<p>Monitoring the changes in food freshness and conducting early detection of food spoilage are recognized as urgent requirements for reducing the impact of food spoilage on food quality. This study has developed a smart label using sodium alginate and bacterial nanocellulose as substrates, with MOFs (UiO- 66-NH₂) loaded with alizarin complexone as indicators. The existence of hydrogen bonds between the substrate and the color-developing material has been demonstrated. While the physicochemical properties of the label have been enhanced by the composite substrate, which showed that the TS and EAB of the label rose to 36.7 MPa and 45.7%, respectively, the WVP decreased to 1.228 (10⁻¹⁰·g·cm⁻¹·s⁻¹·Pa⁻¹), and the WCA rose to 64.548°. This label shows a bimodal color change (pH 2–11): colorimetry changed from yellow to dark red, and fluorescence changed from light blue to violet and then back to dark blue. The RGB colorimetric intensity showed a strong linear correlation with pH (<i>R</i>² = 0.9906 for colorimetric change and <i>R</i>² = 0.9808 for fluorescence change), demonstrating the high sensitivity of the label. The smart label was utilized to monitor the freshness of beef, shrimp, and fish, allowing for rapid, precise, real-time detection. Furthermore, it lays the groundwork for the development of multifunctional smart labels in future research.&#xa0;</p> Graphical Abstract <p></p>