Super-chilling (-0.7 °c) with high-CO₂ packaging inhibits biochemical changes of microbial origin in catfish (Clarias gariepinus) muscle during storage

Controlled freezing-point storage (CFPS) is an emerging preservative technique desirable for fish. In the present study, catfish fillets were stored at -0.7 °C under different packaging atmospheres: air (AP), vacuum (VP), and 60% CO₂/40% N₂ (MAP). Chemical, microbiological, and sensory analyses were performed during storage. Results showed the following descending order of chemical changes (degradation of nucleotides, conversion of protein to volatile-based nitrogen and biogenic amines, and production of trimethylamine nitrogen), as well as loss of sensory properties: 4 °C AP > -0.7 °C AP ≈ 4 °C VP > -0.7 °C VP ≈ 4 °C MAP > -0.7 °C MAP. The chemical changes were well-correlated with microbial growth suggesting the microbiological pathways. Hence, CFPS at -0.7 °C in combination with high-CO₂ MAP can effectively maintain the quality of fresh catfish meat compared to traditional preservation methods.