Objective To establish and optimize a simple and efficient norovirus concentration and detection technique for seawater samples from shellfish farming areas to address global food safety hazards and meet the needs of precise infectious disease prevention and control.

Methods Using murine norovirus as the experimental subject, a nano-alumina ceramic filter-based enrichment technique was combined with a novel azido bromide propidium (PMAxx) nucleic acid dye and real-time quantitative PCR (PMAxx-qPCR) to detect viable viruses. Viruses were first enriched using a filter membrane, initially concentrated with Tralk eluent, and then further concentrated using PEG precipitation. The detection efficacy of this method was evaluated and compared with traditional cell culture techniques.

Results With a 5 000-fold concentration, the recovery rate of this enrichment method reached 3.24%. Optimal detection of viable norovirus was achieved with a PMAxx dye concentration of 50 μmol, followed by 15 minutes of incubation in the dark, 10 minutes of light exposure, and then real-time quantitative PCR amplification.

Conclusions The norovirus concentration and detection method established and optimized in this study significantly improved the recovery rate and detection accuracy of norovirus, which is of great significance for improving food safety testing and infectious disease prevention and control.