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.