Assessment of Histamine Levels and Histamine-producing Bacteria in <i>Euthynnus affinis</i> Marketed in Tanga and Mtwara Coastal Areas, Tanzania

Abstract

Histamine (scombrotoxin) food poisoning is a community health risk associated with consumption of some marine fish species and it has been proposed that some anaerobic bacteria contribute to this form of food poisoning. However, histamine levels and histamine producing bacteria in fish marketed in Tanzania have not been appraised. This study was conducted to determine histamine levels and histamine-producing bacteria in the <i>E. affinis</i> (tuna) value chain in Tanga and Mtwara regions. High-performance thin-layer chromatography (HPTLC) was used to determine histamine levels, Bacteriology and biochemical tests were employed to determine histamine-producing bacteria. A total of 64 tuna fish samples were collected from deep sea fish market and Sahare Tanga and ferry market, Mtwara coasts. The mean level of histamine was found to be 86.4±43.9 in Tanga and 64.8±47.5 in Mtwara and the overall mean was 77.1±46.4. All fish 64 samples were positive for histamine; however, the mean level was within the recommended limit for consumed fishery products according to European Union regulation of 200 mg/kg (m) to 400 mg/kg (m) (EC, 2005).<i> Klebsiella spp, pseudomonas spp, </i>and <i>proteus spp</i> were isolated and confirmed as histamine-producing bacteria based on bacteriology and biochemical characteristics. It concluded that although within the recommended levels, all fish samples were positive to histamine and three bacterial species associated with its production isolated. To prevent raising histamine to concern levels, maintenance of hygiene and low temperature along the production chain should be observed.