Mondelēz International, PepsiCo, pladis Global and Constantia Flexibles are testing invisible digital watermarks on flexible food packaging in Belgium as part of HolyGrail 2.0, aiming to improve automated sorting and enable higher-quality recycling.

Tackling flexible packaging

Flexible PP packaging, including snack wrappers and films, remains difficult to recycle into new food packaging because conventional sorting systems generally cannot distinguish food-contact packaging from non-food packaging.

Digital watermarks and NIR/VIS

The HolyGrail 2.0 system combines digital watermark (DW) detection with NIR/VIS detection. At Hündgen Entsorgung in Germany, equipment supplied by Pellenc ST detects the invisible digital watermarks, while NIR/VIS technology provides material identification for more precise sorting of flexible packaging.

Previous industrial trials of the technology on Pellenc ST Mistral+ sorting equipment achieved detection rates of more than 95%, demonstrating its potential to improve the precision of flexible packaging sorting.

From testing to recycling

The current trial is testing packaging placed on the market and collected through Belgium’s recycling system. Recycling tests are planned for Q4 2026, followed by film production and food-safety assessment.

The ambition is to create a reliable stream of recycled PP suitable for new food packaging and help scale the infrastructure needed to meet Europe’s rising recycled-content targets.

Image credit: AIM