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 applications When 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.

Application of an innovative water-assisted ultraviolet C light technology for the inactivation of microorganisms in tomato processing industries

“…This technology has been used for the decontamination of drinking water and packages. It has also been investigated for inactivation of microorganisms in fresh-cut vegetable washing waters (Lehto et al, 2017;Mahoney et al, 2018). There are many studies on the application of UVC to reduce microorganisms on the surface of fruits, such as apples (Graça et al, 2013), melon (Manzocco et al, 2011), watermelon (Artés-Hernández et al, 2010), strawberries (Birmpa et al, 2013) and tomatoes (Lim and Harrison, 2016;Mukhopadhyay et al, 2014).…”