What Recycled Plastic Cannot Be in the Microwave?

Microwave-Safe Wording

• Recycled-plastic containers without "Microwave Safe" wording should not be used in the microwave. Plastics deemed microwave safe have undergone rigorous testing and can withstand high rapid heating without melting or leaching plasticizers into food.

One-Time Use

• Margarine and yogurt containers, even those manufactured from recycled plastics, are considered one-time use plastics. They are not meant for repeated use. Though margarine containers are convenient for transporting food for brown-bag lunches, they tend to be made from a softer, porous plastic that absorbs colors, fragrance and oils from foods. Additionally, they can melt in the microwave.

Polystyrene Plates and Containers

• Plates and restaurant takeout containers are frequently manufactured from recycled polystyrene plastic, a cousin of Styrofoam. Though safe as a surface for cold foods, polystyrene does melt especially when heated with fatty meats and cheeses. Check the package label for guidance. If it doesn't clearly have "Microwave Safe" on the packaging, don't use it in the microwave.

Plastic Wrap and Food Storage Bags

• Recycled plastic wrap manufactured from food-grade plastics tends to be microwave safe. As a cover for a microwave-safe plate, the plastic prevents heat and essential moisture from escaping the food during the heating process. However, it must be away from the food during the heating process, which can melt it. In contrast, food-grade recycled plastic bags, while popular for storing leftovers, are not usually strong enough to withstand high, rapid heating in the microwave. Unless the bags clearly state "Microwave Safe," keep the bags for cold storage only.