; Food-borne pathogenic bacteria; Contamination; Multi-drug resistance