Abstract
Pathogens detection is a crucial measure in the prevention of foodborne diseases. This study developed a novel multicolor colorimetric assay to visually detect Salmonella Typhimurium (S. Typhimurium), by utilizing the etching process of gold nanorods (AuNRs) with TMB(2+). The strategy involved the construction of nanozyme by assembling magnetic covalent organic framework (MCOF) with aptamer-conjugated AuNPs (Apt-AuNPs), exhibiting remarkable peroxidase-like activity to catalyze the oxidation of TMB/H(2)O(2) and inducing the etching of AuNRs. The presence of S. Typhimurium could inhibit this process, resulting in the generation of vivid colors. The multicolor colorimetric assay could specifically determine S. Typhimurium from 10(2) to 10(8) CFU mL(-1) in 60 min with visual detection limit of 10(2) CFU mL(-1), and instrumental detection limit of 2.3 CFU mL(-1). Moreover, detecting S. Typhimurium in chicken, milk, pork and lettuce samples has shown promise in practical applications.