Inactivation of norovirus attached to brine-dispersed microplastics using ultraviolet-C LED irradiation based on a viability-indicating RT-qPCR assay

Dongchimi is a representative type of water kimchi exposed to cross-contamination by microplastics (MPs) introduced from sea salt. The risk of pathogenic microbial cross-contamination from the microbial community on the surface of MPs (plastispheres) has gained particular attention. This study quantified the inactivation efficacy of UVC-LED irradiation on HuNoV attached to MPs. We conducted multivariate statistical analysis using response surface methodology based on the Box–Behnken design technique to model the correlations and optimized parameters of experimental variables, such as MP concentration, brine agitation, and UVC-LED dose. The optimal inactivation conditions were 300 RPM of agitation speed, MP concentration of 11.9%, and 30 mJ/cm 2 UVC-LED dose. Our model adequately fit the experimental data (R 2 =0.9782) and predicted a maximal inactivation value of 4.33 log 10 genomic copies under the optimized conditions. We found that the frequency and dose of UVC-LED exposure were key parameters that enhance its inactivation efficacy in brine treatment processes using sea salt. In conclusion, the UVC-LED disinfection approach proposed in this study offers valuable insights for designing optimal control strategies and technologies to prevent infectious diseases, particularly those associated with cross-contamination by HuNoV in MPs. • UVC-LED disinfection of HuNoV on microplastics in brine was evaluated • Box–Behnken design and RSM were used to optimize key disinfection parameters • Agitation speed and UVC dose were critical for HuNoV inactivation efficacy • The model showed a strong fit and predicted 4.33 log 10 copy reduction • This approach offers insight for safer brine fermentation using sea salt