Cold storage of salmon and rainbow trout – quality and shelf life

Summary

For many years now, farmed salmon has strengthened its position in the global market. At the same time, rainbow trout farming has declined and today only constitute approximately 5 % of the combined salmon and rainbow trout output. There has been relatively few comparative studies done on a possible quality difference between salmon and rainbow trout in similar environmental conditions. Therefore, a comparative ice-storage experiment on salmon and trout was conducted under similar environmental conditions to examine shelf life and overall quality. Our results show that the muscle quality and shelf life of salmon was somewhat poor compared to that of rainbow trout. After two weeks of ice-storage, the shelf life of rainbow trout was evaluated to be approximately four days and for salmon the result was zero. In addition, the pull to extract pin bone from the filet of rainbow trout was about twice as high, as compared to the pull to extract pin bones from the filet of salmon. Because of this we had to dismiss our original thesis that there were no differences between farmed salmon and trout under similar environmental conditions. Both salmon and trout were given optimum food regimes according to species. It is uncertain how much the different food regimes influenced the quality and there may be other underlying causes for the differences. In view of this, new comparative studies should be done, where all the fish in the study get an identical food regime, to survey if the different food regimes could be the cause of the findings in this trial.