a bacon package has a stiffener sheet formed of plastic having an inner layer of foam polystyrene and solid films of polystyrene on opposite sides of the foam layer and coextruded therewith to form a web . the web of coextruded plastic is fed through an embossing station which forms an embossment defining the outer periphery of the stiffener sheet and , if desired , a plurality of annular embossments within the periphery . the embossed extrudate is then cut with heated knives around each embossment to seal the edges defined by the embossments . apparatus other than heated knives may be used for sealing the edges .