World Centric Wheat Straw Bowls 20 Pack, 11.5 Oz 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.