A circular economy for reusable plastic packaging: digital assessment for cleaning assurance

Single use plastic packaging is widely accepted to cause significant negative environmental impacts. One option to reduce these impacts is to develop commercially viable and socially acceptable reuse systems. Such closed loop packaging systems require careful consideration of reverse (or circular) logistics, financial modelling, and quality control (fulfilling legal requirements and ethical obligations). One of the most prominent barriers to the concept of reusable packaging for food is safety, dictated by challenges of effective cleaning and pack integrity assessment. This research directly addresses cleaning assurance by investigating the application of ultraviolet (UV) induced fluorescence imaging to optically detect residual food fouling on plastic packaging surfaces. This research reports for the first time the evaluation of UV fluorescence imaging @370 nm for the detection of food fouling on washed PET food pots. The technique is compared against the industry standard, adenosine triphosphate swabbing, and is found to provide a comparable range of sensitivity, full surface coverage, faster assessment, and is suitable for full automation without the use of consumables. The technique is evaluated with respect to integration into industrial process systems. Plastic packing design implications are discussed in this context.