Comparative analysis of helium and air surface micro-discharge plasma treatment on the microbial reduction and quality attributes of beef slices.

This work aimed to compare the effects of helium and air surface micro-discharge (SMD) plasma on the microbial safety and quality of beef tissues. For the beef tissue model, the concentration and diffusion depth of hydroxyl radical and ozone have different change patterns over plasma treatment time and distance in helium and air SMD plasma. The inactivation efficiency of helium plasma depended on the plasma treatment time and distance, while the inactivation efficiency of air plasma only depended on the treatment time. For the fresh beef slices, air SMD plasma treatment exhibited a higher antimicrobial activity against S. aureus and E. coli than helium SMD plasma treatment (1.5 versus 0.9; 0.9 versus 0.28 log CFU/g at 10 min). However, air SMD plasma treatment caused more adverse effects on beef quality, leading to a smooth surface, extensive lipid oxidation, protein structure damage, low pH and discoloration compared to helium SMD plasma treatment. This work provides valuable guidelines for the working gas choice in the practical application of plasma to meat decontamination.