Sequential treatment of plasma-activated water and in-package cold plasma treatment enhances microbiological safety and storage stability of mung bean sprouts, shrimp, and bok choy mixtures

This study developed a non-thermal interventional food technology (PAW→ICP) combining plasma-activated water (PAW) washing followed by in-package cold plasma treatment (ICP) for decontaminating mixed food consisting of mung bean sprouts, raw shrimp, and bok choy. The effects of PAW→ICP treatment on the inactivation of Escherichia coli O157:H7 and Listeria monocytogenes were evaluated, along with its impact on inhibiting the growth of aerobic bacteria in mixed food during storage at 4 °C for 10 days. The PAW→ICP treatment, conducted using a novel container designed for ICP, resulted in the microbial inactivation of E. coli O157:H7 and L. monocytogenes by 2.5 ± 0.2 log CFU/g and 2.4 ± 0.1 log CFU/g, respectively, under ICP treatment conditions of 12 kV and 3 kHz for 1 min and PAW formation conditions of 4.3 kW and 10 kHz for 30 and 40 min. The PAW→ICP treatment was more effective in inactivating microorganisms than either ICP or PAW alone (p < 0.05). PAW→ICP treatment effectively inhibited the growth of indigenous aerobic mesophilic bacteria in the mixed food during storage. These findings suggest that the PAW→ICP process is a promising non-thermal technology capable of enhancing microbiological safety and stability of the mixed food.