Disclosed are natural products composites protected against the deleterious effects of microorganisms comprising at least one natural product, at least one thermoplastic resin, and an effective amount of an antifungal agent. The composites are further advantageously protected against weathering and color formation by the incorporation therein of at least one light stabilizer and at least one compound selected from the group consisting of the oxides, hydroxides or silicates of Ca, Mg, Al and Zn. The light stabilizers are selected from the group consisting of the ultraviolet light absorbers and the sterically hindered amines. The metal oxide is for example CaO. The natural products are for example wood flour, flax, hemp, jute, kenaf, or rice husk. The thermoplastic resin is for example polyethylene or polypropylene. The antifungal agent and potential coadditives are incorporated via melt processing such as extrusion, co-kneading, pultrusion and injection molding. The antifungal agent is for example thiabendazole.