Efficiency of Ozone Applied in Flow and at Low Pressures in the Inactivation of Salmonella in Black Peppercorns (Piper nigrum L.) and the Effects of Ozone Treatment on Grain Quality and Essential Oil Composition

Food contamination by <i>Salmonella</i> poses a significant public health risk, rendering products unfit for consumption. This study aimed to evaluate the efficiency of ozone gas (O₃), applied in flow and at low pressures, in inactivating <i>Salmonella</i> on black peppercorns (<i>Piper nigrum</i> L.). Samples were inoculated with a cocktail of four <i>Salmonella</i> serotypes and subjected to ozonation under flow or low-pressure conditions in a hypobaric chamber. For the flow treatment, ozone gas at 16 mg L^-1 was humidified by passing it through a 40% (<i>w</i>/<i>v</i>) sodium chloride solution and applied for 2, 4, and 8 h. For the hypobaric chamber treatment, an inlet O₃ concentration of 60 mg L^-1 was used, with 10, 15, and 20 injections. The results showed that, under flow ozonation for 8 h, <i>Salmonella</i> was absent in 25 g of the sample. Ozone treatment increased pH, total titratable acidity (TTA), antioxidant activity (DPPH*), lightness (<i>L</i>*), color saturation (<i>C</i>*), total phenolic content (TPC), and the concentration of major essential oil compounds in all treatments. Under low-pressure ozonation, <i>Salmonella</i> persisted in all tested conditions, along with changes in color difference (∆<i>E</i>*), moisture content, TTA, DPPH*, <i>L</i>*, <i>C</i>*, pH, TPC, and the concentration of major essential oil compounds. The essential oil yield was not affected. Although the application of ozone at low pressures reduced <i>Salmonella</i> contamination, it was not sufficient for complete inactivation under the tested conditions. However, the flow-applied ozone treatment proved effective in the inactivation of <i>Salmonella</i> in black peppercorns.