Prolonged cross-border multi-serovar Salmonella outbreak linked to consumption of sprouted seeds

Abstract

A cross-border multi-serovar Salmonella enterica outbreak linked to the consumption of sprouted seeds has been ongoing in Europe since 2023. Between January 2023 and January 2025, 509 confirmed cases of salmonellosis meeting the European case definition were identified in nine European Union/European Economic Area (EU/EEA) countries: Belgium (1), Denmark (4), Estonia (1), Finland (94), France (3), Germany (30), the Netherlands (9), Norway (257) and Sweden (110). One case was also reported by the United Kingdom. The outbreak encompasses eight Salmonella serotypes, several of which are rarely reported in the EU/EEA. Sprouts were identified as the vehicle of infection in multiple national investigations, which was confirmed by EU centralised whole genome sequencing (WGS) analysis.

Sharing of epidemiological, traceability, and WGS data across countries in both public health and food safety sectors, was crucial in linking seven national outbreaks in Finland, Germany, Norway and Sweden to a common seed supplier in Italy. Further food investigations linked the common supplier to three seed growers located in the same geographical area of Italy. The role of the environment in the seed contamination at grower level, and of cross-contaminations along the seed supply chain contributing to the multi-strain occurrence, should be further investigated.

Food safety authorities in the countries concerned implemented control measures, including withdrawal and recall of investigated batches. This significantly decreased case notifications. However, several countries have detected new cases, indicating that contaminated seed batches may still be in circulation and further interventions needed. Cases may continue to occur until the point(s) where the seeds were contaminated with Salmonella can be identified and properly controlled. Seed producers should apply all procedures necessary (e.g. Good Agricultural Practices (GAP)) to prevent microbial contamination of seeds intended for sprouting and sprout producers should implement adequate food safety management systems to ensure only safe products reach the market.