A smartphone-enabled hydrogel fluorescent probe for dual-mode meat freshness monitoring and anti-counterfeiting

Dual-mode hydrogel probe for meat freshness and anti-counterfeiting • Smartphone-compatible, visual H 2 S detection within 5 min • Low detection limit of 2.05 μM with high sensitivity and selectivity • Non-destructive monitoring of shrimp freshness at various temperatures • Moldable hydrogel patterns for anti-counterfeiting Hydrogen sulfide (H 2 S), with a smell of rotten eggs, is commonly found in spoiled and deteriorated foods, especially in protein-rich foods. Current methods for detecting meat freshness have several disadvantages, including unclear early indicators of spoilage, long microbial culture cycles, and high detection costs. In contrast, fluorescent probes are more convenient, require fewer complex operations, and are efficient, fast, highly sensitive, and accurate. The novel H 2 S fluorescent probe KJC features simple synthesis, good selectivity, high sensitivity, a wide detection range (0–300 μM), a wide pH range (6–10), and a low detection limit of 2.05 μM. For detecting H 2 S to assess meat freshness, attaching probe KJC to a hydrogel enables detection within 5 min. Combining smartphone-based Red, Green, Blue (RGB) quantification, the hydrogel sensor quantitatively tracked shrimp spoilage at 4 °C, 25 °C, and 35 °C. The hydrogel's RGB signal changes are strongly correlated with total volatile basic nitrogen (TVB-N) levels, confirming its reliability for assessing meat freshness. Furthermore, the hydrogel can be molded into various shapes, demonstrating its potential as an anti-counterfeiting label for food packaging. This dual functionality ensures food authenticity and helps consumers avoid counterfeit or substandard products. Download: Download high-res image (176KB) Download: Download full-size image