Reducing the risk of vulnerable groups contracting listeriosis

01 August 2023

The risk assessment found that while the risk of contracting listeriosis in higher risk individuals from cold-smoked fish is low, the severity of the illness is high, with the potential for severe illness, hospitalisation, and death among higher risk groups. As a result, we are advising pregnant women and those with weakened immune systems (people with certain underlying conditions for example cancer, diabetes, liver and kidney disease), or anyone taking medications which can weaken the immune system to avoid eating ready-to-eat cold smoked or cured fish products.

As the risk of serious illness from listeriosis increases with age, older people should also be aware of the risk of eating cold-smoked and cured fish and consider taking steps to reduce listeria infection. These steps include: eating foods before the use by dates, ensuring the product is kept refrigerated (below 5°C) or using safer alternatives which we will outline on the Listeria section of our website once published.

This targeted advice recognises that most people who are affected by listeriosis will get mild gastroenteritis symptoms which subside in a few days. However, certain individuals are at higher risk of severe illness.

Cold smoked fish and alternatives

If the cold smoked fish is thoroughly cooked, it will be safe to eat, and can be served immediately, or served cold after being chilled in the fridge.

We will be advising that if people wish to add cold-smoked fish to dishes like cooked pasta or scrambled eggs, that they thoroughly cook it first. This is because simply warming it through when preparing a meal will not heat the fish to a high enough temperature to kill any listeria present.

‘Cold-smoked’ fish such as smoked salmon or trout, and cured fish such as gravlax, are not fully cooked during the production process to kill any listeria that may be present, and therefore pose a higher risk of infection. ‘Cold-smoked’ fish is normally labelled as ‘smoked’ fish on packaging or can be sold as ready-to-eat smoked salmon or trout slices for eating cold without further preparation. It may also be found in sushi.

Alternative smoked fish products may be safely consumed, including tinned smoked fish (straight from the tin), thoroughly cooked fish fillets (fresh or frozen) and cooked smoked fish (e.g. as part of a gratin). These products are heated to a high temperature either during production or cooking, killing any listeria that may be present.

If you would like to read the full report please click here, or for more information visit the FSA website.