Non-thermal inactivation of Escherichia coli in milk using a Venturi tube reactor and liquid-phase plasma: A parametric optimization study

Abstract

Milk is an essential part of the human diet but is highly susceptible to microbial contamination, posing significant safety risks. Conventional thermal pasteurization, such as low-temperature long time (LTLT) (occurs at 63 °C for 30 min), high-temperature short time (HTST) (occurs at 85 °C for 2–4 s), flash pasteurization (occurs at 72–75 °C for 15–30 s) and sterilization process that occurs at 120 °C for at least 15 min, while effective, often compromises milk's nutritional and sensory properties. This study introduces an innovative non-thermal pasteurization method combining Venturi tube hydrodynamic cavitation and liquid-phase plasma for effective microbial inactivation while preserving milk quality. Using response surface methodology, we optimized parameters voltage (10–20 kV), flow rate (2–8 l/min), temperature (30–50 °C), and time (1–5 min) to maximize Escherichia coli reduction. Results showed a 5.42 log reduction in Escherichia coli, with voltage and time being the most influential. Compared to conventional methods, which may cause protein denaturation and lipid oxidation, this approach preserved milk's protein, fat, and lactose with minimal sensory changes. This energy-efficient technology offers a scalable alternative for industrial milk pasteurization, ensuring safety while maintaining nutritional and sensory integrity.