Given the fact that every defrosting tray out there should be food-safe, this seemed like an appropriate question to ask. And, you can look right at the Food and Drug Administration (FDA) for the answer. As the FDA claims, a material needs to meet several conditions in order for it to be considered food-safe (as a seller can’t merely just dub their material as food-safe).
First off, it must have a finish that is smooth and easily cleanable and also be resistant to chipping, distorting, scratching, and even corrosion. Also, it must not be allowed to leach any odors, tastes, or other substances to your food. It also needs to withstand repeated washings and to be nonabsorbent.