Oranges, grapes, and tomatoes were infected with green mould (Penicillium digitatum), grey mould (Botrytis cinerea), or black spot (Alternaria alternata); then the fruits were incubated in normal or ozone-enriched atmosphere with concentrations ranging from 0.05 to 1.0 ppm.

In vivo and in vitro experiments revealed the development of lesion and spore production to be markedly reduced in fruit maintained in an ozone-enriched atmosphere.

Higher concentrations and duration of exposure resulted in greater impacts on lesion development and spore production, i.e. clear dose/response relationships were evident. As a result, considerable benefits were found resulting from exposure to low levels of ozone, i.e. below the 0.2 ppm threshold set for the protection of human health.

In vitro studies performed on fungi raised on potato dextrose agar (PDA) for 6-7 days at 13C and 95% relative humidity revealed no direct effects of ozone on fungal development per se, implying that suppression of pathogen development was due in a large part to the impacts of ozone on fruit-pathogen interactions.

Source: N. Tzortzakis, via Postharvest Unlimited

From: Gaseous ozone-enrichment for the preservation of fresh produce, by N. Tzortzakis, Department of Agricultural Sciences, Biotechnology & Food Science, Cyprus University of Technology, 3036, Limassol, Cyprus