Listeria (food poisoning)

What is listeria food poisoning?

Listeriosis is a type of food poisoning caused by a bacteria called Listeria monocytogenes.

Some foods are more likely to be contaminated with listeria than others.

Although listeriosis is rare, some people can die from it.

People at risk from listeria are:

• pregnant women
• unborn children
• newborns
• older people
• people with weakened immune systems — such as people being treated for cancer

Listeria is common in the environment and can contaminate some foods.

Listeriosis in women who are pregnant or newborn babies

While listeriosis can affect anyone, it’s particularly important that you reduce your risk of exposure to listeria bacteria while pregnant.

Listeria infections can appear mild in pregnant women, but can lead to serious outcomes such as:

• miscarriage
• stillbirth
• premature birth
• infection in your newborn

Babies can be born with listeriosis if you’ve eaten contaminated food during your pregnancy. Your baby may become seriously ill.

Once you’ve had your baby you can eat the foods you’ve been avoiding during pregnancy due to the listeria risk. The risk of transmitting listeria to your newborn baby from breastfeeding is very low.

What are the symptoms of listeriosis?

Symptoms of listeria infection in healthy adults may include:

• headache
• fever (high temperature)
• tiredness
• aches and pains

Less common symptoms are:

• diarrhoea
• nausea
• abdominal cramps

Not all people who eat foods that contain the listeria bacteria will become unwell.

Symptoms in pregnant women may be mild, but it’s important to get medical attention straight away.

The average time from infection to symptoms is about 3 weeks (ranging from 3 to 70 days).

How is listeria food poisoning diagnosed?

You should see your doctor if you think you might have listeriosis.

Your doctor will discuss with you the foods that you have eaten and probably take a sample of your blood.

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What is the treatment for listeriosis?

If you get listeriosis, you will be treated with antibiotics. This may prevent the infection passing from you to your unborn baby.

Can listeriosis be prevented?

The best way to avoid a listeria infection is to not eat high-risk foods and stick with freshly cooked foods.

Which foods have a high risk of listeria contamination?

Foods at high risk of carrying listeria bacteria are:

• soft and semi-soft cheeses — brie, camembert, ricotta, blue and feta
• cold meats and packaged, sliced ready-to-eat meats
• paté or meat spreads
• soft serve ice cream
• rockmelon
• pre-prepared fruit or salads
• raw seed sprouts
• chilled seafood — raw oysters, sashimi and sushi, and cooked ready-to-eat prawns
• unpasteurised fruit juices

You should avoid these foods when pregnant.

What other food safety steps can I take?

You can further lower your risk of listeriosis by:

• thoroughly washing fruit and vegetables before eating or juicing
• avoiding food that is past its best before or use by date
• cooking food thoroughly
• refrigerating leftovers promptly and using them within 24 hours, or freezing them
• reheating food until it’s steaming hot

You can find out more about foods to avoid when pregnant here.

Other food handling tips

• Always wash your hands before preparing food.
• Wash knives, cutting boards and kitchen equipment and dry well after preparing raw food.
• If you are keeping food hot, keep it very hot (60°C or hotter).
• Thaw ready-to-eat frozen food in the refrigerator or microwave.
• Don’t leave foods to cool — put them in the fridge once the steam has gone.
• Keep stored foods covered.
• Keep your fridge clean.
• Keep cold food cold (5°C or colder).
• In your fridge, store raw meat separately from cooked and ready-to-eat food. Store it at the bottom of your fridge so that it can’t drip onto other foods.

Resources and support

See your doctor if you have any concerns about listeria infection while pregnant.