Food safety and security are emerging challenges in the modern era. To resolve such challenges, numerous pesticides, drugs and feed additives are used to harvest the foodstuffs. Among those, some are very much toxic to human beings and environment. Therefore, knowing their presence in foodstuffs and measuring their concentrations are very crucial. To encounter such challenges, herein, a formamide functionalized, reusable, nanosized and eco-friendly Hf(IV)-organic framework (1) is developed. After the synthesis and characterization of the porous framework (SBET = 555 m2/g), it was used for the selective and fast fluorescence sensing of extensively used anthelmintic veterinary drug nitroxinil (NX) and organoarsenic feed additive p-arsanilic acid (PAA) in aqueous medium through turn-off and turn-on response, respectively. This fluorescent MOF is the first ever report for both the analytes which can detect them within few seconds (5 s for NX and 15 s for PAA) of their addition with limits of detection (LOD) values of 11.8 nM and 17.2 nM for NX and PAA, respectively. The calculated LOD values are the lowest ever than all the previously reported sensors of both the analytes. Including high reusability, high selectivity and very short response time, the probe can sense the presence of targeted analytes in body fluids (for NX), chicken flesh and liver extracts (PAA), environmental water and soil samples and wide range of pH media with equal efficiency. For the rapid and on-site naked-eye detection of both the targeted analytes, an economical, handy, recyclable and biocompatible MOF@chitosan@cotton composite was fabricated. The composite was capable to change its colour up to nanomolar level concentrations of both analytes. With proper instrumental supports, systematic investigations of the probable mechanisms of both sensing events were investigated.