Smoked salmon, deli meats and other ready-to-eat refrigerated foods can feel like easy wins: convenient, protein-rich and ready when you are. But some of those foods can also create the kind of food safety risk that is hard for shoppers to see.
In a peer-reviewed opinion article published in Current Opinion in Food Science, researchers from the Technical University of Denmark’s National Food Institute argue that ready-to-eat foods need clearer labeling when they are made in ways that prevent Listeria from growing during storage. The proposal is focused on Europe, where new Listeria rules took effect July 1, but the larger issue is familiar anywhere consumers rely on refrigerated foods with long shelf lives.
Listeria is not one of the most common foodborne bacteria, but it can be one of the most serious. The infection is especially dangerous for older adults, pregnant people, people with underlying health conditions and people with weakened immune systems. According to the researchers, Listeria infections in the European Union rose from 0.40 per 100,000 people in 2010 to 0.69 per 100,000 people in 2024. The disease has a case fatality rate of 15.6%.
Ready-to-eat foods are a particular concern because they are usually eaten without another cooking step that could kill bacteria. Smoked or marinated fish, cold cuts and soft cheeses made with unpasteurized milk are among the foods linked to Listeria risk.
The researchers are not arguing that consumers should avoid smoked salmon or similar foods altogether. Instead, they say shoppers need a better way to know whether a product has been made so Listeria cannot grow during its stated shelf life.
“A labelling scheme should be introduced for ready-to-eat foods that have been stabilised during production to prevent the growth of Listeria,” said Martin Laage Kragh, a researcher at the DTU National Food Institute. “This will enable us to reduce the number of people who fall ill with Listeria infections.”
The proposed voluntary label would use the word “STABILISED” to identify products that meet that standard. In this context, a stabilized product is one with the right preservation methods and shelf life to prevent Listeria growth.
That distinction matters because food safety is not only about whether bacteria are present when a product leaves the facility. It is also about whether bacteria can grow over time while the food is refrigerated, transported, stocked and stored at home.
Unlike many foodborne germs, Listeria can grow at refrigerator temperatures. That makes shelf life, acidity, salt levels, packaging and other production choices especially important for foods that may sit in the refrigerator for days or weeks before being eaten.
“The label should only be used by producers who can demonstrate that Listeria cannot grow in their products,” said Professor Lisbeth Truelstrup Hansen from the DTU National Food Institute.
The researchers say there are several ways producers can reduce the risk. Shorter shelf lives can limit bacterial growth. For smoked and marinated fish, small formulation changes, such as adding vinegar during salting in amounts too small to taste, may help prevent Listeria from growing. Frozen products can also prevent growth. For some foods, including cold cuts, heat or high-pressure treatment after packaging may help kill bacteria if contamination occurred during production.
“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 Professor Emeritus Paw Dalgaard from the DTU National Food Institute.
The researchers also argue that cleaning and disinfection in food production remain essential, but are not enough on their own. They say outbreak investigations should look not only for where contamination happened, but also whether the product’s recipe, preservation method or shelf-life allowed Listeria to grow.
For now, people at higher risk can reduce exposure by paying close attention to use-by dates, keeping refrigerated foods cold, avoiding products that have been opened too long and following medical or public health guidance on higher-risk ready-to-eat foods.
The bigger point is that not all ready-to-eat foods carry the same level of risk, and shoppers cannot always tell the difference from the package. A clearer label could help identify products made with Listeria control in mind.
That would be especially useful for consumers who want the convenience and nutrition of ready-to-eat foods, but also need to make safer choices for themselves or someone in their household.
The authors declared no financial or professional conflicts of interest related to the research described in the article.