What is Listeria food poisoning?

Listeria (Listeria monocytogenes) is a type of bacteria that can cause serious food poisoning called listeriosis. You can get it if you eat food contaminated with Listeria.

Although listeriosis is rare, it can lead to serious illness and harm your baby during pregnancy. Some people can die from it.

People at a higher chance of listeriosis include:

• pregnant people
• unborn babies
• newborn babies
• older people
• people with weakened immune systems — such as people having cancer treatment

Listeria is found in soil, water and animals. It can contaminate foods during production or handling.

What are the symptoms of listeriosis?

Symptoms of listeriosis may include:

• headache
• sudden fever (high temperature)
• tiredness
• muscle aches and pains
• nausea, vomiting, diarrhoea and tummy cramps

Sometimes, you may not even feel sick at all or your symptoms may be very mild.

It usually takes about 3 weeks to develop symptoms, but it can range from 7 to 70 days.

Symptoms and effects on your baby during pregnancy

If you get Listeria food poisoning during pregnancy, it can harm your baby even if you don't feel sick.

Listeria can infect your baby before birth. This may lead to symptoms such as:

• less movement from your baby
• contractions
• vaginal bleeding
• your waters breaking early
• an unusually fast heart rate in your baby

What causes listeriosis?

You can get listeriosis by eating foods that are contaminated with the Listeria bacteria. Some foods are more likely to carry it, especially if they're:

• undercooked or ready-to-eat meat
• unwashed or raw vegetables
• dairy products

If you are pregnant, your baby can also develop listeriosis. This is because the Listeria bacteria can pass through your placenta before birth.

During pregnancy, you have a higher chance of developing listeriosis than usual.

When should I see my doctor?

You should see your doctor or midwife straight away if you:

• think you have eaten foods contaminated with Listeria bacteria
• have symptoms of Listeria infection
• are worried

How is listeriosis diagnosed?

Your doctor can diagnose you with listeriosis by doing tests including:

• a blood test
• a swab from your vagina or cervix
• a sample of amniotic fluid (the fluid around your baby)
• testing the placenta (after giving birth)

How is listeriosis treated?

If your doctor thinks you might have listeriosis, they may start treatment straight away before your test results are back.

Treatment usually includes 2 weeks of intravenous antibiotics (given to you through a vein). Your doctor will only give you antibiotics that are safe for you and your baby.

Sometimes you may need to have your baby early. This depends on how severe your illness is and how far along your pregnancy is.

Starting treatment early helps improve outcomes for your baby.

Read more about medicines during pregnancy.

What are the complications of listeriosis?

During pregnancy, listeriosis can cause serious complications, especially for your baby.

Complications for your health are rare but may include:

• loss of consciousness and other neurological symptoms
• sepsis and multiorgan failure
• breathing difficulties

In general, you have a higher chance of food poisoning during pregnancy. Listeriosis is one of the most dangerous foodborne infections for unborn babies. It can lead to:

• premature birth
• miscarriage or stillbirth
• meningitis after birth
• infection of the uterus and placenta (chorioamnionitis)

This is why it's important to know which foods to avoid during pregnancy.

Can listeriosis be prevented?

You can help prevent listeriosis by avoiding high-risk foods and eating freshly cooked food.

High-risk foods include:

• dairy made with unpasteurised milk, raw milk and soft cheeses
• chilled, precooked, smoked and uncooked seafood
• pâté, dips and cold delicatessen meats
• precooked meat and meat products which are eaten without further cooking or heating
• pre-prepared and pre-packaged fruit salads, vegetable salads and coleslaws
• soft-serve ice-cream and fresh fruit juices
• raw sprouts, mushrooms and rockmelon

Read more about how to store and prepare your foods safely.

Resources and support

• Learn more about food safety and Listeria and pregnancy with The Royal Women's Hospital fact sheet.
• Read more about healthy eating and food safety in pregnancy on the Food Authority website.
• Food Safety Information Council has two short videos about Listeria.
• NSW Health has a fact sheet on listeriosis.
• SA Health has tips on how to prevent food poisoning at home.
• The Multicultural Centre for Women's Health has a catalogue of health resources for women, available in more than 70 languages.

Information for Aboriginal and/or Torres Strait Islander peoples

• The Food Safety Information Council has information on food safety for Aboriginal and Torres Strait Islander peoples.
• Watch the No Germs on Me video on hand washing.