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Listeria in food


What is Listeria?

Listeria is a bacterium commonly found in the environment. The specific type of Listeria that infects people is Listeria s (abbreviated as L. monocytogenes or often just called Listeria).

What illness does it cause?

Listeriosis. This illness is a nationally notifiable disease and must be reported to health authorities.

What are the symptoms?

Healthy people might have mild symptoms such as nausea, diarrhoea, fever, headache and muscle aches. In more severe cases, people can get blood poisoning, inflammation of the brain, the brain’s lining and spinal cord, or die.

Pregnant mothers can miscarry or the baby can be born prematurely or stillborn.

Symptoms usually start about 3 weeks after a person becomes infected (e.g. after eating contaminated food), but can start between 3 to 70 days from infection.

Who can get sick?

Listeriosis is rare however people with weak immune systems, pregnant women and their babies and the elderly can get very sick or die.

Where does it come from?

Listeria is found in soil, water, sewage and animals’ guts and can survive in cold, moist locations (including food in the fridge). It can be carried into food premises through people’s shoes, crates, machinery, etc..

Common foods that can be contaminated with Listeria include ready-to-eat foods (foods that won’t be further cooked) such as pre-prepared salads and fruit, soft serve ice cream, soft cheese, deli meats and smoked seafood

How can people get sick?

  • By eating contaminated ready-to-eat food
  • By bacteria on equipment, food or hands being transferred to food that is ready to eat
  • Although it doesn’t generally pass from person to person, pregnant mothers can pass it to their babies during pregnancy or childbirth

How can illness be prevented?

  • Refrigerate perishable foods and eat them as soon as possible
  • Pregnant women should avoid ready-to-eat foods, especially those mentioned above
  • Thoroughly cook raw meats and wash raw fruit and vegetables before eating
  • Avoid cross contamination − for example use separate cutting boards and knives for raw and ready-to-eat food, and store cooked food separately from raw foods
  • Wash hands thoroughly before preparing or eating food


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