ABSTRACT

The present work aimed at the effectiveness of ozonated water in the control of Listeria monocytogenes, adopting different combinations of pH, contact time, and storage time under refrigeration. To obtain ozonated water, the dose applied was 21 mg L⁻¹ min⁻¹, for 15 min. Samples of 1.0 L of water were ozonated at the inlet ozone concentration of 21 mg L⁻¹ and a flow rate of 1.0 L min⁻¹. The initial concentrations of ozone dissolved in water were equal to 5.81 mg L⁻¹ at pH 4.0, 5.20 mg L⁻¹, at pH 7.0, and 7.20 mg L⁻¹ at pH 8.2. Samples of ozonated water with different initial pHs were used and stored at 7℃ for up to 24 h. The storage times of the ozonated water under refrigeration were 0, 6, 12, 18, and 24 h. The contact times of L. monocytogenes with ozonated water were 3.0 and 6.0 min. Ozone decomposition kinetics was evaluated. Ozonated water stored at 7℃ proved effective in controlling L. monocytogenes, especially in water pH values of 7.0 and 8.2. The initial pH of the water affects the effectiveness of ozonated water regarding the control of L. monocytogenes. The sharp reduction in ozone concentration was observed in water with pH 4.0, with a half-life of 13 min. For pHs of 7.0 and 8.2, the half-lives were 65 and 45 min, respectively. It is viable to use ozonated water stored at 7℃, for up to 24 h, to inactivate L. monocytogenes, when adopting initial pHs of 7.0 and 8.2, adjusted with sodium bicarbonate.

摘要

本工作针对臭氧水在控制单核细胞增生李斯特菌方面的有效性，采用不同的 pH 值、接触时间和冷藏条件下的储存时间组合。为获得臭氧水，施用的剂量为 21 mg L ^-1 min ^-1，持续 15 分钟。^{在 21 mg L -1}的入口臭氧浓度和 1.0 L min ^-1的流速下对 1.0 L 水样品进行臭氧化。溶解在水中的臭氧的初始浓度在 pH 4.0 时等于 5.81 mg L ^-1 、在 pH 7.0 时为5.20 mg L ^-1和 7.20 mg L ^-1在 pH 值 8.2 时。使用具有不同初始 pH 值的臭氧水样品并在 7℃ 下储存长达 24 小时。臭氧水在冷藏条件下的储存时间分别为 0、6、12、18 和 24 小时。单核细胞增生李斯特菌与臭氧水的接触时间分别为 3.0 和 6.0 分钟。评价了臭氧分解动力学。7℃储存的臭氧水证明对控制单核细胞增生李斯特菌有效，特别是在水的pH值为7.0和8.2的情况下。水的初始 pH 值会影响臭氧水控制单核细胞增生李斯特菌的有效性. 在 pH 值为 4.0 的水中观察到臭氧浓度急剧下降，半衰期为 13 分钟。对于 7.0 和 8.2 的 pH 值，半衰期分别为 65 和 45 分钟。当采用初始 pH 值 7.0 和 8.2 并用碳酸氢钠调节时，使用 7℃ 储存长达 24 小时的臭氧水灭活单核细胞增生李斯特菌是可行的。