Why should I be aware of this?
Microwave cooking is a technological wonder that has revolutionized the way the world cooks. It is convenient, fast and highly energy efficient.
The advocates of microwave cooking say that it is a much healthier option to conventional cooking as it uses little or no oil and fat and yet cooks food evenly. They also maintain that the cooking process itself is a better way as most vegetables, fruits, fish and meat, when cooked in a microwave, use the natural water molecules in the food along with excess fat from the meat items. So according to the yes sayers, it is a tastier, healthier, more nutritious way to cook food.
They also say that Microwaves do not escape through the small perforations in the door, nor do they get out through the exhaust vents, because of the its inherent physical characteristics. So one is not in any danger due to radiation leak from a microwave oven.
 Microwave cooking and health
Some research has been done on what exposure to large amounts of microwave radiation does to the human body. The effects may vary from painful burns, to low sperm count to cataract. But not many studies have been done on what happens if humans are exposed to low levels of exposure, as happens from a microwave oven. Long term and controlled studies, involving large numbers of people have yet not been conducted to gauge the harmful effect.
There is a stream of thought that believes that the use of microwave ovens are dangerous to humans. Their belief stems from the fact that microwave ovens use alternating current (AC) creating frictional heat which has its strong impact on the human body and the food.
As far back as 1979, Soviet Union banned the use of Microwaves.
There are reports that have been published stating that consumption of food cooked in microwave ovens could cause cancer. They say that microwave cooking changes the basic nutrient structure of food.
And when we consume that, it can cause deterioration in the human system. This school of thought also maintains that besides changing the molecular nature of food through frictional heat, microwave cooking can also deform the structure of molecules. The violent change that microwaving causes to the food molecules forms new life forms called radiolytic compounds. This can create Carcinogens in Foods.
Many people also believe that microwave ovens do result in radiation leaks, which may be carcinogenic.
 Microwave cooking and radiation
Microwave radiation is electromagnetic radiation in the frequency range of 300 MHz - 300 gigahertz (GHz).
However food cooked in a microwave oven does not present a radiation risk as the oven doors are so designed that power is cut off immediately the door is opened. Microwaves cease to exist as soon as the power to the magnetron of a microwave oven is switched off. They do not remain in the food and are incapable of making either it or the oven radioactive.
 All about microwave cooking
 Microwave science
Microwaves are a form of electrical and magnetic waves or "electromagnetic" radiation. Electromagnetic radiation range from x-rays to the less energetic radio frequency waves used in broadcasting. Some of the other forms of this energy are the infrared rays, visible light rays and even electricity. For a microwave oven to work, this microwave radiation is used to cook or heat food. What helps this process more are the two unique characteristics of microwaves –
- Microwaves are capable of passing through paper, glass and plastic, even ceramics though not metal as metal reflects it back.
- Microwaves can be absorbed by food.
 How They Work
As the molecules of food absorb the microwaves, the food molecules begin to vibrate against one another inside the container. This movement ( which is also visible) causes heat to be produced, which in turn cooks the food. In a microwave oven, the outside layer is cooked first and as the heat is conducted to the inner layers, the food gets completely cooked. Which is why the quality of the container, placement of the food inside the oven and cooking quantity determine the efficiency of a microwave cooking.
It is also important to remember that even after the oven is switched off, the molecules still continue to vibrate and produce heat, hence the ‘cooking’ is still happening. Which is why one should not use it to boil water or oil, as on touching the container, it can cause a violent spillage.
Another point to remember is that different foods require different temperatures to cook evenly.
 What can I do about it?
 Some do's and don'ts
- Do read the instructions that come with each microwave oven about kinds of containers to use.
- Do not block the microwave vents.
- Do not switch on the microwave oven when empty as it can cause damage.
- Do not experiment with the microwave ovens. Use them to cook and heat only food and not for any other purpose.
- Do not place metal utensils inside the oven or use metal containers to cook food.
- Do make sure that the door of the oven is closed tight before switching it on to ensure no radiation leak.
- Do remove heated food with care, beware of superheated pockets that may have occured within the food; stir liquids carefully and allow all food to stand before consuming.
- Do clean the interiors of the oven after every use.
- Do unplug the unit from its main socket, when not in use.
 Microwave Cooking Tips
- Never cook whole eggs in the shell or food in sealed containers or pouches, and sealed plastic bags. There is the danger that the pressure build-up may cause explosions and, throw out the contents and cause severe burns.
- Always make a few slits before cooking a dish covered with plastic.
- Be careful when removing the lid of a dish that has recently been removed from a microwave. The direct steam can hurt if directed at the face.
- Never heat oil. It can be very dangerous.
- Potatoes, tomatoes, egg yolks, and other foods with a skin or membrane must be pierced before they are microwaved. This allows the steam to escape and keeps them from exploding.
- Vegetables cook faster in microwave oven. Microwave works best with foods that have high moisture content.
- Always add salt after the cooking is over as salt has a tendency to suck water from the food and so does not allow it to cook in an optimum way.
- Always use the lowest cooking time specified in your recipe.
- In order to make sure that the heat inside a dish is evenly distributed, one can use a cone in the center. It also helps to use more round cooking dishes.
- Never use the microwave for heating a baby's bottle. It may seem cool to the touch from outside but the really hot milk inside can burn a baby. Also the steam in a closed container, such as a baby bottle, could cause the contaner to explode not to mention the loss of some vitamins in infant formula milk due to the heating process.
- Never heat breast milk also in the microwave.
- If one is baking in a microwave oven, it is better to leave the cake mixture (with the baking powder) remain undisturbed for some time before baking.
- No one ever set out to discover the microwave oven. It was an accidental discovery.
- An engineer named Percy Spencer ,who worked at the Raytheon Corporation, invented the first microwave oven in 1946.
- Microwaves can also be used to cure resins and rubber.
- Sugar can be easily caramelized in the microwave without a mess.
- Vegetables retain their natural fresh color and texture when cooked in the microwave.
- Food Safety.gov