Evaluating the Potential of Ozone Microbubbles for Inactivation of Tulane Virus, a Human Norovirus Surrogate

This study investigated the efficacy of low-dose ozone microbubble solution and conventional aqueous ozone as inactivation agents against Tulane virus samples in water over a short period of time. Noroviruses are the primary cause of foodborne illnesses in the US, and the development of effective inactivation agents is crucial. Ozone has a high oxidizing ability and naturally decomposes to oxygen, but it has limitations due to its low dissolution rate, solubility, and stability. Ozone microbubbles have been promising in enhancing inactivation, but little research has been done on their efficacy against noroviruses. The study examined the influence of the dissolved ozone concentration, inactivation duration, and presence of organic matter during inactivation. The results showed that ozone microbubbles had a longer half-life (14 ± 0.81 min) than aqueous ozone (3 ± 0.35 min). After 2, 10, and 20 min postgeneration, the ozone concentration of microbubbles naturally decreased from 4 ppm to 3.2 ± 0.2, 2.26 ± 0.19, and 1.49 ± 0.23 ppm and resulted in 1.43 ± 0.44, 0.88 ± 0.5, and 0.68 ± 0.53 log10 viral reductions, respectively, while the ozone concentration of aqueous ozone decreased from 4 ppm to 2.52 ± 0.07, 0.43 ± 0.05, and 0.09 ± 0.01 ppm and produced 0.8 ± 0.28, 0.29 ± 0.41, and 0.16 ± 0.21 log10 reductions against Tulane virus, respectively (p = 0.0526), suggesting that structuring of ozone in the bubbles over the applied treatment conditions did not have a significant effect, though future study with continuous generation of ozone microbubbles is needed.

本研究针对水环境中的图兰病毒（Tulane virus）样本，探究了短时间内低剂量臭氧微气泡溶液（ozone microbubble solution）与常规水相臭氧（conventional aqueous ozone）作为灭活剂（inactivation agents）的灭活效能。诺如病毒（Norovirus）是美国食源性疾病的主要致病原，开发高效灭活剂至关重要。臭氧具备较强的氧化能力且可自然分解为氧气，但受限于较低的溶解速率、溶解度与稳定性，其应用存在一定局限。臭氧微气泡在提升病毒灭活效果方面已展现出应用潜力，但目前针对诺如病毒的相关灭活效能研究仍较为匮乏。本研究考察了灭活过程中溶解臭氧浓度、灭活时长与有机物存在与否对灭活效果的影响。结果显示，臭氧微气泡的半衰期（half-life）为14 ± 0.81 分钟，长于常规水相臭氧的3 ± 0.35 分钟。在生成后2、10与20分钟时，臭氧微气泡体系的臭氧浓度从4 ppm分别自然降至3.2 ± 0.2、2.26 ± 0.19与1.49 ± 0.23 ppm，对应的图兰病毒log₁₀级病毒灭活率（log10 viral reductions）分别为1.43 ± 0.44、0.88 ± 0.5与0.68 ± 0.53；而常规水相臭氧体系的臭氧浓度从4 ppm分别降至2.52 ± 0.07、0.43 ± 0.05与0.09 ± 0.01 ppm，对应的图兰病毒log₁₀级病毒灭活率分别为0.8 ± 0.28、0.29 ± 0.41与0.16 ± 0.21（p=0.0526）。上述结果表明，本实验所采用的处理条件下，臭氧以微气泡形式存在的结构并未产生显著影响，但仍需开展后续采用持续生成臭氧微气泡方案的相关研究。