A prolonged outbreak of Salmonella Strathcona led to 437 confirmed infections in the EU/European Economic Area (EEA) between 1 January 2023 and 30 September 2025.

Investigations by the European Centre for Disease Prevention and Control (ECDC) identified cherry tomatoes from Sicily as the most likely source. This bacterium was detected in the irrigation water at a production site in Sicily, confirming environmental contamination.

The outbreak has continued across multiple seasons and countries, indicating persistent contamination of primary production. This ongoing transmission increases the risk for repeated cross-border spread and highlights the need for stronger surveillance, sequencing of human isolates, and targeted control measures during the preharvest and harvest phases.

Tomatoes Traced as Source

According to the ECDC, 17 EU/EEA countries have reported confirmed infections since 2023, with Italy, Germany, and Austria reporting the highest numbers. Linked cases have also been reported in the UK, Canada, and the US.

Investigations in Austria in 2025 traced infections in small Sicilian tomatoes, confirming the findings of earlier studies in Italy in 2024 and Austria in 2023.

The same Salmonella Strathcona strain was involved in a 2011 outbreak in Denmark, which was also linked to tomatoes from Sicily.

The Italian Food Safety Authority conducted extensive investigations, including market sampling, targeted inspections, and environmental monitoring of the production process.

Irrigation water from a Sicilian farm tested positive for Salmonella Strathcona, supporting the view that environmental contamination played a role in the outbreak.

Persistent Contamination Challenges

According to the ECDC, continued transmission over several years suggests persistent contamination sources. To prevent further infections, additional investigations are needed to confirm whether Sicilian tomatoes are the source of new cases and to implement effective control measures during preharvest and harvest, including irrigation water monitoring.

The prolonged outbreak highlights the challenges of controlling Salmonella infections across national borders. “Persistent contamination in primary production can trigger multiyear outbreaks in several countries,” the ECDC noted. The agency called for enhanced surveillance and rapid action to prevent further cases.

Although most infections occur in Italy, Germany, and Austria, their spread to other EU countries and North America highlights the challenge of controlling food-borne diseases in the global supply chain. The ECDC recommends that member states sequence human Salmonella isolates to quickly identify epidemiologic links and trace the contaminated products.

Hygiene and Prevention Advice

Consumers are advised to maintain strict food hygiene, including thorough handwashing, careful rinsing of fresh fruits and vegetables, and avoiding cross-contamination by keeping raw and cooked foods separate from each other.

Salmonella Strathcona can cause gastrointestinal illness with symptoms such as diarrhoea, fever, and abdominal cramps. Severe infections mainly affect high-risk groups, including older adults, young children, and individuals with weakened immune systems.

For further details, refer to the ECDC’s first update on the prolonged multicountry outbreak of Salmonella Strathcona ST2559 linked to tomato consumption in the EU/EEA.

This story was translated from Univadis Germany.