The Rules for Plastic in the Microwave

updated May 1, 2019
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(Image credit: Anthony Berenyi)

Safely using plastic in the kitchen is an ever-evolving discussion as we continue to learn more and more about the material. While you could reach for plastic alternatives for storage and reheating purposes and avoid the discussion completely, the truth is that most of us do happen to have plastic containers and plastic wrap in our kitchens. So the real questions is: Is any of it actually safe in the microwave?

The USDA says it is safe to use plastic containers and plastic wrap in the microwave if you follow the rules and take the proper measures. Here’s what you need to know.

1. Check if it’s microwave-safe.

Perhaps the most basic rule, but also the most important. Check to see if that plastic wrap or container is noted to be microwave-safe. It should be labeled on the box or the bottom of the container. If it’s not or you’re just unsure, you’re better off leaving it out of the microwave.

2. Avoid certain plastics.

Takeout trays and containers, yogurt tubs, and other one-time use containers should be avoided altogether. They’re never microwave-safe and can melt and warp when heated. Old plastic containers, even if they are noted to be OK to use, might also not be safe. If you notice lots of scratches on them from overuse, you’re better off not microwaving them, as leaching from the plastic becomes more likely.

3. Don’t let plastic wrap touch the food.

If you’re using microwave-safe plastic wrap, make sure that it’s not actually touching the food. This might mean you have to put whatever you’re heating up in a larger bowl so that’s there’s room between the top surface of the food and the plastic wrap.

4. Leave the lid ajar.

Finally, if you’re putting that microwave-safe plastic container in the microwave, you want to have proper ventilation by leaving the lid ajar. This allows for steam to escape from the food instead of it being trapped inside a tightly sealed container.