Electrical stimulation of table grape berries as new alternative for postharvest Escherichia coli contamination management

Abstract

With a growing global population, food demand is rising, yet large amounts of food are lost to spoilage each year. Unpredictable weather, pest and pathogen pressures, and poor storage contribute to nearly one-third of all food going to waste. Reducing spoilage is crucial to meet population needs, conserve resources, and enhance food security. The application of postharvest antimicrobial agents can efficiently reduce spoilage; however, sustainable alternatives, are increasingly being sought for their lower environmental impact. This study presents a lab-developed setup that uses low electrical currents to inhibit Escherichia coli growth on fruit. When an alternating current (50 mA) was applied to Escherichia coli-contaminated grapes, 99 % of the bacteria were eliminated. After 12 days, visual inspection showed that untreated, contaminated grapes had rotted, while the electrically treated ones remained visually similar to uncontaminated grapes. Quantitative Colony Forming Unit (CFU) reduction assays and Scanning Electron Microscopy (SEM) analysis of grape skins confirmed these findings, showing clear bacterial structural damage on treated grapes, indicating the electrical current's effectiveness in deactivating Escherichia coli. These promising results highlight the potential of this eco-friendly decontamination strategy and make it adaptable to grapes and other fruits and vegetables.