12 August 2026
A multi-state European investigation using whole-genome sequencing has uncovered a troubling pattern of persistent contamination in table eggs, reigniting biosafety concerns across the continent.
Between May and July 2026, health authorities in France identified four distinct clusters of Salmonella Enteritidis sequence type 11 (ST11) infections geographically dispersed across the country. All four outbreaks were linked to the consumption of homemade egg-based dishes, including mayonnaise, tiramisu, and chocolate mousse, prepared with fresh raw eggs.
Microbiological and genomic analyses of egg isolates collected directly from patients' homes yielded positive matches for S. Enteritidis ST11, directly tying the clinical cases to the suspected batches. Subsequent trace-back investigations through the European Union’s Rapid Alert System for Food and Feed (RASFF) uncovered a common origin: all implicated egg batches originated from a single major producer in Poland, specifically involving two packing centers and three laying-hen farms.
What makes this finding particularly critical for veterinary epidemiologists and food safety directors is the historical context: these exact three Polish farms were the central focal point of a massive, multi-country salmonellosis outbreak between 2016 and 2020 that affected 18 European nations.
Two distinct genomic strains of S. Enteritidis ST11 were responsible for the 2026 French outbreaks. The strain isolated from Outbreak 1 (mayonnaise) belonged to EnteroBase cluster HC5_3522, while Outbreaks 2, 3, and 4 (mousse, tiramisu, mayonnaise) shared a second strain, HC5_305390. A query across European databases revealed that the French egg isolates from Outbreak 4 matched clinical isolates from human cases in France and other EU countries, as well as non-human isolates from egg products (tiramisu) in Italy. Official sampling and internal self-monitoring protocols (own-check controls) at the Polish facilities, including boot swabs, dust, fecal samples, feed testing, and environmental swabs, consistently returned negative results for Salmonella prior to and during the outbreak timeframe. The re-emergence of multiple S. Enteritidis ST11 strains from the same production group six years after a major multi-state incident raises fundamental questions regarding poultry biosecurity and primary production surveillance. The repeated isolation of S. Enteritidis despite stringent internal hygiene, vaccination protocols (administered via drinking water at 5 days, 6 weeks, and 12 weeks), and negative environmental swabbing suggests either low-level persistent colonization within breeding pyramids or recurrent reintroduction from upstream sources.
European Food Safety Authority (EFSA), Sarno et al. (2026). Food contamination incident linked to Salmonella Enteritidis ST11 in egg-based products. EFSA Supporting Publications, 2026:EN-10303, 15 pp.
