Effects of on-board and dockside handling on the formation of biogenic amines in mahimahi (Coryphaena hippurus), skipjack tuna (Katsuwonus pelamis), and yellowfin tuna (Thunnus albacares).

Consumer illnesses by scombroid poisonings have been a continuing problem for many years. The intoxications follow the ingestion of fish such as tuna and mahimahi that have undergone bacterial decomposition, leading to the formation of biogenic amines. Research studies have concluded that histamine is one of the indicators of scombrotoxic fish and that other amines, such as cadaverine, could be involved in the illnesses. Guidance for the handling of fish on board fishing vessels to prevent the production of scombrotoxic fish has been limited by a lack of data addressing changes that occur in fish from the water to delivery at dockside. In this study, the changes in selected biogenic amines were determined in mahimahi and tuna, which were captured and held in seawater at 25 to 35 degrees C for incubation times up to 18 h. The fillets from the treated fish were sectioned by transverse cuts and analyzed for histamine, cadaverine, and putrescine. Results showed that at 26 degrees C, more than 12 h of incubation were required before a histamine concentration of 50 ppm was reached in mahimahi. At 35 degrees C, 50 ppm histamine formed within 9 h. Similar results were found for skipjack and yellowfin tuna. Histamine concentrations exceeded 500 ppm within an additional 3 h of incubation in mahimahi. At both temperatures, an increase in the concentration of cadaverine preceded an increase in histamine levels. Changes in putrescine concentrations in the fish were less pronounced. The study also demonstrated that histidine decarboxylase activity was retained in some frozen samples of fish and could result in further increases in histamine on thawing.