World Centric bowls are made from wheatstraw, a leftover agricultural fiber and an annually renewable resource. Lids for Burrito Bowls are made from NatureWorks Ingeo, a product derived from plants grown in the USA. Microwave and freezer safe, can be used for both hot and cold items Soak proof* No plastic or wax lining Suitable for hot foods up to 220 Fahrenheit Conform to FDA guidelines for food use Gluten-free. Wheatstraw is the remaining plant fiber after the grain (which stores the proteins and allergens) has been removed. *Though these compostable plates are soak proof, hot items will cause the plates to "perspire" and some condensation will form at the bottom. Lids for our plant fiber bowls may fit loosely when hot. Therefore, using the bowls with lids for take out is not recommended for hot liquid foods.