Simple and rapid methods for detecting Salmonella enteritidis in raw eggs.

Area of Science:

• Food Microbiology
• Diagnostic Assay Development
• Food Safety

Background:

• Salmonella enteritidis (SE) caused an estimated 300,000 cases in 1997, with egg products frequently implicated.
• Flock surveillance for SE is crucial for egg producers, necessitating rapid and simple detection methods.
• Existing methods require improvement for effective implementation in producer-level testing strategies.

Purpose of the Study:

• To develop and optimize a rapid, simple, and specific method for detecting Salmonella enteritidis (SE) in raw egg samples.
• To evaluate a lateral flow device (LFD) for its efficacy in identifying SE in poultry products.
• To enhance the detection limit of the LFD through novel sample preparation techniques.

Main Methods:

• A commercially available lateral flow device (Neogen) designed for Group D1 Salmonella detection was utilized.
• Studies focused on optimizing test procedures for raw eggs, including various sample preparation methods.
• A novel antigen extraction method was developed and integrated with the LFD for improved sensitivity.

Main Results:

• The novel antigen extraction method increased the detection limit of the LFD by approximately tenfold.
• 100% detection of SE was achieved in raw egg pools inoculated with 10 SE cells/mL.
• Optimal detection involved pre-incubation in buffered peptone water (BPW) or tetrathionate brilliant green broth (TBG) at a 1:10 ratio for 24 hours at 37°C.

Conclusions:

• The developed lateral flow test, combined with the novel extraction method, provides a sensitive tool for SE detection.
• This method offers a simple, rapid, and cost-effective solution for egg producers and processors.
• The test specifically targets Salmonella group D1 serovars, including SE, enhancing targeted food safety interventions.