Indicator label for optically ascertaining the concentration of an analyte in a fluid mixture

A package comprising:

• an interior filled with a modified atmosphere;
• and
• an indicator label comprising:
• a carrier layer;
• an adhesive layer applied flatly on the an underside of the carrier layer;
• and
• an indicator substance dot on an upper side of the carrier layer, which is opposite to the underside, the indicator substance dot comprising an indicator substance that enables a determination of a presence and/or a concentration of an analyte in a multicomponent fluid mixture using an optical sensor through an excitation of the indicator substance with excitation light and reading fluorescence light emitted by the indicator substance using the optical sensor,
• wherein:
• the indicator substance dot has a uniform thickness in a direction that is perpendicular to the upper side of the carrier layer;
• and
• the indicator label is adhered to a location of the packaging that is sufficiently transparent for excitation and fluorescent light.

A packaging machine for packaging foodstuffs or other sensitive goods in a package that passes through the machine in a transport direction at a transport speed, the packaging machine comprising a labelling device for applying an indicator label to an inner side of the package that is in contact with a modified atmosphere in an interior of the package after the package has been sealed at a specified location where the indicator label can be seen optically from outside the package, the indicator label comprising:

• a carrier layer;
• an adhesive layer applied flatly on the an underside of the carrier layer;
• and
• an indicator substance dot on an upper side of the carrier layer, which is opposite to the underside, the indicator substance dot comprising an indicator substance that enables a determination of a presence and/or a concentration of an analyte in a multicomponent fluid mixture using an optical sensor through an excitation of the indicator substance with excitation light and reading fluorescence light emitted by the indicator substance using the optical sensor,
• wherein:
• the indicator substance dot has a uniform thickness in a direction that is perpendicular to the upper side of the carrier layer;
• and
• the specified location is sufficiently transparent for excitation and fluorescent light.