Functional barriers for Cardboard

In a practice-oriented storage test, the boxes of recycled cardboard featuring a barrier layer on the internal surface or an integrated adsorbent available early in 2014 were investigated for their efficiency in reducing migration of mineral oil hydrocarbons (MOH) into dry food. Three cardboards coated or laminated with barrier layers on the food contact side and one containing active carbon as adsorbent were characterized by microtome cuts and infrared spectroscopy. By testing the barrier efficiencies with four surrogate compounds, limited efficiencies were observed for the investigated layers. A one-year storage test was performed with wheat flakes in seven configurations: a box of fresh fibers, two boxes of unprotected recycled cardboard, three cardboards with barrier layers and a cardboard containing active carbon. The highest migration was observed in the boxes of unprotected recycled cardboard. Of the three investigated barrier coatings, only two reduced MOH migration into food below the limits of the third draft of the German mineral oil ordinance (2014) until the end of shelf life. The cardboard box involving active carbon (adsorbent) prevented detectable migration of MOH. Transport boxes contributed significantly to the migration of mineral oil, as observed for the boxes made of virgin fiber.