Natural fungicides mainly include chitosan, serum protein, cinnamon oil, Arhat tar, allicin and natural phenols. Most of them are refined from animals and plants. For example, chitosan is obtained from natural shells, crabs, shrimps, fish bones, insects and other hard parts of animal shells by removing the N-acetyl group. Natural mold inhibitors are environmentally friendly, do not cause pollution to the environment during production and use, and have good biocompatibility.
However, natural mold inhibitors have poor heat resistance and begin to carbonize and decompose at 160-180 ℃, which greatly limits their application range and has a relatively short duration of efficacy.