Venting reclosable bags

A closure for bags, the closure comprising

• a first closure strip comprising a first elongated base, a first extruded interlocking profile extending from the elongated base, and an extruded valve flange laterally spaced apart from the interlocking profile and extending from the elongated base;
• and
• a second closure strip comprising a second elongated base, a second extruded interlocking profile extending from the second elongated base and configured to releasably interlock with the first extruded interlocking profile when pressed together, and a flange contact surface laterally spaced from the second extruded interlocking profile and configured to engage the valve flange of the first closure strip to form an air-tight seal therebetween when the profiles are interlocked, with the closure defining an air space between the interlocked profiles and the valve flange;
• the closure further defining an air vent passage extending into the air space with the profiles interlocked;
• wherein the valve flange is constructed to separate from the contact surface in response to pressure on a first side of the valve flange, and to be biased against the contact surface in response to presence of a vacuum on said first side of the valve flange.