POD activity increased in all ozone-treated fruit stored at ambient conditions, and more activity was associated with fruit treated with high ozone concentrations (Fig. 7). POD activity increased gradually and peaked at day 10 in ozone-treated fruit. POD activity in fruit exposed to 1.5 µL L−1, 2.5 µL L−1, 3.5 µL L−1 and 5.0 µL L−1 ozone were 2.3 fold, 2.5 fold, 2.8 fold and 3.3 fold, respectively, greater than that in control fruit at day 10. POD activity in untreated fruit decreased during ambient storage after day 10. Ozone treatment delayed the decrease in POD activity in stored fruit.