针对酸土脂环酸芽孢杆菌芽孢污染果汁的难题，该研究旨在筛选并评估植物源活性物质协同组合的杀芽孢效果及其作用机理。该研究测定了植物源活性物质的最小抑菌浓度（MIC）和最小杀菌浓度（MBC），并通过测定分级浓度抑菌系数（FICI）筛选出针对酸土脂环酸芽孢杆菌（Alicyclobacillus acidoterrestris）芽孢具有协同效应的组合：根皮素（Ph）与十二醛（La）。结果表明：根皮素的MIC为0.1 mg/mL，MBC>6.4 mg/mL；十二醛的MIC为0.4 mg/mL，MBC>6.4 mg/mL；二者联合作用的FICI为0.5。8PL（2 MIC_Ph+2 MIC_La）组在协同组中杀芽孢效果最佳，在培养基中8PL组处理2 d后芽孢数量减少了10^6.1 CFU/mL；而在苹果汁中接种10⁴ CFU/mL的酸土脂环酸芽孢杆菌芽孢，8PL组处理能在1 d后使芽孢减少到0并维持效果至少14 d；对于接种量为10⁶ CFU/mL的苹果汁样品，8PL组处理需超过3d才能使芽孢减少到0，但14 d后再次检测到10^2.2 CFU/mL芽孢。随着协同组合浓度的增大，芽孢吸光度显著下降，荧光光谱增强；通过扫描电镜观察到芽孢表面的不规则褶皱消失，表面逐渐光滑且凹陷和破碎的程度增加，通过透射电镜观察到芽孢膜裂解；核酸与蛋白质的泄漏量也逐渐增加。结果表明，协同组会对芽孢膜等结构造成损伤。此外，吡啶二羧酸（DPA）的释放也显著增加，使芽孢的抗逆性大大下降。根皮素和十二醛协同组对酸土脂环酸芽孢杆菌芽孢具有较好的杀灭作用，是果汁抑菌防腐的有效策略。

To address the challenge of Alicyclobacillus acidoterrestris spore contamination of fruit juice, this study aimed to screen and evaluate the bactericidal effect of a synergistic combination of plant-derived actives and their mechanism of action. The study determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of plant-derived active compounds. By calculating the fractional inhibitory concentration index (FICI), a synergistic combination against Alicyclobacillus acidoterrestris spores was identified: phloretin (Ph) and lauric aldehyde (La). The results show that the MIC of phloretin is 0.1 mg/mL, and MBC is more than 6.4 mg/mL; the MIC of lauraldehyde is 0.4 mg/mL, and MBC is more than 6.4 mg/mL; the FICI of the combined effect of the two substances is 0.5. The 8PL (2 MIC_Ph + 2 MICLa) synergistic combination shows the best spore-killing effect in the synergistic combinations, and in the culture medium, the number of spores decreases by 10^6.1 CFU/mL after 2 days of treatment in the 8PL synergistic combination; inoculating 10⁴ CFU/mL of Alicyclobacillus acidoterrestris spores in apple juice, the 8PL synergistic combination treatment can reduce the spores to 0 after 1 day and maintain the effect for at least 14 days. For apple juice samples with an inoculation amount of 10⁶ CFU/mL, the 8PL synergistic combination treatment requires more than 3 days to reduce spores to 0 CFU/mL, but after 14 days, 10^2.2 CFU/mL spores are detected again. As the concentration of synergistic combination increases, the spore absorbance significantly decreases and the fluorescence spectrum increases. By scanning electron microscopy, irregular wrinkles on the surface of the spores disappear, and the surface gradually becomes smooth with an increase in the degree of depression and fragmentation. Transmission electron microscopy (TEM) observations revealed spore membrane disruption, accompanied by progressively increasing leakage of nucleic acids and proteins. The above results indicate that the synergistic combination will cause certain damage to structures such as spore membranes. In addition, the release of pyridine dicarboxylic acid (DPA) also significantly increases, greatly reducing the stress resistance of spores. In summary, the synergistic combination of phloretin and lauraldehyde has a good killing effect on Alicyclobacillus acidoterrestris spores, and it is an effective strategy for fruit juice antibacterial and preservative properties.