Combination of paper membrane-based filtration and ultrafiltration to enhance the detection of MNV, HAV, and HCoV from soil-rich post-washing water.

Risk-assessing and controlling virus transmission from soil-rich post-washing water (PWW) are crucial during harvesting raw vegetables. However, viruses are normally difficult to concentrate because of their low concentrations and complex backgrounds. Here, ultrafiltration (UF), virus adsorption-elution (VIRADEL), and optimized paper filtration-coupled ultrafiltration (PFC-UF) methods were employed to evaluate the recovery of non-enveloped murine norovirus (MNV-1), hepatitis A virus (HAV), and enveloped human coronavirus 229E (HCoV-229E) from soil-rich PWW. Among the three methods, PFC-UF outperformed the other methods in the recovery of viruses from PWW with soil content. Under the highest soil condition with virus seeded at a titer of 10 plaque-forming unit (PFU) or TCID, the PFC-UF method exhibited an exceedingly consistent recovery rate of 78.8 ± 13.3 (MNV-1) and 44.4 ± 25.2% (HAV). However, the recovery of enveloped HCoV-229E was inferior to non-enveloped viruses. Overall, PFC-UF provided a reliable method for recovering viruses in soil-rich PWW.