In an antifungal protective film having at least one layer and an acidifying polymer and a disulfite the at least one film layer includes fluid-filled bubbles or cells that are created by foaming. The cells created by foaming during the extrusion enable the generated sulfur dioxide to collect inside this film layer, thereby being buffered and achieving a long-term action releasing the antifungal sulfur dioxide. The film can have a single foamed layer containing the polymer and disulfite or such a layer sandwiched between two outer layers having different properties, all produced by coextrusion.