Enhancing Seafood Freshness Monitoring: Integrating Color Change of a Food-Safe On-Package Colorimetric Sensor with Mathematical Models, Microbiological, and Chemical Analyses

A food-safe on-package label has been developed as a real-time spoilage indicator for fish fillets. This colorimetric sensor is sensitive to Total Volatile Base Nitrogen (TVB-N) levels, providing an accurate indication of fish freshness and spoilage. This study evaluates and predicts the shelf-life and effectiveness of an on-package colorimetric indicator. The sensor, using black rice (BR) dye with polyvinyl alcohol (PVOH), polyethylene glycol (PEG), and citric acid (CA) as binders and crosslinking agents, is applied to PET films. The food-safe pH indicator, prepared via lab-scale flexography printing, is durable in humid environments, making it suitable for practical packaging scenarios. The sensor visibly monitored fish spoilage at 4 ºC for 9 days. Quality assessment included tracking ΔRGB (total color difference), chemical (TVB-N, pH), and microbiological analyses. Results indicate that the fish samples are fresh up to 4 days of storage at 4ºC; the total viable count (TVC), Pseudomonas growth, TVB-N contents and pH reached: 5.2 (log CFU/ml), 4.31(log CFU/ml), 26.22 (mg N/100 gr sample) and 7.48, respectively. Integrating colorimetric sensor data with mathematical modeling can predict spoilage trends over time. Integrated system offers a smart approach to accurately predicting shelf-life, aiding in optimizing storage conditions, minimizing food waste, and delivering fresh, high-quality fish products to consumers.