Listeria: what it is and how to avoid it

3 min read

Listeriosis is a rare infection caused by a bacterium called listeria. It is rare, but pregnant women are about ten times more likely to catch it, and it can cause miscarriage, stillbirth or serious illness in a newborn. The good news is that the risk is easy to lower.

Unlike most bacteria, listeria can grow in the fridge. The foods most linked to it are unpasteurized milk and cheese, soft mold-ripened cheeses such as brie, refrigerated pâté, deli meats and hot dogs, cold-smoked fish, and pre-cut melon or bagged salad kept too long.

What helps: choose pasteurized dairy, heat deli meats and hot dogs until steaming, eat leftovers within a day or two, keep your fridge at 4 °C (40 °F) or colder, and wash fruit and vegetables. Cooking kills listeria, so a hot dish that contains any of these foods is fine.

Symptoms can look like flu: fever, chills, muscle aches and sometimes an upset stomach, and they can start days or even weeks after eating. If you have a fever and think you ate something risky, call your doctor or midwife the same day. Do not wait to see if it passes.