Recycled Cardboard Holds Hidden Danger
The scientific peer review journal Packaging Technology and Science recently reported on a study in Zurich, Switzerland, showing that harmful mineral oils from printing inks used on cardboard can migrate into food if recycled cardboard is used for food packaging. The oils may contaminate food even if the recycled cardboard is used for the corrugated card transport box that holds individual packs.
Researchers found that food rapidly absorbed 10 times the recommended limit for concentration of these contaminating oils from a transport box. The food studied had a two-year shelf life, so it is possible the absorbed amount could increase even more over time. Even if the food was contained in new, clean paperboard boxes—printed with inks free of mineral oil and wrapped by a polyethylene film—mineral oils from the corrugated cardboard transport box far exceeded the limit deemed safe.
Manufacturers could introduce functional barriers such as internal bags to prevent the migration of mineral oil, or line the boxes with special plastics. The technology and the recyclability of lined paperboard, however, still needs to be tested. Many companies have changed their packaging materials to fresh fiber paperboard printed with inks free of mineral oil, but are still using recycled card in the corrugated board transport boxes.