Can You Microwave Styrofoam?

Can You Microwave Styrofoam

In today’s world of packaging convenience, there are increasing numbers of ready to eat foods that come packaged in Styrofoam. The accidental invention of the microwave, by Percy Spencer after World War II, contributed to today’s era of convenience foods. Frozen meals that used to require heating in the oven, could be manufactured to be cooked quicker and easier in the microwave. First sold for home use by Amana in 1967, a microwave is now a standard appliance for just about any household in America.

As the number of two working parent households increased, the microwave became relied upon by many to get dinner on the table in the limited time between homework, baths, and bedtime. But whether you’re a baby boomer, a parent raising children, or a single millennial in a college dorm, there’s still one question that comes up time and again, can you microwave Styrofoam?

What is Styrofoam?

Styrofoam is a type of plastic, it does contain toxic chemicals which could be transferred into your food when exposed to heat. Styrofoam can be put in the microwave but it can indeed melt if left in too long or if used to microwave the wrong types of foods. We’ve all heard the warnings about exposing plastics to heat, right? You may have at one time or another tried to microwave something on a Styrofoam plate or take out a container and felt momentary panic when you realized the Styrofoam bubbled up and melted.

Well like many plastics, in some cases Styrofoam can be designed by manufacturers to be microwavable or microwave safe. But when asking whether or not you can microwave Styrofoam, you should take some precautions as listed later in this article.

Different Types Of Microwaving Plastic?

Microwave Plastic

It was long thought that microwaving plastic could be hazardous to health due to something called dioxins that can be released into food. Dioxins have indeed been linked to cancer in some studies. But according to an updated September 2017 report by Harvard Health Publishing, dioxins are not themselves an inherent component of plastics. They are a chemical that can be created when materials such as plastic, wood, garbage, and even metal are burned. So burning food in a microwave when it’s in plastic or covered with plastic, can cause dioxins. But in truth, as long as the food in or covered doesn’t burn, dioxins are not a threat.

Even though dioxins are not a threat, there are in fact other issues with foods stored or microwaved in plastic, especially BPA plastic and phthalates. Both of these are endocrine disruptors and are not good for humans. When foods in BPA plastic or plastic containing phthalates are microwaved, these can be released into the food even when it doesn’t burn. This is more likely to happen with food high in fat such as cheese and fatty meats (hamburger, sausage, etc.)

But take heart. There are in fact plastics labeled as microwave safe. These containers are required to be tested and the results reviewed by the FDA before they can be labeled and sold to the public as safe for the microwave.

Below are some Styrofoam containers that you might be tempted to microwave:

  • Styrofoam plates or bowls
  • Take Out or Restaurant Leftover Containers
  • Beverage Cups (coffee, hot chocolate, etc.)
  • Dehydrated Cup Noodles (Ramen, etc.)

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To Microwave or Not to Microwave Styrofoam?

Microwave Popcorn

We’ve probably all microwaved something for too long on a Styrofoam plate and had it melt the plate a little. Is this a big deal? Can it make you sick?

When it comes to microwaving Styrofoam, your best bet is to use Styrofoam when you are simply reheating something quickly. Styrofoam contains polystyrene, which can leach into your food. According to reviews published by The National Institute of Standards and Technology, polystyrene begins to release traces of polystyrene at 200 degrees Celsius or around 392 degrees Fahrenheit. For comparison, water boils at 100 degrees Celsius.

Polystyrene starts to break down at approximately 224 degrees Celsius which is when more leaching occurs. In addition to the breakdown temperature of Styrofoam, keep in mind that there may be other chemicals in addition to polystyrene that makes up your Styrofoam container. Those additional chemicals could begin to break down at temperatures lower than 224 degrees Celsius. Also, fatty foods may be more likely to melt the Styrofoam than other foods so it’s probably best to microwave these foods in a microwave-safe container.

Tips and Cautions When Microwaving Styrofoam

  • If you absolutely must microwave using Styrofoam, start off with the microwave on the lowest setting and use the lowest amount of time needed.
  • Heat in 15 to 30-second intervals until food is at the desired temperature. Check carefully in between intervals for any sign that the Styrofoam is getting too hot.
  • Avoid using a thin plastic wrap or plastic film to cover food when possible. If you must use plastic wrap, cover loosely and try to avoid it touching your food.
  • Use a non-Styrofoam paper plate, paper towel, or even a napkin to cover food in the microwave instead of plastic wrap.
  • When using Styrofoam cups, trays, or other containers to microwave food, set your microwave to low or medium power rather than high power.
  • Do NOT use containers meant to be used once, such as cottage cheese or sour cream cartons, margarine tubs, or other “thinner” plastic containers meant to be for cold storage of foods.
  • Never use aluminum foil, Chinese take-out containers, or paper lunch bags in the microwave.
  • If your container or plastic wrap does melt, discard the food to be on the safe side.

Final Verdict

So, the consensus about can you microwave Styrofoam is that it’s not the best idea. This is because of the polystyrene and the fact that it can leach into your food when it reaches temperatures of over 200 degrees Celsius. If you must microwave Styrofoam, however, follow the warnings and tips above. To be safe, never eat any food from a Styrofoam container that has melted or bubbled.