大肠杆菌等致病菌的近红外光谱检测方法研究
发布时间：2019-03-08 08:39
【摘要】：近红外光谱检测技术是近年来发展最快的检测技术之一,具有无损、快速、高效、方便而环保的特点。本文以处于对数生长期的大肠杆菌和单增李斯特菌等致病菌为研究对象,考察了近红外光对致病菌细胞的作用机理,分析了近红外光谱分析技术的光谱预处理方法,利用基于主成分分析技术的投影判别分析对致病菌的鉴别进行了研究,得到了预期结果。 1.采用光电比浊法和平板计数法,对大肠杆菌的对数生长期进行了研究。通过比较大肠杆菌的生长曲线图,研究其生长趋势,确定了大肠杆菌的对数生长期,最后选定14h为大肠杆菌培养时间。 2.通过单因素试验和正交试验,对大肠杆菌细胞破碎参数进行了研究。以大肠杆菌细胞破碎率为指标,研究了大肠杆菌细胞破碎参数,确定最佳破碎参数组合为:破碎功率400W、每次破碎5s、间隔5s、实际破碎总时间50min。 3.根据不同浓度梯度的大肠杆菌细胞壁和细胞质的近红外光谱,分别考察了矢量归一法、多元散射校正法、一阶导数法、一阶导数+矢量归一法等近红外分析技术的光谱预处理技术,结果表明,一阶导数法和一阶导数+矢量归一法进行光谱预处理的效果很不理想,而采用矢量归一法和多元校正法进行光谱预处理可得到满意的效果。 4.利用基于主成分分析技术的投影判别分析,研究了近红外光对大肠杆菌细胞壁和细胞质的作用情况,结果表明,致病菌浓度对近红外光的吸收并不成浓度比例关系,而细胞壁和细胞质对近红外光的吸收则明显有所不同,即利用其近红外吸收光谱可以区分二者。 5.采用基于主成分分析技术的投影判别分析,不论是利用细胞壁或者是细胞质的近红外光谱,都可以将大肠杆菌和单增李斯特氏菌区分开来,但采用细胞壁的近红外光谱来区分两种致病菌,准确度更高。
[Abstract]:Near infrared spectroscopy (NIR) is one of the fastest developing detection techniques in recent years. It has the characteristics of nondestructive, rapid, efficient, convenient and environmentally friendly. In this paper, the action mechanism of near-infrared light on pathogenic bacteria such as Escherichia coli and Listeria monocytogenes in logarithmic growth period was investigated, and the spectral pretreatment method of near-infrared spectroscopy was analyzed. The identification of pathogenic bacteria was studied by projection discriminant analysis based on principal component analysis (PCA), and the expected results were obtained. 1. The logarithmic growth period of Escherichia coli was studied by photoelectric turbidimetry and plate counting. By comparing the growth curve of Enterobacter coli, the growth trend of E. coli was studied, and the logarithmic growth period of E. coli was determined. Finally, 14 h was selected as the culture time of E. coli. 2. The breaking parameters of E. coli cells were studied by single factor test and orthogonal test. Taking the breaking rate of E. coli cells as an index, the breaking parameters of E. coli cells were studied. The optimum breaking parameters were determined as follows: crushing power 400W, breaking power 5s, interval 5s, actual total breaking time 50min. 3. According to the near infrared spectra of the cell wall and cytoplasm of Escherichia coli with different concentration gradient, vector normalization method, multiple scattering correction method and first order derivative method were investigated, respectively. The results show that the first derivative vector normalization method and the first derivative vector normalization method are not ideal for the spectral pretreatment of near infrared analysis techniques, such as the first derivative vector normalization method and the first derivative vector normalization method, and the results show that the first derivative vector normalization method and the first derivative vector normalization method are not ideal. The method of vector normalization and multi-element correction can be used to pre-process the spectrum, and the results are satisfactory. 4. The effects of near infrared light on the cell wall and cytoplasm of Escherichia coli were studied by projection discriminant analysis based on principal component analysis. The results showed that the concentration of pathogenic bacteria did not proportional to the absorption of near infrared light. The absorption of near-infrared light by cell wall and cytoplasm is obviously different, that is to say, the near-infrared absorption spectra can be used to distinguish the two. 5. The projection discriminant analysis based on principal component analysis can distinguish Escherichia coli and Listeria monocytogenes from Listeria monocytogenes by using cell wall or near infrared spectrum of cytoplasm. But using the near infrared spectrum of cell wall to distinguish the two pathogens, the accuracy is higher.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R378
本文编号：2436629
[Abstract]:Near infrared spectroscopy (NIR) is one of the fastest developing detection techniques in recent years. It has the characteristics of nondestructive, rapid, efficient, convenient and environmentally friendly. In this paper, the action mechanism of near-infrared light on pathogenic bacteria such as Escherichia coli and Listeria monocytogenes in logarithmic growth period was investigated, and the spectral pretreatment method of near-infrared spectroscopy was analyzed. The identification of pathogenic bacteria was studied by projection discriminant analysis based on principal component analysis (PCA), and the expected results were obtained. 1. The logarithmic growth period of Escherichia coli was studied by photoelectric turbidimetry and plate counting. By comparing the growth curve of Enterobacter coli, the growth trend of E. coli was studied, and the logarithmic growth period of E. coli was determined. Finally, 14 h was selected as the culture time of E. coli. 2. The breaking parameters of E. coli cells were studied by single factor test and orthogonal test. Taking the breaking rate of E. coli cells as an index, the breaking parameters of E. coli cells were studied. The optimum breaking parameters were determined as follows: crushing power 400W, breaking power 5s, interval 5s, actual total breaking time 50min. 3. According to the near infrared spectra of the cell wall and cytoplasm of Escherichia coli with different concentration gradient, vector normalization method, multiple scattering correction method and first order derivative method were investigated, respectively. The results show that the first derivative vector normalization method and the first derivative vector normalization method are not ideal for the spectral pretreatment of near infrared analysis techniques, such as the first derivative vector normalization method and the first derivative vector normalization method, and the results show that the first derivative vector normalization method and the first derivative vector normalization method are not ideal. The method of vector normalization and multi-element correction can be used to pre-process the spectrum, and the results are satisfactory. 4. The effects of near infrared light on the cell wall and cytoplasm of Escherichia coli were studied by projection discriminant analysis based on principal component analysis. The results showed that the concentration of pathogenic bacteria did not proportional to the absorption of near infrared light. The absorption of near-infrared light by cell wall and cytoplasm is obviously different, that is to say, the near-infrared absorption spectra can be used to distinguish the two. 5. The projection discriminant analysis based on principal component analysis can distinguish Escherichia coli and Listeria monocytogenes from Listeria monocytogenes by using cell wall or near infrared spectrum of cytoplasm. But using the near infrared spectrum of cell wall to distinguish the two pathogens, the accuracy is higher.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R378
【引证文献】
相关硕士学位论文 前1条
1 张雅琪;基于傅里叶变换近红外光谱法的食源性致病菌的鉴别研究[D];河南科技大学;2011年
，本文编号：2436629
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