This study aimed to determine the post‐harvest quality of lettuce treated with ozonised water obtained in a microbubble system. The inlet ozone concentration was fixed at 3.5 mg L ⁻¹ , which allowed obtaining 1.60 mg L ⁻¹ of ozone in the water. Six treatments were adopted: (i) control (untreated lettuce); (ii) ozonised water/5 min; (iii) ozonised water/10 min; (iv) oxygen/5 min; (v) oxygen/10 min; and (vi) chlorine/15 min. After the treatments, the samples were stored at 5°C and at a relative humidity of 80%. Microbiological and physicochemical analyses were performed immediately after ozonation (day 0) and after 3 and 6 days of storage. Reductions in the count of aerobic mesophiles and molds and yeasts were observed, immediately after the treatments with ozonised water. For the treatments ozonised water/5 min and ozonised water/10 min, the reductions of aerobic mesophiles were equal to 0.71 and 1.59 log reduction respectively, when compared to the control. Despite the significant increase in the leakage of electrolytes, especially when it was adopted exposure time to ozonated water of 10 min, it was considered that the conditions adopted favour the lettuce sanitation, without causing changes that make the product non‐tradable.

Ozone gas (O₃) is a promising alternative for fungal inactivation in agricultural commodities. This study aimed to (i) investigate the influence of airflow on the saturation of popcorn kernels with ozone gas, (ii) evaluate its effectiveness in controlling Aspergillus flavus, and (iii) analyze the quality of ozonated grains. Samples of 3.0 kg of kernels were exposed to oxygen (control) or ozone at specific flow rates of 0.15 or 1.00 m³ min⁻¹ t⁻¹, with an input ozone concentration of 16.0 mg L⁻¹ for 0, 6, 12, 24, 36, or 48 h. Quality parameters assessed included expansion volume, water content, electrical conductivity, and color. At 0.15 m³ min⁻¹ t⁻¹, ozone consumption and saturation time were lower, with an 80% reduction in A. flavus infection after 6 h. This flow rate did not affect grain expansion or water content. Conversely, at 1.0 m³ min⁻¹ t⁻¹, reductions in water content and expansion were observed with extended exposure. Electrical conductivity increased in both treatments, more significantly at the lower flow rate. In conclusion, ozonation at 0.15 m³ min⁻¹ t⁻¹ effectively inactivated A. flavus without compromising grain quality.

Food contamination by Salmonella 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 Salmonella on black peppercorns (Piper nigrum L.). Samples were inoculated with a cocktail of four Salmonella 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% (w/v) 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, Salmonella was absent in 25 g of the sample. Ozone treatment increased pH, total titratable acidity (TTA), antioxidant activity (DPPH*), lightness (L*), color saturation (C*), total phenolic content (TPC), and the concentration of major essential oil compounds in all treatments. Under low-pressure ozonation, Salmonella persisted in all tested conditions, along with changes in color difference (∆E*), moisture content, TTA, DPPH*, L*, C*, 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 Salmonella contamination, it was not sufficient for complete inactivation under the tested conditions. However, the flow-applied ozone treatment proved effective in the inactivation of Salmonella in black peppercorns.