by Torry Research Station, Aberdeen, UK (Now Food Science Laboratory, Torry)

General appearance (5 marks) Score marks
Eyes perfectly fresh, convex black pupil, translucent cornea; bright red gills, no bacterial slime, outer slime water white or transparent; bright opalescent sheen, no bleaching 5
Eyes slightly sunken, grey pupil, slight opalescence of cornea; some discolouration of gills and some mucus; outer slime opaque and somewhat milky; loss of bright opalescence and some bleaching 3
Eyes sunken; milky white pupil, opaque cornea; thick knotted outer slime with slime bacterial discolouration 2
Eyes completely sunken pupil; shrunken head covered with thick yellow bacterial slime; gills showing bleaching or dark brown discolouration and covered with thick bacterial mucus; outer slime thick yellow-brown; bloom completely gone; marked bleaching and shrinkage 0
Flesh Including Belly Flaps (5 Marks)
Bluish translucent flesh, no reddening along the backbone and no discolouration of the belly flaps; kidney bright red 5
Waxy appearance, no reddening along backbone, loss in original brilliance of kidney blood, some discolouration of belly flaps 3
Some opacity, some reddening along backbone, brownish kidney blood and some discolouration of the flaps 2
Opaque flesh, marked red or brown discolouration along the backbone, very brown to earthy brown kidney blood, and marked discolouration of the flaps 0
Odours (10 marks)
Fresh seaweedy 10
Loss of fresh seaweediness, shellfish 9
No odours, neutral 8
Slight musty, mousy, garlic-peppery, milky or caprylic and like 7
Bready, malty, beery, yeasty 6
Lactic acid, sour milk, or oily 5
Some lower fatty acid odours (for example acetic or butyric acids), grassy, 'old boots', slightly sweet, fruity or chloroform-like 4
Stale cabbage water, turnipy, 'sour sink', wet matches, phosphene-like 3
Ammoniacal (trimethylamine and other lower amines) with strong ;byre-like' (o-toluidine) 2
Hydrogen sulphide and other sulphide odours, strong ammoniacal 1
Indole, ammonia, faecal, nauseating, putrid 0
Texture (5 marks)
Firm, elastic to the finger touch 5
Softening of the flesh, some grittiness 3
Softer flesh, definite grittiness and scales easily rubbed off the skin 2
Very soft and flabby, retains the finger indentations, grittiness quite marked and flesh easily torn from the 1 backbone 1