Can You Microwave Plastic?

Q. I have a small army of plastic containers that my mother used for storing and microwaving foods when I was a kid. They don’t appear to have any markings related to microwave-safe plastics. Is there a way to know if they are safe? Can you microwave plastic? With all the media reports of the dangers of plastic and heating consumables in plastic around, and some friends insisting that all plastics are going to give me cancer, I don’t know what to think!

Can you microwave plastic?

A. Most people these days have either seen social media posts or read articles about the dangers of microwaving food in plastic containers or plastic wrap. They hear that chemicals leaching out of the plastic and into the food will cause cancer, reproductive problems, and other illness. As usual with such internet fueled “urban-legends” there is a kernel of truth, and a lot of misinformation.

As you might know “plastic” is no single substance. The term covers a variety of materials made of various organic and inorganic compounds. Substances are often added to plastic to help shape or stabilize it. Two of these substances are believed to be “endocrine disruptors.” They mimic human hormones which can result in severe imbalances.

These two plasticizers are bisphenol-A (BPA) and phthalates. BPA is added to make clear, hard plastic and phthalates are added to make plastic soft and flexible. If you microwave food in plastic, BPA and phthalates may leak into the food and any migration will likely be greater with fatty foods such as meats and cheeses.

The FDA closely regulates plastics which may be in contact with food. Your microwave safe plastics are deemed safe because they are not prone to leach into your food. Even unmarked plastics may be safe, but just haven’t been FDA reviewed.

You can purchase a wide variety of plastic products these days which are certified microwave-safe. These are usually affordable and they are the only ones you should use if you’re putting plastic in the microwave.

If you’re unsure about your plastic’s markings or just don’t feel good about it, then use glass in the microwave. Personally I wouldn’t microwave my food in unmarked, possibly non microwave safe plastic but you can still use those containers in the fridge or even for storing trinkets.