Microbial Control of Fresh Produce using Electrolyzed Water

Abstract

The demand for fresh salad vegetables, such as iceberg lettuce, has increased worldwide in recent years. Numerous sanitizers have been examined for their effectiveness in killing or removing pathogenic bacteria on fresh produce. However, most of the sanitizers are made from the dilution of condensed solutions which involves some risk in handling and is troublesome. A sanitizer that is not produced from the dilution of a hazardous condensed solution is required for practical use. Electrolyzed water and ozonated water were investigated for bactericidal effects on fresh-cut produce as a convenient and safe alternative sanitizer. Although the efficacy of acidic electrolyzed water (AcEW) as a sanitizing agent was dependent on the kind of produce treated, AcEW could be sufficiently effective to offer an alternative solution to conventional sanitizers, such as sodium hypochlorite solution (150 ppm). A novel produce-washing procedure using a combination of alkaline electrolyzed water (AIEW), AcEW and mild heat demonstrated significant bactericidal effect compared with the treatment with ambient temperature. Besides the bactericidal effect, the progress of browning on lettuce was suppressed by using mild heat treatment. Furthermore, as a novel usage of AcEW, we examined the use of AcEW-ice for preserving vegetables. AcEW-ice inactivated the spoilage and pathogenic bacteria on lettuce and reduced the temperature of lettuce during storage.