In a review published on September 15, 2021, in the journal Food Additives & Contaminants: Part A, Koni Grob, retired from the Official Food Control Authority of the Canton of Zurich, Switzerland, discusses approaches to reduce chemical migration from recycled paperboard such that it meets current safety requirements for food packaging applications.
Previous studies have demonstrated that chemicals migrate from paper and board packaging – even in amounts exceeding migration from plastics (FPF reported) – and that especially recycled paperboard can leach a high number of (toxic) contaminants into food (FPF reported). Still, recycled paperboard is seen as advantageous in terms of sustainability. As he considers the reduction of the number of chemicals and the completion of safety evaluation of each substance as unrealistic to archive, Grob proposes to limit chemical migration instead. In the review, he evaluates three measures to limit migration concerning the previously derived criterion that migration of individual compounds from recycled paperboard folding boxes used to pack dry food should be below 1% by weight of its content in the material (FPF reported).
The article emphasizes that “the measures to be taken strongly depend on the application of the recycled paperboard…to keep migration low for extended periods of time.” The three measures Grob discusses include (1) internal bags with an incorporated barrier, (2) barrier layers, and (3) functional sorbents added to the board. The review finds that internal bags are available and can be customized for an application, but they may not be suitable for very humid food. In contrast, barrier layers with a sufficient barrier function can be difficult to apply, care needs to be taken to prevent set-off during storage and to avoid migration from chemicals on the external surface through closures into the food. Concerning the measure of functional sorbents, Grob describes that they represent a promising simple solution but “further work is needed to ensure the effectiveness, in particular with regard to the sorption capacity, and to develop a corresponding testing method.” Transport boxes, mostly made of corrugated board and less considered when analyzing the safety of food packaging, are also discussed. Here, the author concludes that “[m]igration may be substantial and overall might contribute to the exposure of the consumers more than the folding boxes,” and that a specific safety criterion is still needed for transport boxes.
Further aspects the review touches upon include existing European regulations on recycled paperboard, mechanisms of chemical migration from paperboard, and the requirements for recycling PET and why “recycling of paper and board compares unfavorably.” More information on the recyclability and chemical safety of paper and board in food packaging can also be found in the Food Packaging Forum’s fact sheets on recycling (FPF reported).
Migration from (not recycled) paper cups with a barrier layer was also recently analyzed by Abdullah Akhdhar and co-authors from the University of Jeddah, Saudi Arabia. The research article published online on September 2, 2021, in the journal Environmental Chemistry Letters reported the rapid release of several metals into 95 °C hot water. While the concentrations of all were below the World Health Organization’s (WHO) acceptable limits in drinking water, the authors found that “the levels of vanadium at 1.24 μg/L and fluoride ions at 1.03 mg/L are likely to induce a health risk by bioaccumulation after long-term water ingestion.”
Grob, K., et al. (2021). ”How to make the use of recycled paperboard fit for food contact? A contribution to the discussion.” Food Additives & Contaminants: Part A. DOI: 10.1080/19440049.2021.1977853
Akhdhar, A. et al. (2021). “Rapid release of heavy metals and anions from polyethylene laminated paper cups into hot water.” Environmental Chemistry Letters. DOI: 10.1007/s10311-021-01315-7