Inactivation Kinetics and Mechanism of a Human Norovirus Surrogate on Stainless Steel Coupons via Chlorine Dioxide Gas

Abstract

e Acute gastroenteritis caused by human norovirus is a significant public health issue. Fresh produce and seafood are examples of high-risk foods associated with norovirus outbreaks. Food contact surfaces also have the potential to harbor noroviruses if exposed to fecal contamination, aerosolized vomitus, or infected food handlers. Currently, there is no effective measure to decontaminate norovirus on food contact surfaces. Chlorine dioxide (ClO 2 ) gas is a strong oxidizer and is used as a decontaminating agent in food processing plants. The objective of this study was to determine the kinetics and mechanism of ClO 2 gas inactivation of a norovirus surrogate, murine norovirus 1 (MNV-1), on stainless steel (SS) coupons. MNV-1 was inoculated on SS coupons at the concentration of 10 7 PFU/coupon. The samples were treated with ClO 2 gas at 1, 1.5, 2, 2.5, and 4 mg/liter for up to 5 min at 25°C and a relative humidity of 85%, and virus survival was determined by plaque assay. Treatment of the SS coupons with ClO 2 gas at 2 mg/liter for 5 min and 2.5 mg/liter for 2 min resulted in at least a 3-log reduction in MNV-1, while no infectious virus was recovered at a concentration of 4 mg/liter even within 1 min of treatment. Furthermore, it was found that the mechanism of ClO 2 gas inactivation included degradation of viral protein, disruption of viral structure, and degradation of viral genomic RNA. In conclusion, treatment with ClO 2 gas can serve as an effective method to inactivate a human norovirus surrogate on SS contact surfaces. Human norovirus (NoV) is the most prevalent cause of foodborne illnesses worldwide (1-3). This etiological agent accounts for more than 58% of all foodborne illnesses, causing 5.5 million cases of acute gastroenteritis in the United States annually (1). It is estimated that human NoV is responsible for more than 95% of nonbacterial acute gastroenteritis. Human NoV transmission occurs primarily through the fecal-oral route, either via person-to-person contact or contaminated food, water, fomites, and environmental surfaces (4, 5), and airborne transmission of viral particles may also be possible due to aerosolized vomitus or fecal material (6). Human NoV is highly contagious, with an infectious dose as low as 10 particles, and outbreaks often occur in confined settings, including restaurants, coach buses, hotels, nursing homes, hospitals, and cruise ships (7-11). Although human NoV causes significant health and emotional burdens, research on human NoV has been hampered due to the lack of an in vitro cell culture method and a small animal model (12). Therefore, we must rely on proper surrogates to study the survival of human NoV. Currently, cultivable animal caliciviruses, such as murine norovirus (MNV), feline calicivirus (FCV), and Tulane virus (TV), are used as surrogates for the study of human NoV (13,14). Studies have shown that MNV is more resistant to acid, heat, and environmental stresses than FCV (15). While MNV and TV have similar long-term storage stability and resistance to heat ...

Irrigating Lettuce with Wastewater Effluent: Does Disinfection with Chlorine Dioxide Inactivate Viruses?

“…This effect was significant in NoV GI and GII for the two ClO 2 concentrations tested, whereas it was significant in HAstV only for the highest disinfectant concentration (11 mg L −1 ). Wigginton et al (2012) and Sigstam et al (2013) reported extensive degradation of viral proteins by ClO 2 , while Yeap et al (2016) showed that ClO 2 inactivation of murine norovirus included disruption of viral structure.…”

Low-cost, Small-scale Decontamination of Laboratory Equipment by Using Chlorine Dioxide Gas

“…8 Although murine norovirus has outstanding environmental stability, a greater than 5 log 10 reduction has been achieved by using a ClO 2 gas dose of 24 ppm-h at 85% RH. 44 In contrast, vegetative bacteria such as Escherichia coli and Staphylococcus aureus showed a greater than 5 log 10 and greater than 2 log 10 reduction, respectively, with a total ClO 2 gas dose of 0.25 ppm-h at 52% RH. 26 A direct comparison of the exposure doses mentioned above is not possible because the RH varied in each report; the general trend is consistent with the principle of a hierarchy in chemical germicidal resistance.…”

Efficacy of chlorine dioxide as a disinfectant

“…Furthermore, 0.03 ppm of ClO 2 has been indicated to prevent aerosol-induced influenza A virus by denaturing the envelope proteins of the virus [12] . The mechanism of norovirus inactivation by ClO 2 is attained through degradation of viral protein, including viral genomic RNA and disruption of viral strucutre [15] . In addition, an observation on ClO 2reduced lysozyme activities showed the potential role of ClO 2 in denaturation and degradation of protein using Raman spectroscopy and gel electrophoresis [16] .…”

“…However, concentrations of ClO 2 equal to or more than 0.6 mg/L are required for a complete inactivation of viruses such as hepatitis A viruses, Norwalk and Norwalk-like viruses [19] . A 3-log reduction in murine norovirus 1 (MNV-1) was found when stainless steel contact surfaces were treated with ClO 2 gas at 2 mg/L for 5 minutes and 2.5 mg/L for 2 minutes while a complete virus inactivation was shown in a 1minute treatment with 4 mg/L of ClO 2 gas [15] . Although free residues of chlorine over a concentration of 2.19 mg/L of ClO 2 in wastewater do not entirely inactivating E. coli and f2 phage, it is able to completely inactivate SARS-CoV [20] .…”