A sensitive SERS-based assay technique for accurate detection of foodborne pathogens without interference

Area of Science:

• Analytical Chemistry
• Biotechnology
• Nanotechnology

Background:

• Accurate detection of foodborne pathogens like Escherichia coli (E. coli) is vital for food safety and public health.
• Existing methods for pathogen detection can be time-consuming and lack sensitivity.
• There is a need for rapid, sensitive, and interference-free assays for E. coli detection.

Purpose of the Study:

• To develop a simple, novel, and sensitive surface-enhanced Raman scattering (SERS) assay for detecting Escherichia coli (E. coli).
• To utilize p-mercaptobenzoic acid (MBN)-modified gold nanoparticles (Au NPs) and magnetic beads for interference-free E. coli detection.
• To establish a rapid, reliable, and portable method for E. coli quantification in food samples.

Main Methods:

• A SERS assay was developed using MBN-modified Au NPs and magnetic beads for E. coli detection.
• The assay involved reducing silver ions on E. coli, capturing bacteria with magnetic beads, and then releasing silver ions for SERS detection.
• The SERS signal intensity of MBN correlated with E. coli concentration, with a distinct signal at 2228 cm⁻¹ to avoid spectral overlap.

Main Results:

• The developed SERS assay demonstrated a low limit of detection (LOD) of 10 colony-forming units (cfu) per milliliter for E. coli.
• The assay showed high accuracy and reliability due to controlled aggregation of Au NPs and minimal spectral overlap.
• The method was successfully applied to detect E. coli in real food samples, including bottled water and milk.

Conclusions:

• The novel SERS-based assay provides a sensitive, accurate, and rapid method for detecting E. coli.
• The use of magnetic beads and MBN-modified Au NPs ensures interference-free detection and operational simplicity.
• This SERS assay holds significant potential for application in food safety monitoring and pathogen detection.