A Fluorescent Metal–Organic Framework for Food Real‐Time Visual Monitoring

Abstract Due to increasing food‐safety issues, exploiting efficient approaches for food quality assessment and instrumentation has attracted concerns worldwide. Herein, a smart evaluation system based on a fluorescent metal–organic framework (MOF) is developed for real‐time visual monitoring of food freshness. Via post‐synthetic modification, a ratiometric fluorescent MOF probe is constructed by covalently coupling fluorescein 5‐isothiocyanate (5‐FITC) with NH 2 ‐rich lanthanide MOF. The probes exhibit a dual‐emissive‐responsive to biogenic amine, resulting in an increase in FITC emission along with a decrease in Eu 3+ emission accompanied by a clear distinguishable color transition from orange red to green. After doping the probes on a flexible substrate, the obtained MOF composite film can be integrated with a smartphone‐based portable platform easily. It is proved that this smart evaluation system can be used for on‐site inspection of the freshness of raw fish samples. This work develops a fluorescent MOF‐based smart evaluation system as a novel platform for application in food monitoring, which not only has enormous economic value but also holds great public health significance.