Repeated European Salmonella Outbreaks Traced to Polish Egg Firm
The European Food Safety Authority (EFSA) has published a technical report on four Salmonella Enteritidis ST11 outbreaks identified in France between May and July 2026, which were linked to homemade egg-based foods and traced to a common egg distribution network in Poland.
Epidemiological and microbiological investigations identified homemade mayonnaise, chocolate mousse, and tiramisu as vehicles of infection. Five S. Enteritidis ST11 isolates recovered from eggs and egg-based products at patients’ homes belonged to two distinct strains and matched the representative human strains from the four outbreaks.
Traceability investigations linked the eggs implicated in all four outbreaks to two packing centers and three laying-hen farms belonging to the same food group in Poland. The three farms had previously been implicated in a multinational, polyclonal salmonellosis outbreak associated with contaminated eggs that affected 18 European countries between 2016 and 2020. However, EFSA found no genomic link between isolates from the earlier outbreak and those collected in France in 2026.
WGS Suggests Possible Genetic Relatedness
As part of its investigation, EFSA analyzed whole genome sequencing (WGS) data for S. Enteritidis ST11 isolates. A total of 14 genomic profiles submitted in response to an EFSA data call were used to query EFSA and European Center for Disease Prevention and Control (ECDC) databases, using a threshold of five allelic differences.
When the analysis was restricted to 2026 data, two clusters contained both human and non-human profiles. One included isolates from eggs associated with the fourth French outbreak, five isolates from tiramisu sampled in Italy, and three human profiles, including one from France and two from other countries. Another cluster contained two Austrian isolates from liquid egg products and one human profile from another country.
EFSA cautioned that the limited genomic diversity of S. Enteritidis ST11 means genetically similar isolates can occur in epidemiologically unrelated contexts. Therefore, WGS findings indicate possible genetic relatedness rather than direct evidence of a recent common source.
EFSA Calls for Further Investigation of Egg Producer
EFSA said the repeated detection of Salmonella in egg products traced to the Polish production group suggested persistent contamination or possible reintroduction upstream in the egg production chain. The agency called for further investigation into potential sources of vertical and/or horizontal egg contamination.
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EFSA also said the identification of a human and non-human cluster spanning France and other countries suggested a possible cross-border dimension to the incident.
Food safety authorities were encouraged to submit relevant S. Enteritidis ST11 food and environmental sequences to the EFSA WGS system, share associated traceability information through the Rapid Alert System for Food and Feed (RASFF), and coordinate with public health authorities when related human infections are identified.
