Ozonation as an emerging technique for inactivating microorganisms and mitigating pesticides in apple juice

Abstract

Microorganisms and pesticide residues are among the major health concerns associated with food products. Although ozone (O3) is currently being employed in various applications in apple processing, there are few studies investigating the effects of O3 treatments on microorganisms and pesticides in apple juice. The purpose of this study was to investigate the effects of O3 treatment on microorganisms, pesticide residues, and physicochemical properties of apple juice and to compare with that of classical pasteurization. O3 was as effective as pasteurization against E. coli and coliform bacteria; the counts of these microorganisms were below the detectable level after a treatment for 15 min. O3 was also effective in reducing the counts of total aerobic mesophilic bacteria and yeast-mold, but longer treatments were required for total inactivation. All the pesticides investigated were degraded by O3, but at different rates. Reduction rates were quite high (75-100%) for methoxyfenozide, dimethoate, and pyrimethanil, however, acetamiprid and imidacloprid were degraded by only 7.1% and 14.5%, respectively. O3 treatment caused drastic decreases in color and turbidity values, total phenolic content, and antioxidant activity of apple juice. Results revealed that the use of ozone in juice processing has potential as a technological solution to product contamination problem.