“…Based on the characteristic of the color change in relation to the acidic or basic media, pH colorimetric indicators have presented great potential for use in monitoring food freshness when relating the pH values with oxidation and microbial deterioration in fish (Huang et al, 2019;Aghaei et al, 2020), seafood (Wu et al, 2019;Mohammadalinejhad et al, 2020), pork (Chen et al, 2019), and packaged foods in general, for example, pork, milk and seafood (Qin et al, 2019). While biogenic amines are currently found among the decomposing agents of meat products, volatile amines such as ammonia, dimethylamine (DMA) and trimethylamine (TMA), designated as total volatile basic nitrogen (TVB-N), are responsible for the typical taste and smell of fish at the beginning of microbial decomposition (Wei et al, 2019). Due to the toxicity of these compounds, the production of amine indicator films offer advantages for fish and seafood consumers (Dudnyk et al, 2018;Aghaei et al, 2020).…”