脉冲强光对馒头表面金黄色葡萄球菌的杀菌效果

目的研究脉冲强光技术在馒头表面金黄色葡萄球菌杀菌中的效果及其机制。方法控制闪照距离为9~21 cm,单脉冲能量为100~500 J,闪照次数为0~20次,分析不同条件下金黄色葡萄球菌的失活规律,并将该优化条件应用于馒头表面金黄色葡萄球菌的杀菌试验,最后采用透射电子显微镜技术分析脉冲强光技术对金黄色葡萄球菌形态结构的影响,从而分析其杀菌机制。结果脉冲强光在闪照距离为9 cm,单脉冲能量为500 J的情况下,闪照16次能对金黄色葡萄球菌产生良好的杀菌效果。该脉冲强光处理技术能降低馒头表面的金黄色葡萄球菌1.72 log CFU/g。透射电镜观察结果说明了脉冲强光可破坏金黄色葡萄球菌的细胞膜和菌体胞质内容物,从而造成细胞的失活。结论脉冲强光可对金黄色葡萄球菌产生较强的杀菌效果,在馒头加工业中具有一定的应用前景。

Evaluation of pulsed light treatment on the inactivation of Staphylococcus aureus on steamed bread

Objective To evaluate the inactivation effect and mechanism of pulsed light treatment on Staphylococcus aureus on surface of steamed bread. Methods By controlling the treatment distance ranging from 9 to 21 cm, the single pulse energy ranging from 100 to 500 J, and the flashed time ranging from 0 to 20 times, the inactivation pattern of S. aureus were analyzed. The optimized results were applied on the inactivation of S. aureus on the surface of steamed bread. Therefore, the morphological changes of S. aureus under pulsed light treatment were analyzed using transmission electron microscope (TEM). Results When the pulse distance and single pulse energy were set at 9 cm and 500 J, respectively, the highest inactivation effect of S. aureus could be obtained after 16 pulse times. When the pulsed light treatment conditionswere applied on the inactivation of S. aureus on the surface of steamed bread, 1.72 log CFU/g reduction was observed. The TEM observation primarily revealed that the pulsed light treatment damaged the cell membrane and content in cell cytoplasm of S. aureus, which caused cell death as a result.Conclusion Pulsed light can cause a desired inactivation effect on S. aureus, which exhibits an application prospect in the processing industry of steamed bread.