How to Prevent Listeriosis Outbreaks

Posted October 19, 2011 | 0 comments

By Howard Seltzer, National Education Advisor, Center for Food Safety and Applied Nutrition, FDA

The ongoing multistate outbreak of food poisoning associated with cantaloupes has put a bad bug called Listeria monocytogenes in the spotlight.

What is Listeria Monocytogenes?

It's a harmful bacterium that causes a foodborne illness called listeriosis. It's found in the environment – soil, water, decaying vegetation, and the intestinal tract of animals.

What happens when people get Listeriosis?

A person with listeriosis usually has fever and muscle aches. People who think they might have become sick with listeriosis should consult their doctor.

Listeriosis is relatively rare but can be fatal, especially in people at high risk for listeriosis: older adults; young children; people with compromised immune systems, such as cancer, diabetes, or HIV/AIDS patients; and pregnant women. In pregnant women, listeriosis can cause miscarriage, stillbirth, and serious illness or death in newborn babies.

What Causes Listeria in our Food?

If food is processed, packaged, or handled in unsanitary conditions, it can become contaminated with Listeria. This is of particular concern with ready-to-eat, refrigerated foods, such as luncheon meats and pates or meat spreads, because most of these are not reheated before eating – a step that would kill Listeria. In addition, unpasteurized milk and products made with unpasteurized milk can carry Listeria, as well as other dangerous bacteria, such as Salmonella and E. coli.

It’s very important to understand that, unlike most other foodborne bacteria, Listeria can grow at refrigerator temperatures. That means the longer foods contaminated with Listeria are stored in the refrigerator, the more opportunity Listeria have to multiply. What’s more, foods contaminated with Listeria can cross-contaminate surfaces they come into contact with – surfaces in the refrigerator and around the kitchen.

How can I prevent Listeriosis?

Consumers, especially at-risk consumers and those who take care of them, should follow these simple steps to help prevent listeriosis:

Avoid foods containing unpasteurized milk
- Wash hands with warm water and soap for at least 20 seconds before and after handling food. Clean refrigerators and other food preparation surfaces regularly and effectively. Wash the inside walls and shelves of the refrigerator, cutting boards and countertops; then sanitize them with a solution of one tablespoon of chlorine bleach to one gallon of hot water; and finally dry with a clean cloth or paper towel that has not been previously used.
Always wash hands with warm water and soap following the cleaning and sanitization process.
Wipe up spills in the refrigerator immediately.

For more information on Listeria and listeriosis see: