Aldi UK and dairy cooperative Arla have launched a new operational pilot using invisible ultraviolet tags to follow milk bottle packaging through the recycling system. Developed with recycling technology specialist Polytag, the project is intended to provide more reliable data on what happens to packaging after consumers place it in recycling collections.

The eight-week trial builds on an earlier collaboration between Aldi and Polytag in 2023. In this latest phase, UV identifiers are printed directly onto wraparound labels applied to selected Arla milk bottles at the company’s Oakthorpe production site.

The labels are produced by Saica Flex using a specially developed fluorescent ink from Sun Chemical. The tags remain invisible during normal use and do not alter the appearance of the bottle, but they can be detected when the packaging reaches participating materials recovery facilities.

Polytag’s detection units scan the identifiers as bottles move through sorting infrastructure. Each detection creates packaging-level data that can be accessed through a digital dashboard, giving Aldi and Arla greater visibility of where and when their bottles enter the recycling process.

This information could help both companies compare recycling activity across locations, understand the performance of different packaging formats and identify gaps between the quantity placed on the market and the material captured by recycling systems.

The UV ink can be applied through conventional printing methods, allowing the technology to be integrated without significantly slowing label production or bottle-filling operations. Unlike the pressure-sensitive labels used in the previous trial, the new wraparound format is expected to provide greater coverage and durability throughout distribution, consumption and collection.

The food-safe ink has also undergone safety and recycling assessments. Because the identifier is added during label printing, brands can introduce traceability without using batteries, electronic chips or visible codes that would require consumers to take additional action.

For Aldi and Arla, the pilot offers a way to evaluate packaging performance using verified operational data rather than estimates alone. The findings may support future decisions on material selection, bottle design and recycling communications, while helping the companies measure progress against packaging sustainability targets.

The project also demonstrates how smart packaging can serve the recycling system without changing the consumer experience. If deployed at greater scale, invisible tagging could give retailers, producers and compliance organisations a clearer understanding of packaging flows and provide stronger evidence for Extended Producer Responsibility reporting and circular economy initiatives.