Packaging with pressure driven oxygen egress

A food package comprising:

• packaging comprising:
• a flexible liner defining a wall aperture and an internal chamber, the internal chamber having an internal atmosphere;
• a check valve mounted to the flexible liner and covering the wall aperture, wherein said check valve is configured to occupy:
• (i) a closed state blocking fluid communication between the internal chamber and ambient via the wall aperture, and
• (ii) an open state enabling fluid flow from the internal chamber, through the wall aperture, and into ambient;
• said check valve comprising an inner barrier and a rigid outer barrier, the rigid outer barrier forming a dome, and the inner barrier comprising a peripheral adhesive and a central inner barrier comprising one or more layers of perforated film, the central inner barrier and the rigid outer barrier having different material compositions, the one or more layers of perforated film having a melting temperature less than the rigid outer barrier to permit the one or more layers of perforated film to melt and close perforations in the one or more layers of perforated film to permanently seal the check valve in the closed state when localized heat is applied to the check valve;
• and
• said check valve disposed completely external to the interior chamber such that venting fluid crosses the wall aperture before reaching the check valve.