Prediction of Injured and Dead Inactivated Escherichia coli O157:H7 Cells after Heat and Pulsed Electric Field Treatment with Attenuated Total Reflectance Infrared Microspectroscopy Combined with Multivariate Analysis Technique
Prediction of Injured and Dead Inactivated Escherichia coli O157:H7 Cells after Heat and Pulsed Electric Field Treatment with Attenuated Total Reflectance Infrared Microspectroscopy Combined with Multivariate Analysis Technique
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DOI：
10.1007/s11947-013-1195-4
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发表时间：
2014-07-01
影响因子：
5.6
通讯作者：
De Lamo-Castellvi, Silvia
中科院分区：
文献类型：
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作者：
Kidanemariam Gelaw, Tilahun;Espina, Laura;De Lamo-Castellvi, Silvia
衰减全反射红外显微光谱结合软独立建模类类比（SIMCA）多元技术被用来区分活的，死的，受伤的大肠杆菌O 157：H7细胞。E.将大肠杆菌O 157：H7细胞悬浮在pH 4.0和7.0的柠檬酸盐磷酸盐缓冲液中，并通过在54 ℃下加热5、10、20和90分钟或在35 kV/cm下脉冲电场（PEF）10、25、50和60个脉冲来处理。SIMCA分析证实，未处理和处理的E.大肠杆菌细胞中，（1）酰胺I带位于1，638和1，618 cm（-1），对应于β折叠二级蛋白结构的变化（在pH 7.0和4.0下热处理的细胞，以及在pH 4.0下PEF处理的细胞），和（2）在1，078和993 cm（-1），对应于磷酸二酯或脂多糖的P = O（PO（2）（-））伸缩和不同多糖的C-O-C或C-O伸缩的变化（pH 7.0下的PEF处理的细胞）。偏最小二乘回归分析的使用允许正确预测的热处理的幸存者。损伤细胞可以通过比较在含有氯化钠和胆盐的非选择性和选择性平板培养基中预测的细胞计数来估计。预测结果产生的灭活值的决定系数（R（2））为0.83或更高，交叉验证的标准误差在0.11和0.37个灭活对数循环之间。
Attenuated total reflectance infrared microspectroscopy combined with soft independent modeling of class analogy (SIMCA) multivariate technique was used to differentiate between alive, dead, and injured Escherichia coli O157:H7 cells. E. coli O157:H7 cells were suspended in citrate phosphate buffer at pH 4.0 and 7.0 and treated by heat at 54 A degrees C for 5, 10, 20, and 90 min or pulsed electric field (PEF) at 35 kV/cm for 10, 25, 50, and 60 pulses. The SIMCA analysis confirmed that major contribution to the discrimination of the untreated and treated E. coli cells were (1) the amide I band at 1,638 and 1,618 cm(-1) corresponding to changes in beta-pleated secondary protein structure (heat-treated cells at pH 7.0 and 4.0, and PEF-treated cells at pH 4.0), and (2) the bands at 1,078 and 993 cm(-1) corresponding to changes in P = O (PO (2) (-) ) stretching of phosphodiesters or lipopolysaccharides and C-O-C or C-O stretching of different polysaccharides (PEF-treated cells at pH 7.0). The use of partial least squares regression analysis allowed for correctly predicting the survivors of the thermal treatment. Injured cells could be estimated from the comparison of cell counts predicted in nonselective and selective plating media with sodium chloride and bile salts. The prediction results yielded inactivation values with a coefficient of determination (R (2)) of 0.83 or higher and a standard error of cross validation between 0.11 and 0.37 log cycles of inactivation.