Antifungal Properties of Ozone Treatment against P. citrinum and R. stolonifera in Fresh-Peeled Garlic

Abstract

Garlic is susceptible to decay and presents a potential vehicle for foodborne disease transmission. Ozone treatment has proven to be an effective and innoxious method to provide bacterial resistance in this globally popular pungent vegetable. This study was conducted to evaluate the effects of different ozone treatments (differing in terms of concentration, treatment time and temperature) against Penicillium citrinum and Rhizopus stolonifer in spoiled fresh-peeled garlic. The results have shown that the most inhibitory conditions for in vitro treatments were achieved with an ozone concentration, treatment time and temperature of 6 ppm, for 20 min at 20 °C, respectively, on the P. citrinum and 8 ppm, for 20 min at 25 °C, respectively, on the R. stolonifer. The optimum in vivo ozone treatment conditions for fresh-peeled garlic inoculated with the same two kinds of spoilage molds remained the same for both, consisting of an ozone concentration of 6 ppm, a time of 15 min and a temperature of 20 °C. Following these ozone treatments, the total number of colonies of yeast and mold, as well as the incidence, lesion diameter and depth of spoilage in the fresh-peeled garlic was significantly reduced during storage, with improved bactericidal inhibition effects. In conclusion, this study showed that ozone treatment effectively inhibits the growth of spoilage molds, destroys cell structures, and affects the metabolic and physiological processes of P. citrinum and R. stolonifer. Thus, it provides a protective shield and extends the shelf life of fresh-peeled garlic.