The efficacy of preharvest application of electrolyzed water and chemical sanitizers against foodborne pathogen surrogates on leafy green vegetables

Abstract

AbstractPreharvest control strategies, to reduce or eliminate pathogenic bacteria in leafy vegetables that may be consumed raw, may provide additional food safety protection and shelf life quality extension beyond what is possible to achieve with postharvest sanitation alone. The aim of this study was to characterize the efficacy and effect of contact time of electrolyzed water (e‐water), 1‐bromo‐3‐chloro‐5‐dimethylhydantoin (BCDMH), and peracetic acid (PAA) at 80 and 150 ppm against pathogen surrogates Escherichia coli M23 (E. coli M23)and Listeria innocua ATCC 33090 (L. innocua), and a representative spoilage microorganism Pseudomonas fluorescens (P. fluorescens) on leafy green vegetables (LGV) mizuna, rocket (arugula), and red chard. Each of the leafy vegetables has a distinctly different leaf architectures that could alter the effectiveness of preharvest sanitation treatments. e‐Water, BCDMH and PAA were equally effective in inactivating plant total viable count, E. coli M23, L. innocua and P. fluorescens (reduction compared to water control—0.5–4.0 log CFU/g). On average an additional 0.8 (0.4–1.1) log CFU/g inactivation was obtained by increasing sanitizer contact time from 30 min to 2 h, whereas increasing sanitizer concentrations produced, at maximum, an extra 0.5 log CFU/g inactivation. These findings suggest that e‐water, BCDMH, and PAA are all useful for in‐field preharvest application on a wide range of plants and increasing contact time rather than concentration improves sanitation efficacy.