Myth 1: Microwave ovens cause cancer
False. Microwaves use electricity to generate electromagnetic waves that are similar to radio waves. The waves are not radioactive, nor do they cause food cooked in the microwave to become radioactive. Microwaves do not change the chemical components in food, and do not generate carcinogens. Health Canada has studied the health effects of microwaving foods and found no evidence of toxicity or carcinogen formation.
Caveat: Some microwaves may leak energy if not maintained properly. However there are no known health effects from this leakage.
Myth 2: Cooking food in a microwave kills bacteria that cause food poisoning
False. Don't assume that microwaving your food means you have killed harmful bacteria. One study that looked at a Salmonella outbreak following a picnic found that, of the 30 people who got sick from eating re-heated pork, all of them used a microwave oven to re-heat the meat.
The reason has to do with how microwave ovens work. Food is heated from the outside in -- not from the inside out -- which can result in cold spots where bacteria can thrive.
Tips: Cut food into small pieces and arrange them uniformly to promote even heating. For solid foods, add a little liquid to help foods cook more uniformly. For foods that need more time to cook, stir foods or rotate them at regular intervals.
Myth 3: Microwave cooking destroys the nutrients in food
False: Cooking food in the microwave often takes less time and uses less water than other cooking methods. The shorter the cook time and the less water used for cooking, the more certain that water-soluble vitamins are preserved, such as vitamin C, folate and thiamin. A study at Cornell University found that spinach retained nearly all of its folate when cooked in the microwave - but lost 77 per cent when cooked on the stove.
One difference: antioxidants found in vegetables. Research shows that, compared to boiling and steaming, microwave cooking destroys far more antioxidants. A study published in the Journal of the Science of Food and Agriculture found that microwaving broccoli on high power destroyed 97 per cent of one type of antioxidant. Steaming, on the other hand, resulted in a loss of only 11 per cent. The researchers speculate that high temperatures generated by microwave cooking may inactivate the enzyme that converts phytochemicals in cabbage-family vegetables to their active form.
Tip: Use as little water as possible (15 ml to every 125 ml of vegetables) when cooking vegetables in the microwave. The effect on water soluble vitamins is similar to steaming.
Tip: To maximize the amount of antioxidants you get from these vegetables, microwave on low power, steam, quickly saut�, or eat them raw! If, for some reason, you need to boil broccoli, save the leftover cooking liquid to add to soups, sauces, stews or vegetable juices.
Myth 4: It's safe to heat plastic containers in the microwave
True -- As long as they are labeled "microwave safe", plastic wrap and plastic containers are safe to use in the microwave. There is some evidence to suggest that certain plasticizers (additives used to make plastic flexible) called phthalates, can leach out and cause cancer and reproductive problems in animals. But the effect isn't clear in humans. Phthalates are commonly found in soft plastics, like the kind meat is wrapped in, and in take-out containers.
To ensure safe use of plastic containers or wrap in the microwave:
- Do not use plastic containers or wrap unless they are labeled "microwave safe". If it's not specified, use heat-resistant glass or Corning ware to prevent burns. Soft plastic containers like margarine tubs, yogurt containers, take out containers, whipped topping bowls, and other one-time use containers are not considered safe.
- Do not let plastic wraps touch the food when heating. Leave one inch between the food and plastic wrap when heating in the microwave. Do not use thin plastic storage bags, plastic grocery bags or aluminum foil in the microwave.
- Remove food from the store wrap before thawing or reheating in the microwave, unless the manufacturer has indicated that it's meant for microwave use.
