05 March 2026
A comprehensive study published in Poultry Science has shed new light on the prevalence and environmental drivers of Salmonella infections within Israel's egg-laying sector. Analyzing data from over 24,500 sampling events between 2018 and 2023, researchers identified critical management and environmental factors that significantly influence the risk of contamination. The study revealed a substantial presence of Salmonella in the Israeli poultry industry (commercial layers), with rates notably higher than those reported in the US and European Union.
Overall Prevalence: 42.56% of all monitored flocks tested positive for Salmonella spp. at least once during the study period. The public health-relevant serovars S. Enteritidis (SE) and S. Typhimurium (ST) were detected in 2.98% and 2.09% of flocks, respectively. The detection of these specific serovars led to the culling of approximately two million birds to protect public health.
Major Risk Factors: Through multivariable regression modeling, the researchers identified several variables that significantly increased the odds of a flock testing positive:
Bird Age: Hens older than 85 weeks were at the highest risk across all models, likely due to a waning immune response or prolonged environmental exposure.
Flock Size: Maintaining larger flocks (more than 10,000 birds) was associated with an increased risk of infection.
Housing Systems: Caged housing systems were found to pose a significantly higher risk compared to cage-free systems.
Proximity to Dairy Farms: Flocks located within 300 meters of a dairy farm showed an increased risk for any Salmonella spp.
Seasonality: The fall season was identified as a peak period for Salmonella detection in Israel. The researchers concluded that while vertical transmission (from breeders) is nearly non-existent in Israel, horizontal transmission from the environment remains the primary threat.
These findings emphasize the role of flock management and environmental context in Salmonella epidemiology, the authors noted, suggesting that these insights can be extrapolated to other regions with intensive egg production systems.
In addition to the biological and environmental factors identified in the study, several regulatory and structural aspects of the Israeli egg market impact production quality and public health. In Israel, it is mandatory to vaccinate all pullets against Salmonella Enteritidis to mitigate infection risks. The sector operates under a quota system with government-controlled egg prices, factors that have been noted to negatively affect competition and overall production quality within the table-egg industry.
Regulatory Gaps: Oversight in certain areas remains limited compared to international standards: Traceability: Unlike European standards, there is currently no comprehensive mandatory stamping policy for table eggs in Israel to ensure full transparency and traceability. Egg Washing: There is a lack of clear regulation regarding the washing of table eggs, leaving it undefined whether the practice is permitted or prohibited. Consumer Guidance: Packaging for table eggs often lacks standardized warnings or specific instructions for the correct handling of eggs.
