脉冲强光对黄曲霉菌孢子的杀菌效果、微观结构及动力学的影响

脉冲强光是一种新兴的非热杀菌技术。为研究和预测脉冲强光对黄曲霉菌孢子的杀菌作用,在强度2.86,1.60,1.08,0.93 W/cm2脉冲强光下对固体培养基中黄曲霉菌孢子处理1~60 s,并对处理前、后孢子的微观形态进行扫描电镜分析。运用Log-linear模型、Weibull模型和Weibull+tail模型对杀菌致死曲线进行动力学分析。研究表明,随着照射强度增加和时间的延长,脉冲强光对黄曲霉菌孢子的杀菌效果增强。初始菌落数为5.15 lg(CFU/mL)的孢子在2.86 W/cm2下处理19 s可被全部杀死。电镜照片显示脉冲强光处理后孢子细胞结构崩溃。Weibull模型和Weibull+tail模型较Log-linear模型能更好地拟合脉冲强光处理黄曲霉菌孢子的杀菌曲线(R2>0.95)。其中Weibull+tail模型能更加精确地拟合杀菌动力学过程(R2=0.9727)。

Effect of Pulsed Light Irradiation on the Inactivation Effect,Microstructure and Kinetics Model of Spores of Aspergillus flavus

Pulsed light is a novel non-thermal sterilization technology.In order to study and predict the sterilization effect of pulsed light on Aspergillus flavus(A.flavus)spores,A.flavus spores on solid medium were treated by pulsed light with intensities of 2.86,1.60,1.08 and 0.93 W/cm2 from 1 s to 60 s.Micro morphology of the spores with and with out treatments were observed by scanning electron microscope(SEM).Log-linear model,Weibull model and Weibull+tail model were used to fit the kinetics model.The results showed that with the increase of irradiation intensity and time,the inactivation effect of pulsed light on A.flavus spores was enhanced.After 19 s of treatment under intensity of 2.86 W/cm2,all the spores with initial population of 5.15 lg(CFU/mL)were inactivated.SEM demonstrated the structure of spores collapsed after the treatment.Compared with the Log-linear model,both Weibull+tail model and Weibull model could fit the inactivation curves better(R2>0.95).But Weibull+tail model was more accurate(R2=0.9727).