Revisiting small-molecule fluorescent probes in food freshness detection.

Food spoilage driven by microbial growth severely endangers public health and global food security. Traditional methods for food freshness evaluation suffer from cumbersome operation, time-consuming procedures, and poor portability. In contrast, fluorescent probe-based detection offers distinct advantages including high sensitivity, fast response, and visual detectability. This review summarizes recent advances in organic small-molecule fluorescent probes for food freshness assessment over the past 3 years. We focus on representative sensing mechanisms of these probes, including nucleophilic substitution, protonation/deprotonation, hydrogen-bonding interactions, Lewis acid-base reactions, and Michael addition as well as typical target analytes such as biogenic amines, hydrogen sulfide, sulfur dioxide derivatives, pH, ATP, and hydrazine. The representative applications of fluorescent probes in portable test strips, smartphone-assisted sensing platforms, and intelligent detection systems are emphatically introduced. Although these probes have achieved remarkable results in sensitivity, response speed and practicality, challenges still exist such as single detection target, insufficient anti-interference ability, and lack of prospective prediction function. Future research will focus on expanding detection scopes, developing multi-target recognition probes, combining artificial intelligence to construct spoilage prediction models, and promoting the industrial application of portable and intelligent food freshness detection technology.