Listeria and Pregnancy

What's listeria? How does it affect pregnant moms?

Listeria is a bacteria that is found in nature and lives in some foods. Listeria can be found in most animals, soil, vegetation and sewerage. Because of this, Listeria can easily enter our food chain. An infection with Listeria can cause mild ‘flu-like’ symptoms, urinary tract infections or even quite serious illness. In adults who have an impaired immune system, Listeria can cause illnesses such as meningitis, pneumonia and encephalitis. The bacteria that causes Listeria is called Listeria monocytogenes.

In pregnancy this bacteria can pass across the placenta and reach the baby. Listeria during pregnancy can cause abortion, premature rupture of membranes, premature birth and very sick babies. Listeria infections are not new, however it has only been known since 1980’s that it can be passed onto humans through food.

An infection with Listeria can be easily missed as it often presents with vague symptoms. A blood test or a test on the amniotic fluid can identify a Listeria infection. Listeria can be treated with certain antibiotics. If a baby contracts a Listeria infection it can become extremely sick with respiratory problems or meningitis. The baby can even die. Listeria infection is quite rare in Australia, but when it occurs in pregnancy it can have serious complications. It is for this reason that information is now being made available to pregnant women, so that they can make safe choices on the foods to eat during pregnancy.

The bacteria that causes Listeria is sensitive to heat. So by cooking food well, you are able to destroy it. When cooking meats ensure that the meat is cooked right through. Rare meat is not recommended. If you use the microwave to reheat, ensure that the food is steaming hot right through to the centre. While heat destroys Listeria, refrigeration does not. Listeria is one of the few bacteria that are able to grow on food in the refrigerator. So if food has been stored for longer than twelve hours after cooking - it is recommended that you do not eat it. Also avoid chilled ready to eat foods.

The best way to avoid Listeria is to have good food hygiene. Wash your hands before preparing any food. Raw fruit and vegetables should be thoroughly washed before eating. Food should be well cooked; no raw or partially cooked meats and seafood should be eaten in pregnancy. Food should be served piping hot. Do not eat lukewarm food. If using the microwave ensure that the food is well heated through to the centre. Hot soapy water should used to wash all food utensils. It is particularly important to wash chopping boards and knives after preparing raw food. Proper storage of food is essential. Store all your cooked food separately from uncooked products. Make sure that the raw food cannot drip onto cooked food. If you have cooked leftovers, place them straight into the fridge once they have stopped steaming (do not let food cool on the bench). Use all left overs within 12 hours of cooking or alternatively freeze for later use. Ensure that cooled food is kept below 5 degrees Celsius. Also do not eat food that has passed its used by date.

There are certain foods that are considered to be of high risk of Listeria contamination. The foods to avoid during pregnancy include:
Soft white cheeses eg. Ricotta, brie, camembert, blue vein and fetta
Pate
Unpasturised dairy products
Cold meats
Dried/fermented sausages
Raw seafoods eg. Oysters, sashimi
Smoked seafood (canned is okay)
Pre packed and prepared salads
Soft serve ice-cream

Freshly prepared and freshly cooked foods are the safest for consumption during pregnancy. It is important to eat a well balanced diet that contains plenty of fresh fruit and vegetables, breads, cereals, meat, fish, eggs, lentils and nuts. Ensure meat is well cooked. All hot food should be piping hot. The following foods are safe to eat in pregnancy:
Washed fruit and vegetables
Home made salads
Hard Cheese
Processed cheese
Canned foods
All meats - thoroughly cooked, hot and fresh
Pasteurised diary products

Information extracted from here.