Had the microwave oven not been invented, i'd have starved to death long ago . . .
No Link Between Microwave Cooking and Cancer, Expert Says
Auburn, Sept. 10, 2002 --- An Alabama Cooperative Extension food scientist has this advice for people disturbed by a widely forwarded e-mail claiming that microwave cooking of food in plastic wrap causes cancer: Relax.
In fact, if you're really intent on reducing potentially harmful trace amounts of carcinogens in your food during cooking, she advises giving your frying pan a rest instead.
The e-mail, which has since proven to be largely a hoax, claims a seventh-grade Arkansas student discovered that two supposedly cancer-causing substances, DEHA and dioxin, leach into food from plastic wrap during microwave cooking.
Part of this is true. A seventh-grade Arkansas student named Claire Nelson was, in fact, curious to learn whether potentially harmful chemicals released from heated plastic during microwave cooking ended up in food.
It's also true that Nelson, working with the FDA-affiliated Center for Toxicological Research in Jonesboro, Ark., tested the effects on olive oil enclosed in plastic wrap during microwave cooking. Her testing revealed that one of the substances, known by its initials DEHA, turned up in trace amounts in the oil after cooking and migrated into the oil at between 200 parts and 500 parts per million. The current FDA standard for DEHA is 0.05 parts per billion.
DEHA is a phthalate, one of many types of plasticizers commonly added to plastics to enhance their flexibility.
Likewise, xenoestrogens, believed to reduce sperm-count levels in men and cause breast cancer in women, also were found in the oil. However, it was difficult for Nelson to determine how much was too much, since there currently are no FDA guidelines establishing tolerance levels for xenoestrogens in foods.
This much is true.
What is not true is that DEHA is a known cancer-causing agent or that dioxin was one of the substances uncovered during testing, says Dr. Jean Weese, an Alabama Cooperative Extension System food scientist.
"While some forms of phthalates have been shown to cause health effects, including cancer, in laboratory mice and rats, DEHA isn't one of them," Weese says.
"In fact, the most recent studies involving DEHA and some other phthalates have shown no link with cancer," she adds, stressing that the EPA and the European Union agencies currently do not recognize DEHA as a known carcinogen.
Equally untrue is the claim that dioxin is produced from plastic wraps during microwave cooking. While dioxin is a serious health risk, causing a variety of health problems, including cancer, Nelson's studies turned up no evidence that dioxin was released into food during microwave cooking.
"It is true that dioxins are produced by the burning of plastics, especially polyvinyl chloride, but to my knowledge, no scientific study has ever shown that dioxins are formed in plastics heated by microwaves," Weese says.
Indeed, frying is the only form of cooking that has ever been associated with the production of trace amounts of dioxins in food. The problem stems from the fact that oils and fats typically used in frying contain triglycerides.
"Once these substances reach high temperatures from frying, the fats attached to this glycerol backbone begin breaking down into peroxide and other substances, including, in some cases, dioxins and PCBs, another known carcinogen," Weese says.
Under the circumstances, she says, consumers would be better off putting away the frying pan and broiling your food instead.
She also offers this advice to consumers who still harbor any lingering concerns about using plastics in the microwave.
First, use only cookware that is labeled for use in the microwave oven.
Second, avoid using plastic storage containers such as margarine tubs, takeout containers and other one-time use containers, all of which can melt or warp, possibly causing chemicals to migrate into the food.
Third, never use thin plastic storage bags, brown paper, plastic grocery bags, newspaper or aluminum foil in the microwave oven.
On the other hand, microwave plastic wraps, wax paper, cooking bags, parchment paper, and white microwave-safe paper towels are safe to use. And to be extra safe, be sure to not let plastic wrap touch foods during microwave cooking, Weese advises.
(Source: Dr. Jean Weese, Extension Food Scientist)
From the USDA:
Cooking Safely in the Microwave Oven
Microwave ovens can play an important role at mealtime, but special care must be taken when cooking or reheating meat, poultry, fish, and eggs to make sure they are prepared safely. Microwave ovens can cook unevenly and leave "cold spots," where harmful bacteria can survive. For this reason, it is important to use the following safe microwaving tips to prevent foodborne illness.
Microwave Oven Cooking
Arrange food items evenly in a covered dish and add some liquid if needed. Cover the dish with a lid or plastic wrap; loosen or vent the lid or wrap to let steam escape. The moist heat that is created will help destroy harmful bacteria and ensure uniform cooking. Cooking bags also provide safe, even cooking.
Do not cook large cuts of meat on high power (100%). Large cuts of meat should be cooked on medium power (50%) for longer periods. This allows heat to reach the center without overcooking outer areas.
Stir or rotate food midway through the microwaving time to eliminate cold spots where harmful bacteria can survive, and for more even cooking.
When partially cooking food in the microwave oven to finish cooking on the grill or in a conventional oven, it is important to transfer the microwaved food to the other heat source immediately. Never partially cook food and store it for later use.
Use a food thermometer or the oven's temperature probe to verify the food has reached a safe temperature. Place the thermometer in the thickest area of the meat or poultry?-not near fat or bone?-and in the innermost part of the thigh of whole poultry. Cooking times may vary because ovens vary in power and efficiency. Check in several places to be sure red meat is 160 °F, whole poultry is 180 °F, and egg casseroles are 160 °F. Fish should flake with a fork. Always allow standing time, which completes the cooking, before checking the internal temperature with a food thermometer.
Cooking whole, stuffed poultry in a microwave oven is not recommended. The stuffing might not reach the temperature needed to destroy harmful bacteria.
Microwave Defrosting
Remove food from packaging before defrosting. Do not use foam trays and plastic wraps because they are not heat stable at high temperatures. Melting or warping may cause harmful chemicals to migrate into food.
Cook meat, poultry, egg casseroles, and fish immediately after defrosting in the microwave oven because some areas of the frozen food may begin to cook during the defrosting time. Do not hold partially cooked food to use later.
Reheating in the Microwave Oven
Cover foods with a lid or a microwave-safe plastic wrap to hold in moisture and provide safe, even heating.
Heat ready-to-eat foods such as hot dogs, luncheon meats, fully cooked ham, and leftovers until steaming hot.
After reheating foods in the microwave oven, allow standing time. Then, use a clean food thermometer to check that food has reached 165 °F.
Containers and Wraps
Only use cookware that is specially manufactured for use in the microwave oven. Glass, ceramic containers, and all plastics should be labeled for microwave oven use.
Plastic storage containers such as margarine tubs, take-out containers, whipped topping bowls, and other one-time use containers should not be used in microwave ovens. These containers can warp or melt, possibly causing harmful chemicals to migrate into the food.
Microwave plastic wraps, wax paper, cooking bags, parchment paper, and white microwave-safe paper towels should be safe to use. Do not let plastic wrap touch foods during microwaving.
Never use thin plastic storage bags, brown paper or plastic grocery bags, newspapers, or aluminum foil in the microwave oven.
