Exploration on the application potential of DUV-LED in fresh rice noodles: Spoilage characteristics of Bacillus cereus-group spoilage isolate, inactivation and the impact in the model.

Fresh rice noodles are highly susceptible to microbial spoilage due to their high moisture content. This study investigated bacterial composition in fresh rice noodles provided by different manufacturers, isolated a spoilage isolate belonging to the Bacillus cereus (B. cereus) group from commercially available naturally deteriorated fresh rice noodles, and systematically evaluated its growth characteristics and spoilage potential on rice noodle model quality. B. cereus-group spoilage isolate (BCSI) inoculation significantly increased lightness, shifted flavor toward sourness/bitterness with elevated spoilage-related volatile organic compounds, and changed appearance. To mitigate this issue, deep-ultraviolet light-emitting diode (DUV-LED) was optimized as a non-thermal intervention. At 11 min exposure, it achieved ∼4.7-log reduction in viable spores, and sustained growth inhibition. Compared to conventional UVC (254 nm, 150 W, 495.00 mJ/cm2, 87.5% sublethal injury rate), DUV-LED (275 nm, 5 W, 489.24-1793.88 mJ/cm2) resulted in no colony growth on selective and non-selective media. Short time DUV LED (489.24 mJ/cm2) reduced the amount of biofilm by more than 85% and increased membrane permeability. The advantages of DUV-LED in preserving and reducing bacteria in rice products were verified. DUV-LED effectively reduced the total aerobic plate counts and maintained the appearance of rice noodle model after 7 d of storage. These findings demonstrate that the potential application of DUV-LED in inactivating bacteria, providing a promising preservation strategy for maintaining quality and enhancing the safety of high-moisture rice products.