Simulation of the migration of mineral oil from recycled paperboard into dry foods by Tenax®?

Conventional migration testing for long-term storage at ambient temperature with Tenax® was applied to a recycled paperboard as well as to the same paperboard with a polyethylene or polypropylene film in between. Test conditions were from the European Union plastic Regulation 10/2011, that is, 10 days at 60°C, but previous standard conditions of 10 days at 40°C were also applied. The results were compared with the migration into real packs made of the same packaging material containing six test foods and stored over 9 months. For the direct contact, simulation at 60°C overestimated the maximum migration of the saturated hydrocarbons in the real packs by 73%. Simulation reflected hardly any effect by the plastic films and resulted in an overestimation of the maximum migration into the real packs by a factor of 5.1 and 27 for the polyethylene and the polypropylene film, respectively. Analogous simulation was performed with polenta (corn semolina) instead of Tenax®. Three main causes for this deviation were identified: (i) at 60°C, migration reached beyond n-C₃₅, whereas it ends at about n-C₂₄ in reality. (ii) Tenax® is a far stronger adsorbent than foods, resulting in almost complete extraction. (iii) The significant barrier effect of polypropylene films at ambient temperature is lost at increased temperature. The suitability of such simulation for the prediction of long-term migration is questioned.