Listeria and listeriosis
Key facts
- Listeria is a type of bacteria that can cause an illness called listeriosis.
- Listeriosis is caused by eating foods contaminated with listeria, such as unpasteurised dairy products, soft cheeses, raw seafood, cold meats or chicken and unwashed raw vegetables.
- Listeria rarely causes illness in healthy people, but it can lead to serious infection in people who are older, pregnant, have a weakened immune system or a chronic illness.
- Symptoms of listeriosis include fever, nausea, headaches, tiredness and muscle aches and pains.
- Listeriosis can be treated with antibiotics.
What is listeria and listeriosis?
Listeria (listeria monocytogenes) is the name of a type of bacteria. If you become infected with listeria, you can develop an illness called listeriosis.
Listeria bacteria can be found in many different places. However, the illness listeriosis is rare. Eating foods contaminated with listeria bacteria does not cause illness in most healthy people, but it can be dangerous for certain groups of people.
Who is at risk of listeriosis?
You are at a greater risk of listeriosis if you:
- are pregnant
- are a newborn baby
- are over 65 years of age
- have a weakened immune system, for example due to illnesses such as cancer, diabetes, kidney disease or HIV (human immunodeficiency virus)
- take medicines that suppress your immune system (such as prednisolone or cortisone)
What are the symptoms of listeriosis?
Listeriosis can cause symptoms such as:
Symptoms of listeriosis are usually mild. However in rare cases, listeria can lead to serious complications such as septicaemia or meningitis. These conditions can be life-threatening.
Meningitis affects the central nervous system and can cause symptoms such as:
- headaches
- stiff neck
- confusion
- loss of balance
- convulsions
- coma
Meningitis is a medical emergency. If you are worried that you or someone you care for may have meningitis, go to your nearest emergency department or call triple zero (000) and ask for an ambulance.
Listeriosis can take weeks or even months to develop after you have been exposed to the bacteria.
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What causes listeriosis?
Listeriosis is usually a foodborne disease. This means that you can catch it by eating foods contaminated with listeria. Foods more commonly affected include:
- unpasteurised dairy products, such as raw milk and soft serve ice cream
- soft cheeses such as brie, camembert, ricotta, blue and feta
- raw seafood such as oysters, or cooked ready-to-eat seafood
- pre-prepared fruit or vegetables, such as from a salad bar or supermarket
- unwashed raw vegetables
- pâté or meat spreads
- cold meats or chicken, including packaged sliced meats
Listeria bacteria are easily killed by heat. However, cooked foods may become contaminated during handling or storage if food safety practices aren't followed. Listeria can even grow in refrigerated food that is stored for long periods.
When should I see my doctor?
You should see your doctor if you think you have eaten food contaminated with listeria or if you think you have listeriosis.
If you are pregnant, you should see your doctor urgently. Your unborn baby could become seriously unwell, even if you only have mild symptoms.
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How is listeriosis diagnosed?
Your doctor can diagnose listeriosis by growing listeria bacteria from a sample of your blood, poo, spinal fluid or your placenta, if you are pregnant.
How is listeriosis treated?
Listeriosis can be treated with antibiotics. You may need to be hospitalised.
If you are pregnant and have listeriosis, antibiotics can help prevent your unborn baby from becoming infected.
What are the complications of listeriosis?
During pregnancy, listeriosis can cause serious complications such as:
- miscarriage
- stillbirth
- infection of your newborn baby, which can be serious
If you are at a higher risk of infection, you have a chance of developing serious complications including septicaemia and meningitis, even if you are treated with antibiotics.
Can listeriosis be prevented?
If you are at a high risk of developing listeriosis, here's how you can reduce your risk:
- Avoid eating high-risk foods.
- Avoid food that has passed its 'use by' date.
- Eat only freshly prepared food.
- Prepare food carefully — cook it thoroughly or re-heat until steaming.
- Store leftovers in the fridge (less than 5°C) and eat them within 24 hours.
- Wash your hands before preparing food.
Learn more about food safety.
Resources and support
- Queensland Health has more information about listeria and listeriosis.
- Read The NSW Government Food Authority's key tips for keeping food safe.
- Call healthdirect on 1800 022 222 at any time to speak to a registered nurse (known as NURSE-ON-CALL in Victoria) for more information and advice.
Do you prefer to read in languages other than English?
The Victorian Government Department of Health has a food safety guide translated into many community languages.
Looking for information for Aboriginal and/or Torres Strait Islander people?
The Food Safety Information Council has information on Aboriginal and Torres Strait Islander peoples and food safety.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: August 2024
