DETERMINATION OF HISTAMINE AND BACTERIAL ISOLATION IN MARLIN FILLETS (MAKAIRA NIGRICANS) IMPLICATED IN A FOODBORNE POISONING

Abstract

ABSTRACT An incident of foodborne poisoning causing illness in seven victims due to ingestion of marlin fillets occurred in August, 2008, in Kaohsiung City, southern Taiwan. The two suspected marlin samples contained 47.8 and 43.5 mg/100 g of histamine, which is greater than the 5.0 mg/100 g allowable limit suggested by the U.S. Food and Drug Administration. Given the allergy‐like symptoms of the victims and the high histamine content in the suspected marlin samples, this foodborne poisoning was strongly suspected to be due to histamine intoxication. Two histamine‐producing bacterial strains capable of producing 3.10 ppm and 4.20 ppm of histamine in trypticase soy broth (TSB) supplemented with 1.0% l‐histidine (TSBH) were identified as Bacillus subtilis by 16S rDNA sequencing with polymerase chain reaction amplification. However, major histamine‐forming bacteria might have been killed during the preparation of fillets before serving and these two B. subtilis isolates might not be the main contributors to histamine accumulation in suspected fillets. PRACTICAL APPLICATIONSBased on the finding that high contents of histamine (>40 mg/100 g) were detected in the suspected marlin samples, we speculate the temperature abuse of the fillets before cooking contributed to the presence of high histamine levels in marlin fillets and resulted in foodborne poisoning. Although two histamine‐producing Bacillus subtilis strains were isolated from suspected fish samples, both might not to be the main contributors to histamine accumulation because of low histamine production. These results re‐emphasize proper handling temperature for seafoods and offer an important awareness which Makaira nigricans fillets could become a hazardous food item in causing histamine poisoning even though no quality deficiency was observed on the fillets.