Rapid and simple quantitative identification of Listeria monocytogenes in cheese by isothermal sequence exchange amplification based on surface-enhanced Raman spectroscopy

• DOI: 10.3168/jds.2022-22181
• Publication Date: 2022-10-04T23:57:33Z
• Authors: Yang Li; Yan Gao; Na Ling; Yizhong Shen; Danfeng Zhang; Dexin Ou; Xiyan Zhang; Rui Jiao; Changqing Zhu; Yingwang Ye
• Keywords: Food Contamination; SF250.5-275; Spectrum Analysis, Raman; isothermal sequence exchange amplification; Listeria monocytogenes; 01 natural sciences; surface-enhanced Raman spectroscopy; 0104 chemical sciences; cheese; Dairying; SF221-250; Cheese; Food Microbiology; bacteria detection; Streptavidin; Dairy processing. Dairy products; DNA Primers

Foodborne pathogens detection is important to ensure food safety and human health. In this study, we designed a comet structure to rapidly and sensitively detect foodborne Listeria monocytogenes. This method combined isothermal sequence exchange amplification (SEA) and surface-enhanced Raman spectroscopy. Listeria monocytogenes DNA could be rapidly amplified at a constant temperature via SEA with a pair of modified primers, which rendered the precise thermal control instrumentation unnecessary. Efficient SEA amplification generated a large number of DNA duplexes that could be easily captured by streptavidin-modified magnetic bead and AuMB@Ag-isothiocyanate fluorescein antibody (anti-FITC). AuMB@Ag-anti-FITC was used as a signal probe, which generated a significant excitation signal at 1,616 cm-1 for quantitative detection and analysis. The results displayed sensitive detection of L. monocytogenes in cheese from 2.0 × 101 cfu/mL to 2.0 × 106 cfu/mL within 1.0 h with a detection limit of 7.8 cfu/mL. Furthermore, this comet structure displayed the desirable specificity as its specific primers and amplified DNA ends were attached to streptavidin-modified magnetic beads and AuMB@Ag-anti-FITC, respectively. We expected that the method devised would provide a promising new approach to screening for L. monocytogenes and guarantee the microbiological safety of dairy products.