Immunological detection of Cronobacter and Salmonella in powdered infant formula by plasmonic label-free assay

Area of Science:

• Food safety microbiology
• Immunodiagnostics
• Biosensor technology

Background:

• Cronobacter and Salmonella are significant foodborne pathogens, particularly concerning for infant health.
• Current detection methods for these bacteria in products like powdered infant formula (PIF) are time-consuming, taking several days.
• There is a need for rapid, validated methods for the simultaneous detection of Cronobacter and Salmonella in PIF.

Purpose of the Study:

• To develop and validate an innovative, easy-to-operate assay for the simultaneous detection of Cronobacter and Salmonella.
• To produce dedicated polyclonal antibodies for enhanced assay specificity and sensitivity.
• To reduce the time required for pathogen detection in PIF samples.

Main Methods:

• Development of a Plasmonic Immuno-Assay (PlasmIA) utilizing antibody-arrays.
• Application of Surface Plasmon Resonance imaging for detection.
• Integration of standardized bacterial enrichment with on-biochip culture.
• Use of dedicated polyclonal antibodies for target pathogen capture.

Main Results:

• The PlasmIA enables multiplex detection of both Cronobacter and Salmonella in a single step.
• The assay can detect concentrations lower than 30 CFU per 25g of PIF.
• The entire detection process is completed in less than one day, a significant improvement over existing methods.

Conclusions:

• This study presents the first multiplex immunoassay for the rapid and specific detection of Cronobacter and Salmonella in food samples.
• The developed PlasmIA combines protein microarrays, on-biochip culture, and optical detection for efficient pathogen identification.
• The assay successfully detects viable Cronobacter and Salmonella during the enrichment phase, enhancing food safety assurance.