The optimized modified atmosphere for packaging of pre-rigor filleted farmed cod (Gadus morhua) is 63 ml/100 ml oxygen and 37 ml/100 ml carbon dioxide

The optimal initial gas composition to maintain quality of modified atmosphere (MA) packaged pre-rigor filleted farmed Atlantic cod (Gadus morhua) at 0 °C was determined through sensory evaluation of raw odour and chemical, physical, and microbiological analyses. Cod packaged under gas to product ratio of 2:1 and gas mixtures according to a simplex centroid mixture design spanning the whole area from 0 to 100 ml/100 ml and in between mixes of all the three major packaging gases, CO2, O2 and N2 were analysed after 7, 10 and 14 days of storage. Aerobic and psychrotrophic plate count decreased and formation of exudates increased with increasing CO2 concentration. H2S-producing bacteria were not present or not able to grow under the different gas mixtures. Odour scores and trimethylamine oxide content decreased and the formation of trimethylamine increased in the fish with decreasing CO2 and O2 levels. The weighted optimum gas mixture for MA packaging of farmed cod was determined to be 63 ml/100 ml O2 and 37 ml/100 ml CO2.