Smart bilayer film: Quality monitoring for freshness of fish and minced pork delights

Global concern over food spoilage and the pressing need for efficient spoilage detection methods have far-reaching implications for the well-being of millions of people worldwide. So, the emergence of systems capable of providing early detection and visible evidence of food spoilage has gained recognition as an essential tool in the fight against food spoilage. A smart bilayer label (SBL) was developed, which exhibits distinctive qualities, encompassing robust antioxidant and antimicrobial characteristics, responsive color alteration triggered by minor pH fluctuations, and the capability to exhibit color changes upon exposure to acetic acid and ammonia gas. The SBL shows robustness regarding mechanical, thermal, and barrier properties, including water and oxygen resistance and overall hydrophilicity. The ability of SBL to detect the freshness of fresh fish and minced pork at 6 °C was determined. Over time, for both fish and pork, an increase in pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total viable counts (TVC) were detected. Notably, SBL changed to green on days 8 and 10 for fish and minced pork, respectively, corresponding to pH ranges of 7, indicating spoilage. This study validates the SBL as an effective freshness indicator, with a color change discernible to the naked eye (ΔE > 12), and highlights its potential for monitoring the quality of protein-rich products. Strong positive correlations between pH, TVB-N, TVC, and storage time underscore their interdependence (P < 0.01). The SBL’s ΔE positively correlates with pH, TVB-N, and TVC, affirming its effectiveness as a visual freshness indicator. These insights advance our understanding of the evolution of meat quality and endorse the SBL's role in real-time monitoring and enhancing meat industry practices.