A new study has revealed that recycled paper food packaging may leach toxic metals into food, especially under acidic conditions, posing potential health risks previously underestimated.
The figure illustrates the migration process of toxic metals from recycled paper food contact materials (FCMs) under foreseen usage conditions and exhaustive extraction methods used for unforeseen conditions, followed by sample preparation for elemental analysis through ICP-MS. Image Credit: Maastricht University
Recycled paper and cardboard are increasingly used in food packaging as part of global sustainability efforts. However, these materials may pose hidden risks in the form of toxic metals, often introduced through inks, adhesives, or processing agents. These metals can migrate into food, potentially leading to serious health issues such as cancer, neurological disorders, and metabolic diseases.
While the European Union has established regulations for contaminants in plastic food packaging, standardized safety protocols for paper-based packaging are still lacking. Previous studies have detected metals like chromium and mercury in recycled paper food contact materials (FCMs), but the health risks from metal migration remain insufficiently explored. This gap in knowledge highlights the urgent need for more comprehensive research into the safety of recycled paper packaging.
A study published on January 11, 2025, in Food Quality and Safety by researchers from Maastricht University and the Netherlands Food and Consumer Product Safety Authority (NVWA) examined the migration of toxic metals from recycled paper FCMs using various food simulants, including acetic acid and ethanol. The findings were alarming: levels of aluminum, lead, and other metals frequently exceeded regulatory thresholds, raising concerns about the adequacy of existing safety assessments.
The study found significant variation in toxic metal migration depending on the type of food simulant and the packaging composition, with acidic conditions posing the greatest risk. Using four simulants—3 % acetic acid (for acidic foods), 10 % and 50 % ethanol (for aqueous and fatty foods), and Tenax (for dry foods)—the researchers discovered that 3 % acetic acid extracted exceptionally high concentrations of metals.
Lead was detected at 34.83 mg/kg, and aluminum reached 10 g/kg—levels exceeding Dutch safety limits by factors of 8000 to 10,000. Ethanol-based simulants showed moderate migration, while conditions simulating dry foods resulted in minimal metal release, suggesting that dry goods like bread may carry lower risks.
A key finding was that traditional exhaustive extraction methods significantly underestimated metal levels compared to migration tests, suggesting that actual consumer exposure could be much higher than current testing methods predict. Of particular concern was the presence of unregulated metals such as uranium and cobalt at potentially harmful levels, revealing critical gaps in existing regulations.
The study emphasizes that both food acidity and packaging composition play a crucial role in metal migration, with acidic products—such as juices and vinegar-based items—being most at risk when packaged in recycled paper materials. These findings challenge assumptions about the safety of recycled paper FCMs and call for more rigorous, real-world testing protocols.
Our findings reveal that recycled paper packaging is not as inert as assumed. The high migration of toxic metals, especially under acidic conditions, demands immediate regulatory attention. Harmonized safety standards and improved testing methods are essential to protect public health.
Dr. Athanasios Kourkopoulos, Study Lead Author, Maastricht University
The study calls on policymakers to establish EU-wide migration limits for toxic metals in paper packaging, similar to those already in place for plastics. It also urges manufacturers to consider alternative materials or protective coatings to reduce metal leaching, particularly for acidic or fatty foods. In the meantime, consumers may wish to avoid recycled paper packaging for such products until safer options become available.
The research also advocates for advanced testing methods that better reflect real-world conditions to ensure accurate risk assessments. Ultimately, achieving a balance between sustainability and food safety will be essential for the future of packaging.
Journal Reference:
Kourkopoulos, A., et al. (2025) Migration of toxic elements from recycled paper food contact materials to food simulants: compatibility and influence of sample preparation methods. Food Quality and Safety. doi.org/10.1093/fqsafe/fyaf002