tending to pull apart gas impermeable layer 34 and gas permeable layer 32 or the delaminateable film 38 as illustrated in fig3 and fig4 respectively the heat seal 30 holds the gas permeable layer 32 or the portion 38 u2033 intact and secured to tray 12 if a force of sufficient magnitude is applied the layer s of the lid 24 or 24 u2032 below the gas impermeable layer 34 is are supposed to break at the heat seal and thereby initiate delamination of the gas impermeable film from the rest of the lid as described above however in packages 10 with a heat seal pattern similar to that disclosed in us pat no 5 779 050 the delamination of the lid can be problematic the force exerted on the pull tab of the lid can cause the flange 22 to bend upward and prevent removal of gas impermeable layer 34 the gas impermeable layer 34 may tear resulting in an incomplete removal of the gas impermeable layer in addition if the lower layer of the lid does not break when the tab is pulled the force can rupture the heat seal 30 between the flange 22 and the lid such failures are thought to result primarily from a non optimum distribution of the peel force along the exterior edge of the heat seal 30 the present invention utilizes a film fracture feature on an exterior edge of the heat.