Comparative Life Cycle Assessment of Food Waste Prevention Interventions: Retail Price Discounting of Sub-Optimal Tomatoes and Supply Chain Shelf-Life Optimisation of Yogurt

In this study, two independent comparative Life Cycle Assessments (LCAs) were conducted to evaluate the environmental performance of food waste prevention interventions under real supply chain conditions. The first assessed a retail-level price discount intervention (PDI) for sub-optimal tomatoes implemented by an online fresh produce retailer in Spain, while the second assessed a shelf-life allocation optimisation intervention (SLOI) for yogurt implemented by a Danish dairy manufacturer in collaboration with two wholesalers. Both studies followed the ISO 14040/44 standards, adopted an attributional framework, and applied the Environmental Footprint (EF) v3.1 method across 16 midpoint impact categories, comparing each intervention against a baseline reflecting conventional practice. The PDI achieved a 98.6% reduction in unsold tomatoes ending up as waste, lowering upstream cultivation demand by 6.7% per functional unit (1 t of tomatoes sold by retailer) and key impact categories by 6.7–7.1%, with tomato cultivation identified as the dominant hotspot (60–99% of total impacts). The SLOI reduced overproduction by 76% and total yogurt output by 5.9% per functional unit (1 t of yogurt supplied by wholesalers), resulting in a 94.6% reduction in factory waste and 18.8% reduction at the wholesale level. Environmental impacts decreased by 5.8–6.7%, with milk production as the dominant hotspot (88–99% of total impacts). No burden-shifting effects were observed, and sensitivity analyses confirmed the stability of results. Overall, both case studies showed that food waste prevention interventions, whether implemented at retail or supply chain levels, consistently reduced upstream environmental burdens per unit of product delivered.