Effect of Cold Atmospheric Plasma Fusion 222 nm UV and PAHP on Cold Pasteurisation of Egg Surfaces

This study used a combination of cold atmospheric plasma (CAP) and ultraviolet (UV) 222 nm with plasma-activated hydrogen peroxide (PAHP) pre-treatment to optimise the pasteurisation of fresh eggs and to investigate their freshness quality. The optimal treatment conditions (power density of 2.5 W/cm3, treatment distance of 7.8 cm, and an airflow rate of 4 m3/min) resulted in significant reductions in Salmonella Enteritidis by 1.25 log CFU/egg, Campylobacter jejuni by 1.47 log CFU/egg, and Staphylococcus aureus by 2.32 log CFU/egg. The pasteurisation mechanism was attributed to reactive oxygen species particles generated by the plasma and enhanced plasma micro-discharges induced by UV light. Importantly, the freshness quality of the eggs, including various parameters such as Haugh unit, yolk index, eggshell hardness, egg yolk pH value, eggshell thickness, and egg yolk colour, remained unchanged during shelf-life storage under refrigeration conditions. Overall, the combination of PAHP pre-treatment and cold atmospheric plasma fusion of 222 nm ultraviolet proved effective in sterilising and preserving fresh eggs.