Listeria (Listeria monocytogenes) are bacteria that can cause serious illness and in some cases death, particularly in vulnerable people. In Australia each year around 150 people are hospitalised with listeriosis and about 15 people die.
People at greater risk from listeriosis include pregnant women, their unborn and newborn babies, the elderly and other people whose immune systems have been weakened by illness or drugs (for example: cancer patients, organ transplant recipients, and people on drugs like cortisone).
Eating foods contaminated with Listeria is the most common way of contracting the illness. Listeria is common in the environment and can contaminate different types of food. Listeria is tolerant to low temperatures so it can grow in food even if it is stored in the refrigerator.
What are the symptoms of listeriosis?
While Listeria generally doesn’t affect healthy people, it can cause severe illness in pregnant women and their babies, the elderly and people with weakened immune systems.
In healthy adults and children, listeriosis causes few or no symptoms and may be mistaken for a mild viral infection or flu. Symptoms may include headache, fever, tiredness and aches and pains. Less common symptoms include diarrhoea, nausea and abdominal cramps.
In vulnerable people listeriosis can be serious and fatal. It can lead to sepsis and meningitis (infection and inflammation of membranes surrounding the brain).
It can take weeks after infection for symptoms to appear, so sufferers may not be aware they have listeriosis and may not seek medical advice. Symptoms in pregnant women may appear mild, but listeriosis can cause miscarriage, premature birth, or stillbirth. It is important that pregnant women who have symptoms of listeriosis seek medical attention immediately.
How do I avoid Listeria?
If you (or someone in your household) have a weakened immune system or are pregnant, the best way to avoid Listeria is to eat freshly cooked or freshly prepared food.
Try to avoid foods that have a higher risk of Listeria contamination such as:
- cold meats from delicatessen counters and sandwich bars, and packaged, sliced ready-to-eat meats
- cold cooked ready-to-eat chicken (whole, portions, or diced)
- pre-prepared or pre-packaged fruit or vegetable salads, including those from buffets and salad bars
- chilled seafood such as raw oysters, sashimi and sushi, smoked ready-to-eat seafood and cooked ready-to-eat prawns
- soft, semi-soft and surface-ripened cheeses such as brie, camembert, ricotta, blue and feta
- refrigerated paté or meat spreads
- soft serve ice cream
- unpasteurised dairy products.
You can further reduce your risk by:
- avoiding food that is past its best before or use by date
- refrigerating leftovers promptly and using them within 24 hours, or freezing them
- cooking food thoroughly
- reheating food until it is steaming hot.