Whole genome sequencing has identified 12 linked cases of listeriosis since 2020, with six since January 2022. Sick people live in England and Scotland. The majority reported eating smoked fish. One pregnant woman was also affected.

Smoked fish is a chilled, ready-to-eat food product that can be already cooked so often does not require further cooking.

Change in public advice
Professor Saheer Gharbia, interim deputy director gastrointestinal infections and food safety (One Health) at UKHSA, said: “Listeria infection in most people is usually either unnoticed or may cause very mild gastrointestinal illness. However, it can have more serious consequences for some people, particularly those with pre-existing health conditions that cause weakened immunity, and people who are pregnant.”

Information for pregnant women has been updated to advise that they thoroughly cook smoked fish before eating it, even if it’s packaging says it has been cooked. Advice for avoiding listeriosis infection is being changed to include smoked fish as a high-risk product which should be thoroughly cooked before being eaten by anyone in a high risk group.

Tina Potter, FSA head of incidents, said members of the public do not need to avoid smoked fish products, but should ensure risks are reduced as far as possible.

“You can do this by keeping chilled ready-to-eat smoked fish cold at 5 degrees C (41 degrees F) or below, always using products by their use-by date, following the storage and usage instructions on the label, and cooking or reheating smoked fish until it is piping hot right through,” she said.

About Listeria infections
Food contaminated with Listeria monocytogenes may not look or smell spoiled but can still cause serious and sometimes life-threatening infections. Anyone who has developed symptoms of Listeria infection should seek medical treatment and tell their doctors about the possible Listeria exposure.

Also, anyone who has eaten any of the recalled products should monitor themselves for the food poisoning symptoms during the coming weeks because it can take up to 70 days after exposure to Listeria for symptoms of listeriosis to develop.

Symptoms of Listeria infection can include vomiting, nausea, persistent fever, muscle aches, severe headache, and neck stiffness. Specific laboratory tests are required to diagnose Listeria infections, which can mimic other illnesses.

Pregnant women, the elderly, young children, and people such as cancer patients who have weakened immune systems are particularly at risk of serious illnesses, life-threatening infections, and other complications. Although infected pregnant women may experience only mild, flu-like symptoms, their infections can lead to premature delivery, infection of the newborn, or even stillbirth.

(To sign up for a free subscription to Food Safety News, click here.)