Background. The food industry contributes significantly to global greenhouse gas emissions, water consumption, and waste generation. Although environmental impact assessment tools have rapidly diversified, methodological fragmentation continues to limit comparability across studies and the formulation of coherent sustainability strategies. Objective. This study conducted a systematic review to synthesize, critically appraise, and map the evidence on methods, technologies, and applications used in assessing the sustainability of food industry processes, with a view to identifying the most effective approaches and the main research gaps. Data sources and eligibility. The Web of Science Core Collection was queried on November 27, 2025 using a structured strategy based on Boolean operators and Topic fields. Original articles and reviews in English, published between 2020 and 2025, that reported quantitative or qualitative indicators of environmental impact, according to the PICO framework, were included. Results. From an initial 1000 records, 225 studies were included and narratively synthesized into seven major themes. LCA predominated as the standard method, but with significant heterogeneity in system boundaries and functional units. Emerging technologies indicated potential for reducing resource consumption, dependent on subsector and scale. Conclusions: Harmonization of assessment frameworks, industrial validation of circular technologies, and robust comparative studies are essential for the transition to a sustainable food system.