Efficacy of gaseous ozone for the inactivation of Listeria monocytogenes and Saccharomyces cerevisiae in fresh peach and grape juice

Ozonation is an emerging non-thermal technology with potential applications for reducing the microbial load of foods. The present research aimed to evaluate the impact of gaseous ozone treatment on artificially inoculated Listeria monocytogenes as pathogenic target and Saccharomyces cerevisiae as spoilage target. Moreover, the ozone's effect (with an O₃ concentration between 0.49 and 1.14 ppm up to 15 min) on the key quality parameters of the PGJ was also assessed and compared to a conventional thermal treatment (90 ± 1 °C for 1 min). Despite ozone being demonstrated to completely inactivate L. monocytogenes in 4 min, only a 2-log reduction was obtained after 15 min on S. cerevisiae. The juice's physicochemical and microbiological quality parameters were not significantly affected either. Although the decrease in nutritional parameters after the most extended ozone treatments was not significantly different from the ones found with the thermal procedure, color degradation of PGJ resulted significantly more significantly after the thermal treatment, compared to the ozone exposure. Ozonation may be a promising technology to preserve safety, visual aspects, physicochemical, and functional properties while extending the self-life of peach and grape juice.