Ready-to-eat foods such as fish cakes, smoked salmon, and sliced cold cuts are popular choices in busy everyday life – but they also pose a potential risk of listeria infection in individuals with weakened immune systems. Over the past 15 years, listeria infections have increased significantly across the EU, and Denmark continues to exceed the EU average, with approximately one case per 100,000 inhabitants annually. This is highlighted in the latest Zoonosis Report, which provides an overview of diseases transmitted to humans from food and animals. The report is prepared by the DTU National Food Institute in collaboration with the Danish Veterinary and Food Administration and Statens Serum Institut.
In response to the high number of listeria cases, the EU has decided to tighten regulations from 1 July 2026 regarding acceptable levels of listeria in ready-to-eat foods.
“The revised EU regulations introduce a zero-tolerance policy for listeria in food. This means that producers must ensure the absence of Listeria monocytogenes throughout the entire shelf life, unless they can document that the bacteria cannot grow to harmful levels. Both businesses and authorities will thus be better equipped to prevent future outbreaks,” says Sørine Quaade Møller, Head of Section at the Danish Veterinary and Food Administration.
DTU National Food Institute is also continuously working on developing methods to reduce the growth of listeria bacteria in food.
“We continue to see persistent occurrences of listeria in certain food products, and it is crucial that producers and the broader food supply chain take responsibility. We hope the new regulations will strengthen both prevention and response,” says Professor Lisbeth Truelstrup Hansen from DTU National Food Institute.
Fish cakes and smoked salmon remain common sources of infection during the 2022–2024 period.
“By mapping the entire genetic material, it is possible to trace the listeria bacteria from patients directly back to specific products,” says Susanne Schjørring, Head of Unit at Statens Serum Institut.
Two long-term listeria outbreaks in 2024
In 2024, two prolonged listeria outbreaks were investigated, and the bacteria were found in fish products that could be traced back to the same company. One strain of listeria was first detected at the company seven years ago.
“The fact that listeria outbreaks can repeatedly be traced back to the same companies highlights the need for improved control of listeria growth in food products,” says Professor Lisbeth Truelstrup Hansen.
In addition to maintaining high hygiene standards, companies must be able to ensure that their products are protected against listeria growth during shelf life.
“There are many ways to prevent listeria growth in food – for example, through preservation methods, shortening shelf life, or decreasing the storage temperature,” Lisbeth Truelstrup Hansen adds.
Read More
See the full report: Annual Report on Zoonoses in Denmark 2024. You can also request a copy by emailing food@food.dtu.dk.
The report is published by the DTU National Food Institute and prepared in collaboration with the Danish Veterinary and Food Administration and Statens Serum Institut. The three organisations form the Central Outbreak Management Group (COMG), which jointly investigates foodborne disease outbreaks.
Contact
Professor Lisbeth Truelstrup Hansen, DTU National Food Institute, +45 20640677, litr@food.dtu.dk
Head of Section Sørine Quaade Møller, Danish Veterinary and Food Administration, +45 72276452, squm@fvst.dk
Head of Unit Susanne Schjørring, Statens Serum Institut, +45 32688341, ssc@ssi.dk
