The indicator is e.g. an acid/base indicator, a metal indicator or a redox indicator.

The scavenger/indicator also contains a complexing agent or redox indicator for the sorbent material and an electrolyte.

A fluorescent redox indicator, preferably riboflavin, is dispersed in a carrier and placed on an impermeable substrate.

The indicator effect is caused by a change in physical properties of the oxygen sorbent material which is initiated by complex formation and/or interaction with the redox indicator.

A redox indicator (2) and test object (3) are vacuum-sealed between a support (1) and a peelable barrier film (4).