Purpose: This study was conducted to evaluate the virucidal efficacies of chemical disinfectants against human norovirus GII.4 (NoV GII.4) on various food contact surfaces using immunomagnetic separation (IMS) technique and real time RT-qPCR.
Methods: The NoV GII.4 monoclonal antibody conjugated magnetic beads captured intact viral particles of NoV GII.4 to allow for subsequent quantitative real-time RT-qPCR after disinfection treatments on various surfaces. Viral suspensions of approximately 5.89 log genomic copies were inoculated on glass, stainless steel, polyvinyl chloride(PVC), rubber, wood, and ceramic tile. We evaluated the optimum elution buffer among the various elution buffers and then 0.25 M glycine-0.14 M NaCl (pH 9.5) buffer was decided to use for eluting the NoV from surfaces. The virucidal efficacy of the ethanol, sodium hypochlorite, and quaternary ammonium compounds was evaluated using a modified European CEN EN 1276 method (Dilution-Neutralization Method) based on quantitative suspension testing.
Results: For all kinds of tested surfaces, ethanol (50 to 70%), Sodium hypochlorite (200 to 2,000 ppm), and quaternary compounds(1,000 to 2,000 ppm) were investigated, and the log reduction values among the tested disinfectants were below <1 log except for 2,000 ppm sodium hypochlorite (between 1.04±0.07 to 1.63±0.24 log reductions).
Significance: These results illustrated that the necessity of developing suitable strategy for inactivation the NoV with disinfectants on environmental surfaces. In addition, we suggest that IMS technique could be diversely applied to investigate efficacies of chemical disinfectants against NoV.