Migration of mineral oil from printed paperboard into dry foods: survey of the German market

Abstract

From the German market, 119 samples of dry food were analyzed for the migration of mineral oil. The products selected were packed in paperboard boxes and intended for storage for extended periods of time at ambient temperature. The 0.6 mg/kg limit for mineral oil saturated hydrocarbons (MOSH) derived from the WHO/JECFA evaluation was frequently exceeded by a factor of 10–100. Typically, 10–20% of the migrating mineral oil consisted of aromatic hydrocarbons (MOAH). Most samples were merely 2–3 months old and far from the end of their shelf life (usually 1–3 years). From the assumption that about 70% of the MOSH and MOAH which are eluted from GC up to the C₂₄ n-alkane (<C24) end up in the food (potential of migration), it was estimated that migration might almost triple before the products reach the end of their shelf life, reaching 31 mg/kg on average, with several samples exceeding 100 mg/kg. At the time of the analysis, products without an internal bag and with a bag of paper or polyethylene reached up to about 80% of the potential of migration (average, 30–50%). Bags of polypropylene, acrylate-coated polypropylene, PET or with an aluminum layer seemed to block migration (with one possible exception), but it was premature to reach conclusions on long-term functional barrier properties. From the comparison with <C₂₄ MOSH concentrations in unprinted recycled paperboards, it was estimated than on average about a quarter of the migrating mineral oil was from printing ink used for decorating the box.