## 2 Materials and Methods
### Goal and Scope
#### 2.1.2 System Boundaries  
This study conducts an LCA to evaluate the environmental trade-offs associated with implementing RFID technology in the fresh food supply chain (FSC), with a focus on the EU's fresh milk sector. The system boundaries include two parallel sub-systems: (i) the full life cycle of RFID tags (from raw material extraction to disposal), and (ii) the cradle-to-grave life cycle of 1 L of packaged fresh milk. All processes within both systems are modeled using a consistent attributional LCA approach.  
As shown in Figure 11, the RFID tag system includes raw material extraction, component manufacturing (chip, antenna, adhesives), assembly, transport, and end-of-life disposal. A 1% mass cut-off was applied for omitted elements. RFID readers and gate infrastructure were excluded from the assessment due to their high usage-to-impact ratio; each reader typically processes tens of thousands of tags over its operational lifetime. For instance, assuming 100,000 reads per unit and a power demand of 50 watts, the environmental impact per individual tag read is several orders of magnitude lower than that of the tag itself. Nonetheless, we acknowledge that a quantitative sensitivity analysis would provide stronger justification for this exclusion and recommend it as a focus for future refinement.  
The life cycle system for milk (Figure 11) covers raw milk production, transport to dairies, pasteurization, filling and packaging, and delivery to distribution centers. The associated environmental flows include emissions from fodder cultivation, fertilizer and pesticide use, feed production and transport, on-farm energy and water use, and packaging. The disposal of expired milk into landfills and the associated packaging is modeled as the end-of-life scenario. A conservative modeling choice was made to allocate all upstream and processing burdens entirely to the milk product, and infrastructure (buildings, tanks, equipment) was excluded. While the environmental impact of milk production and packaging is thoroughly considered, the refrigerated storage phase at distribution centers is excluded. Since milk and its packaging are typically disposed of together, landfill disposal is considered the end-of-life scenario, with potential alternative methods like recycling or remanufacturing noted. This comprehensive approach enables a full evaluation of the environmental sustainability of the fresh milk supply chain.  
Furthermore, this study's system boundaries are limited to pre-consumer stages (farm to retail), as RFID interventions are typically implemented prior to the point of sale. While our model shows that RFID can reduce expiration-related waste at the retail and distribution stages, it does not capture consumer-level food waste, which, as shown in Supplementary Table S6, accounts for over 70% of total milk waste in the EU. As a result, the quantified environmental benefits presented here represent only a partial contribution to addressing the broader milk waste mitigation challenge. This boundary condition does not undermine the value of upstream interventions, but it should be clearly acknowledged when interpreting the results and their generalizability.