Influence of pH on the efficacy of ozonated water to control microorganisms and its effect on the quality of stored strawberries (Fragaria x ananassa Duch.)

Abstract

ABSTRACT Ozonation has been proposed as an alternative for the post-harvest treatment of plant products. Therefore, the objective of this study was to evaluate the influence of the pH on the efficacy of ozonated water to control microorganisms and to determine the possible effects of ozone on the quality of stored strawberries. To evaluate the influence of pH on ozonated water in Portola variety strawberries, the strawberries were divided into six batches. Three batches were exposed to ozonated water and three batches were exposed to non-ozonized water with different pH levels and an immersion time of 5 min. The pH values used were 3.0, 6.5 and 8.7. After the ozonation, the fruits were stored in a cold chamber at 5 °C for 6 days, and analyses were performed every two days. A completely randomized design was adopted using a 6x4 factorial scheme with three replications. The aerobic mesophiles, molds and yeasts, total coliforms and Escherichia coli were quantified, and the presence of Salmonella spp. was assessed. For the quality evaluation, the mass loss, titratable acidity (TA), pH, soluble solids (SS), SS/TA ratio and color were analyzed. The pH of the water was verified to influenced the effectiveness of the ozonated water to control the aerobic mesophiles and molds and yeasts. The ozonated water can retard fresh mass losses and maintain the pH, soluble solids, titratable acidity, SS/TA ratio and color variables.