Oxygen scavengers independent of transition metal catalysts

A method of detecting seal breakage or incomplete seal formation in a package, said method comprising the steps of:

• (i) providing said package, prior to sealing, with a strip or ring of an indicator comprising an oxygen scavenging composition which includes a source of labile hydrogen or electrons and at least one reducible organic compound, wherein said strip or ring is located on an internal surface adjacent to where a seal is to be formed,
• (ii) treating the strip or ring with visible or ultraviolet light of a predetermined intensity or wavelength or γ-rays, corona discharge, an electron beam or heat so as to reduce the reducible organic compound to a reduced form which is oxidizable by ground state molecular oxygen reguardless of the presence of a transition metal catalyst and such that, when oxidised, there is a detectable change in a characteristic of said composition selected from the group consisting of:
• colour, fluorescence emission and UV-visible, infrared or near-infrared absorption,
• (iii) subjecting said packaging to a sealing process intended to seal the package, and
• (iv) detecting, in the sealed package, a change in said characteristic of said composition, wherein any detected change is indicative of seal breakage or incomplete seal formation;
• wherein steps (ii) and (iii) may be carried out in either order.