More than 500 people have been sickened over two years in multiple European countries as part of Salmonella outbreaks linked to sprouted alfalfa seeds.
Between January 2023 and January 2025, 509 ill people were reported in 10 countries. The most affected nation was Norway, with 257 cases, followed by Sweden with 110, and Finland with 94.
Thirty people were sick in Germany, nine in the Netherlands, four in Denmark, three in France, and one person each in Belgium, Estonia, and the United Kingdom.
The majority of cases, 336, were female and adults but they range in age from 1 to 90. Information on hospitalization was available for 100 cases, the majority of which were infected with Salmonella Typhimurium sequence type 36 and Salmonella Newport ST 31. No deaths were reported.
The European Centre for Disease Prevention and Control (ECDC) said the outbreak includes eight Salmonella strains, some of which are rarely seen in Europe. Serotypes with the most cases are Salmonella Typhimurium with 246, followed by Salmonella Newport with 107, and Salmonella Enteritidis with 92. Other Salmonella types in the outbreak are Adelaide, Hvittingfoss, Richmond, Kinondoni, and Kisarawe.
Outbreaks by country
Epidemiological investigations, including whole genome sequencing analysis and food tracing, pointed to a supplier in Italy which sourced seeds from three growers in the same region.
ECDC said further investigations are needed to determine how seeds became contaminated and whether there was any cross-contamination along the supply chain.
Authorities in affected countries implemented control measures, including withdrawals and recalls of investigated batches. This significantly decreased notifications. However, several countries have detected new cases, indicating contaminated seeds may still be in circulation.
The first outbreak occurred in Germany in January 2023 caused by Salmonella Adelaide. While a source was not identified during the initial investigation, the outbreak strain was later detected in sprouted seeds. In autumn 2023, Finland reported an outbreak of Salmonella Enteritidis and the outbreak strain was isolated from products consumed by patients.
Norway has reported three outbreaks: Salmonella Typhimurium in May 2024, Salmonella Hvittingfoss in August 2024, and Salmonella Newport in October 2024. In August 2024, Sweden recorded an outbreak of Salmonella Typhimurium.
Trace back findings
Traceability investigations pointed to 10 sprout products, including two with no labeling information. In total, 13 sprout batches were identified. Seven sprout products were positive for different types of Salmonella. These Salmonella-positive products were from six producers in five countries, with seeds traced back to the same supplier in Italy with a link to another supplier. Six of the seven positive products came from three growers located in the same area of Italy.
In February 2025, local Italian authorities carried out official sampling at the seed supplier but Salmonella was not detected in five samples taken from an alfalfa seed batch. An audit was carried out by national Italian authorities in mid-February 2025 at the supplier. In October 2023, an official control at the plant did not find any non-compliances.
In early 2025, the food authority in Italy reported the identification of alfalfa sprout products positive for Salmonella. Official samples were collected in November 2024 at an Italian sprout producer. Serotyping revealed the presence of Salmonella Richmond and Salmonella Kinondoni. However, these products were not released onto the market. The sprout producer purchased the seeds used for sprouting from an Italian seed supplier. This batch contained organic seeds from another seed supplier.
“Further investigations are needed to assess the role of the environment in the seed contamination at grower level and the possible role of cross-contaminations along the seed supply chain contributing to the multi-strain occurrence. Cases may continue to occur until the point where the seeds were contaminated with Salmonella can be identified and properly controlled,” said ECDC.
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