Title: Inactivation of human norovirus using chemical sanitizers Authors
Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 16, 2013
Publication Date: February 1, 2014
Citation: Kingsley, D.H., Vincent, E., Meade, G.K., Watson, C., Fan, X. 2014. Inactivation of human norovirus using chemical sanitizers. International Journal of Food Microbiology. 171:94-99. Interpretive Summary: In this publication, we evaluated the potential of common disinfectants used by the food and public health industries to inactivate human norovirus. Because human norovirus cannot be replicated in the laboratory, a newly developed porcine gastric mucin-magnetic bead (PGM-MB) binding method was used as a surrogate assay for virus infectivity after exposure to disinfectants. Essentially, this assay only detects norovirus with relatively undamaged outer coats, which retain the ability to initiate infection. Results demonstrated that chlorine, but not chlorine dioxide, causes a substantial loss of PGM binding activity by norovirus. Results also showed that hydrogen peroxide and peroxyacetic acid (PAA) did not prevent the capsid from binding to PGM-MB, suggesting that these are relatively poor sanitizers, or their mechanism of action is not against the outer coat of the virus. Interestingly, trisodium phosphate which has a high pH was somewhat effective against norovirus. While it cannot be said with certainty that PAA, hydrogen peroxide, and chlorine dioxide are ineffective sanitizers for norovirus, results published here do validate the use of chlorine and trisodium phosphate as sanitizers against human norovirus.
Technical Abstract: The porcine gastric mucin binding magnetic bead (PGM-MB) assay was used to evaluate the ability of chlorine, chlorine dioxide, peroxyacetic acid, hydrogen peroxide, and trisodium phosphate to inactivate human norovirus within 10 percent stool filtrate. One min free chlorine treatments at concentrations of 33 and 189 ppm reduced virus binding in the PGM-MB assay by 1.48 and 4.14 log, respectively, suggesting that chlorine is an efficient sanitizer for inactivation of human norovirus (HuNoV). Five min treatments with 5 percent trisodium phosphate (pH 12) reduced HuNoV binding by 1.6 log, suggesting that TSP, or some other high pH buffer, could be used to treat food and food contact surfaces to reduce HuNoV. One min treatments with 350 ppm chlorine dioxide dissolved in water did not reduce PGM-MB binding, suggesting that the sanitizer may not be suitable for HuNoV inactivation in liquid form. However a 60 min treatment with 350 ppm chlorine dioxide did reduce human norovirus by 2.8 log, indicating that chlorine dioxide had some, albeit limited, activity against HuNoV. Results also suggest that peroxyacetic acid has limited effectiveness against human norovirus, since 1-min treatments with up to 195 ppm reduced human norovirus binding by <1 log10. Hydrogen peroxide (4 percent) treatment of up to 60 min resulted in minimal binding reduction (0.1 log10) suggesting that H2O2 is not a good liquid sanitizer for HuNoV. Overall this study suggests that HuNoV is remarkably resistant to several commonly used disinfectants and advocates for the use of chlorine (sodium hypochlorite) as a HuNoV disinfectant wherever possible.