What is Listeria?

Listeria is a rare but potentially life-threatening disease. Most adults experience only mild infections of the eye and skin or gastroenteritis. It can, however, lead to severe illness including blood poisoning (septicaemia) or meningitis.

Older people and individuals with weakened immune systems, including those who have cancer, AIDS or issues with alcohol misuse, are all susceptible. Listeria is particularly dangerous in pregnancy as it can present as a mild and ‘flu-like’ illness which is not serious to the mother but can cause miscarriage, premature delivery, still birth or severe illness in a newborn child.

How do you get Listeria?

Infection usually occurs after eating food contaminated with Listeria bacteria. Foods associated with transmission are most often ready-to-eat, refrigerated and processed foods. Listeria monocytogenes has been found in a range of chilled ready-to-eat foods such as pre-packed sandwiches, pate, butter, soft mould-ripened cheeses, cooked sliced meats, and smoked salmon.
It is impossible to tell from appearance if food is contaminated. It will look, smell and taste normal.
Listeria is also widespread in the environment and can be found in raw food, soil, sewage and in the faeces of many animals, birds and fish.

How can I prevent Listeria infections?

  • Thoroughly cook raw food from animal sources, such as beef, pork, or poultry
  • Wash raw vegetables thoroughly before eating
  • Keep uncooked meats separate from vegetables and from cooked foods and ready-to-eat foods
  • Avoid unpasteurised (raw) milk or foods made from unpasteurised milk
  • Wash hands, knives, and cutting boards after handling uncooked foods
  • No foods should be eaten after their use by date
  • Patients in hospitals and those attending hospital day services should only eat foods provided by hospital staff and should not eat foods from other sources such as hospital canteens, shops or restaurants
  • Visitors are urged not to bring food into hospitals for patients unless agreed with the ward manager
  • Chilled ready-to-eat foods should be eaten as soon as possible after serving
  • Leftover food should be promptly disposed of.

Advice for those involved in the preparation and supply of food in healthcare settings

Temperature Control 

  • Keep chilled ready-to-eat food cold – at 5ºC or below
  • Preparation of chilled ready-to-eat foods must be carried out without delay
  • Chilled conditions must be maintained from production of food until serving. This includes the supply and distribution of food items.


  • All chilled ready-to-eat foods including sandwiches should be eaten as close to the date of production as possible
  • Bulk pre-packed foods, when opened, should be used within two days, unless the manufacturer’s instructions state otherwise
  • Chilled ready-to-eat foods should be purchased from reputable suppliers only.

Information Sheet