Distribution of histamine-producing bacteria in fresh albacore and their proliferation in muscle during storage at 25 °C were monitored. Histamine formers constituted a minor portion of the bacterial flora in albacore. Only weak histamine formers were detected in the gill and skin of fresh fish after enrichment. Histamine formers were isolated from the muscles when APC reached >107 CFU/g during storage. Hafnia alvei was most prevalent in both fresh and temperature-abused fish. The most prolific histamine former, Morganella morganii, was rarely isolated even from spoiled muscles. The prevalence of weak histamine formers resulted in low levels of histamine accumulation in muscle, 67.1 mg/100 g, for 6 d of storage.