There's nothing risky about microwave radiation - but there are health concerns about heating up plastic.You can also check your container's universal recycling symbol, often on the bottom of a product - those with a number 3 and the letters "V" or "PVC" include phthalates. ?Is cooking or reheating food in a microwave safe? ?Even if you avoid plastics, there are other potential risks of heating food in the microwave - including uneven heating, and the high temperatures used. ?First, consider using microwaves to reheat, rather than cook, food, as it may cook unevenly. ?"Temperatures will be different in a cross-section of the food.It's hard to achieve a completely uniform temperature, especially when talking about raw foods."?"Some plastic isn't designed for microwaves because it has polymers inside to make it soft and flexible, which melt at a lower temperature and may leach out during the microwave process if it goes beyond 100C (212F)," says Juming Tang, professor of food engineering at Washington State University.?Microwaving mobilises contaminants," says Rolf Halden, professor and director of the Biodesign Center for Environmental Health Engineering at Arizona State University.?And the potential risks don't necessarily increase with how often an individual microwaves food in plastic containers, Trasande argues - as the relationship is non-linear between the amount of chemical exposure and risk of hormone disruption.