Microbial inhibition in mixed vegetables packaged in plastic containers using combined treatment with hydrogen peroxide and cold plasma

Abstract

A combined nonthermal treatment method for the decontamination of fresh-cut vegetables packaged in plastic containers has been developed using cold plasma (CP) and H2O2 (HCP treatment) based on the concept of hurdle technology. This study investigated the effects of HCP treatment on mixed vegetables (kale, cabbage, and paprika) by evaluating the inactivation of indigenous microorganisms and foodborne pathogens, changes in microbiological safety and stability, food properties (color, CO2 generation, and antioxidant activity), sensory properties, and microbiome during storage at 4 or 10 °C. Additionally, alterations in the concentration of endocrine-disrupting chemicals in polyethylene terephthalate (PET) containers were determined. HCP treatment for 3 min reduced the numbers of indigenous aerobic bacteria, Escherichia coli O157:H7, and Listeria monocytogenes in mixed vegetables by 1.6, 1.2, and 1.3 log CFU/g, respectively. The numbers of indigenous aerobic bacteria and yeast and molds in mixed vegetables were lower in the HCP group than in the control group by 1.6–2.4 and 1.7–2.1 log CFU/g, respectively, during storage at 4 °C and by 0.4–1.6 and 0.7–2.1 log CFU/g, respectively, at 10 °C. HCP treatment effectively inhibited E. coli O157:H7 and L. monocytogenes growth in mixed vegetables during 14-day storage at 4 °C. The antioxidant activity, CO2 generation, and color of HCP-treated and untreated mixed vegetables were not significantly different over 14 days of storage at 4 °C. The proportions of Pseudomonas and Pantoea were lower in the HCP group than those in the control group after 3 days at 4 °C due to a shift in the microbial community composition and diversity. HCP treatment did not change the concentrations of phthalates in PET containers. The results revealed that HCP treatment effectively inactivated microorganisms of concern in mixed vegetables and inhibited their growth without affecting the quality properties of the vegetables or generating endocrine disruptors in PET containers.