Alfalfa sprouts linked to large Salmonella outbreak in Norway
What it found
In a nationwide outbreak in Norway, 230 people fell ill with Salmonella infections linked to eating alfalfa sprouts.
The outbreak involved four different Salmonella types and lasted from October to December 2024.
What they found
Studies in people
Outbreak size and severity
A total of 230 cases were identified across Norway, with 33% requiring hospitalization. The median age was 48 years and 69% were female.
Sprout consumption link
Among interviewed cases, 69% reported eating sprouts. In a case-control study, cases were three times more likely to have eaten sprouts than controls.
Studies in people and animals
Genetic links to sprouts
Whole-genome sequencing found identical or closely related Salmonella strains in human cases, alfalfa sprouts, and environmental samples from the sprout producer.
Multiple Salmonella types
Four different Salmonella serovars were involved: S. Newport, S. Typhimurium, S. Kisarawe, and S. Kinondoni. This suggests multiple contamination points rather than a single event.
Other findings
Seed supplier traceback
Traceback identified seeds from an Italian supplier, previously linked to two other Salmonella outbreaks in Norway in 2024 and multiple outbreaks in the EU. The supplier reported negative Salmonella findings in their own checks.
Control measures
Products were withdrawn from the market, seeds were quarantined, and public health advisories were issued. The producer's facility was decontaminated and sampling was intensified.
What the authors conclude
“Alfalfa sprouts present a significant public health risk, particularly in Nordic countries where they are often consumed raw.”
Also in their conclusions
- They say alfalfa sprouts present a significant public health risk, particularly in Nordic countries where they are often consumed raw.
- They advise that vulnerable groups, such as children, immunocompromised individuals, and pregnant women, should avoid raw sprouts.
- They call for improved detection methods, stricter regulations, and enhanced surveillance to prevent future outbreaks.
How it was done
The authors investigated this outbreak to assess its scope, identify the source, and implement control measures to prevent further cases.
They interviewed people who got sick, ran a case-control study with 12 cases and 35 controls, analysed grocery receipts from 17 cases, and used whole-genome sequencing to compare Salmonella from human cases, food, and environmental samples. They also traced the sprouts back to a Norwegian producer and its Italian seed supplier.
What it can’t tell you
- This investigation cannot prove that alfalfa sprouts were the only source, as other foods may have contributed.
- Recall bias may have affected the results, as people may not remember whether they ate sprouts.
- Milder cases may have been missed because surveillance mainly captures severe cases.
Who paid
- Conflicts
- Declarations. Conflict of interest: The authors declare no competing interests. Ethics approval: Ethical approval was not required as outbreak investigations are covered under national legislation. Cases were asked for consent to participate at the start of the interviews. Use of artificial intelligence tools: None declared.
- Authors work at
- Norwegian Institute of Public Health, Norway; European Centre for Disease Prevention and Control, Sweden; The Norwegian Food Safety Authority, Norway
The paper
- Title
- A large outbreak of multiple Salmonella serovars linked to alfalfa sprouts in Norway, October to December 2024
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Rakover A, Ødeskaug LE, Lund H, et al (2025). A large outbreak of multiple Salmonella serovars linked to alfalfa sprouts in Norway, October to December 2024. Infection. doi:10.1007/s15010-025-02556-2Free full textPubMed 40394450DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error