A novel NMR immunosensor based on O-CMCS-targeted Gd probe for rapid detection of Salmonella anatum in milk

Rapid screening and early warning of pathogenic bacteria in food is the key to prevent and control the spread of foodborne diseases . Biotin–streptavidin system and membrane filtration technology were combined to develop a novel nuclear magnetic resonance (NMR) immunosensor based on biomacromolecule O-carboxymethyl chitosan (O-CMCS) target gadolinium (Gd) probe for rapid detection of Salmonella anatum in milk. Under optimal experimental parameters, the proposed NMR immunosensor could detect Salmonella in milk with a limit of detection of 1.8 × 10 4  cfu mL −1 within 2 h. Furthermore, the immunosensor exhibited good specificity, sensitivity and reproducibility, which could achieve the direct determination of biological samples with complex composition. Hence, the developed assay might have great application potential for the rapid detection of Salmonella in food.