Food Poisoning Myths

By Kathleen M. Zelman, MPH, RD, LD
WebMD Feature

MYTH: Mayonnaise is often the cause of food-borne illness.

REALITY: Mayonnaise does not cause food poisoning, bacteria do. And bacteria grow best on foods that contain protein and are at temperatures between 40-140 degrees F. Commercially prepared mayonnaise is safe to use. At greater risk for developing bacteria are the foods mayonnaise is commonly mixed with for picnics and potlucks, such as pasta, potatoes, eggs, chicken, or tuna. But even these will be safe if you keep your cooler below 40 degrees F.

"Small, cut-up surfaces allow the bacteria to grow in the right environment," says Mildred Cody, PhD, RD, head of the nutrition division at Georgia State University. "Try taking whole foods like cherry tomatoes that are easy to eat and leave the mixed salads at home unless you can store them properly."

MYTH: Washing your hands briefly before you start preparing food is enough to keep you safe.

REALITY: Hands need to be washed often and properly, before and after touching food, and after using the bathroom, changing diapers, or handling pets.

"Proper hand washing requires warm, soapy water; a clean paper towel; and 20 seconds of scrubbing between fingers, under nails, and up to your wrist," explains Britt Burton-Freeman, PhD, MS, nutrition director for the National Center for Food Safety and Technology.

MYTH: As long as you cook eggs, they're safe to eat.

REALITY: You can safely enjoy your eggs over easy, but not sunny-side up. "Cook the eggs by flipping once so that the egg white is completely cooked and the egg yolk is starting to gel to ensure a safe egg," says Egg Nutrition Center nutrition director Marcia Greenblum, MS, RD.

MYTH: Using the same utensils, cutting boards, and plates for foods eaten at the same meal is safe as long as they start out clean.

REALITY: Raw meat and other foods contain bacteria that can cross-contaminate other foods if not kept separate. Use separate utensils, cutting boards, and serving plates for meats and produce, or carefully wash them between tasks. Put cooked meat on a clean platter, not the same one that held the meat before it was cooked. Make sure sponges and counters are disinfected and kept clean to avoid contaminating food. "Dirty hands, dish towels, sponges, and countertops can also transfer bacteria or cross- contaminate, so be sure everything is clean before you start food preparation," says Burton-Freeman.

MYTH: If food is kept in a cooler, it will be maintained at the proper temperature.

REALITY: "Bacteria grow in the danger zone, which is anywhere from 40-140 degrees F, and when the weather is warm and you are eating outdoors, it is a challenge to keep food at or below 40 degrees F unless you take precautions," says food safety expert Cody. The only way to know for sure if your cooler or refrigerator is at the proper temperature is with a thermometer.

Cody advises packing raw meat in a separate cooler from other foods to avoid any potential cross-contamination from spilled juices. Pack your coolers tight with ice, store in a cool spot, and keep them closed until it is time to cook or serve the food. Keep drinks in their own cooler so you can open and shut it frequently without having to worry about lowering the temperature of the food.

MYTH: You can tell when meat is properly cooked by looking at it and pressing on it.

REALITY: Even the most talented chefs can't tell the exact temperature just by looking and touching. "The only way to know if a food is cooked properly to kill the bacteria is with a meat thermometer," says Cody. She warns against cooking meats partially ahead of time, then finishing them the grill on location because this promotes bacterial growth. Burgers should be cooked to an internal temperature of 160 degrees F.

MYTH: Food can be left at room or outdoor temperature for more than two hours.

REALITY: Because bacteria grow rapidly in the "danger zone" between 40 degrees F and 140 degrees F, food left at room temperature for more than two hours should be discarded. When the temperature outside is 90 degrees F or hotter, food should be discarded after just one hour.

MYTH: You can tell when food is spoiled because it looks or smells bad.

REALITY: Most of the time, you can tell if a food is spoiled -- but not always. Bacteria are invisible and you can't always tell if they are present. When in doubt, throw it out, food safety experts say.

MYTH: Misting at the grocery store adequately washes produce.

REALITY: Misting produce keeps it looking fresh, but don't mistake that for a proper cleaning. "Wash produce using cold streaming water (no soap or bleach) and where possible, use a soft scrub brush or in the case of greens, submerge it in a water bath to properly clean and reduce residuals and potential bacteria," says Burton-Freeman.

Produce with a thick peel, like bananas, may not need to be washed unless you are cutting into them with a knife. "Bacteria on the peel can be transferred to the interior with a knife, so melons and other thick-skinned fruits should be thoroughly washed," she advises. Bags of prewashed produce are considered safe, but consumers are advised to carefully inspect the vegetables before eating.