Cold Plasma-Activated Water in Food Processing: Process Engineering, Mechanistic Insights, and Sustainability Perspectives

Growing demand for safe, sustainable, and minimally processed foods has increased interest in emerging non-thermal preservation technologies capable of reducing environmental impact while maintaining nutritional and sensory quality. Among these technologies, cold plasma-activated water (CPAW) has gained considerable attention as an eco-efficient and versatile processing medium for food applications. CPAW is generated through the dissolution of plasma-induced reactive oxygen and nitrogen species (RONS) in water, producing a chemically active solution with antimicrobial, oxidative, and enzyme-modulating properties. Depending on its reactive-species composition and storage conditions, CPAW may retain activity for delayed application, offering greater operational flexibility than direct plasma treatment. Building on established plasma–liquid applications in water purification, this review critically examines current knowledge on the generation of CPAW, its physicochemical characteristics, and mechanisms of action, with emphasis on its interactions with microorganisms, food macromolecules, and enzymes. It also covers recent advances in analytical characterization, application strategies, safety assessment, and sustainability considerations, discussing how plasma operating conditions, gas composition, and storage parameters shape CPAW stability and performance. The review highlights the limitations of treatment-time-based reporting and the need for standardized physicochemical dose descriptors to improve reproducibility and cross-study comparison. Although CPAW offers potential as a low-residue technology with promising sustainability advantages, challenges related to mechanistic understanding, scalability, process standardization, regulatory acceptance, and consumer acceptance remain significant barriers to industrial adoption. Addressing these limitations through interdisciplinary research and technological optimization will be necessary for the successful integration of CPAW into next-generation sustainable food-processing systems.