Innovative intelligent packaging using a CuMOF immobilized on cellulose matrix: A dual-mode sensing platform for fish spoilage detection

This study presents a copper-based metal-organic framework (CuMOF) immobilized on a cellulose matrix (CuMOF@CM) for colorimetric and fluorescent detection of fish spoilage. Volatile nitrogen and sulfur compounds released during spoilage cause CuMOF@CM to change from blue to brown and significantly reduce fluorescence intensity. The CuMOF@CM colorimetric indicator exhibited rapid response and high selectivity, with detection limits (LOD) of 1.03 μM for H₂S and 3.32 μM for ammonia, enabling real-time freshness monitoring. The fluorescence system also effectively detected H₂S (LOD of 0.42 μM) and ammonia (LOD of 0.72 μM). Copper ions in CuMOF selectively bind to analytes, making it suitable for food packaging. FTIR analysis confirmed Cu-S and Cu-N bond formation upon exposure to fish spoilage. CuMOF@CM displayed clear color changes: white/yellow for fresh fish, cream/orange for semi-fresh, and brown for spoiled fish. This study demonstrates CuMOF@CM’s potential in intelligent packaging for real-time fish spoilage detection and enhanced food safety.