Required barrier efficiency of internal bags against the migration from recycled paperboard packaging into food: a benchmark.

The use of recycled paperboard and corrugated board for food packaging is in the interest of the sustainability of resources, but in most applications the food must be protected against contamination from these materials, such as by an internal bag with a functional barrier. Producers of packaging need a specification to find the most suitable and economical barrier for a given application, and the customer needs the confidence that a solution offered to him is adequate. An accurate determination of the barrier efficiency is not possible due to the large number of migrants, most of which have not been evaluated or not even identified. Hence the specification must be based on assumptions and verifiable by a simple test. The proposed benchmark presumes that the migration of all non-evaluated or even unknown substances in recycled paperboard will remain below 0.01 mg kg(-1) food, the conventional detection limit, if their transfer does not exceed 1% of the content in the paperboard. Some substances, such as mineral oil or fatty acids, will exceed the 0.01 mg kg(-1) limit, but they are known, evaluated and of no concern at the reduced migration. Since the critical substances must be assumed to be unknown, the criterion of the 1% migration is tested with three surrogate substances of similar volatility and covering a broad range of polarity. The cornerstones of the method are specified.