Al-Qadiri Hamzah M, Lin Mengshi, Cavinato Anna G, Rasco Barbara A
Department of Food Science and Human Nutrition, Box 646376, Washington State University, Pullman, WA 99164-6376, United States.
Int J Food Microbiol. 2006 Aug 15;111(1):73-80. doi: 10.1016/j.ijfoodmicro.2006.05.004. Epub 2006 Jul 24.
Fourier Transform Infrared (FT-IR) spectroscopy (4000-400 cm(-1)) combined with multivariate statistical methods were used to identify and detect Escherichia coli O157:H7 from Alicyclobacillus spp. recovered from apple juice. Four treatments and a control in triplicate experiments (N=3) were studied; the first three treatments of pasteurized apple juice were inoculated with E. coli O157:H7 ATCC 35150, Alicyclobacillus acidoterrestris 1016 and Alicyclobacillus spp. C-Fugi-6 respectively. The fourth treatment was a 1:1 (v:v) mixed culture of both A. acidoterrestris 1016 and Alicyclobacillus spp. C-Fugi-6. The control was uninoculated pasteurized apple juice. The second derivative transformation and loadings plot over the range of 1800-900 cm(-1) highlighted the most distinctive variations among bacterial spectra. Loadings 1 and 2 were distinctively representative of the bacterial spectral data and accounted for 73% of the total variability. Treatments were noticeably segregated with distinct clustering by principal component analysis (PCA). Using soft independent modeling of class analogy (SIMCA) analysis, 88.3% of (E. coli O157:H7 ATCC 35150) spectra, 75.0% of (A. acidoterrestris 1016) spectra, 88.3% of (Alicyclobacillus spp. C-Fuji-6) spectra, and 80.0% of the mixed culture of both Alicyclobacillus strains spectra were correctly classified. Using the spectral features of bacterial cellular constituents such as nucleic acids, proteins, phospholipids, peptidoglycan, and lipopolysaccharides from examined bacterial cells, pure and mixed cultures of Alicyclobacillus spp. cells, and the pathogenic E. coli cells could be detected in apple juice.
傅里叶变换红外（FT-IR）光谱法（4000 - 400 cm(-1)）结合多元统计方法，用于从苹果汁中分离出的嗜酸耐热芽孢杆菌属中鉴定和检测大肠杆菌O157:H7。研究了四个处理组和一个对照组，每组进行三次重复实验（N = 3）；前三组处理分别是向巴氏杀菌苹果汁中接种大肠杆菌O157:H7 ATCC 35150、嗜酸耐热芽孢杆菌1016和嗜酸耐热芽孢杆菌属C-Fugi-6。第四组处理是嗜酸耐热芽孢杆菌1016和嗜酸耐热芽孢杆菌属C-Fugi-6的1:1（v:v）混合培养物。对照组为未接种的巴氏杀菌苹果汁。在1800 - 900 cm(-1)范围内的二阶导数变换和载荷图突出了细菌光谱中最显著的差异。载荷1和2是细菌光谱数据的显著代表，占总变异性的73%。通过主成分分析（PCA），各处理组明显分离并形成独特的聚类。使用类软独立建模（SIMCA）分析，88.3%的（大肠杆菌O157:H7 ATCC 35150）光谱、75.0%的（嗜酸耐热芽孢杆菌1016）光谱、88.3%的（嗜酸耐热芽孢杆菌属C-Fuji-6）光谱以及80.0%的两种嗜酸耐热芽孢杆菌菌株混合培养物光谱被正确分类。利用所检测细菌细胞中核酸、蛋白质、磷脂、肽聚糖和脂多糖等细菌细胞成分的光谱特征，能够在苹果汁中检测到嗜酸耐热芽孢杆菌属细胞的纯培养物和混合培养物以及致病性大肠杆菌细胞。
