Some plastic tupperware or food storage containers are not suitable for use in a microwave oven due to several reasons:
Melting: Many plastics have a relatively low melting point, and when exposed to high temperatures in a microwave, they can soften or melt. This not only ruins the container but can also release harmful chemicals into your food.
Leaching of chemicals: Some types of plastic containers may contain additives, such as plasticizers or colorants, that can leach into your food when heated in the microwave. These chemicals may be harmful to your health when ingested in significant amounts.
Release of toxic fumes: When certain plastics, especially those not intended for microwave use, are heated to high temperatures, they can release toxic fumes. These fumes can be harmful to your health and contaminate your food.
Warping and deformation: Microwaving certain plastics can cause warping or deformation of the container, making it unusable and potentially leading to spillage or burning.
To ensure safety, look for microwave-safe symbols or labels on the bottom of the container. Microwave-safe plastics are typically made from materials like polypropylene (PP), polyethylene (PE), and polytetrafluoroethylene (PTFE). These plastics are designed to withstand microwave heating without leaching harmful chemicals or melting. Additionally, using microwave-safe glass or ceramic containers is generally a safe alternative to using plastic containers in the microwave.