Listeria and food – the risk to people with weakened immune systems
(Last updated November 2010)
Listeria infection causes few or no symptoms in healthy adults and children. However, it can be very serious for people whose immune systems are weakened by disease or illness as well as pregnant women and their unborn children, newborn babies and the elderly. While health authorities seem to be getting the message across about the risk of Listeria to pregnant women, the awareness among other ‘higher risk’ groups is not as high.
People with immune systems that are weakened by disease or illness are at risk from listeria regardless of age. This can include people suffering from cancer, leukaemia, AIDS, diabetes, liver or kidney disease. It can also include anyone on medication that can suppress the immune system (for example, corticosteroids such as prednisone or cortisone – but not topical creams and ointments), including organ transplant patients.
Health authorities advise people with compromised immune systems, and their families, that they need to consider taking precautions against contracting listeriosis.
Listeria may be found in certain types of foods, especially ready-to-eat foods that have not been stored or handled correctly after being produced or cooked. Unlike most microorganisms, listeria can multiply in some foods such as soft cheeses, smoked salmon and sandwich meats even when stored under refrigeration for a long time. Therefore you can reduce your risk of contracting listeriosis by avoiding specific foods and by practising good food hygiene.
The foods to avoid include:
- cold meats, including chicken, from delicatessen counters and sandwich bars, and packaged sliced ready-to-eat meats
- pre-prepared or pre-packaged fruit and vegetable salads including those available from buffets and salad bars
- chilled seafood such as raw oysters, sashimi and sushi, smoked ready-to-eat seafood (such as smoked salmon) and cooked ready-to-eat peeled prawns in salads, sandwiches or prawn cocktails
- soft, semi-soft and surface ripened cheeses such as brie, camembert, ricotta, blue and feta
- unpasteurised dairy products
- refrigerated types of paté and meat spreads
- soft serve ice cream
You can further reduce your risk of listeriosis by following these food safety tips:
- eat freshly cooked or freshly prepared food
- use food within its ‘best before date’
- wash fruits and vegetables before using
- refrigerate leftovers promptly and use within 24 hours, or freeze
- reheat food thoroughly until it is steaming hot.
Also remember to always wash your hands before preparing or eating food.
There is comprehensive advice about safer food choices, safe food handling and dates on packaged foods on the Food Standards Australia New Zealand website at: http://www.foodstandards.gov.au/_srcfiles/Listeria.pdf
Answers to commonly asked questions about Listeria may be found at: http://www.foodstandards.gov.au/_srcfiles/Listeria_Q_%20A_Version_FINAL.pdf