Can You Microwave Plastic?
Only microwave plastic containers that are specifically labeled microwave-safe. Not all plastics can withstand microwave heat - some melt, warp, or may leach chemicals into food. Look for the microwave-safe symbol (wavy lines) or text on the container before heating.
Key Takeaways
- Plastics are made from various compounds, and their heat tolerance varies widely.
- Plastic wrap can be used in microwaves if it does not touch the food directly and is microwave-safe.
- Takeout containers, yogurt cups, and butter tubs are generally not microwave-safe even though they held food.
Explanation
Plastics are made from various compounds, and their heat tolerance varies widely. Some plastics remain stable when heated, while others can melt, release harmful chemicals, or contaminate food. The FDA tests and approves certain plastics for microwave use.
Microwave-safe plastics are designed to withstand the temperatures reached during normal microwave cooking without melting or leaching significant amounts of chemicals. These containers will be marked with a microwave-safe symbol or recycling codes 2, 4, or 5 (though the symbol is most reliable).
Even microwave-safe plastic should not be used if it is damaged, stained, or has been through many uses. Old plastic containers may break down over time. When heating fatty or oily foods, which reach higher temperatures, glass or ceramic is the safest choice.
The recycling numbers on plastic containers provide useful guidance. #1 (PETE/PET) is generally considered safe for single use but should not be microwaved. #2 (HDPE) and #5 (PP/polypropylene) are the most heat-resistant and commonly microwave-safe. #3 (PVC) contains phthalates and should never be heated. #6 (polystyrene/styrofoam) can release styrene when heated. #7 is a catch-all category that may or may not contain BPA—avoid microwaving unless explicitly labeled safe.
The FDA's testing protocol for microwave-safe labeling measures chemical migration at temperatures up to 250°F (121°C) over extended periods. However, foods high in fat or sugar can exceed these temperatures in the microwave—butter can reach 300°F and sugar solutions can hit 350°F. This is why experts recommend transferring fatty foods like bacon, butter-based sauces, and sugary items to glass or ceramic before microwaving, even from containers labeled microwave-safe.
Things to Know
- Plastic wrap can be used in microwaves if it does not touch the food directly and is microwave-safe.
- Takeout containers, yogurt cups, and butter tubs are generally not microwave-safe even though they held food.
- Never microwave plastic containers that previously held non-food items like cleaning products.
- Scratched or discolored plastic containers have a compromised surface that increases the potential for chemical leaching—replace them rather than continuing to microwave food in them.