The European Food Safety Authority (EFSA) and the European Center for Disease Prevention and Control (ECDC) recently published a summary of a joint investigation of a multi-country foodborne illness outbreak of Salmonella Seftenberg that was possibly linked to cherry-like tomatoes. Genetic similarity of the human outbreak strains discerned by whole genome sequencing (WGS) analysis suggests that a common source—cherry tomatoes—caused illnesses across 11 EU/European Economic Area (EEA) countries, the UK, and the U.S. over a period of ten months.
Specifically, 92 cases of S. Seftenberg ST14 that were reported Between August 2022 and July 2023 are considered part of the outbreak, including five in Austria, four in Belgium, four in Czechia, one in Estonia, 12 in Finland, 16 in France, 26 in Germany, one in Ireland, five in the Netherlands, one in Norway, 11 in Sweden, four in the UK, and two in the U.S. The first case was reported in France and was isolated on August 22, 2022, and the most recent case was reported on June 24, 2023 in Sweden. The majority of cases were reported between October 2022 and March 2023.
A single patient has died as a result of the outbreak.
Patient interviews conducted in France, Germany, and Austria as part of the outbreak investigation pointed to cherry-like tomatoes as their likely source of exposure to Salmonella. The outbreak strain was detected in France from a mixed salad dish containing cherry tomatoes and green leafy vegetables. Tomatoes from the salad in France and tomatoes in Austria were suspected as the vehicle of infections by national authorities and were traced back to wholesalers in Germany, the Netherlands, and Spain, and to growers in the Netherlands, Spain, and Morocco. However, in the absence of microbiological evidence from the tomatoes, the source of the infections could not be confirmed.
As the number of cases associated with the outbreak has declined since December 2022, the risk of new infections has decreased to a low level.
According to the ECDC/EFSA report, S. Seftenberg is not an overly common serotype associated with human cases of salmonellosis. Between 2007 and 2021, a total of 2,174 human cases of S. Senftenberg were reported to ECDC, ranking the serotype 48th most prevalent out of 1,210 serotypes, with an average annual number of cases of 145 during the same period. In 2020 and 2021 respectively, 36 and 75 cases of S. Seftenberg were reported to ECDC.