These Compostable Knives are made from PSM (PLA Starch Material), which is an unrefined form of PLA bio-plastics. They can withstand high temperatures, thus being great for both cold or hot foods. Sourced from renewable resources and 100% biodegradable, they contain no GM traces. Made from plants all items are compostable, so they can turn back to soil in only 12 weeks after use.