The O2 must desorb and/or diffuse from the food matrix or occluded void volume to eventually come in contact with OS, causing the delayed lag time for OS to decrease headspace O2 to below 0.01% (Table 2). OS with the capacity of 100 ml can completely reduce 100 ml of O2 in the empty PVDC-coated nylon bag flushed with 500 ml of atmospheric air within 24 h (data not shown).