<p>Foodborne pathogens have posed a major threat to food safety and public health, necessitating the development of accurate and sensitive methods for the detection of foodborne pathogens. In this study, a metal–organic framework (MOF) nanozyme-based CRISPR/Cas12a colorimetric biosensing system was developed and integrated with a smartphone-based portable device to meet the demand for on-site detection of <i>Salmonella</i> Typhimurium. Inspired by the catalytic characteristics of gold nanoparticles (AuNPs), the ZIF-8@AuNPs nanozyme with oxidase-like activity was synthesized by immobilizing AuNPs onto zeolitic imidazolate framework-8 (ZIF-8) via a self-assembly method. In this detection system, the target DNA is preamplified via the recombinase-aided amplification (RAA) procedure to achieve primary signal amplification. The amplified target DNA subsequently triggers colorimetric signal readout and secondary signal amplification through CRISPR/Cas12a-mediated specific recognition and cleavage, and the high catalytic performance of the ZIF-8@AuNPs nanozyme, thereby facilitating the biosensor to exhibit excellent detection sensitivity and specificity. The concentration of bacteria can be quantified and analyzed using a self-programmed “DeepFood” APP with the help of smartphones and 3D-printed devices. Consequently, this method allows the quantitative detection of <i>Salmonella</i> Typhimurium within a linear range of 10¹ to 10⁷&#xa0;CFU/mL, with detection limits of 11&#xa0;CFU/mL for colorimetric detection and 65&#xa0;CFU/mL for smartphone-based RGB detection in the range of 10² to 10⁷ CFU/mL. Additionally, this method facilitates sensitive, specific, and portable detection of Salmonella Typhimurium in milk samples, in comparison with traditional methods. The inherent programmability of CRISPR RNA also enables the detection of other bacterial pathogens, making this platform a valuable tool for food safety monitoring.</p> Graphical Abstract <p></p>