Purpose: The aim of this study was to develop a protocol to test the efficacy of disinfectants against HuNoV on soft surfaces.
Methods: Feline Calicivirus (FCV) strain F9 and Murine Norovirus (MNV) strain 1 were dried onto 1x1 in coupons of glass, cotton, and polyester and recovered using sonication for 5 min at 40 kHz and stomaching for 5 min at 260 rpm. For disinfection viruses were inoculated and dried in the same manner and subjected to disinfection with 5,000 ppm Clorox or 2,6000 ppm Virox for 5 min followed by neutralization in PBS+0.02%Tween80+10%FBS. Viruses were enumerated using plaque assay and confirmed via reverse-transcriptase-PCR.
Results: Recovery efficiency from glass, polyester, and cotton was 35, 6, and 0.15% for FCV, and 9.2, 3.1, and 0.57% for MNV, respectively. Longer drying time (40 min) resulted in less recovery of viruses from soft surfaces. Clorox (5,000 ppm) and Virox (ca. 2,600 ppm) inactivated FCV below the limit of detection (1.34 PFU) corresponding to inactivation rates of >99.99, >99.9, and >90% for glass, polyester, and cotton, respectively.
Significance: Our results indicate virus recovery can be affected by virus type, surface characteristics, and attachment time. Due to the low recovery rates associated with cotton, it will be especially challenging to demonstrate complete 3 log inactivation (>99.9%) of viruses on soft surfaces.