The Food Standards Agency (FSA) and Food Standards Scotland (FSS) have issued advice today (27^th July 2023) that pregnant women and those with a weakened immune system should avoid eating ready-to-eat cold-smoked or cured fish, following publication of a risk assessment showing they are at higher risk of severe illness from listeriosis. Products include smoked salmon, smoked trout, and gravlax.

As the risk of serious illness from listeriosis increases with age, the FSA and FSS are also advising that older people should be aware of the risks associated with eating these products.

The FSA and FSS’s joint risk assessment, commissioned in response to an ongoing outbreak of Listeria monocytogenes linked to ready-to-eat cold smoked fish, 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. This means there is the potential for severe illness, hospitalisation, and death among higher risk groups.

Professor Robin May, FSA Chief Scientific Adviser, said: 

“Our risk assessment shows that there is still an ongoing risk to health associated with eating cold-smoked fish for specific groups of vulnerable people, including pregnant women and individuals with impaired immunity.

“In light of the risk assessment, we are advising that these consumers avoid ready-to-eat cold-smoked and cured fish products.

“If you are in the group of people more at risk of listeria infection, and you decide to consume these products, we strongly recommend that you first cook them until steaming hot all the way through. This will ensure that any listeria present in the product is killed before it is eaten.”

The FSA, FSS, and UK Health Security Agency have been investigating and taking steps to tackle an ongoing outbreak of Listeria monocytogenes linked to smoked fish since cases were first reported in 2020. There have been 19 linked cases of listeriosis dating back to 2020, and sadly four people have died.

Dr Gauri Godbole, Consultant Microbiologist at UKHSA said: 

“While smoked fish has a higher risk of carrying listeria, the overall risk to the population is very low. However, some people are more likely to get a serious infection including those who are pregnant and those with weakened immune systems. The risk also increases with age.

“Most people who are affected by listeriosis will have no symptoms or experience mild diarrhoea which subsides in a few days. Those who are more vulnerable can be at risk of severe illness such as meningitis and life-threatening sepsis. Listeriosis in pregnancy can cause very serious illness in mothers and their babies.”

The updated advice applies to pregnant women and those with weakened immune systems, such as people with certain underlying conditions for example cancer, diabetes, liver and kidney disease, or anyone taking medications which can weaken the immune system.

The level of risk will depend on whether the individual has underlying health conditions. The risk also increases with advancing age and in pregnancy.

Cold-smoked fish such as smoked salmon or trout, and cured fish such as gravlax, have not been fully cooked during the production process to kill any listeria that may be present, and therefore present a higher risk of infection.

‘Cold-smoked’ fish is normally labelled as ‘smoked’ fish on packaging. Ready-to-eat cold-smoked fish typically comes in thin slices, and it can be eaten cold. It may also be found in sushi.

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

If consumers would like to add cold-smoked fish to dishes like cooked pasta or scrambled eggs, it is important to cook it first. This is because simply warming it through while preparing a meal will not heat the fish to a high enough temperature to kill any listeria present.

Smoked fish products that have been heat-treated during production, such as tinned smoked fish, may be safely consumed without further cooking. These tinned products are heated to a high temperature during production, sufficient to kill any listeria that may be present.

Most people who are affected by listeriosis will get mild gastroenteritis which subsides in a few days. However, certain individuals are particularly at risk of severe symptoms which can include meningitis and life-threatening sepsis.  Listeriosis in pregnancy can cause miscarriages and severe sepsis or meningitis in new-born babies.

Cases of listeriosis from smoked fish remain rare overall. If you have eaten these products recently, you do not need to do anything unless you get symptoms of the infection. These include a high temperature of 38C and above, aches and pains, chills, feeling and being sick, or diarrhoea. Contact NHS 111 or your GP surgery if you are unwell and pregnant or have a weakened immune system and you think you could have listeriosis.

More information on listeria is available on the FSA’s listeria guidance page.