Food safety requires confirmation of the provenance and authenticity of a product. Nanobarcodes
incorporated into printing inks or coatings show excellent potential for the management of
product tracing and the authenticity of the packaged product (Han et al. 2001). Food quality
indicators have also been developed to provide visual indications to the consumer of when a
packaged foodstuff starts to deteriorate. Used for meat, a nanosilver layer is opaque light brown
initially, but if the meat starts to deteriorate, silver sulphide is formed and the layer becomes
transparent, indicating that the food may be unsafe to consume (FAO/WHO 2010). In addition,
spoilage can be revealed, for example, by an indicator that turns from transparent to blue,
informing the consumer that air has entered the modified atmosphere of the packaged materials.
For this type of application, nanotechnology-derived printable inks have been developed. An
oxygen-detecting ink containing light-sensitive (TiO2) nanoparticles detects only oxygen when
‘switched on’ with UV light (Park et al. 2007). Other conductive inks for ink jet printing based
on copper nanoparticles have also been developed (Park et al. 2007; FAO/WHO 2010).