Purpose: The objective in this study was to evaluate the antiviral effects of NA-20 on NoV GII.4 and MS2 phage, a surrogate of norovirus, and to identify the mechanism of action of NA-20.
Methods: The antiviral efficacy of four solutions (NA-20, NA-20 without PE, 50% ethanol, and PBS as the control) against NoVs was evaluated by quantifying the amount of residual noroviral genome using quantitative real-time RT–PCR. The antiviral efficacy against MS2 phage was examined with an infectivity assay (plaque assay) and quantification of the residual genome. The effects of the four solutions on the morphology of MS2 phage were assessed with transmission electron microscopy.
Results: The amount of residual viral genome of both viruses decreased significantly when treated with NA-20 (P < 0.05). NA-20 inactivated MS2 phage by 3.06 log PFU/ml, whereas NA-20 without PE and 50% EtOH did not reduce the infectivity of MS2 phage (0.03 and 0.04 log reduction, respectively). MS2 phage particles were denatured and aggregated by the NA-20 treatment.
Significance: These results indicate that the reduction of both viral genomes and the inactivation of MS2 phage were caused by the astringency of the PE in NA-20. This suggests that NA-20 is useful for the disinfection of NoVs in the kitchen and food industry because it is harmless and can be used with cookware and hands.