Advanced Non-Thermal Processing: Combined Cold Plasma and Pulsed Electric Field for E. coli Inactivation in Milk

Milk, rich in proteins, vitamins, and bioactive compounds, is highly susceptible to microbial contamination by pathogens like Escherichia coli, posing risks to food safety. Conventional thermal pasteurization often degrades nutritional and sensory qualities. This study developed a non-thermal ACP-PEF system to inactivate E. coli while preserving milk's properties. Using Response Surface Methodology (RSM) with a Box–Behnken design, four parameters, electric field strength (5–10 kV/cm), exposure time (5–35 s), argon-to-air ratio (0–1), and nozzle angle (0°–90°) were optimized via Design-Expert software. Optimal conditions (10 kV/cm, 35 s, ratio 0, angle 53.87°) achieved a 4.656-log reduction (99.9978%) in E. coli. Quality analysis revealed minimal changes: pH (0.44%), fat (10%), protein (7%), lactose (7%), SNF (4%), and FFP (2%) reduction, compared to untreated milk, outperforming thermal pasteurization (reductions of 2%–20%). Color difference (ΔE = 0.81 ± 0.10) was insignificant. The ACP-PEF system, combining electroporation and RONS, offers a scalable, energy-efficient alternative for safe, high-quality milk production.