Danish Researchers Propose Voluntary Labeling Scheme for Listeria-Stabilized RTE Foods
In a new paper published in Current Opinion in Food Science, researchers from the Technical University of Denmark National Food Institute (DTU-NFI) proposed a voluntary labeling scheme for ready-to-eat (RTE) foods designed to help consumers identify products in which Listeria monocytogenes growth is inhibited, with the goal of reducing listeriosis cases.
The researchers suggested that manufacturers be allowed to use the label claim "STABILIZED" on RTE products if they can demonstrate that L. monocytogenes cannot grow in the product throughout its stated shelf life. The researchers believe such a label would help consumers identify products with a lower risk of transmitting listeriosis, which is especially important information for vulnerable populations.
“The label should only be used by producers who can demonstrate that Listeria cannot grow in their products,” said Lisbeth Truelstrup Hansen, Ph.D., author on the paper and DTU-NFI Professor of Microbiology and Hygiene.
European Food Businesses Face Stricter Listeria Standards for RTE Foods
The proposal comes as new EU requirements took effect on July 1, 2026, which extend the responsibility for ensuring that RTE foods placed on the market will not support the growth of L. monocytogenes above 100 colony forming units (CFU/g) throughout their shelf life from just the original food manufacturer to food business operators across the supply chain.
Additionally, under the regulations, if manufacturers cannot validate that an RTE food will not support the growth of L. monocytogenes above the threshold, the pathogen must be absent from a 25-gram sample before the product is placed on the market.
Addressing Rising Listeriosis Rates Across EU
The incidence of listeriosis in the EU increased from 0.40 cases per 100,000 people in 2010 to 0.69 cases per 100,000 in 2024, according to DTU-NTI. The disease has an estimated case fatality rate of 15.6 percent and is most commonly associated with RTE foods, including smoked fish, deli meats, and soft cheeses made from unpasteurized milk.
DTU-NFI researcher Martin Laage Kragh, M.Sc., the paper’s first author, explained that the proposed label scheme would help reduce the number of listeriosis infections while allowing vulnerable population groups, such as older adults, to confidently eat RTE foods that, aside from being prone to L. monocytogenes contamination, are otherwise healthy and nutritious (e.g., smoked fish).
Looking for quick answers on food safety topics?
Try Ask FSM, our new smart AI search tool.
Ask FSM →
Protecting Against Listeria Growth Through Formulation, Processing
The researchers argued that cleaning and sanitation remain essential to Listeria control in food production environments, but these practices alone have not been sufficient to reverse increasing listeriosis rates. The researchers advocated for combining existing hygiene measures with product stabilization strategies to prevent L. monocytogenes from growing if contamination occurs.
Products can be stabilized through formulation or processing changes that inhibit Listeria growth. Examples include adding small amounts of vinegar during the salting of smoked or marinated fish, reducing product shelf life, freezing products, or applying heat or high-pressure processing to packaged foods. The appropriate approach depends on the food category.
“Many products have a shelf life that is too long given the way they are made. But by changing the recipe—and often this requires only a small change—the products can be made safe,” said study author and DTU National Food Institute Professor Emeritus Paw Dalgaard, Ph.D.
Considering Product Formulation in Outbreak Investigations
The authors also recommended expanding outbreak investigations beyond identifying the contamination source to evaluate whether product formulation, preservation methods, or shelf-life practices contributed to pathogen growth. They suggested that identifying these factors could help prevent recurring outbreaks associated with the same products or manufacturers.
