Rapid detection of Salmonella in milk by biofunctionalised magnetic nanoparticle cluster sensor based on nuclear magnetic resonance

Abstract Controlling foodborne pathogens is important to ensure food safety and prevent foodborne diseases. In this study, a Fe 3 O 4 nanoparticle cluster (Fe 3 O 4 NPC) biosensor based on nuclear magnetic resonance was developed for Salmonella detection. The capture antibody of Salmonella was used, and the biotinylated antibody specifically recognised Salmonella at different sites. Fe 3 O 4 NPC modified with streptavidin were used to capture biotinylated antibody by biotin and determine streptavidin interaction. Finally, Fe 3 O 4 NPC immobilised on 96-well microplates were eluted, thereby reducing the transverse relaxation time (T 2 ) of neighbouring water molecules. The method detected Salmonella at 10 5  cfu mL −1 , which was also the limit of detection in spiked milk samples, and showed high selectivity over other non-target bacteria. The proposed biosensor could be a potential tool for sensitive and rapid detection of foodborne pathogens in food, environmental, and agricultural samples.