Listeria infections are on the rise, with about 15% of people dying from the disease in the EU.
Researchers at the DTU National Food Research Institute have proposed a new labeling system aimed at giving consumers a better chance of choosing ready-to-eat foods such as smoked salmon and spiced pork rolls without risking listeria infection.
Listeria monocytogenes accounts for approximately 32% of deaths associated with foodborne illness outbreaks in the EU. This infection poses a particular risk to pregnant women, as well as the elderly, people with underlying health conditions, and other vulnerable populations.
“A labeling system should be introduced for ready-to-eat foods that have been stabilized during production to prevent the growth of Listeria monocytogenes. This will reduce the number of people who become ill with Listeria monocytogenes infections. This label should give consumers peace of mind when eating these normally healthy fish products that are susceptible to Listeria monocytogenes,” says Martin Lage-Krach, a researcher at the DTU National Food Research Institute.
There are already products manufactured to prevent Listeria monocytogenes from growing. However, it is currently difficult for consumers to determine which products have been stabilized to prevent Listeria monocytogenes growth and are safe to eat.
The researchers are proposing a voluntary labeling system using the term “stabilization” to help consumers choose foods that minimize the risk of Listeria infection.
This label should only be used by producers who can demonstrate that Listeria monocytogenes cannot grow in their products. ”
DTU National Food Research Institute, Professor Lisbeth Truelstrup Hansen
In other words, stability means that the storage of the product must be adequate for the stated shelf life.
“The shelf life of many products is too long given the way they are made,” said Emeritus Professor Poe Dalgaard of DTU’s National Food Research Institute. “But by changing the recipe, and often with only small changes, we can make the product safe.”
A short storage period limits the growth of Listeria monocytogenes and generally reduces the risk of Listeria infection.
In the case of smoked and marinated/gravid fish, which are the cause of most listeria infections, the growth of Listeria monocytogenes in the product can be prevented, for example, by adding an imperceptible amount of vinegar during the salting process.
Another option is to sell frozen products. This can effectively prevent the growth of Listeria monocytogenes.
For other types of food, including cold cuts, heating or high-pressure processing of the product within consumer packaging may be a solution. This will kill Listeria monocytogenes if bacteria enters the product during packaging.
The approach to making a product safe depends on the type of food involved.
Traditionally, efforts to combat Listeria monocytogenes have focused on cleaning the food industry, but this alone has proven insufficient.
Researcher Martin Lage Krach said: “While cleaning at the production stage is very important in terms of preventing Listeria monocytogenes, it does not prevent more people from getting sick. We suggest a continued focus on cleaning, but at the same time an equally important new focus on producing food in such a way that Listeria monocytogenes cannot grow in ready-to-eat products.”
It is necessary to analyze the causes of the current epidemic
The researchers also suggest that products that have recently caused listeria outbreaks should be analyzed in new ways to quickly determine why Listeria monocytogenes has grown in the products.
Currently, authorities often identify the source of infection during an outbreak, but are often unable to prevent new outbreaks.
“We suggest that research should also be carried out to find out whether manufacturers are using formulations that can improve shelf life, or whether the shelf life of the product needs to be shortened, for example, to prevent new outbreaks,” says Poe-Dalgaard.
In fact, listeria outbreaks have been found to occur repeatedly and can be traced back to the same product and, in some cases, the same manufacturer. Therefore, it is important to identify what is going wrong with these specific products during manufacturing and distribution.
sauce:
Danish University of Technology
Reference magazines:
Klar, M.L.; others. (2026). The solution to the L. monocytogenes problem in the food industry is product stabilization combined with cleaning and disinfection. Current views in food science. DOI: 10.1016/j.cofs.2026.101414. https://www.sciencedirect.com/science/article/pii/S2214799326000378
