Listeria symptoms to be aware of as food safety experts issue warning over smoked fish

Experts have issued a warning for older people and those who are pregnant about eating smoked fish due to its listeria link.

Listeria is a type of food poisoning which is caused by bacteria from ready-to-eat smoked fish, including smoked salmon.

There have been 14 recorded cases of listeriosis since 2020, eight of them since January this year as part of an ongoing outbreak in the UK, the Food Standards Agency (FSA) said.

Ian McWatt, Food Standards Scotland (FSS) Deputy Chief Executive, said: “While the risks to the general public of becoming seriously ill due to listeria are very low, we need people who are vulnerable to be aware of the ongoing risks of consuming ready-to-eat smoked fish.

He added: “If anyone from these groups is eating ready-to-eat smoked fish, we are reminding them of the advice to ensure that it is thoroughly cooked before they eat it, including when served as part of a dish.”

Older people are especially at risk due to their weakened immune system, which could cause serious health problems including sepsis or meningitis.

Among women who are pregnant, the issue of listeria could lead to a miscarriage or stillbirth.

What is listeria?

Listeria, or Listeria monocytogenes (L. Monocytogenes), is a foodborne bacterial illness which can live in soil, water, dust, animal poop, and other substances.

The bacteria can survive and even grow under refrigeration and other food preservation measures.

“L. monocytogenes is generally transmitted when food is harvested, processed, prepared, packed, transported or stored in environments contaminated with L. Monocytogenes,” says The Food & Drug Association (FDA).

It added: “Environments can be contaminated by raw materials, water, soil, and incoming air. Pets can also spread the bacteria in the home environment if they eat food contaminated with L. Monocytogenes.”

How to properly cook fish to avoid listeria
Eight cases of listeria have been identified in England and Scotland since January 2022.

The Food Standards Agency (FSA) is responsible for food safety and food hygiene in England, Wales and Northern Ireland and are now warning those aged over 65, pregnant women or those with underlying medical conditions such as cancer to ensure they are thoroughly cooking their fish.

Cooking smoked fish until it is steaming hot should kill any dangerous bacteria, making it safe for anyone to eat, the FSA said.

“While the risks to the general public of becoming seriously ill due to listeria are very low, we need people who are vulnerable – specifically those over 65, pregnant women and people with weakened immune systems – to be aware of the ongoing risks of consuming ready to eat smoked fish,” warns Dr Caroline Handford, acting head of incidents at the FSA.

She continued: “If anyone from these groups is eating ready-to-eat smoked fish, we are reminding them of the advice to ensure that it is thoroughly cooked before they eat it including when served as part of a dish.

“People can also further reduce the risk by keeping chilled ready-to-eat smoked fish cold – 5C (41F) or below – always using products by their use-by date, following the storage instructions on the label, and cooking it until it is piping hot right through.”

What a re the symptoms of listeria?
Early signs may include:

Fever
Diarrhoea
Muscle aches
Headaches
Chills
Stiff neck
Confusion
Loss of balance
Convulsions
Listeria and meningitis link
Listeria can develop up to two months after contaminated food consumption with symptoms appearing after several days.

The bacteria are known to cause an invasive infection spreading from the intestines to the blood increasing bloodstream infection risk or even worse spreading to the central nervous system causing meningitis.

Meningitis is a serious infection of the protective membranes which surround the brain and spinal cord affecting anyone.

Professor Saheer Gharbia, a food safety specialist at the UK Health Security Agency, which was also involved in investigating the outbreak, added: “Most people won’t have any symptoms of the infection or will only experience mild symptoms such as abdominal pain or diarrhoea, which usually pass within a few days without the need for treatment.

“However, some are at higher risk of much more serious illness.”

The NHS urges people to get help from 111 if you’re pregnant and think you have listeria, have a weaker immune system, or if you’re pregnant.