What Is Listeria?

Listeria is a type of bacteria that is most frequently found in raw meats, raw milk and soft cheeses. It can, however, also be found in fresh produce such as spinach. Unlike many other types of bacteria, listeria can survive refrigeration. Cooking your food can kill it, but it's not a guarantee. You shouldn't assume that your food is 100 percent safe because it's been cooked. If you are in a demographic at high risk for infection -- like those with compromised immune systems incapable of effectively fighting infections -- you shouldn't count on the bacteria being completely eliminated, even when it's cooked.

Infection Protection

To prevent your spinach from growing listeria, keep it separated from foods that can carry and spread the bacteria, like cold smoked fish and soft cheeses. Wash your spinach thoroughly before preparing it, and cook it thoroughly before eating it. Do not eat spinach after the "use by" date printed on the bag. Because spinach is infrequently a high-risk food for listeria infection, you generally don't need to be concerned unless otherwise warned -- spinach sold by certain commercial brands has, in the past, been recalled as the result of a listeria risk. If you have any reason to suspect that your spinach is contaminated, cooking it can kill the bacteria, but you're better off not taking even a miniscule risk -- just throw it away.

Are You At Risk?

Some people are at a higher risk for listeria infection than others -- particularly anyone with a compromised immune system that is incapable of fighting off the bacteria. This includes pregnant women, the elderly and people suffering from conditions like HIV, cancer and diabetes. Pregnant women especially should avoid any risk of contracting the bacteria, as an infection can spread to the fetus and cause complications like premature delivery or miscarriage. This doesn't mean that pregnant women should avoid spinach, though -- it's too-infrequently associated with listeria to be as big a concern as foods like soft cheeses and raw fish. Washing and cooking your spinach is generally sufficient, unless the government has issued a recall or a listeria warning for raw spinach.

Waiting for the Symptoms

If you've already consumed spinach -- raw or cooked -- at the time of a listeria-related recall, watch for the signs of infection so you can seek medical treatment if necessary. Listeria infections are typically associated with symptoms like gastrointestinal upset and cramps, fever, muscle aches, vomiting and chills. These symptoms typically take two to three days to develop after you consume the bacteria, so monitor your health and see a doctor immediately if you notice any of the signs of infection.