Listeria monocytogenes

Listeria monocytogenes

Listeriosis is an illness that is caused by eating raw, chilled, and ready-to-eat foods that are contaminated with bacteria called Listeria monocytogenes (Listeria). Listeriosis is rare but can cause serious symptoms and even death in particular vulnerable groups.  In healthy adults, Listeria can cause a flu-like illness.  It can cause very serious illness in the elderly, pregnant women and their unborn babies, new babies and people who have an impaired or weakened immune system.

Listeria monocytogenesHow can I be exposed to this infection?

Listeria is widespread in the environment and so can contaminate many foods. Foods of most concern are those that do not require any further cooking or reheating such as chilled ready to eat foods including:

  • Soft cheeses including those ripened by mould
  • Smoked fish
  • Cooked sliced meats (sold as ready-to-eat)
  • Cured meats (sold as ready-to-eat)
  • Pate from meat, vegetables or fish (Tinned pate is ok)
  • Pre-packed salads and sandwiches
  • Pre-cooked shellfish (sold as ready-to-eat)

How do I know if I have listerosis?

Infection in healthy adults usually produces no symptoms, or a mild flu-like illness. However, in certain people including the elderly, pregnant women and their unborn babies, and new babies and people who have a weakened immune system, it can cause very severe illness, or even death. A person with a Listeria infection can have symptoms such as fever, tiredness and headache. Sometimes the symptoms are mild, so you might not know you have it. If you have any concerns about symptoms or illness please consult your General Practitioner.

How can I avoid getting infected?

You can reduce the risk from infection by eating freshly cooked or freshly prepared foods and avoiding foods that could contain Listeria.

Also, follow the steps below:

  • Clean: Wash all fruit, vegetables and salad fully just before you eat them.
  • Cook: Cook food right through and serve it when it is still very hot.
  • Chill: Make sure that your fridge is at 5°C or below. Put chilled food in the fridge straight away. Throw out food that has passed the ‘use by’ date, and if the food packet has been opened, use within 2 days.
  • Separate: Keep cooked food and raw food away from each other.

See our leaflet ‘Listeria and Pregnancy’, available in a number of different languages, which contains useful information and advice on how pregnant women can protect themselves and their babies throughout the pregnancy.