Eleven countries, including the United States, have recorded almost 150 Salmonella infections that could be linked to tomatoes.

Since January 2023, 149 cases of Salmonella Strathcona have been reported. Germany has the most patients, with 47, while Italy has 34. Most people fell sick between August and October.

The U.S. has eight cases. Six interviewed sick people had been to Spain, Italy, Croatia, France, and Slovenia. Four patients reported travel to Italy.

Austria has 17 cases, the Czech Republic and the United Kingdom have 13, and France has nine. Other affected countries are Finland, Denmark, Luxembourg, and Norway.

Different age groups are affected with no significant difference between genders.

Interviews of 52 cases revealed 32 reported consumption of fresh tomatoes before disease onset. In addition, 25 had consumed eggs, and 24 reported eating cheese.

A teleconference occurred earlier this month with experts in EU countries, the UK, and the United States to discuss the ongoing investigations.

A re-occurring seasonal incident, Salmonella Strathcona is a rare serotype in Europe. In 2022, 89 cases were recorded. An increase was seen between 2018 and 2019 when 28 and 98 cases were reported.

Denmark investigated a multi-country outbreak of Salmonella Strathcona in 2011, wher datterino tomatoes from an Italian producer were suspected of being the vehicle of infection. In total, 43 cases were reported in Denmark and 28 from Germany, Italy, Austria, and Belgium.

Since then, outbreaks have occurred in Denmark and Germany in 2019 and 2020.

The 2023 outbreak has isolates that are genetically closely related to cases reported since 2011, indicating a common infection source.

The European Centre for Disease Prevention and Control (ECDC) said the incident appears to be a re-emerging, seasonal outbreak.

“Microbiological evidence indicates a common source. Epidemiological and microbiological data indicate that the most plausible hypothesis of the vehicle of infection could be tomatoes, but this hypothesis needs further investigation.

“The risk for new infections remains as long as the seasonal deliveries of contaminated produce continue. New outbreaks will likely occur in future seasons until the contaminated vehicle has been identified, traced back and control measures implemented.”