Hybrid RCA-DLS assay combined with aPCR for sensitive Salmonella enteritidis detection

Area of Science:

• Food Science
• Microbiology
• Analytical Chemistry

Background:

• Salmonella enteritidis is a significant foodborne pathogen.
• Contaminated meat, raw eggs, milk, and water pose infection risks.
• Rapid and sensitive detection methods for S. enteritidis are crucial for public health.

Purpose of the Study:

• To develop a novel, fast, and ultrasensitive detection method for Salmonella enteritidis.
• To enable accurate detection in diverse sample types, including food and water.
• To improve food safety by providing a reliable diagnostic tool.

Main Methods:

• A hybrid assay combining rolling circle amplification (RCA) with dynamic light scattering (DLS).
• Utilized DNA-probe-modified gold nanoparticles (AuNPs) for capture.
• Integrated asymmetric polymerase chain reaction (aPCR) for enhanced sensitivity.
• Particle size sensing tool for detection.

Main Results:

• Achieved a limit of detection (LOD) of 3 × 10^0 CFU/mL in pure culture.
• Detected 2.0 × 10^0 CFU/mL in spiked milk samples without pre-enrichment.
• Total assay time, including DNA extraction and aPCR, was approximately 6 hours.
• Demonstrated high specificity and sensitivity for S. enteritidis.

Conclusions:

• The hybrid RCA-DLS assay combined with aPCR provides a promising tool for specific and sensitive S. enteritidis detection.
• The method's speed and sensitivity are advantageous for food safety applications.
• Ultrasensitive detection is achievable in complex matrices like milk.