a pasteurizable , cook - in shrink bag is provided that comprises a first or sealing and food contact layer composed of propylene homopolymer or copolymer ; a second or heat shrinkable layer composed of a blend of propylene homopolymer or copolymer and butylene homopolymer or copolymer ; a third or adhesive layer composed of ethylene methacrylate copolymer ; a fourth or barrier layer composed of vinylidene chloride copolymer ; a fifth or adhesive layer as in said third layer ; and a sixth or optical clarity layer as in said first layer ; further provided that the foregoing bag structure is oriented and irradiated to a dose of about 4 - 12 megarads after orienting or alternatively , though less preferred , to about 6 - 12 megarads before orienting . associated method for making said bag is also provided .