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

Area of Science:

• Food Science and Technology
• Microbiology
• Biophysics

Background:

• Milk is susceptible to microbial contamination, notably by Escherichia coli, posing food safety risks.
• Conventional thermal pasteurization can negatively impact milk's nutritional and sensory qualities.
• Non-thermal processing methods are sought to ensure milk safety while preserving quality.

Purpose of the Study:

• To develop and optimize a non-thermal Atmospheric Cold Plasma-Pulsed Electric Field (ACP-PEF) system for Escherichia coli inactivation in milk.
• To assess the impact of ACP-PEF treatment on key milk quality parameters.
• To compare the efficacy of ACP-PEF with traditional thermal pasteurization.

Main Methods:

• Response Surface Methodology (RSM) with a Box-Behnken design was employed to optimize ACP-PEF parameters.
• Key parameters optimized included electric field strength, exposure time, argon-to-air ratio, and nozzle angle.
• Escherichia coli inactivation was quantified, and milk quality attributes (pH, fat, protein, lactose, SNF, FFP, color) were analyzed.

Main Results:

• Optimal ACP-PEF conditions achieved a significant 4.656-log reduction in Escherichia coli.
• Minimal changes were observed in milk's pH, fat, protein, lactose, SNF, and FFP content compared to untreated milk.
• Color difference (ΔE) was insignificant, indicating preserved visual quality.
• The ACP-PEF system demonstrated superior quality preservation compared to thermal pasteurization.

Conclusions:

• The developed ACP-PEF system is a highly effective non-thermal technology for inactivating Escherichia coli in milk.
• This method offers a promising alternative for producing safe, high-quality milk with minimal nutritional and sensory degradation.
• The ACP-PEF system is scalable and energy-efficient, suitable for industrial application in milk processing.