Within the food packaging industry, just like in other fields, the importance of being able to provide traceability throughout the value chain has recently increased. Here the word traceability refers to the possibility of being able to trace and control for example the origin of the packaging laminate, converting parameters, product process parameters, and parameters for packaging, sterilising and filling in a packaging line. More in detail it refers to the possibility of being able to determine the origin of the base material from which the packaging laminate is made of, from which batch and reel the packaging laminate is originating, from where the product originates (farm/producer, batch), how the product has been treated in the processing plant, and how the filling and packaging has been performed (filling machine type and id, dairy/packaging plant, sterilization parameters, packaging date). The latter information may be used to generate a best-before-date for the package with content.
Traceability throughout the value chain facilitates quick recall of packages and the possibility of ensuring a high quality of the final product and, in the end, such offers safety for the consumer and consumer trust for the food producer.
In practice, traceability is a complex issue. The value chain for e.g. a milk package is long and with several involved parties and numerous process steps. Paper and polymer granules are manufactured and supplied to the packaging laminate producer which in turn, through converting processes, manufactures packaging laminate. The packaging laminate is delivered to the dairy where it is loaded in the filling machines. The dairy also receives milk from one or several nearby farms and processes the milk within the processing plant of the dairy. After processing, the milk is supplied to the filling machine for packaging. The filling machine produces packages and subsequently said packages are distributed to stores where consumers may pick them from the shelves and buy them.
It is known within the packaging industry to provide a packaging laminate having magnetisable particles with a possibility for magnetic marking. Some various aspects are disclosed in WO 2006/135313 and EP-0 705 759, in which several applications are disclosed.
All relevant traceability data for a packaging material laminate, e.g. batch number and reel number which traces back to base materials and converting processes information, can magnetically be encoded and read if the laminate comprises suitable magnetic particles arranged as strips, marks, fully covered surfaces or by other means. The magnetic mark may function as an information carrier, keeping non-visible information.
The latest development of magnetic sensors allows reading without physical contact between the sensor and the layer with magnetic particles. A readings distance up to 1-2 mm is practically possible. This allows the magnetic layer to be located non-visible on the ready made package, e.g. on the opposite side from printing on a paperboard, thus saving space for graphics and written information on the surface of the package.