Exploring magnetic capture to improve the detection of human norovirus in strawberries

Abstract

Human norovirus is a leading cause of foodborne illness worldwide, and its detection in foods remains a challenge due to the difficulty of eluting and enriching trace amounts of viral particles. In this study, we developed porcine gastric mucin–labeled magnetic capture probes and optimized the conditions for their binding with norovirus, elution of viral particles, and RNA isolation based on the previous research. We evaluated the magnetic capture-based pretreatment method in artificially contaminated strawberry samples and compared it with the conventional polyethylene glycol precipitation–based method using reverse transcriptional-quantitative PCR (RT-qPCR). The results revealed that Tris·HCl (pH 9.5) was the optimal buffer for the binding of magnetic probes with viral particles, and RNA recovery rate obtained by heating-based release was significantly higher than that obtained by a commercial kit, with only active virus being captured. This buffer was similar to the RT-qPCR buffer, which facilitated the sensitivity of RT-qPCR. Furthermore, the buffer was an effective solution for eluting viral particles from foods in previous research and was optimized to ensure maximum elution and no inhibitory effect on viral capture. We explored multiple factors or steps to ensure that the sensitivity of our method was three orders of magnitude higher than that of the conventional method. Our findings suggest that magnetic capture-based detection has great potential for the sensitive detection of human norovirus.