Following the collection of food exposure information and national investigations that took place in 2023, food safety authorities in Austria, Denmark, and Italy investigated ten food products (six contaminated by S. Enteritidis ST11 cluster 1 and/or cluster 2) from seven final producers in Poland and one in Austria. Traceability information revealed that three Salmonella-contaminated kebabs shared a number of Polish food business operators. The trading link of the suspected kebab suggests one or more common point(s) of contamination in Austria, Denmark, and Italy.

Following the collection of genomic information, the cluster analysis revealed the presence of the outbreak strains in the food chain in multiple European countries. Most positive foods sampled in 2022–2023 with shared epidemiological data originated from Poland. Given the information collected, contaminated chicken kebab and chicken meat are the plausible vehicles of the human infections reported in these three clusters. However, in the absence of conclusive microbiological evidence and comprehensive traceability, the role of the identified final producers, their meat suppliers, and the possible involvement of other food business operators as sources of the infections could not be confirmed or excluded.

The 335 cases have been reported between January and October 2023, but scientists expect that new cases are likely to occur in the multi-country outbreak as the source has not yet been identified. EFSA and European Center for Disease Precention and Control (ECDC) experts recommend further investigations to identify the potential locations within the chicken meat production chain where the contamination may have occurred.