Electrochemical Biosensing of Salmonella

A rapid and simple electrochemical immunosensor enables the detection of Salmonella in milk. Bacteria are captured and concentrated from samples by antibody-coated magnetic beads and simultaneously labeled with a horseradish peroxidase (HRP) conjugate. The complexes are captured onto an electrode to achieve, upon the addition of HRP substrate, an amperometric signal proportional to the bacterial load. The method detects about 10⁴ CFU mL^-1 in diluted milk within 50 min without enrichment. After an 8-h pre-enrichment step, the sensitivity improves to below 1 CFU mL^-1, equivalent to ~1-3 CFU in 25 g of milk.