What Is Lysteria?

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By Ochsner Medical Center
    Listeria is a food-borne organism that most of us have heard about over the past several months in the news with some of the more well-known outbreaks of listeriosis including those caused by packaged salads, ice cream and prepared breakfast sandwiches. You may be asking yourself these questions: So, what exactly is listeriosis? What are the symptoms? Is it something you need to be worried about? What can you do to prevent contact with the listeria organism that causes the illness? 
    First of all, it’s very important to understand that healthy children and adults seldom get infected with listeria and rarely become seriously ill from the bacteria. In the United States, an estimated 1,600 people get sick from listeria a year, of which 260 die. Those at highest risk include pregnant women, older adults and those with weakened immune systems (anyone with chronic liver or kidney disease, diabetics, alcoholics, people with HIV/AIDS and patients on steroids, chemotherapy, or radiation).
    “Listeriosis is caused by eating food contaminated with the bacterium Listeria monocytogenes,” says Laura Walsh, a Gastroenterology Physician Assistant at Ochsner Medical Center – Baton Rouge. “The most common foods that are contaminated with listeria are processed/delicatessen meats, hot dogs, soft cheeses, pates and fruits. The organism can survive and multiply at refrigerator temperatures; however, hot, properly cooked foods are not a vehicle of transmission for listeria,” she continued.
    Symptoms of listeriosis usually include fever and muscle aches, and may be preceded by diarrhea or other GI symptoms. Almost everyone who is diagnosed with the illness has “invasive” infection, meaning the infection has spread beyond the gastrointestinal tract.
    To prevent listeria exposure, it is recommended that you follow the general guidelines used to prevent all food-borne pathogens. This includes proper washing and handling of food, keeping your kitchen and environment clean, cooking meat and poultry thoroughly and safe storage of food. 
    For a list of Ochsner physicians practicing gastroenterology, visit and look for the “Find A Doctor” tab.