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

•The decontamination efficacy of air gas plasma was tested towards L. monocytogenes and E. coli.•Bacteria were inoculated in deionised water alone and on celery and radicchio in deionised water.•An effective inactivation of pathogens in deionised water (higher than 6 Log CFU/mL) was obtained after 40 min.•The presence of vegetables appeared to reduce the inactivation of pathogens (up to 2.5 and 3.7 Log CFU/cm2).•Celery qualitative attributes did not significantly change after the treatments.

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/cm2 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.