Today, many households rely on microwave ovens to whip up quick and nutritious meals. Here’s a guide to avoid some of the health hazards believed to be caused by this gadget

Few know that World War II gave birth to a gadget that we take for granted in our homes today — Percy Spencer, an American engineer, was inspired by radar technology used in the war to invent the microwave oven. When you switch on your microwave oven, an inbuilt tube called the magnetron produces low levels of electromagnetic radiation (also called microwaves). This radiation causes the water molecules in your food or liquid to vibrate. These molecules spin millions of times every second, creating a friction so intense, that it generates heat, enough to have your food piping hot in seconds or to cook raw foods thoroughly.

Microwave radiation — are we at risk?

While the microwave is such a convenient gadget, the debate still rages about whether it is completely safe. You may not be aware that a tiny amount of radiation leaks every time you use it. These leakages are strictly controlled by manufacturers today, but the effects caused by such exposure have not been properly studied or documented.

No large-scale tests have been conducted to find out whether these low levels of radiation can eventually become harmful when accumulated over the course of years, something worth considering if the microwave is a fixture in your kitchen and you use it often. In any case, these ovens are designed so that radiation stops once you open the door. If your microwave doesn't close properly or has defective hinges, have it serviced right away. Also, purchase models only from reputed companies.

The Food Safety and Inspection Service of the USDA (United States department of agriculture) and the World Health Organisation both maintain that food cooked in the microwave does not become radioactive in any way and is perfectly safe to consume, but there are other precautions that would help prevent the hazards.

Select safe containers

Glass is the safest for microwave cooking, followed by ceramics and plastic. One must use specially manufactured, appropriate containers, even if you're only reheating foods for a minimal time. This is important, because when you close the microwave door, electromagnetic radiation is reflected around the small compartment. While this radiation passes through containers made of glass, plastic and ceramic, it can set fire to aluminium or steel. “Avoid re-using cheap plastic containers (the kinds that usually contain leftovers from restaurants) or old ice cream tubs in the microwave as these cannot withstand high temperatures. They melt easily and the plastic from the container can leech into your food or drink. Aluminium foil should also be avoided, as even the slightest trace can set off sparks and cause damage to the oven. The bowls, wraps and lids used must be labelled ‘safe for microwave cooking,’" says Saritha Rajiv, senior nutritionist and dietician, who runs the Nutrifill clinics ( in Goa.

Ensure food retains its nutrients

"It is a myth that microwave cooking destroys all the nutrients in food," says Hemangini Hoskote, senior nutrition consultant, based in Gurgaon. "Studies have also established that when compared to other methods of cooking such as frying, boiling and pressure-cooking, microwaving results in smaller losses of nutrients. Vegetables cooked in a microwave retain antioxidants and Vitamin C. This kind of cooking is ideal for meat too as it prevents charring and does not produce a significant amount of cancer causing compounds. But the most important benefit from a nutritional perspective is that you can make tasty food with a minimal amount of oil."

In order to prevent nutrient depletion, Hemangini advises keeping an eye on the settings. “Ensure that the power is not too high and regulate the time the food is exposed/cooked," she says.

Navigate hot and cold spots

One of the challenges of microwave cooking is to cook food evenly. “If big chunks of meat or food are being thawed, defrosting can take place unevenly. This can leave certain areas frozen or cold. Harmful microbes can thrive in these areas and cause food poisoning," warns Saritha. “To avoid this, use a food thermometer to check the internal temperature of the food being cooked. This will allow you to check for cold spots and re-heat if required. Also, keep the lid of your container slightly open (while microwaving) to allow steam to escape," she says.

Stirring the food at least once midway while cooking can help distribute the heat evenly. “If you're cooking rice for 6 minutes, stop the microwave in 3 minutes and stir the rice. This results in well-cooked grains,” advises Hemangini. “Cut food into smaller pieces and debone larger pieces of meat before microwaving. Roasting dry foods such as semolina is best done when it is spread over in a plate rather than in a bowl. Place thicker/larger portions of food towards the outside of a dish and allow a standing time of at least two minutes after the food is cooked. If you're cooking eggs, pierce the shell several times or slightly crack a corner of the egg, otherwise the build-up of steam may cause it to explode.” Be wary of scalding, especially while heating liquids.

When used appropriately, the microwave can be a great tool to prepare a nourishing diet.

The author can be contacted at