Can You Microwave Styrofoam?

If you enjoy take-out from time to time, then chances are that you’ll end up with meals that are served in Styrofoam containers.

While most of us have no problem chucking our left overs into the fridge in these containers from the restaurant, many of us wonder whether it’s safe or even healthy for us to reheat our food in Styrofoam containers. We really don’t want the hassle of having to transfer leftovers to another dish; we still worry about the implications of heating food in a Styrofoam container.

If you’re looking for answers to this dilemma, then you’re in the right place.

Can You Microwave Styrofoam?

Firstly, the belief that Styrofoam and plastics should never be microwaved is not accurate, despite this misconception being spouted in lots of places. There are several types/grades of Styrofoam and their ‘microwave-ability’ depends on several things.

Related: Can You Microwave Cardboard?

So What is Styrofoam Really?

Styrofoam is actually the common name for the product polystyrene foam. Now, polystyrene is a type of plastic made from petroleum. It’s an extremely lightweight material, which is made up of 95% air. One of the main reasons why Styrofoam is popular is its ability to provide insulation. In the case of food, it keeps your food warm for a long time. Where it’s used in housing (inside wooden walls), it has the same effect.

As indicated above, Styrofoam is also used for applications outside of the food industry (but that’s not our concern). In the food and beverage sector, Styrofoam is one of the most common container elements because it’s easy to mass produce and cheap as well. Styrofoam containers range from cups to plates and bowls.

Ok, now to the crux of this article.

Should You Be Microwaving Styrofoam and What Happens When You Do This?

Several things can happen when Styrofoam is heated.

The first and most visible is that it might lose its shape and crumple up. When this happens, Styrofoam particles can stick to or coat the food that’s being heated, making it inedible. In the case of liquid, the Styrofoam can break up, forming holes that allow the liquid or beverage to leak out.

Another thing that can happen with microwaved Styrofoam when it gets too hot is that chemicals can leach out of the product and into the food being heated. The leaching is also likely to be more severe depending on the type of food being heated. It’s thought that foods that are fatty and rich in oils such as cheeses and meats are quicker to absorb leached polystyrene elements.  While it is not fully known how the petroleum elements in the product interact with the inner workings of the human body, many persons believe that there can be long term effects from leaching. Scientists have even suggested that exposure over time might lead to cancer.

Related: Can You Microwave Aluminium Food Containers?

So What’s the Verdict? Should You Be Microwaving Styrofoam?

The vast majority of Styrofoam containers sold and distributed across the world (including coffee cups, Styrofoam plates, and take-out containers) are more than likely not microwave-safe.

In addition, many of the common containers that we believe to be Styrofoam are actually not pure polystyrene foam. The mixture of other elements could have the effect of changing the properties of Styrofoam for better or for worse where microwaving is considered.  

Therefore, when in doubt, throw it out! If your Styrofoam container does not explicitly say that it is microwave safe or microwave friendly, do not heat food in it. It’s safer to simply transfer your food or drink to a container that is glass, ceramic or certified to be microwave safe.

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