Is Microwaving Food Hazardous?

3 Mins
April 3, 2017

The microwave technology, since the mid-20th century, has made significant contributions to the way we handle and even process food. This has come not without consumer concerns about the effect of the technology on the quality of the food and the long-term health implications. Readers from across the globe have asked me about whether or not it is safe to use microwave to warm our foods and what the consequences on health might be. All of these concerns will be addressed in detail in this post.

How it works

Basically, the microwave oven operates using a form of electromagnetic waves (waves that have both electrical and magnetic energies) similar to the waves that enable us to receive radio signals, however, microwaves are smaller (in terms of wavelength). This electromagnetic wave is referred to as the microwave radiation. When you turn on a microwave oven, it supplies the food in the oven with these microwave radiations causing some molecules in the food such as the water molecules to vibrate, generating heat within the food. And it is with this heat generated in the food that the food is heated and/or cooked. So, foods that have more water in them will become evenly hotter faster as compared to those that have less water.

In fewer words, the microwave oven exposes the food to microwave radiation which heats up the water in the food thereby heating or cooking the food. Nonetheless, studies have shown non-uniformity in the distribution of temperature in the food after microwaving it pointing out that in several instances when you heat food, the part of the food closest to the corners and walls of the container becomes steaming hot while the center of the food becomes nippy.

Microwave radiations: are they safe?

In recent times, the word radiation has sparked up conversations about safety across board; from the phone industry to healthcare. These concerns arise because at certain doses, some radiations could cause biological changes in the body in a manner that could threaten life. Microwave radiations from a microwave oven pose a health risk when you are exposed to large doses of the radiations through leaks from gaps around the door and seals of the oven. Leakages of the microwave radiations could affect your eyesight especially if you stand directly in front of the oven while it is operating. Though microwave ovens are built to prevent such high-level leakages, it is advised that you adhere to the following when operating the microwave oven as prescribed by the FDA

  • Always adhere to the manufacturer’s manual for operating the microwave oven
  • Use only cookware that is safe for use in a microwave oven. Ideally, the one provided by the microwave manufacturer. Don’t use materials made of polythene, polystyrene or rubber to warm food in a microwave oven as some of these materials may undergo some chemical changes which may lead to the release of certain chemicals into the food which may be harmful. Materials such as glass and ceramic do not cause any     problems.
  • If the microwave oven door is unable to close firmly, bent or damaged, do not operate the oven.
  • A microwave oven that continues to operate when the door is open should not be used at all.
  • Also, don’t stand directly in front of the oven for long periods of time while it is operating. This applies to children too.
  • Do not heat water or liquids in the microwave oven longer than what is recommended by the manufacturer.
  • Some ovens should not be operated when empty. Refer to the instruction manual for your oven.
  • Regularly clean the oven cavity, the outer edge of the cavity, and the door with water and a mild detergent. A special microwave oven cleaner is not necessary. Be sure to not use scouring pads, steel wool, or other abrasives.

It is evident that the container and/or the lid used to contain and/or cover the food for microwaving has an effect on the food which may have health consequences. It is therefore important that you bear the following in mind:

  • Plastic wraps may melt so do not use them to wrap or cover food for microwaving. Wax paper, kitchen parchment paper and white paper towels are better alternatives.
  • These are not microwave-safe: most takeout containers, water bottles, and plastic tubs or jars made to hold     margarine, yogurt, whipped topping, and foods such as cream cheese, mayonnaise and mustard.
  • Takeout dinner trays that are microwave-safe will indicate they are microwave-safe on the package and are made for one-time use only.
  • Either lift the edge of the cover or leave the lid completely open before you microwave food.

 Does microwaving food affect the nutrients?

Microwaving food does not make the food radioactive, as some believe. Generally, some nutrients are affected by heat. A good example of such nutrient is vitamin C. Nonetheless, comparing popular methods of cooking, microwaving foods containing vitamin C helps to preserve the vitamin C which would have otherwise been lost.

In the case of certain vegetables like cabbage and broccoli some components in the vegetables that help prevent cancer when eaten is lost when the vegetable is microwaved for 2 minutes or more. For such vegetables, you get more of the health benefits of consuming them when you steam them for less than 7 minutes as this would preserve more natural components which confer certain health benefits on them.

In a nutshell, microwave ovens are very helpful and do not pose any health threats when used following the guidelines listed above.

What have your experiences with microwave ovens been? Share them with us in the comments box below. Also share this article with a friend who will need to know this.

Hello! I am Bezalel Adainoo, the author of Stay Well Now. My friends call me Bez. As a professional food scientist, I have been asked many questions by people from different walks of life seeking the right information on what food to eat and how that will affect their health.