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

• Super-chilling at −0.7 °C inhibits microbial growth on catfish fillets.
• High-CO2 packaging accentuates the antimicrobial efficacy of super-chilling.
• The microbial inhibition leads to better texture and flavor of catfish fillets.
• Minimized biochemical changes of microbial origin allow a longer fillet shelf-life.

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.