<p>The rapid detection of <i>Salmonella</i> is an essential precautionary measure to ensure food safety and prevent foodborne illness. In this study, based on the specific binding between mannan oligosaccharides (MOS) and type I fimbriae of <i>Salmonella typhimurium</i> (<i>S. typhimurium</i>), an efficient sensing strategy was developed. Obtained by enzymatic hydrolysis of konjac glucomannan, MOS were grafted to mannan-oligosaccharide modified carbon dots (g-CDs-MOS). It is worth noting that the introduction of MOS reduced the dissociation constant (K_D) between fabricated g-CDs-MOS and Con A from 25.4 µM (g-CDs and ConA) to 6.22 µM. This enhanced binding affinity stem from elevated density of MOS on surface of g-CDs. Furthermore, to construct recovery-type fluorescent probe, g-CDs-MOS was bonded onto two-dimensional quencher such as 3-aminobenzeneboronic acid-functionalized graphene oxide (GO-PBA), MnO₂ or MoS₂. The g-CDs-MOS/MoS₂ exhibited the best sensitivity due to the high electron mobility of MoS₂. Its fluorescent intensity was logarithmically responsive to concentration of <i>S. typhimurium</i> within the range of 10²-10⁸ CFU·mL^− 1, and the corresponding limit of detection was as low as 11.79 CFU·mL^− 1. This fluorescent sensor shows promise for the detection of <i>S. typhimurium</i> in food safety.</p> Graphical Abstract <p></p>