Grading Fish for Quality. 3. Grading of Recently Cut Fillets

Abstract

Panels of experienced fish-plant foremen and government fresh-fish inspectors graded cod and haddock in the round or as gutted whole fish, and subsequently graded the same fish as fillets. The results show that in general the two sets of gradings were very similar, and that both showed a close correlation with the trimethylamine (TMA) value of the fish muscle. When the fish was relatively fresh (TMA value 0.1 to 1.5), there was a slight tendency for the panels to be more severe in grading the fillets than the corresponding whole fish. As spoilage progressed, this trend reversed.The results suggest that during the earlier stages of spoilage it is easier for a grader to judge the quality of a fish by examining the changes occurring on the exterior of the whole or gutted fish than by examining the fillet cut from it. This is particularly so where the grader cannot give careful attention to the early spoilage odours developing in the fillet.There are definite exceptions to the usual close correlation between the quality of cod or haddock fillets and their TMA values. Bilgy fish, ungutted fish, and certain types of very soft-textured fish may be of very poor quality and still have a relatively low TMA value. These exceptions are discussed in their relation to a system of grading for cod and haddock based on organoleptic examination and supported by TMA values as objective standards of quality.