Listeria update

What is listeria?

Listeria (also known as listeriosis) is a rare but potentially severe illness caused by eating foods that have been contaminated by bacteria called Listeria monocytogenes.

What causes listeria infections?

Listeria bacteria are common in the environment and are found in some raw or precooked/processed foods. For example, foods that have been associated with listeria infection include:

  • Seafood (e.g. smoked fish, mussels, precooked prawns and raw seafood such as sushi and
  • Sashimi)
  • Precooked cold meats (deli meats like ham and salami, pate, cooked chicken)
  • Premixed raw vegetables (e.g. coleslaw) or raw vegetable garnishes
  • Pre-prepared fruit salad or vegetable salads from sandwich bars or salad bars
  • Drinks made from fresh fruit and vegetables where food-washing procedures are unknown
  • e.g. juice bars
  • Dairy products (soft and semi-soft cheeses like ricotta, brie, feta, camembert, soft-serve ice-cream, unpasteurised milk or foods made from unpasteurised milk).

What are the symptoms of listeria infection?

The symptoms of listeriosis can take anywhere from a few days to many weeks to appear after contamination. Symptoms may include fever, chills, headaches, tiredness, neck stiffness, sensitivity to light, muscle aches and pains and diarrhoea.

How dangerous is listeria infection?

Listeriosis can be particularly dangerous for pregnant women and newborn babies. Even a mild infection can cause a miscarriage, premature birth or even stillbirth. Listeria is not normally transmitted between people but may be passed from a pregnant woman to her unborn baby. Babies whose mothers have listeriosis may be very ill when they are born.

Other people at high risk of listeria infection include older people and people with weak immune systems. The infection can result in serious illnesses including meningitis (infection of membranes surrounding the brain and spinal cord) and septicaemia (infection of the blood).

In the recent listeriosis outbreak the source of contamination was linked to the Jindi Cheese Factory in Victoria. To date, three people have died and one women had a miscarriage, while a further 23 people have become infected with listeriosis.

Reducing the risk of listeria infection

You can reduce your risk of exposure to listeria by avoiding the high-risk foods listed above and following these simple steps:

Handling food

  • Thoroughly wash and dry your hands before preparing food, and between handling raw foods and pre-mixed processed foods.
  • Thoroughly wash and dry knives, cutting boards and kitchen appliances after they have been used.
  • Don’t use the same cutting boards and knives for cooked foods that you used for raw foods unless they have been washed in warm, soapy water.
  • Thoroughly wash and dry raw fruit and vegetables before eating or juicing.
  • Defrost all frozen food in the fridge or use a microwave. Do not defrost or thaw at room temperature.
  • Thoroughly cook all raw meat, chicken and fish.

Storing and reheating food

  • Don’t leave foods to cool on the bench or stove. Put them in the refrigerator once they have stopped steaming.
  • If reheating cooked food, make sure it is thoroughly reheated until it is steaming hot.
  • Keep your refrigerator clean and set the temperature to below 5°C.
  • Keep hot foods hot (60°C or hotter) and keep cold food cold (5°C or colder).
  • Keep stored foods well wrapped and covered.
  • Store raw meat separately from other foods in the refrigerator. Make sure there is no chance that raw meat juices can drip onto other foods or touch other foods.
  • If you are pregnant

Follow the above steps and avoid eating foods that have a high risk of containing listeria.

Where can I find more information?

You can find further information about listeria from the following sites:

Food Standard Australia and New Zealand website:

The NSW Health Department’s listeria factsheet:

You can find more information about good food hygiene from the Food Safety Information Council website:

If you have any further questions or concerns please do not hesitate to contact us here at Dr van der Griend’s rooms.