Identification of foodborne pathogenic bacteria using confocal Raman microspectroscopy and chemometrics

Jin Zhang; Pengya Gao; Yuan Wu; Xiaomei Yan; Changyun Ye; Weili Liang; Meiying Yan; Xuefang Xu; Hong Jiang

doi:10.3389/fmicb.2022.874658

Identification of foodborne pathogenic bacteria using confocal Raman microspectroscopy and chemometrics

Front Microbiol. 2022 Nov 7:13:874658. doi: 10.3389/fmicb.2022.874658. eCollection 2022.

Authors

Jin Zhang^{1

2}, Pengya Gao², Yuan Wu², Xiaomei Yan², Changyun Ye², Weili Liang², Meiying Yan², Xuefang Xu², Hong Jiang¹

Affiliations

¹ Criminal Investigation School, People's Public Security University of China, Beijing, China.
² State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.

Abstract

Rapid and accurate identification of foodborne pathogenic bacteria is of great importance because they are often responsible for the majority of serious foodborne illnesses. The confocal Raman microspectroscopy (CRM) is a fast and easy-to-use method known for its effectiveness in detecting and identifying microorganisms. This study demonstrates that CRM combined with chemometrics can serve as a rapid, reliable, and efficient method for the detection and identification of foodborne pathogenic bacteria without any laborious pre-treatments. Six important foodborne pathogenic bacteria including S. flexneri, L. monocytogenes, V. cholerae, S. aureus, S. typhimurium, and C. botulinum were investigated with CRM. These pathogenic bacteria can be differentiated based on several characteristic peaks and peak intensity ratio. Principal component analysis (PCA) was used for investigating the difference of various samples and reducing the dimensionality of the dataset. Performances of some classical classifiers were compared for bacterial detection and identification including decision tree (DT), artificial neural network (ANN), and Fisher's discriminant analysis (FDA). Correct recognition ratio (CRR), area under the receiver operating characteristic curve (ROC), cumulative gains, and lift charts were used to evaluate the performance of models. The impact of different pretreatment methods on the models was explored, and pretreatment methods include Savitzky-Golay algorithm smoothing (SG), standard normal variate (SNV), multivariate scatter correction (MSC), and Savitzky-Golay algorithm 1st Derivative (SG 1st Der). In the DT, ANN, and FDA model, FDA is more robust for overfitting problem and offers the highest accuracy. Most pretreatment methods raised the performance of the models except SNV. The results revealed that CRM coupled with chemometrics offers a powerful tool for the discrimination of foodborne pathogenic bacteria.

Keywords: chemometrics; classification; confocal Raman microspectroscopy (CRM); foodborne pathogenic bacteria; pretreatment.