In order to develop a new active packaging technology for prepared beef, the effect of cold plasma (CP) combined with modified atmosphere packaging (MAP) with different oxygen concentrations (0%, 20%, 40%, and 60%; denoted respectively as T₁–T₄) on the safety, protein and fat oxidation, and physicochemical indicators of prepared beef during storage at 4 ℃ for up to 8 days was investigated using air packaging without CP treatment as control. The results showed that compared with the control group, CP combined with MAP significantly inhibited the growth of total viable count, lactic acid bacteria, Brochothrix thermosphacta and Pseudomonas during storage (P < 0.05), and this effect (except for Pseudomonas) increased with O₂ concentration inside the packaging. The combined treatment inhibited the increase in pH and total volatile basic nitrogen (TVB-N) content. After 8 days, moisture content and tenderness were significantly higher in groups T₁–T₄ than in the control group (P < 0.05), and groups T₃ and T₄ had the highest moisture content and the best tenderness. However, free radicals generated by CP resulted in oxidation of proteins and lipids. Thiobarbituric acid reactive substances (TBARS) value and carbonyl content in beef significantly increased with O₂ concentration inside the packaging (P < 0.05); TBARS value exceeded the limit in group T₄ on the 6^th day, while it was still below the limit in groups T₁–T₃ on the 8^th day. Oxidation caused a significantly lower redness value in groups T₁–T₄ than the control group during the late period of storage (P < 0.05), but the color of groups T₃ and T₄ was still acceptable on the 8^th day. In conclusion, CP combined with 40% O₂ MAP maintained TBARS value below the limit during the 8-day storage period, significantly inhibited the growth of microorganisms and TVB-N content, and preserved good physicochemical indexes, thereby maintaining the quality of beef.

In this study, the effect of treatment with plasma-activated water (PAW) on the biogenic amine content and sensory quality of air-dried pork tenderloin was investigated with the aim of exploring the feasibility of applying cold plasma technology in dried meat products. PAW was prepared using a dielectric barrier discharge (DBD) system at voltages of 50, 60 and 70 kV. Dried meat products were prepared by curing pork tenderloin with NaCl dissolved in PAW or pure water, followed by drying and maturation. The pH, nitrite residue and biogenic amine content of the products were analyzed. The flavor composition was studied using an electronic nose combined with principal component analysis (PCA) and loading analysis (LA). Finally, sensory evaluation was carried out. The results showed that (1) the amount of residual nitrite in the 50, 60 and 70 kV treatment groups were 8.12, 10.11 and 15.24 mg/kg, respectively, which were all lower than the national maximum allowable limit; (2) PAW treatment significantly inhibited the formation of biogenic amines in products, at 50, 60 and 70 kV voltages decreasing cadaverine content by 8.21%, 11.29% and 19.49% and spermine content by 9.64%, 16.54% and 27.56%, respectively (P < 0.05); (3) electronic nose analysis showed that the overall flavor difference between the PAW and control groups was not significant; and (4) sensory evaluation results showed that there was no significant difference in the flavor, taste, texture or acceptability between the PAW and control groups, while high-intensity PAW treatment could impart a better color to products.