One of the top foodborne bacteria that causes illness, Listeria is a scary prospect, especially if you are pregnant or have a weakened immune system. Most commonly found in ready-to-eat meats, raw sprouts, and unpasteurized milk and dairy products, this bacteria is different from others in its ability to grow in your refrigerator. But heat kills the hardy bacteria and it does not grow in dry baked items.
Listeria monocytogenes is the name of the bacteria that causes listeriosis. Found in water, soil, poultry and cattle, this bacteria only becomes dangerous when it enters your body through contaminated foods. Food most often becomes contaminated in processing plants when equipment becomes contaminated and spreads the bacteria to other items as part of processing. This powerful bacteria that is present all around you can continue to grow at a slow rate during refrigeration, but is killed by cooking and pasteurization.
Baked Goods and Listeria
Baked goods that are shelf stable are not at risk of growing Listeria, as the cooking process kills the bacteria. Listeria is killed when cooked at 158 degrees Fahrenheit for two minutes. Baked goods are commonly cooked to temperatures ranging from 170 to 210 F, so they don't pose a risk. It's still important to handle and store baked goods properly to avoid other sources of foodborne illness. Store baked goods in a covered container and wash your hands before serving or handling baked items.
High-Risk Listeria Foods
The foods that are at highest risk for becoming contaminated with Listeria include processed meats, such as lunch meats and hot dogs, cheeses and other products made from unpasteurized milk, refrigerated smoked salmon and refrigerated pate or meat spreads. If a healthy adult eats these foods, it might not cause a huge problem, but can cause serious illness if you are pregnant, elderly or suffer from other illness that mean you have a suppressed immune system. If you become ill with fever and a stiff neck after eating these high-risk foods, seek medical attention immediately, as antibiotics can prevent serious complications when administered early.
While dry baked goods are not at risk for growing Listeria, the bacteria can be transferred to almost any item in your kitchen if your kitchen becomes contaminated with the bacteria. Store all high-risk foods and uncooked meats away from vegetables, fruits and cooked foods and regularly clean your counters and refrigerator after preparing raw meats in your kitchen. Always rinse fresh fruits and vegetables thoroughly before serving when eating raw and wash your hands, utensils and cutting boards thoroughly after use. If you are in a high-risk group due to a weakened immune system, always cook all meats thoroughly.
- U.S. Food and Drug Administration: Food Safety for Moms-to-Be: Listeria
- Department of Health, Victoria, Australia: Listeria - the facts: Advice for pregnant women, the elderly and anyone with suppressed immunity
- FoodSafety.gov: Listeria
- The Ohio State University Extension Research: A Review of Listeria monocytogenes –A Pathogen That Likes Refrigerated Temperatures
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