Surface degradation assessment of post-consumer reusable plastic food packaging for a circular economy

The growing use of disposable plastics in the food industry has many negative environmental implications. One solution for reducing the impacts of plastic packaging is to take a circular economy approach which includes multiple reuses of packaging before closed-loop recycling. This research focuses on the most concerning issue relating to the reuse of food packaging: prevention of contamination by crossover from the old product to the new. Specifically, this work investigates surface roughness that may have influence on the effectiveness of cleaning plastic food packaging and on post-cleaning assessment. In this research the surface roughness of post-consumer reusable food packaging trays is examined that will likely change due to several use-clean cycles. The surface roughness profile of the post-consumer food packaging was determined via a mechanical method before being assessed via a novel UV fluorescence imaging process and industry-standard adenosine triphosphate assay. These assessments highlight the usefulness of the imaging technique to detect residual food fouling on various roughness of used polypropylene packaging. Specifically, the technique is able to identify residual food fouling on rough surfaces and highlight areas of deeply scratched polypropylene. It is proposed that the technique could underpin future reusable packaging assessment processes.