Investigation on Scombrotoxin fish poisoning associated with Zanzibar landed fishes

Histamine is the main cause of Scombrotoxin Fish Poisoning (SFP) worldwide and threatens the health of all fish and fish products dependent consumers. It’s assessment therefore, is of paramount importance. This study aimed to determine histamine level, assesses SFP awareness among health personnel and fish consumers and fish preservation associated with marine landed fish in Zanzibar. The study was carried out on three fish species, Auxis thazard, Sardinella gibbosa, Lethtrinus mahsena. The samples were taken on board, landing sites and markets of Malindi and Chwaka area. In order to measure histamine level, a competitive ELISA was employed using a Biofish - 300 HIS of Biolan technology. Two hundred and seventy fish consumers and two hundred and seventy fishing boats and seventy two health care personnel were recruited in the study through randomly sampling and provided with structured questionnaires for SFP knowledge and PM assessment. The results showed that 68 samples out of 72 contained detectable levels of histamine. The maximum value was 27 mg/kg (5.46 ± 1.18) in 5. gibbosa, followed by 23 mg/kg (5.21 ± 1.10) in A. thazard and minimum value was 1 mg/kg (3.42 ± 0.67) in L. mahsena. In addition, the study found significant increase in histamine level from on board to final consumers at Chwaka (F = 5.502; df = 2, 33; p = 0.009) and insignificant increase at Malindi (F = 2.919; df = 2, 33, p = 0.068). The study further found that, there is poor fish handling in Zanzibar and both health care personnel and fish consumers were not aware of SFP. These results indicate poor storage facilities and SPF knowledge in Zanzibar fisheries and fish consumers. Therefore, there is a need to educate the public on SFP poisoning and conduct more investigations particularly to determine histamine levels in imported fish and other seafood products.