Listeria are bacteria that can cause the serious illness, listeriosis, in some people. Eating foods contaminated with Listeria is the most common way of contracting the illness.
People at higher risk of 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).
What are the symptoms of listeriosis?
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.
For people with weakened immune systems, symptoms can progress to more serious forms of illness including septicaemia (blood infection), meningitis (infection and inflammation of membranes surrounding the brain) and even death.
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.
What precautions should I take if I am at risk?
The food industry and governments work together to ensure our food is safe. However, if you or anyone in your household is in the at risk group, it is important you reduce your risk by taking a few simple precautions. These include:
- preparing, storing and handling food hygienically;
- avoiding certain foods which have a higher risk of Listeria contamination; and
- being careful about food prepared by others.
Eat freshly cooked or freshly prepared foods
Ideally, eat only freshly cooked food and well-washed freshly prepared fruit and vegetables. However, leftovers can be eaten if they are refrigerated promptly and kept no longer than a day. It’s important that you do not eat food if there is any doubt about its hygienic preparation or storage.
Cook foods thoroughly
Thorough cooking of food kills Listeria bacteria. Ensure food is cooked thoroughly.
Reheat foods to ‘steaming’ hot
If you plan to eat previously cooked and refrigerated leftovers, only keep them in the refrigerator for a day and reheat them thoroughly to steaming hot. This will kill Listeria bacteria.
When reheating food, especially in a microwave, make sure the food is steaming hot throughout.
Make safer food choices
As a general rule, avoid perishable foods (need to be refrigerated) that have been prepared well in advance and are to be eaten without further cooking.
The tables overleaf list some examples of higher risk foods and safer alternatives. You should avoid consuming these higher risk foods, especially if you are unsure about how they have been prepared, stored and handled. Food is safe if you cook it or reheat it to steaming hot throughout and serve it hot.
Avoid ready-to-eat food from salad bars, sandwich bars, delicatessens and smorgasboards
Ready-to-eat foods from salad bars may have been prepared and refrigerated some time before they are put on display. Listeria bacteria may have grown in these foods so they are best avoided.
Foods on open display in delicatessen counters are more likely to become contaminated by Listeria than foods that are sold packaged by the manufacturer. Avoid these foods.
Avoid foods that are past their ‘best before’ or ‘use by’ date
Choose and consume foods well within their ‘use by’ or ‘best before’ date. Once opened, eat promptly.
Do not eat refrigerated foods that are past their ‘use by’or ‘best before’date.
Only buy ready-to-eat hot food if it’s steaming hot
If you buy ready-to-eat hot food, for example a cooked chicken, make sure it’s very hot and either eat it or refrigerate it promptly on arriving home. Use it within a day.
If eating out, order hot meals
Choose menu items that are cooked to order and served hot. Do not eat food that is served lukewarm. It is best to avoid smorgasbords and salad bars. If this isn’t possible, choose the hot foods only.
Good food hygeine
Take some simple food hygiene steps to reduce the risk of foodborne disease.
- Thoroughly wash and dry your hands before preparing food, particularly before preparing ready-to-eat food.
- Keep your refrigerator clean and operate it below 5°C.
- Wash knives, cutting boards and kitchen appliances and dry thoroughly after handling raw food to prevent contamination of cooked and ready-to-eat foods.
- Thoroughly wash and dry raw fruit and vegetables before eating or juicing.
- Thaw ready-to-eat frozen food in the refrigerator or microwave – don’t thaw at room temperature.
- Thoroughly cook all raw meat, chicken and fish.
- Don’t leave foods to cool on the bench or stove top. Put them in the refrigerator after the steam has gone.
- If you are keeping food hot, keep it very hot (60°C or hotter). Keep cold food cold (5°C or colder).
- Thoroughly reheat food until it is steaming hot.
- Keep stored foods covered.
- Store raw meat separately from cooked and ready-to-eat food in the refrigerator. Store it below other foods so that there is no chance it will drip onto other foods.