Is recycled newspaper suitable for food contact materials? Technical grade mineral oils from printing inks

Abstract

Recycled paper and board used in food packaging materials (boxes, paper bags) often cause migration of mineral oil into food at levels which are unacceptable according to present toxicological assessments. When foods in recycled board are densely packed into larger boxes or onto pallets, most of the hydrocarbons up to n-C₂₀ may migrate into the packed food within a few weeks, those up to n-C₂₈ at a decreasing rate. Unprinted recycled board contained 300–1,000 mg/kg mineral oil <n-C₂₈. The main sources are the inks used for printing newspapers: newspapers contained roughly 3,000 mg/kg mineral oil <n-C₂₈. These mineral oils fall into classes for which JECFA established a tolerable daily intake of 0.01 mg/kg body weight. Using standard assumptions for calculating specific migration limits, a maximum tolerable concentration in food of 0.6 mg/kg is derived. This evaluation assumes highly refined white oils, whereas the oils found in recycled board are of technical quality and contain 15–25% aromatic compounds, predominantly with 1–3 aromatic rings, as shown by comprehensive GC × GC. This finding precipitates authorities into a dilemma: recycling is supported for the sustainable use of materials, but on the basis of present toxicological assessments the migration is often far beyond acceptable.