This paper explains the physical and chemical changes inherent to decomposition, which forms the basis for organoleptic testing. It analyses the advantages the disadvantages of the method, shows how its introduction as a regulatory measure has affected trade and suggests how the tuna industry could best use it for quality control benefits on a practical level.

Organoleptic testing, like the dolphin-safe issue, has had tremendous impact on the tuna industry. In Thailand alone, after the USFDA introduced the method in 1992 as a regulatory measure, there was considerable business disruption as firms sought to get off automatic detention or slowed down production for fear of automatic detention. As a result, Thai canned tuna exports to the US market dropped drastically by nearly half. The method has been labelled as 'protectionist", "unreliable", "not scientific" and "subjective", possibly because it is not understood. As one who has seen organoleptic testing used by both the regulators and the regulated, I shall attempt to offer some insights on whether the method could effectively detect decomposition and how the industry could use it to advantage.

Tuna, probably evenmore so than other types of seafood or meat, spoils easily because of the kind of handling it undergoes and the nature of the fish itself. Unlike food sources such as livestock, chicken or pig, the tuna are not eviscerated right away. They are frozen or transported whole and ungutted, making microbial contamination from the viscera highly possible. The fish has a relatively weak armour because of its thin skin, soft flesh and scales that fall off easily. Such vulnerability increases when nets or other harvesting methods damage the skin and expose the flesh to bacteria from sea water, among which are types that retain a capacity to breakdown substances within the fish even at low temperatures. The mucus-like film covering the fish surface provides good food for such microorganisms. A multitude of other bacteria introduced during handling from the air, earth, facilities, equipment and even human beings, invade the fish. The high water and protein content of the flesh and high level of post-mortem enzymatic activity all help speed up decomposition.