Dave Smith Appliance Service

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Questions of Microwave Safety

Of all household appliances, the microwave oven is probably the most mysterious.  Most people know little about how it operates, and rumors abound of radiation leaks and mutated food.  While some of these stories have small elements of truth behind them, trouble can largely be averted with more thorough understanding.  Furthermore, there are practical concerns that are less well known.  Keep in mind that all cooking methods have an amount of inherent risk.  With all things considered, microwave ovens are not a particularly dangerous way to prepare your meals.

How Does a Microwave Oven Operate?

At the heart of every microwave oven is a magnetron.  This device has a cathode ray inside it that sends out a stream of electrons just like an old-fashioned television set.  Each electron circles about in a magnetic field.  The stream of electrons resonates with pockets cut out of the surrounding metal, and microwaves are generated from these vibrations.

Microwaves are like radio waves, but with a shorter wavelength.  Microwave radiation is in no way similar to the ionizing radiation such as x-rays or gamma rays.  It is unrelated to alpha and beta radioactivity associated with nuclear waste.  Microwave energy is short-lived, easy to contain, and relatively safe.

Do not worry about your food emitting microwave energy after being cooked.  Food at only radiates infrared rays at these temperatures.

What Effect Do Microwaves Have On Your Food?

Microwaves heat up your food by moving the molecules around.  They make the electromagnetic field in the oven switch polarity rapidly, making polar molecules such as water and sugar alternate in orientation.  Vibrating particles produce heat through friction.

Frequently people think that microwave ovens destroy nutrients, but all methods of cooking change the nature of your food in various ways, including texture and nutrient levels.  Whether microwaving ovens will yield more or less nutritious food than other cooking methods is a complicated question.  It ultimately depends on what type of meal is being prepared.  For example, boiling corn on the cob in water causes much of the nutrition to be leeched into the water; microwaving corn on the cob retains more nutrients.

Various poisonous chemicals can be released by your microwave oven if you insert improper materials.  For example, unwholesome plastic molecules loosen from containers and drift into your food.  Although products labeled “microwave-safe” are generally much safer than unlabeled products, the term “microwave-safe” is not regulated.  Some containers labeled as such do discharge toxins.  Foam trays should be discarded as well.  Paper bags and newspapers may contaminate your food or catch fire.  Surprisingly, many microwave popcorn bags contain a carcinogen named perflourooctanoic acid, a residual from the manufacturing process.


Will Your Appliance Leak Microwaves?

Your microwave oven is designed to keep all of its rays inside the oven cavity by means of reflective shielding.  You must never run your microwave oven without anything inside.  If you do, energy will build up in the cooking chamber, and your appliance might leak microwaves or damage itself.  Also, ovens with worn down door gaskets can expel microwaves.  When there is a leak, it is usually strongest at the surface of the appliance and rapidly diminishes as distance increases.  It is not healthy to be exposed to microwave energy; if you are concerned, you can have your appliance tested.  Contact us at Dave Smith Appliance Services, and we can test your microwave oven either in shop or at your home.

Remember that the microwave oven is more secure than it seems.  It looks as if rays can seep through the small holes in the window.  However, the electromagnetic waves, being almost five inches long, simply cannot make their way through a space that tiny.  An additional safety feature is that there are two independent systems that shut down the appliance whenever the door opens.

How Does Metal React with Your Microwave Oven?

Metal reacts differently inside the microwave oven than other substances.  Instead of vibrating the molecules, electricity passes freely through metal, sometimes reflecting the electromagnetic waves, other times producing electrical currents.  Arcs, like tiny lightning bolts, can form as the air becomes ionized around the metal.  They can poke holes in the walls of the microwave and make scorch marks.  A fire may start.  If any arcing occurs, turn the microwave off right away.  Large hunks of metal lack resistance and produce little heat, but light coats of metal too thin to pass electric currents are exceptionally sensitive to the microwaves and will flash and spark and heat even to melting temperatures.

People will unknowingly put metal into the microwave oven occasionally.  Many plates have inconspicuous decorative metallic paint on them.  Merely a small staple on a teabag can create problems.

Since metal redirects electric fields, wrapping a food item, such as a baked potato, in foil will shield it from microwaves.  Your food will go uncooked and your oven will be damaged as if it had been run with nothing in it.

On the other hand, sometimes metal is alright to microwave.  Some microwave ovens come with metal racks or turntables that are shaped and situated in such a way that the waves do not conflict with them.  Be careful though, because there will be problems if these racks are positioned incorrectly.  Many foods packaged in foil are safe to microwave if you follow the instructions on the container.

Can Arcing Occur Any Other Way?

Situations not involving metal can also lead to arcing.  Hot dogs and raw carrots, because of their shape and conductivity, can channel electrical currents and prompt violent reactions in your microwave oven.  Cooking multiple objects at once can set off form arcs in between them.  One especially irritating source of arcing is from food splatters on the walls.  These also emit odors and smoke.  You can clean these stains up easier if you do it right away.  If they are being stubborn, first soften them up by boiling some water in the cooking chamber with a pinch of baking soda or lemon juice.  Furthermore, internal malfunctions in your microwave can cause arcing.

Why Does Water Sometimes Explode After Being Microwaved?

When water temperature rises above boiling point, bubbles normally form to cool it off.  Water molecules transition into a gas state only when they can separate from the molecules around them.  If water is microwaved in a very smooth glass with nothing else in it, there is nothing to disturb the symmetry of the molecules, and they stay in a liquid state.  When you disturb this superheated fluid by picking it up or sticking a spoon into it, your entire drink can erupt in a chain reaction as froth suddenly materializes throughout the vessel.  Scalding water would then burst in all directions.  To prevent this catastrophe, you can stick a wooden spoon, toothpick, coffee grounds or the like into the water before turning the oven on to ensure that there is a place for bubbles to establish themselves.  Pieces of cookware labeled as “microwave-safe” are meant to have textures that prevent superheating.

Does Your Microwave Oven Thoroughly Eliminate Bacteria?

Although it is counterintuitive, it may be that one of the greatest risks that microwaved food poses is bacteria.  This is because microwave ovens cook foods unevenly, and potentially dangerous bacteria will remain in cold pockets of food.  Material far from the source of the microwaves is going to be less heated.  Interior portions of your meal will be more shielded from rays.

To make your food cook more evenly, occasionally rotate it, turn it upside down, or stir it.  Arrange it evenly.  Many microwaves have turntables.  If you are not concerned about your food getting soggy, add water.  This will allow hot and colds fluids to flow and even out the temperature.

Should You Be Worried About Your Microwave?

Now that you have a grasp of what exactly a microwave oven does and what can go wrong, you can make up your own mind about this appliance.   Remember, other methods of cooking present safety risks as well.  Stovetop burners can catch fire to nearby materials, such as napkins, towels, or even loose clothing.  Natural gas leaks go undetected by individuals who have a poor sense of smell.  Your house could become flooded with odorless carbon monoxide gas.  These are hazards that simply are not present with your microwave oven.  At the end of the day, a careful examination of your microwave oven reveals a well-designed, safe, and convenient household appliance.

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