Enhancing microbial safety and enzymatic stability of green peas using sequential sodium hypochlorite washing and continuous in-package DBD plasma treatment

A continuous in-package DBD plasma system was integrated with NaClO washing as a potential hurdle strategy for fresh green peas. • Sequential treatment achieved 2.97–4.03 log CFU/g reductions of L. monocytogenes and E. coli on green peas. • The hurdle strategy caused severe bacterial membrane damage, with E. coli showing greater susceptibility. • POD and LOX activities were significantly suppressed, offering a nonthermal alternative to blanching. • The treatment inhibited native microflora throughout storage and enhanced oxidative stability by limiting peroxidation. Green peas are highly perishable and susceptible to microbial and quality deterioration, posing challenges to microbial safety and quality preservation. This study investigated the efficacy of sequential sodium hypochlorite (NaClO) washing and continuous in-package dielectric barrier discharge (DBD) plasma treatment for inactivation of Listeria monocytogenes and Escherichia coli O157: H7 on fresh green peas. Treatments were applied individually and in combination at two motor speeds of 500 r/min (48 s, CP48) and 200 r/min (120 s, CP120), which corresponded to different treatment times. For L. monocytogenes , individual treatments of CP48, CP120, and NaClO achieved reductions of 1.81, 2.21, and 1.13 log CFU/g, respectively, while combined treatments (NaClO-CP48 and NaClO-CP120) significantly enhanced inactivation to 2.97 and 3.74 log CFU/g. Similarly, E. coli reductions were 2.03, 2.81 and 1.97 log CFU/g for CP48, CP120, and NaClO, respectively, which increased to 3.95 and 4.03 log CFU/g under NaClO-CP48 and NaClO-CP120 treatments. This enhanced efficacy of NaClO-CP combined treatment is attributed to severe disruption of cell membrane integrity, evidenced by a decreased proportion of membrane-intact cells (F G /F R ratio reduced from 0.80 to 0.92 to 0.25–0.44), with E. coli exhibiting greater susceptibility than L. monocytogenes . In addition, combined treatments effectively suppressed native aerobic bacteria (>2 log reduction) and molds and yeasts (>1.9 log reduction), maintaining microbial levels below 2.5 log CFU/g throughout 7-day refrigerated storage. Reductions in firmness and ascorbic acid were observed under combined treatments. Total color difference (ΔE) increased slightly but remained below visual perception thresholds (ΔE < 5). Combined treatments resulted in greater inhibition of peroxidase and lipoxygenase activities compared to individual treatments, with reductions of >50% relative to the control after 7 days of storage, contributing to improved oxidative stability. These findings demonstrate that the sequential NaClO and in-package DBD plasma hurdle strategy effectively enhances microbial safety and enzymatic stability of fresh green peas, with acceptable quality trade-offs. Download: Download high-res image (181KB) Download: Download full-size image