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Published on July 01, 2015

Should You Be Worried About Listeria?

Food recalls and reports of people getting sick have thrust listeria into the headlines. First, the bacteria was linked to cantaloupes and then, most recently, certain brands of dairy products and hummus.

During the cantaloupe-related outbreak in 2011, there were several deaths and many people sickened by listeria infections, which is enough to scare anyone. But how common and how dangerous is the foodborne illness?

“We probably all consume it in our foods, at least in small amounts, frequently,” said Roger Nieman, MD, a member of the Infectious Diseases Department of Abington Hospital-Jefferson Health. “It's usually not harmful in small amounts unless someone has a severely compromised immune system.”

In fact, according to Dr. Nieman, if stool samples of healthy adults were tested, about 5 percent of them are carrying listeria bacteria but do not show signs of illness.

Listeria is a type of bacteria found in soil and water. Vegetables and fruits can become contaminated with the bacteria from soil or manure used as fertilizer. Animals can also carry the bacteria without appearing sick, which can then translate into contamination of meats and dairy products.

Listeria is most commonly found in foods, such as uncooked meats and vegetables, in addition to processed foods that become contaminated after processing, such as soft cheeses and cold cuts. Unpasteurized dairy products may also contain the bacteria.

Are You At Risk?

While consuming small amounts of the listeria bacteria is generally harmless, certain groups are at a higher risk of becoming infected. According to Dr. Nieman, those with a higher risk of being sickened include pregnant women, elderly adults, newborns and infants, and people with compromised immune systems.

People with these risk factors should take the following precautions with these types of food:

Soft and Mexican-style cheeses: Unless it’s clear from the packaging that the soft cheeses like feta, Brie, Camembert, blue cheese and queso fresco are made with pasteurized milk, don’t eat them.

Hot dogs, lunch and deli meats: Unless these foods are reheated until steaming hot, don’t eat them. Also be sure to keep any fluids from hot dog packages away from other food, surfaces and cooking utensils. Always wash your hands after handling these types of meats.
Meat spreads: Don’t eat any refrigerated pates or meat spreads.

Take Precaution

Even if you don’t have any risk factors that make you prone to a listeria infection, there are precautions you can take in your kitchen to help avoid listeria.

“Always rinse or wash fruits and vegetables in water before you cut them,” Dr. Nieman said.

When the listeria outbreak related to cantaloupes occurred, the skin and the outer surface of the fruit was contaminated with listeria. When people cut the fruit or it was cut and prepared in a store, cutting through the skin transferred the bacteria from the skin into the fruit, contaminating it, he said.

“With foods like cantaloupe, it’s hard to decontaminate the outside skin since it’s not a smooth soft surface. Try to scrub it before cutting into it,” he said.

As a general rule to prevent foodborne illness, always wash your hands thoroughly with warm soapy water before and after handling food. After cooking, wash utensils, tools and surfaces with hot soapy water.

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