Non-typhoidal Salmonella contamination of food sources from animal origin in Israel between 2007 and 2021

Non-typhoidal Salmonella (NTS) are one of the main causes of food poisoning, a major global threat for human health. Consumption of contaminated food products of animal origin contributes to majority of the NTS illness outbreaks. Poultry, an important protein source, is considered the main animal source for NTS. However, contamination with different serotypes of NTS may be attributed to various animal hosts. We aimed to determine the prevalence, trends, and potential risk factors for NTS contamination of food sources in Israel. A dataset including 192,340 test results for the detection of NTS contamination in food products in Israel between 2007 and 2021 was analyzed. Food samples were collected as part of routine testing and targeted programs for NTS detection from different facilities, such as food factories and slaughterhouses. The collected food samples included: non-thermally treated (raw) and mainly thermally treated ready-to-eat (RTE) products. Data were summarized and associations between NTS detection and different covariates were estimated using either: (i) Poisson regression model; or (ii) chi 2-tests. The odds ratio (OR) or prevalence ratio and 95 % confidence intervals (CI95 %) were calculated. The number of food products tested for NTS identification and further serotype classification has declined in recent years. However, the percentage of NTS positive results increased over time, reaching 18.11 % positive samples by 2021. The risk for NTS contamination was significantly higher in raw vs. RTE products: OR (CI95 %) = 290.60 (239.39-352.76), p < 0.001. The percentage of samples found positive for NTS in RTE products varied between sources, yet remained below 0.49 % for each source. However, in raw products, the NTS prevalence ranged between 1.05 % and 35.03 %, with food products from the chicken source significantly more positively associated with NTS contamination in comparison beef, fish, pig and turkey sources. Imported food, and slaughterhouses had a significantly higher prevalence of NTS contamination compare to factories food hygiene testing. With certain facilities, within each category, demonstrating significantly higher contamination compared to others. Moreover, the ten most common serotypes reported in human infections throughout this period were mostly found in chicken and turkey sources. The identification of certain sources and facilities/importers/slaughterhouses which may pose higher risk for NTS contamination was possible despite the declining resources invested in sampling and classification of NTS isolates in recent years. Therefore, our study further emphasizes the potential and importance of establishing a real-time surveillance for better tracing of NTS contaminations in food sources to protect public health.