Immunomagnetic separation combined with RT-qPCR for evaluating the effect of disinfectant treatments against norovirus on food contact surfaces

Despite the importance of preventing the spread of human norovirus (NoV), effective disinfectants are lacking. In this study, the efficacy of disinfectants against NoV on various non-porous surfaces was investigated by immunomagnetic separation (IMS) and quantitative real-time reverse transcription (RT-q)PCR. Monoclonal anti-NoV antibody-conjugated magnetic beads captured intact viral particles for RT-qPCR after the treatment of surfaces with disinfectants. Viral suspensions of approximately 5.97 log(10) genomic copies were inoculated onto rubber, glass, stainless steel, ceramic tile, wood, and polyvinyl chloride surfaces. Various elution buffers were used to elute NoV from surfaces. Ethanol (50-70%), sodium hypochlorite (NaOCl, 100-1000 ppm), sodium metasilicate (SMS, 0.1% and 0.3%), and quaternary compounds (1000-2000 ppm) were investigated as disinfectants; the observed reductions were < 1 log(10), except for SMS (1.17 +/- 0.21 to 2.71 +/- 0.06 log(10) reduction) and 700-1000 ppm NaOCl (1.04 +/- 0.07 to 2.03 +/- 0.05 log(10) reduction). Ethanol and quaternary compounds exhibited low efficacy against NoV GII.4 on all surfaces. These results indicated that SMS is the most effective disinfectant and emphasized the need to develop suitable agents to inactivate NoV on surfaces.