EVALUATING THE POTENTIAL OF OZONE MICROBUBBLES FOR INACTIVATION OF TULANE VIRUS, A HUMAN NOROVIRUS SURROGATE

Microbubbles are small gas-filled bubbles with diameters ranging from 50 to 1 μm, and less than 200 nm are called nanobubbles. Their small sizes and large specific surface area result in a high gas dissolution rate and long lifetime in liquid. Ozone is a strong oxidant that destroys microorganisms and only produces oxygen as the final by-product in fresh water. However, due to the poor stability of aqueous ozone, critical gas waste happens during treatments which leads to a high economic loss. Microbubbles have shown promising enhancement of ozone treatment. In previous studies, ozone microbubbles exhibited excellent efficacy in the removal of organic contaminants and inactivation of microorganisms including bacteria, spores, and fungi, but few articles discuss the virus inactivation of ozone microbubbles treatment. Human noroviruses (NoVs) are the primary cause of foodborne illnesses in the US, and the development of effective inactivation methods is crucial. Because of the absence of suitable in vitro cultivation methods for NoVs and the constraints of the available infectivity models for these viruses, most of the studies about inactivation use surrogate viruses that are similar to NoVs in genetics and structure. Tulane virus is a NoV surrogate that can identify the same putative co-factor. This study focuses on the influence of treatment time, disinfectant air exposure, and the presence of organic contaminants on the inactivation efficacy of ozone microbubbles or millimeter bubbles. The results demonstrate that more than one log10 reduction was produced when the Tulane virus was exposed to ozone millimeter bubbles and ozone microbubbles for a short period of time, even in the presence of high organic load (FBS), and the protective effect of the organic load was shown when the disinfectant induced volume increased. The findings indicate that conducting further research on ozone microbubbles in aqueous applications in food-related applications is useful