Can You Put Styrofoam in the Microwave? Reheat Food Safely


Microwave ovens are a useful addition to any kitchen and in most circumstances, they are considered to be a time-saving alternative for heating, cooking, and defrosting a variety of foods. One of the most common uses for this technology is the reheating of leftovers which poses the question, "Can you put styrofoam in the microwave?" This popular material is often used by restaurants and fast food establishments, but while it may work well to store and transport your food it may not be the best option to reheat food safely. Read on to learn the potential risks of styrofoam usage and alternative solutions from the team of professionals at Mr. Appliance®.

What is Styrofoam?

Styrofoam is a registered trademark of Dow Chemical, which has become synonymous with all types of plastic foam material. The polystyrene foam used in a number of applications from takeout containers to packing peanuts is a petroleum-based material that is made from styrene and benzene. It has a number of attributes that contribute to its popularity including:

  • The composition is approximately 95 percent air, making it incredibly lightweight.
  • Styrofoam is a great insulator with an R-value of about R-5 per inch.
  • Due to the high content of air, styrofoam is virtually unsinkable.
  • Styrofoam does not break down or lose its shape over time.

Can You Put Styrofoam in the Microwave?

Polystyrene foam and Styrofoam containers are ideal for keeping hot food hot, cold food cold, holding their shape, and protecting the contents within. Before deciding whether or not to put your takeout into the microwave it's important to note that there are two distinct types of foam containers on the market, with some important differences.

Traditional Styrofoam

During normal use Styrofoam remains stable, but once it has been exposed to high temperatures the material begins to melt and break down, those toxic chemicals contained within can leech into your food. At high enough levels these compounds are carcinogenic, can pose a threat to your health and reproductive system, and should be avoided.

Microwave-safe Styrofoam

This alternative material is constructed using safer materials, lower levels of hazardous chemical compounds, and is designed to remain more stable at higher temperatures. In order for this type of Styrofoam to be considered safe for microwave use, it must display microwave-safe labeling on the packaging materials or the container.

To answer the question "Can you put Styrofoam in the microwave?" unless the container is clearly marked safe for use choose an alternative method for reheating—and if you see any visible signs of damage to the Styrofoam after removing it from the microwave discard both the food and the container.

How to Reheat Food Safely

Eliminate the risk of chemical exposure by following these safety tips:

  • Transfer the food from your container on to a plate before reheating, covering with a damp paper towel to prevent splattering.
  • Place the food in an oven-safe container, cover with foil, and reheat in your conventional oven.
  • Never reheat food more than once.
  • Before consuming, ensure the internal temperature of the leftovers is a minimum of 165°F, or in the case of liquids bring them to a rolling boil and allow to cool to a safe temperature.
  • To reheat soups, stews, and chili, pour the contents into a saucepan and place it on the stove.

For all your appliance repair needs, contact the experts at Mr. Appliance, or call to schedule an appointment today.