A shelf life indicating structure including a substrate printed with an oxygen sensitive ink in combination with an oxygen scavenging layer is disclosed. The oxygen scavenging layer prevents oxygen reaching the substrate for a predetermined interval. Once the finite oxygen scavenging capability of the layer is exhausted, oxygen reaches the substrate, thereby activating a visible indication such as a color change, in the ink. The substrate and layer may be formed into a patch or label for a package, and covered with an oxygen impermeable layer, such as a strip of aluminum foil which can be peeled off to initiate a shelf life indication structure. A method associated with the shelf life indicating structure is also provided.