EFFECTS OF EXPOSURE TO GASEOUS OZONE AND NEGATIVE AIR IONS ON CONTROL OF EPIPHYTIC FLORA AND THE DEVELOPMENT OF BOTRYTIS CINEREA AND PENICILLIUM EXPANSUM DURING COLD STORAGE OF STRAWBERIES AND TOMATOES

The aim of this study is to compare the effects of gaseous treatments on the control on postharvest decay. Specifically, cold-stored tomatoes (Solanum lycopersicum L.) and strawberries (Fragaria x ananassa Duch.) were kept at 12 degrees and 2 degrees C, respectively, under 95% RH and exposed to Air (control), Ozone (0.5 ppm), Negative Air Ions (NAI, 6.1 x 10(6) ions/cm(3)) and a NAI+Ozone mixture (0.5 ppm and 6.1 x 10(6) ions/cm(3)) for 15 days. The effects of the gaseous treatments on control of epiphytic microflora and the development (disease incidence and aerial mycelial growth) of Botrytis cinerea Pers. and Penicillium expansum Link on the artificially inoculated fruits were evaluated. The examined treatments reduced superficial microbial contamination after 15 days of exposure. The best performance was achieved by the NAI+ Ozone treatment combined with electrostatic filters; this treatment resulted in decreases in bacteria and yeast by 2.5 Log(10) cfu/g. Visible mycelia and spore production on the artificially inoculated fruits were also considerably suppressed in the presence of ozone and/or NAI with a variable degree of success. The most promising results were obtained with the NAI+ Ozone treatment; the disease incidence was considerably reduced, and the mean sporulation index never surpassed a value of 1, which completely inhibited spore formation. The fungistatic effect vanished when the fruits were removed from the atmosphere enriched with oxidizing agents.