Ready-to-eat ham, deli meats and turkey have the greatest risk of carrying disease-causing, potentially deadly listeria bacteria and should be consumed shortly after purchase, says the U.S. Food and Drug Administration.

A new FDA study shows that consumers can follow to simple steps to reduce the risk of illness or outbreaks from Listeria monocytogenes by more than 50 percent. All consumers need to do is to keep refrigerated foods stored at 40 degrees Fahrenheit and use perishable items that are precooked or ready-to-eat as soon as possible.

"This risk assessment clearly demonstrates that manufacturers, retailers, and consumers alike can all take simple actions to drastically reduce the risk of listeriosis," says Mark B. McClellan, FDA commissioner. "To minimize the risk of this foodborne illness, perishable and ready-to-eat foods should be transported, offered for sale, kept at 40 degrees Fahrenheit, and used as quickly as possible. Food manufacturers should build on their progress to reformulate and monitor susceptible foods to prevent significant levels of Listeria monocytogenes."

The study evaluated the risks associated with many foods including these food categories: seafood, produce, meats, dairy products and deli-type salads.

FDA estimates that Listeria monocytogenes causes 2,500 serious illness and 500 deaths each year. If consumers and food processors follow its recommendations, FDA estimates the number o flisteria cases could be cut in half.

Foods with the highest listeria risk are deli meats, hot dogs, pate, unpasteurized milk, smoked seafood, and ready-to-eat shrimp and crabs, according to the FDA. Soft cheeses, such as cottage cheese and cream cheese, were rated as a moderate risk. Better alternatives are reheated luncheon meat and canned meat and seafood, along with cheese made with pasteurized milk.

The risk assessment is available on the FDA Web site at http://www.cfsan.fda.gov, www.foodsafety.gov http://www.foodsafety.gov, and at www.foodriskclearinghouse.umd.edu