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Listeria prevention techniques you can take in the kitchen to stay safe

With listeriosis in bagged lettuce being in the news I have been answering questions through emails and phone calls. Several of you have suggested I address the subject in my column.

So, what is listeriosis? Listeriosis (lis-tier-e-O-sis) is an infection caused by the bacterium Listeria monocytogenes (MONO-cy-TAH-gin-ees). The disease occurs worldwide, but is diagnosed more often in humans in urban areas in developed countries. Few people get listeriosis, but it is an important disease because of its high death rate due to brain inflammation and blood infection. The disease primarily affects newborns, pregnant women, older adults and people with weakened immune systems.

The general guidelines recommended for the prevention of listeriosis are similar to those used to help prevent other foodborne illnesses, such as salmonellosis. In addition, there are specific recommendations for persons at higher risks for listeriosis. All of us in the food safety education business recommend the following for washing and handling food.

First, rinse raw produce such as vegetables and fruits under running tap water before eating, cutting or cooking. Even if the produce will be peeled, it should still first be washed with tap water.

Produce that is firm such as melons and cucumbers should be scrubbed with a clean produce brush. It is also a good idea to clean the brush with hot soapy water and a little bleach, or place the brush in the dishwasher. Once you have the produce rinsed you need to get it dry. Dry the produce with a clean cloth or paper towel. Always remember when placing food in the grocery store cart, grocery bags and refrigerator to separate uncooked meats and poultry from vegetables, cooked foods and ready to eat foods.

You and your family need to keep your kitchen environment clean and safe. Develop the habit of washing hands, knives, countertops and cutting boards after handling and preparing cooked foods. You need to know that Listeria monocytogenes can grow in foods in the refrigerator. Use an appliance thermometer, such as a refrigerator thermometer, to check the temperature inside your refrigerator. The refrigerator should be 40 degrees Fahrenheit or lower and the freezer 0 degrees Fahrenheit or lower. This reminder goes along with keeping the refrigerator clean. Everyone should clean up spills in the refrigerator right away with a dish cloth and hot soapy water.

When it comes to planned-overs, divide food into shallow containers to promote rapid, even cooling. Cover with airtight lids or enclose in plastic wrap or aluminum foil. Use leftovers within 3 to 4 days. Do not eat or drink unpasteurized milk products. Pregnant women or people with weak immune systems should avoid soft-style cheeses and deli meats.

Use precooked or ready-to-eat food as soon as you can. Do not store the product in the refrigerator beyond the use-by date. Follow USDA refrigerator storage time guidelines. With hot dogs, store opened package no longer than 1 week and unopened package no longer than 2 weeks in the refrigerator. With lunch and deli meat, store factory-sealed, unopened package no longer than 2 weeks and store opened packages and meat sliced at a local deli no longer than 3 to 5 days in the refrigerator.

Remember to thoroughly cook all food, especially meats. Beef, pork and poultry need to be cooked to a safe internal temperature. For a list of recommended temperatures for meat and poultry, visit the safe minimum cooking temperature page at

For more recipes and tips from Purdue Extension Educator Mary Ann Lienhart-Cross, subscribe to the Food & Nutrition email newsletter.

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