Listeria Infection: How to Avoid It and Recognize the Symptoms
Learn more about what causes this foodborne illness and who's at risk
News headlines continue to announce outbreaks of foodborne illness caused by listeria. The most recent nationwide outbreak is linked to one of the largest vegetable packing companies in the United States. So you’re probably wondering how to protect yourself.
Here's the lowdown on listeria.
What is listeria?
Listeria monocytogenes is a bacterium that can survive refrigeration and freezing. It causes listeriosis, a serious infection and the third leading cause of death from food poisoning according to the Centers for Disease Control and Prevention (CDC).
Some 1600 illnesses and 260 deaths occur annually in the United States due to listeria infection, according to the CDC.
Aside from contaminated raw vegetables including salad greens, listeria can show up in processed deli meats, infected animal meat and unpasteurized milk products, according to the Mayo Clinic. It can also live in food processing plants.
In 2015 outbreaks were caused by soft cheeses and ice cream. In 2014 an outbreak was linked to prepackaged caramel apples. In 2011, contaminated cantaloupes caused the deadliest foodborne disease outbreak in the United States in nearly 90 years, according to the CDC.
Who’s at risk?
Listeria infection usually affects older adults, pregnant women, newborns and adults with weakened immune systems, says the CDC. At least 90 percent of people who get the infection are in this high-risk group.
Pregnant women can pass down the infection to the baby through the placenta, according to the Mayo Clinic. While the mother may experience only mild symptoms, the infection could result in miscarriage, stillbirth, premature birth or a potentially fatal infection after birth. Antibiotics given promptly can prevent transmission according to foodsafety.gov.
Symptoms of listeria infection
People with listeriosis may start showing symptoms within a few days after ingesting contaminated food. However, the bacteria can stay in the body a long time before making a person sick, according to the CDC. It may take up to two months for the symptoms to show up, notes the Mayo Clinic.
The most common symptoms include:
- Muscle aches
According to the CDC, anyone in the high risks categories mentioned above who experiences symptoms after eating a contaminated food should see their doctor. A blood test is the most effective way to determine if you have the infection. In some cases the doctor may also test urine or spinal fluid.
Mild symptoms usually require no treatment according to the Mayo Clinic. Serious listeria infections are treated with antibiotics.
Mayo Clinic recommends seeking emergency care if you develop symptoms of bacterial meningitis, a serious complication of listeriosis. They include:
- High fever
- Severe headache
- Stiff neck
- Sensitivity to light
The only way to kill the listeria is through cooking and pasteurization. FoodSafety.gov has this advice for protecting yourself:
- Avoid raw milk. Don’t drink raw milk or eat foods that may contain unpasteurized milk.
- Follow smart food prep practices. Wash your hands, countertops and cutting boards after preparing uncooked foods.
- Clean your produce. Rinse all raw produce under running tap water before eating.
- Keep uncooked meat separate from produce and cooked foods. That goes for poultry and seafood too.
- Cook meat to safe internal temperatures. Use a food thermometer.
- Heat those deli meats and hot dogs. This is a smart precaution for people in one of the high risk groups.
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