Six different published methods of determining TVB-N were evaluated for accuracy, precision, suitability as an index of quality, and both cost and speed of determination, using gutted Atlantic cod stored in ice for up to 18 days. Although the method of determination affected the actual values obtained, it did not affect the overaIl relationship between TVB-N and sensory assessment of raw or cooked fish. The method of determination also affected .precision and both cost and speed of determination. If high operational costs could be tolerated, MgS04 ext/steam distillation would be the preferred method but if variability of results could be tolerated, TCA extraction/steam distillation would be the method of choice.

A controlled study to assess effect of method of catching and time of season upon blood clot, color, discoloration/bruising, odor, texture and final overall grades of fresh raw cod, muscle pH of thawed cod, and firmness (shear-compression force) of cooked muscle was conducted. Sensory analyses revealed that method of catching significantly (P 5 0.001) affected only color, discoloration/bruising, and final overall grades. Time of season did not significantly affect any sensory variables. Muscle pH was significantly (P 5 0.001) affected by both method of catching and time of season. Any significant effect of time of season upon firmness of cooked cod muscle depended upon method of catching. In general, method of catching was the most important factor affecting sensory quality of fresh raw Atlantic cod.

A portable instrument was developed to rapidly and objectively determine texture (firmness and resilience) of raw Atlantic cod (Gadus morhua) fillets. A controlled study determined the texture of raw fillets from 774 cod, caught at three different times of year. Compared to texture grades of fillets assessed by trained and experienced Fish Inspection Officers, this instrument was a dependable method of rapidly determined texture of raw fillets.

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