Food loss and waste constitute significant challenges for food security and pose a major environmental risk. The food waste hierarchy prioritises prevention, followed by reuse and upcycling over recycling and disposal. This study applies an attributional life cycle assessment (LCA), combined with system expansion, to evaluate the environmental performance of food surplus and waste management strategies at a Danish food service provider. System expansion was implemented as a substitution approach to account for avoided production (e.g., food products, electricity, and flour) and does not represent consequential modelling or market-mediated effects. Recycling, reuse, and upcycling were assessed using operational data from 2018 (baseline: recycling via anaerobic digestion) and 2021 (recycling and reuse), alongside a prospective scenario incorporating upcycling of organic carrot peels into carrot flour. The results show that recycling through anaerobic digestion resulted in a climate impact of +46 kg CO 2 -eq. per tonne of food surplus. Combining recycling and reuse reduced the climate impact by -11 kg CO 2 -eq. per tonne, primarily due to avoided food production from the reuse of approximately 8% of food surplus. The upcycling scenario showed the highest climate impact under current energy conditions (56 kg CO 2 -eq. per tonne), driven by emissions from the energy-intensive drying process. However, sensitivity analysis demonstrated that supplying renewable energy to the upcycling process substantially improved its environmental performance, resulting in upcycling becoming the most climate-friendly option, with a net reduction of -13 kg CO 2 -eq. per tonne of treated food surplus. Overall, the findings support the prioritisation of food surplus reuse and upcycling in the food service sector to enhance sustainability and resource efficiency. The results are consistent with the food waste hierarchy and indicate that, under future low-carbon energy systems, upcycling can significantly mitigate current environmental hotspots and contribute to more circular food waste management systems. The results further highlight that the environmental performance of upcycling is highly dependent on energy system conditions, whereas reuse provides consistent benefits under current systems. • Comparative LCA assessed recycling, reuse and upcycling of food surplus • Food surplus reuse showed the lowest climate impact under current energy conditions • Anaerobic digestion offered limited climate benefits in a low-carbon energy system • Upcycling was constrained by energy-intensive drying processes • Renewable energy systems can make upcycling the most climate-efficient option
Bairaktari et al. (Wed,) studied this question.