Novel indicators for food packaging

The C02-sensitive indicator film is relatively fast in responding when the ambient atmosphere is changed from that of the MAPed package to air, but when encapsulated in the polymer sheath used in the AOF label, which uses polyethylene terephthalate, PET, as a gas diffusion barrier, under the same conditions its recovery time is ca. 30 h (at 25 °C).

Key to its commercial function - as a consume within indicator - at 5 °C, the label’s recovery time is ca. 96 h (i.e. 4 days). The potential of the AOF label as a ‘consume within’ indicator to help minimise the large amount of unnecessary household food waste associated with many developed countries is discussed briefly.A C02-sensitive, smart adhesive is reported in which a C02-sensitive pigment, comprising the pFI-sensitive dye, phenol red, PR, coated onto nano-particulate silica particles, is dispersed in a hot melt, pressure sensitive adhesive.