Contamination Status and Serotypes Distribution of Salmonella in Food in Yantai City, China: A 14-Year Continuous Monitoring Study.

Salmonella is a foodborne zoonotic pathogen that threatens food safety and public health. However, few people have conducted long-term and systematic studies on Salmonella contamination in food in Yantai City. In order to investigate the situation of Salmonella contamination in food and improve the ability of early warning and control of foodborne diseases, a total of 3420 samples from 20 categories were collected from 13 monitoring points in Yantai City, from 2010 to 2023. The difference in detection rate and bacterial strain of different monitoring points, different types, and different sources of samples was compared. Of the 3420 samples, 80 were positive with a detection rate of 2.34%. Salmonella detection rates were significantly different for samples collected at different monitoring sites. Salmonella was detected only in meat and meat products and catering food, and none of the other types were detected. The detection rate of Salmonella was higher in raw animal meat and raw poultry. Samples collected at the market stage had the highest detection rate (5.81%), and there was a significant difference in detection rate between samples from different sources (χ² = 36.93, p < 0.05). Eighty-one strains of Salmonella were detected out of 3420 samples (2 different strains were detected in 1 positive sample). The serological test identified 8 groups and 27 serotypes. The dominant serum groups were group B 30.86% (25/81), group E1 23.46% (19/81), and group D 16.05% (13/81). The main dominant serotypes were Salmonella give 17.28% (14/81), Salmonella enteritidis 16.05% (13/81), and Salmonella derby 13.58% (11/81). Meat and meat products and catering food were the main food products contaminated with Salmonella. The resulting secondary contamination is the hidden threat of foodborne diseases and should be given sufficient attention.