UV‐C Inactivation of Target Bacteria and Fungi Screened via Selenium‐Sand Melon Surface Metagenomics With Modeling of Fungal Inactivation Kinetics

ABSTRACT Selenium‐sand melon (SSM), a unique melon variety rich in selenium, is an economically and nutritionally significant crop, which is very suitable for processing into juice, but microbial inactivation is the biggest challenge in its processing. In order to address this problem, in this study, an innovative combination of metagenomic analysis, inactivation assay, and kinetic modeling techniques was used to first screen 7 bacterial and 5 fungal strains as target strains from the results of macro genomic analysis of SSM and soil samples. Then, after inoculating these microorganisms into SSJ respectively, we applied the liquid food UV‐C sterilization equipment over a wide irradiation dose range of 28–168 J/mL to comprehensively cover the inactivation study of bacteria and fungi, and focused on constructing an inactivation model of fungi in selenium sapodilla juice. The results showed that UV‐C exhibited significant bactericidal effects, and bacteria population decreased by approximately 7 log 10 at 56 J/mL, while fungal loads were reduced by nearly 5 log 10 at 168 J/mL. Fungal inactivation kinetics were modeled using multiple mathematical approaches. Among them, SWeibull2 model provided the best fit ( R 2 ≥ 0.999, lowest RMSE, AIC, and BIC values, and smallest D ‐value), outperforming the Allometric1 model and Linear models. Notably, resistance to UV‐C varied across fungal species, with Mortierella circinelloides demonstrating stronger resistance. This study highlights UV‐C as a viable nonthermal alternative for SSJ processing, validating SWeibull2 as reliable for predicting fungal inactivation kinetics under UV‐C.