Sanitisation of fresh-cut celery and radicchio by gas plasma treatments in water medium

Abstract

The antimicrobial efficacy of dielectric barrier discharge atmospheric gas plasma (DBD) was tested against Listeria monocytogenes and shigatoxin-producing Escherichia coli serogroups O157 and O26. Challenge tests were carried out with samples of cut celery and radicchio leaves inoculated with a mix of five strains of L. monocytogenes or the two strains of E. coli immersed in deionised water. The treatment efficacy was also assessed considering only the contaminated deionised water.For deionised inoculated water alone, a treatment time-dependent strong effect was observed and a pathogens reduction higher than 6 Log CFU/mL was obtained after 40 min of treatment. With the vegetables presence in the liquid medium, the efficacy appeared reduced and related to the treatment time, microorganism, substrate and storage duration (reduction up to 2.5 and 3.7 Log CFU/cm 2 for L. monocytogenes and E. coli, respectively). No significant changes were observed on celery visual attributes, soluble solids content and textural parameters. A significant decrease of the Chroma colour parameter during storage was noted in treated radicchio samples respect to control ones.

Nonthermal Plasma–Liquid Interactions in Food Processing: A Review

“…In the case of PAW treatment of fresh food, Ma et al (2016) observed acceleration in fruit ripening due to the oxidative species in PAW for Chinese bayberries causing a faster fruit decay with higher treatment times. They claimed that the prevention of fruit decay by PAW was not a dose-dependent effect, in contrary to the findings by others (Berardinelli et al, 2016;Herceg et al, 2016;Scholtz et al, 2010;Tang et al, 2008). Therefore, NTP and PAW treatment conditions and the resulting bactericidal properties in nonfood substrates could be completely different from food materials.…”

“…Berardinelli et al. () also stated that the inactivation efficiency of PAW varies with respect to the kind of vegetables. Almeida et al.…”

“…Using PAW for fresh foods to eliminate microorganisms could pose some challenges due to the irregularity of shape, surface texture, and so on (Berardinelli et al., ; Joshi et al., ). Guo et al.…”

“…They also stressed on the importance of considering the presence of organic matter including food constituents while using PAW for food-related applications. Berardinelli et al (2016) also stated that the inactivation efficiency of PAW varies with respect to the kind of vegetables. Almeida et al (2017) compared the degradation of fructooligosaccharides in water and orange juice after NTP treatment.…”

Nonthermal plasma for pesticide and microbial elimination on fruits and vegetables: an overview

“…Although the maximum temperature of apple surface treated with plasma reached 51°C, it was below the threshold for thermal killing of the pathogens. Similarly, DBD atmospheric plasma applied in the study of Berardinelli et al (2016) appeared to be a potential sanitising technology for decontamination of L. monocytogenes and E. coli O157 and O26 producing shiga toxin. On spinach, oxygen NTP gave the higher efficacy than washing method using 3% concentration of hydrogen peroxide.…”