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Listeria

What you can do to reduce the chances of your food being infected with listeria.

Last updated: 4 April 2022

Listeria monocytogenes (listeria) is a bacterium that causes an illness called listeriosis. Cases of foodborne illness from listeria are rare but can involve serious symptoms in certain groups of people. These include:

  • people who are pregnant
  • newborn babies
  • people aged 65 or over
  • people with a condition that weakens their immune system, such as cancer or kidney disease
  • people having treatment that weakens their immune system, such as chemotherapy or steroid tablets

The types of food listeria can be found in

Listeria is widespread in the environment and can contaminate a wide range of foods. It is of most concern in chilled ready-to-eat foods that do not require further cooking or reheating, such as:

  • cooked sliced meats
  • cured meats
  • smoked fish
  • cooked shellfish
  • blue-veined and mould-ripened soft cheeses, like camembert and brie
  • pâté
  • pre-prepared sandwiches and salads
  • Some cut fruits, including melon
  • unpasteurised milk
  • dairy products made from unpasteurised milk
Important

Due to a listeria outbreak linked to smoked fish, people at higher risk of serious infection should only eat smoked fish products that have been thoroughly cooked.

When cooking smoked fish products at home, make sure they are steaming hot all the way through.

What you can do to avoid listeria

To reduce the risk of listeriosis when preparing food at home, it’s important to:

  • wash your hands regularly with soap and water
  • wash fruit and vegetables before eating them
  • store ready-to-eat foods as recommended by the manufacturer keep chilled ready-to-eat foods cold - make sure your fridge is working properly and is set to 5°C or below
  • keep raw and ready-to-eat foods separate to avoid cross-contamination
  • always use foods by their use-by date
  • do not eat, cook or freeze your food after the use-by date. The food could be unsafe to eat or drink, even if it has been stored correctly and looks and smells fine 
  • follow the storage instructions on the label and use opened foods within two days unless instructions on the packaging say otherwise 
  • ready-to-eat food must be eaten within four hours of being taken out of the fridge 
  • cook or reheat foods until they are piping hot right through
FSA Explains

Foodborne bacteria

Foodborne bacteria live in the gut of many farm animals. During rearing, slaughter and processing it can be transferred into:

  • meat
  • eggs
  • poultry
  • milk

Other foods like green vegetables, fruit and shellfish can become contaminated through contact with animal and human faeces. For example, from manure used to improve soil fertility or sewage in water.

Foodborne bacteria can be spread by cross-contamination. For example, if raw and cooked foods are stored together, bacteria can spread from the raw food to the cooked food.

Some foodborne bacteria can also be spread from pets to people and from person to person through poor hygiene. This includes things like failing to wash your hands properly after going to the toilet or after handling pets.

Advice for healthcare and social care organisations

We have developed guidance for healthcare and social care organisations to help protect people within their care from contracting listeriosis.

England, Northern Ireland and Wales