Abstract：
Bacillus cereus causes food poisoning by producing toxins that cause diarrhea and vomiting and, in severe cases, endocarditis, meningitis, and other diseases. It also tends to form biofilms and spores that lead to contamination of the food production environment. Citral is a potent natural antibacterial agent, but its antibacterial activity against B. cereus has not been extensively studied. In this study, we first determined the minimum inhibitory concentrations and minimum bactericidal concentrations, growth curves, killing effect in different media, membrane potential, intracellular adenosine triphosphate (ATP), reactive oxygen species levels, and morphology of vegetative cells, followed by germination rate, morphology, germination state of spores, and finally biofilm clearance effect. The results showed that the minimum inhibitory concentrations and minimum bactericidal concentrations of citral against bacteria ranged from 100 to 800 μg/mL. The lag phase of bacteria was effectively prolonged by citral, and the growth rate of bacteria was slowed down. Bacteria in Luria-Bertani broth were reduced to below the detection limit by citral at 800 μg/mL within 0.5 h. Bacteria in rice were reduced to 3 log CFU/g by citral at 4000 μg/mL within 0.5 h. After treatment with citral, intracellular ATP concentration was reduced, membrane potential was altered, intracellular reactive oxygen species concentration was increased, and normal cell morphology was altered. After treatment with citral at 400 μg/mL, spore germination rate was reduced to 16.71%, spore morphology was affected, and spore germination state was altered. It also had a good effect on biofilm removal. The present study showed that citral had good bacteriostatic activity against B. cereus vegetative cells and its spores and also had a good clearance effect on its biofilm. Citral has the potential to be used as a bacteriostatic substance for the control of B. cereus in food industry production.
摘要：
蜡状芽孢杆菌通过产生引起腹泻和呕吐的毒素而引起食物中毒，在严重的情况下，心内膜炎,脑膜炎,和其他疾病。它还倾向于形成生物膜和孢子，导致食品生产环境的污染。柠檬醛是一种有效的天然抗菌剂，但其对蜡样芽孢杆菌的抗菌活性尚未得到广泛研究。在这项研究中,我们首先确定了最低抑菌浓度和最低杀菌浓度，生长曲线，在不同介质中的杀伤效果，膜电位，细胞内三磷酸腺苷（ATP），活性氧水平，和营养细胞的形态，其次是发芽率，形态学,孢子的发芽状态，最后是生物膜清除作用。结果表明，柠檬醛对细菌的最低抑菌浓度和最低杀菌浓度范围为100～800μg/mL。柠檬醛有效地延长了细菌的滞后期，细菌的生长速度减慢。Luria-Bertani肉汤中的细菌在0.5h内被柠檬醛以800μg/mL降低到检测限以下。大米中的细菌在0.5h内被柠檬醛以4000μg/mL降低到3logCFU/g。细胞内ATP浓度降低，膜电位改变了，细胞内活性氧浓度增加，正常细胞形态发生改变。用400μg/mL的柠檬醛处理后，孢子萌发率降至16.71%,孢子形态受到影响，孢子萌发状态发生改变。对生物膜的去除也有很好的效果。本研究表明，柠檬醛对蜡样芽孢杆菌营养细胞及其孢子具有良好的抑菌活性，对其生物膜也有良好的清除作用。柠檬醛有可能在食品工业生产中用作控制蜡状芽孢杆菌的抑菌物质。
