The bacterium Listeria monocytogenes is responsible for the listeria infection, which is also known as listeriosis. It may be uncommon, but listeria is a serious and potentially fatal bacterial infection which can infect an unborn baby. It can also cause miscarriage, trigger premature birth, or lead to stillbirth. It is important that pregnant women know the precautions to take to avoid listeria infection during their pregnancy, and thus protect the health of their unborn child.
How Do People Get Infected with Listeria?
Listeria infection is mainly caused by eating food that has been contaminated with the bacterium Listeria monocytogenes. Foods that may be contaminated include unwashed vegetables, uncooked meats and fish, unpasteurised milk products, cooked delicatessen meats, refrigerated smoked seafood, chilled pâtés and spreads, and ready-meals.
Listeria bacteria are destroyed by cooking and pasteurisation, but not refrigeration. Although some foods such as cold cuts of meat and ready-meals are already cooked, they can become contaminated with listeria when they are chilled.
Symptoms and Treatment of Listeria Infection
It is unlikely that a healthy person will become ill due to listeria infection; however, some groups of people are more vulnerable to listeriosis. These include pregnant women, newborn babies, people with compromised immune systems and elderly citizens.
Listeriosis can have flu-like symptoms, including fever, muscle aches and pains, as well as nausea, vomiting and diarrhoea. The listeria infection may also attack the nervous system, leading to headaches, neck stiffness, confusion, impaired balance and even convulsions. In severe cases, listeria can lead to septicaemia (blood poisoning) or meningitis. For pregnant women, it may lead to premature birth, miscarriage, stillbirth or a very ill newborn baby.
Although a pregnant woman may only have mild symptoms of listeriosis, the infection may still be passed to the developing foetus. A blood test can be carried out to see if listeriosis is present, in which case the infection can be treated with antibiotics to prevent its transmission from mother to baby. Antibiotics can also be given to newborn babies who have caught the infection.
Avoiding Listeria Infection During Pregnancy
Unborn babies can become infected with listeria if their mothers eat contaminated food during pregnancy. To avoid the risk of listeria infection during pregnancy, the mother-to-be should keep away from certain foods and ensure food is handled and prepared safely. She should:
- avoid eating unpasteurised dairy products including milk and cheeses such as brie, camembert, feta, and blue-veined and Mexican cheeses
- avoid eating deli meats and hot dogs unless they have been reheated until piping-hot
- heat ready-meals thoroughly
- avoid eating chilled pâtés and spreads
- avoid eating refrigerated smoked seafood unless it is cooked in a meal
- avoid eating foods past their use-by date
- wash vegetables and fruits properly before eating, making sure all soil is removed
- cook meat, poultry and fish thoroughly before eating
- keep uncooked foods separate from other foods
- wash hands, kitchen utensils and food surfaces thoroughly after handling and preparing raw meat, deli meats or hot dogs
If a pregnant woman contracts listeria, it can put the health of her unborn child at risk. Knowing what is unsafe to eat, as well as how to safely handle and prepare foods, will help women to avoid listeria infection during pregnancy.
For more information about nutrition during pregnancy, readers may be interested in Which Foods Should Women Avoid During Pregnancy?, Drinks Women Should Avoid During Pregnancy, and Why is Folic Acid Important During Pregnancy?
Women who are planning a pregnancy may be interested in reading Foods to Increase Fertility.
Resources:
- CDC. “Listeriosis.” (Accessed 25th November 2009)
- Todar’s Online Textbook of Bacteriology. “Listeria Monocytogenes.” (Accessed 25th November 2009)
- KidsHealth. “Listeria Infections.” (Accessed 25th November 2009)
Sharon Kirby - Sharon is a freelance health writer and contributes to various print and online publications. Writing credits include Nursing Times, Good ...
