SPECIAL REPORT—Listeriosis is a serious infection that is contracted by consuming contaminated food containing the bacterium Listeria monocytogenes. Listeria generally effects elderly consumers, pregnant women, newborns and those with weakened immune systems, however on rare occasions, healthy individuals can become sick due to Listeria. 

Listeria is a hardy germ that can survive and grow even at refrigerator temperatures, whereas most food-borne bacteria cannot. It does not affect how food smells or tastes and is virtually undetectable prior to the symptoms of infection.

Listeria monocytogenes is found in both soil and water. Vegetables can become contaminated from the soil or from manure used as fertilizer. Animals can carry the bacterium without appearing ill and can contaminate foods of animal origin such as meats and dairy products. The bacterium has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing, such as soft cheeses and cold cuts at the deli counter. Unpasteurized (raw) milk or foods made from unpasteurized milk may contain the bacterium.

Listeria is killed by pasteurization and cooking; however, in certain ready-to-eat foods such as hot dogs and deli meats, contamination may occur after cooking but before packaging.

Symptoms of Listeriosis are: fever, chills, muscle aches with some gastrointestinal symptoms—such as diarrhea, nausea and vomiting—occurring in some people. In some cases, the bacterium can affect the nervous system causing stiff neck, confusion, loss of balance, or even convulsions. While in most cases, Listeria infection appears much like influenza-like symptoms, it is especially dangerous during pregnancy, which can result in stillbirths, miscarriages and infection of newborns.   

Consumers should avoid some foods and take special care with others to prevent infection.  People can reduce their risk by keeping their refrigerator set at 40 degrees Fahrenheit (4 degrees Celsius) or colder and also using precooked and ready-to-eat foods as soon as possible.

--Some soft cheeses are more susceptible to Listeria, however most common cheeses such as Cheddar, Swiss and Mozzarella are safe to eat. Pasteurized process cheeses that come in slices and spreads are also safe, along with cream cheese and cottage cheese.

--Raw meats and seafood should be cooked all the way through and never eaten raw.

--Most canned foods, such as tuna and meat spreads are safe to eat from the can, however they should be consumed as soon as possible and avoid prolonged refrigeration. 

--Ready-to-eat meats such as hot dogs, cold cuts and lunchmeats should be reheated until steaming hot and not eaten directly from the package. Even cured meats should be heated. 

--Leftovers should not be eaten cold and should be reheated until steaming hot.

--Fruits and vegetables can harbor Listeria. Consumers should not buy fruit or melons already sliced. Produce should be washed thoroughly with water. Textured produce such as cucumbers and melons should be scrubbed with a produce brush.

--Consumers are also advised to clean your refrigerator often and use a thermometer. Use pre-cooked and ready-to-eat foods as soon as possible and read labels, refrigerating items after opening foods that require it.

Finally, wash your hands before and after preparing raw foods with warm, soapy water. Consumers should wash knives, cutting boards and other utensils with hot, soapy water before reusing them again.