Abstract: A method is described herein for slowing, inhibiting, and/or preventing the growth of microbes, or for killing microbes, within and/or on a product/good that is stored in a package. The method can include applying a film cover over a perforated portion of a package and securing the film cover to the package at the perimeter of the perforated portion with an adhesive or by heat stacking. The film cover can include a material for changing the atmosphere within the package. The package may be an existing pre-perforated package, or may be a package that requires perforation. If the package requires perforation, the method can further include perforating at least a portion of the package prior to positioning the film cover over the perforated portion. The film cover can be formed of a three-phase material or other material.