Microwaving Meltdown? Is it Safe to Microwave Plastics?

Posted in Food Safety on July 16, 2018

In this fast-paced world, we are always looking for things to make our lives easier.  But at what cost.  Take the simple task of re-heating food.  While some people may have the time to prepare and cook a full meal three times a day, most of us opt for leftovers for lunch or even “plan-overs” for an additional dinner.  I often cook a meal that will last for at least 2 days to cut down on kitchen time.

Depending on the meal, you might want to consume it hot.  Some meals are best served cold, such as tuna, potato, or pasta salad.  Maybe even slices of pizza if your desire it.  But for the most part you are going to want to re-heat it.

In the modern kitchen you might have a few options.  Reheat on the stove or in the oven.  Maybe even the toaster oven.  For some items the steamer works quite well.  This often leads to additional dishes, and let’s face it…  Less time re-cooking food means more time enjoying it and more time with your family.  This is exactly the dilemma the modern family faced in the mid-sixties to seventies, when microwaves begin rising in popularity.  Microwaves helped take the mom out of the kitchen for the hours at a time that she would typically spend.

How Exactly Do Microwaves Work?

A microwave is not just the name of an appliance, but the type of energy used by the appliance.  You may have heard of sound waves or light wavelengths.  Well, a microwave is very small, measuring about 12 cm or around 5 inches.  Other radio waves are often much longer, often measuring tens of kilometers or miles between one wave crest and the following one.

You might be wondering how the microwave actually heats the food.  Inside the metal box shell of your microwave is a magnetron.  This is simply a microwave generator.  The appliance takes the electric power from the wall outlet and converts it into high powered, short radio waves.  These waves are aimed through a channel called a wave guide.  The waves bounce off the inside of the microwave and penetrate the food.  As the microwaves pass through the food, they make the molecules in the food vibrate really fast.  This vibration is what causes the food to heat.  The faster the vibration, the hotter the food becomes.

Microwaving Plastic.  What You Need to Know.

You might know that there are certain things that cannot be put into a microwave.  Metal and microwaves do not mix, much like electricity and water.  But what about plastics?

The biggest fear right now is BPA or bisphenol-A that is used to make clear, hard plastics.  The lesser household named material, phthalates, are used to make more soft, flexible plastics are also a concern.  What happens to these products as they are heated.  Many people worry that the chemicals contained will leach into our foods when heating.

One big buzz word is “dioxins.”  Dioxins are released into our food when plastics are heated and cause cancer.  While yes, dioxins are a thing, and they are released when items such as wood, metal, and plastics are burned, unless you are burning your food or the plastic container in the microwave (and using a microwave safe container), you should be good.

While not all plastic material can be microwaved, many forms of plastic can.  The easiest way to identify what is safe and what isn’t is as simple as looking for the microwave icon.  The microwave icon looks like three horizontal wavy lines and should be present on the plastic item, often on the bottom.  This symbol is regulated and approved by the U.S. Food and Drug Administration (FDA).  In fact, the FDA regulates this in plastic materials, citing that containers bearing this mark undergo stringent testing that limits the chemical leaching from the plastic to be no more than 100 to 1,000 times less than what is shown to harm lab animals.

If there is no label on the product, it doesn’t necessarily mean that you cannot heat the container in the microwave, as many plastic products are perfectly safe to do so.  It just means that it has not been tested to be proven save.

Microwaving Tips

First, look for the microwave safe icon.  Without the icon, it is unknown whether the product is safe enough to be heated in the microwave.  When in doubt you can go conservative and opt to avoid plastic all-together by transferring food to glass or ceramic containers that are labeled for use in microwave ovens.  Yes, you should still be looking for a microwave safe icon there.

When covering food in a microwave, avoid plastic wrap.  Opt for kitchen parchment paper, paper towels, or a domed container that fits over the plate or bowl as a better option.

While we often hear “reduce, reuse, recycle” as a method of conservation, not everything can be re-used.  And certainly not everything should be heated in the microwave.  Your butter tub or whipped topping container might be safe for refrigerator storage.  But do not place in the microwave.  Pay close attention to plastic take-out containers.  Not all of those containers are safe to use in the microwave.  Look carefully for the microwave safe icon or explicit wording indicating it has been tested safe.

Some containers are only labeled to be heated once.  If this is the case, the product will say so on the packaging.  For these, a one-time-use is about all you will get out of it.

Heavily worn containers such as old or scratched and cracked containers may not be as safe as they once were.  Containers that have been microwaved many times may leach out more chemicals.

Plastic storage bags such as zipper seal bags or grocery store bags are not meant to microwave.  Heating food in these thin plastics is dangerous and should not be done under any circumstance.

For best results, vent the container when you are microwaving food.  This can be achieved by leaving the lid slightly ajar or by lifting the edge of the cover.

Companies Respond to Movement

As more people become aware of potential health risks associated with unsafe plastic storage, companies known for their plastics have needed to keep up.  Tupperware, for example modified their plastic makeup to conform to the desires of their customers.  Rubbermaid followed suit a little time after.

According to the Tupperware,

“Tupperware follows the recommendations and guidelines of governmental regulatory agencies regarding materials that may be used in our high quality products. The Company also acknowledges the attitudes of consumers regarding products containing BPA. In its continuous search for the best materials for use in its products, Tupperware has found other materials with improved performance characteristics that have been approved by regulators to be BPA free to replace polycarbonate. As of March 2010, items sold by Tupperware US & CA are BPA free.”

According to Rubbermaid,

“In 2011, Rubbermaid Commercial Products decided not to enter the debate over BPA. It decided to eliminate the risk entirely along with any concerns about the safety of its products. In all, 169 Rubbermaid SKUs were affected, including items from their food storage, food preparation, table service and food transportation lines. Rubbermaid set out to manufacture all these SKUs from a BPA free compound. By February 2012, Rubbermaid Commercial will have achieved its goal!”

What will you choose the next time your meatloaf needs reheating?  Personally, I turn to Tupperware or Pyrex depending on the nature of the food item.  Both satisfy my need for convenience and frugality of time.

By: Heather Van Tassell, Contributing Writer (Non-Lawyer)