The effectiveness of ozone in post-harvest preservation of citrus fruits: Preliminary research

Citrus fruits are among the most widely cultivated crops globally. Recently, exotic species and hybrids like kumquat, limequat, and lime have gained popularity due to their rich content of antioxidants, polyphenols, essential oils, minerals, and vitamins. With growing consumer demand for safe and organic produce, especially for fruits consumed with their peel, extending the shelf life of fresh produce while preventing mould contamination is crucial. Traditionally used pesticides, such as imazalil, often leave residues and face increasing resistance, prompting the need for more environmentally friendly methods. Ozone treatment is being explored as a viable alternative to slow down fruit decay and extend shelf life. This research aimed to evaluate the effectiveness of ozone gas treatments on kumquat, limequat, and lime fruits inoculated with blue mould (Penicillium italicum). The study also monitored the effectiveness of imazalil fungicide in extending the shelf life of infected fruits. Ozone treatment variants included single, double, and triple exposures lasting 10, 30, and 60 minutes, with ozone concentrations ranging from 3.3 to 20 ppm. Results showed that ozone treatments were successful in extending shelf life. Specifically, 30-minute treatments with 20 ppm ozone reduced infection rates to 10-50% of fruits. Compared to conventional fungicide methods, ozone treatments produced equal or superior outcomes, suggesting that ozone could partially or fully replace traditional fungicidal treatments. These findings provide valuable insights into extending the shelf life of exotic citrus fruits using ozone, offering a promising alternative to chemical fungicides.