Label-free detection of the foodborne pathogens of Enterobacteriaceae by surface-enhanced Raman spectroscopy

Abstract

Label-free and rapid assessment of foodborne pathogenic contamination, which can have significant implications for food safety, is critically important. In this study, seven foodborne bacteria (Salmonella typhimurium ATCC 50013, Salmonella O7HZ10, Shigella boydii CMCC51514, Shigella sonnei CMCC51529, Shigella dysenteriae CMCC51252, Citrobacter freundii ATCC43864, and Enterobacter sakazakii 154) have been examined, which are classified as Enterobacteriaceae according to biological taxonomy. They often have high rates of outbreak. A rapid and sensitive measurement method has been developed based on surface-enhanced Raman spectroscopy (SERS) coupled with gold nanoparticles as SERS substrates. The respective SERS spectra of the pathogens and their reproducibility have been compared. The principal component analysis (PCA) multivariate statistical technique has been employed to analyze the data, and a dendrogram cluster was constructed by hierarchical cluster analysis (HCA). Our results have shown that a rapid, sensitive, label-free identification of the foodborne pathogenic bacteria could be obtained by using gold nanoparticles as effective and stable SERS substrates.