1：Experimental Design and Method Selection:

The study used a batch-type UV treatment system with a 222-nm KrCl excilamp to inactivate pathogens in PBS and apple juice. Acid adaptation was induced by growing cells in TSB without dextrose at pH 5.0, and non-acid adaptation at pH 7.3. Survival curves were modeled using Weibull or Weibull with tail models to calculate D5d values. Mechanisms were investigated through assays for cell membrane damage (PI uptake), lipid peroxidation (DPPP assay), ROS generation (CM-H2DCFDA assay), and fatty acid composition analysis.

2：0, and non-acid adaptation at pH Survival curves were modeled using Weibull or Weibull with tail models to calculate D5d values. Mechanisms were investigated through assays for cell membrane damage (PI uptake), lipid peroxidation (DPPP assay), ROS generation (CM-H2DCFDA assay), and fatty acid composition analysis. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Bacterial strains of E. coli O157:H7 (ATCC 35150, ATCC 43889, ATCC 43890) and S. Typhimurium (ATCC 19585, ATCC 43971, DT 104) were used. Samples included phosphate-buffered saline (PBS) and commercially clarified apple juice.

3：List of Experimental Equipment and Materials:

Equipment included a DBD excilamp (UNILAM), UV fiber optic spectrometer (AvaSpec-ULS2048, Avantes), magnetic stirrer (TM-17R, Jeio Tech), spectrophotometer (Spectramax M2e, Molecular Devices), pH meter (Mettler Toledo), digital refractometer (Atago), turbidity meter (Lutron Electronic Enterprise), gas chromatograph (model 7890A, Agilent Technologies), colorimeter (CR400, Minolta), and various reagents and media (e.g., TSB, TSA, XLD, SMAC, SPRAB, PI, DPPP, CM-H2DCFDA).

4：Experimental Procedures and Operational Workflow:

Pathogens were cultured, adapted to acid or non-acid conditions, inoculated into PBS or apple juice, and treated with UV light at various doses. Enumeration was done on selective media. Assays for membrane damage, lipid peroxidation, ROS, and fatty acids were performed post-treatment. Quality indicators (color, total phenols, DPPH activity) were measured in apple juice.

5：Data Analysis Methods:

Data were analyzed using ANOVA and LSD t-test in SAS. Survival curves were fitted with GInaFiT software, and D5d values were calculated using Microsoft Excel.