Neutral electrolyzed water (NEW), chlorine dioxide, organic acid based product and ultraviolet–C for inactivation of microbes in fresh-cut vegetable washing waters

Abstract

The effect of decontamination methods on fresh-cut vegetable washing waters was evaluated. NEW, ClO2, organic acid-based product FPW, and UV-C were tested with and without an interfering carrot juice of 1% (IS), on Yersinia enterocolitica and Yersinia pseudotuberculosis, Escherichia coli, and yeast Candida lambica. The use of ClO2 (50 ppm active chlorine) resulted in >4 log reduction of Y. enterocolitica, Y. pseudotuberculosis, E. coli and >3 log reduction of C. lambica. The antibacterial effect of NEW was less effective in the presence of IS when compared with ClO2. The inactivation of C. lambica by FPW reached a maximum of 2.8 log cfu/mL (concentration 0.125%), but the antimicrobial effect was delayed by the IS. The effect of FPW on E. coli was significantly reduced by 1% IS. The inactivation of E. coli and C. lambica with UV-C IS decreased the inactivation and lengthened its time. Filtration improved the effect of UV-C inactivation. Practical applicationsWhen chemical decontamination methods were used in fresh-cut vegetable processing, the presence of organic matter in process water increased the reaction times and the need for higher concentrations of the chemical decontamination and the time of physical decontamination. Yersinia required longer inactivation times than E. coli. When UV-C is used for decontamination of process waters, waters should be filtered to enhance the disinfection efficacy.