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Efficacy of electrolyzed water, chlorine dioxide and photocatalysis for disinfection and removal of pesticide residues from stone fruit

Calvo, Hector, Redondo, Diego, Remón, Sara, Venturini, María E., Arias, Esther
Postharvest biology and technology 2019 v.148 pp. 22-31
apricots, chlorine dioxide, cold, cold storage, commercialization, cyprodinil, disease incidence, disinfection, electrolyzed water, food plants, fruits, human health, humans, iprodione, laws and regulations, microbial contamination, nectarines, oxidants, peaches, pesticide residues, photocatalysis, sodium hypochlorite, spoilage microorganisms, tap water, tebuconazole, toxicity, washing
Concerns about chemicals and pesticides in food plants have increased dramatically during the last decade. Following stricter legislation and studies about toxicity and human health risks, new ways of reducing toxic residues are urgently required. In this study, oxidizing agents such as electrolyzed water (EW), chlorine dioxide (ClO2) and photocatalysis have been used during the postharvest phase in order to remove the residues of cyprodinil, tebuconazole and iprodione from the surface of peaches, nectarines and apricots. Moreover, the disinfection capability of these agents has also been tested as an alternative to sodium hypochlorite. Our results show that pesticide removal from stone fruits by oxidizing technologies significantly varies depending on the treatment used and the target substance. ClO2 significantly reduced tebuconazole residues from all the fruits (by more than 60%) and photocatalysis similarly reduced iprodione residues (between 50 and 70%). However, EW achieved a percentage of residue reduction similar to that of tap water, never exceeded 40%. In contrast, EW reduced the superficial microbiota to undetectable counts, also decreasing the percentage of rotted fruit from 32 to 7%. Photocatalysis produced similar results since it was able to decrease the microorganisms present on the fruit surface by nearly 2 log units and the incidence of disease by 50%. It was concluded that a strategy combining photocatalysis treatment during cold storage to reduce pesticide residues and spoilage microorganisms with electrolyzed water washing to reduce any remaining microbial contamination prior to commercialization will substantially reduce disease and ensure the safety of stone fruits for human consumption.