Listeria infection: symptoms and advice

Listeria can be life-threatening for certain people

Getting listeriosis is rare, but it can be life-threatening, especially for high-risk groups. Caused by the bacterium Listeria, listeriosis is most dangerous for:

pregnant people
newborns
older people, usually aged over 65
anyone with a weakened immune system.

Ask your healthcare professional if you are unsure whether you have low immunity or if you have questions.

Food safety information for high-risk groups

Having low immunity means your body can’t adequately fight off infections to prevent you developing serious diseases.

This happens when you have illnesses such as cancer, HIV/AIDS, inflammatory bowel disease, type 1 diabetes, or multiple sclerosis. As a result, people with weakened immune systems need to be more careful about what they eat.

Listeria is particularly dangerous during pregnancy because it can cause miscarriage, premature labour, stillbirth, or infection in the newborn baby. Know which foods to avoid while pregnant.

As you age, and particularly over 65, your immune system gets weaker, making it harder for you to fight off harmful foodborne bacteria like Listeria and easier to get infected. This means that foods you safely ate in the past may no longer be safe for you to eat.

Find out more

Food safety advice for people with low immunity

Food and pregnancy

Food safety advice for over-65s [PDF, 405 KB]

Food safety advice for over-65s: order print copies

Symptoms of Listeria infection

The foodborne bacterium Listeria causes the illness listeriosis.

Infection in healthy adults is unlikely to be severe. At most, it will cause mild diarrhoea and flu-like symptoms a few days after eating contaminated food.

Symptoms in pregnant people are also usually mild. They generally take 2 to 3 weeks to appear and can include fever and flu-like symptoms. However, pregnant women need to be careful because Listeria they eat can lead to miscarriage, premature labour, stillbirth, or infection in the newborn baby.

In older, perhaps frail, and immuno-compromised people, listeriosis can lead to meningitis, blood poisoning, and death. Symptoms usually take 2 to 3 weeks to appear and typically include:

fever
muscle pain
fatigue
headache
stiff neck
confusion
loss of balance
seizures.

Contact your healthcare professional straight away if you think you're infected.

How you can get sick

Most Listeria infections come from eating or drinking food that has high levels of the foodborne bacterium Listeria.

Higher-risk foods include:

ready-to-eat meat products (like deli meats and pâtés)
smoked seafood (especially cold smoked fish)
soft cheeses (like brie and camembert)
uncooked paneer cheese
unpasteurised dairy products (like raw milk and cheese)
soft serve ice-cream
some fruit (like melons)
leafy greens and bagged salad (like mesclun and spinach)
uncooked sprouts (like alfalfa and mung beans) and enoki mushrooms
uncooked frozen vegetables
some refrigerated foods with a long shelf life
ready-to-eat cooked meals.

A list of high-risk foods for Listeria and safer substitutes [PDF, 677 KB]

While Listeria can be found in the environment, it can multiply quickly once it gets into food. Unlike other harmful bacteria, it can still grow in the fridge and even at temperatures colder than 2°C.

Cross-contamination of infected food

If you're not careful, Listeria can be spread to different foods and surfaces.

For example, if you have brie cheese on a platter with bread and olives, Listeria from the cheese could spread to everything on the platter. This is called 'cross-contamination'.

To help prevent cross-contamination, separate high-risk foods from those that are low-risk or already cooked. Use different chopping boards and knives, and wash your hands.

Cross-contamination of food and how to avoid it