Histamine formation and microbiological quality of deboned milkfish (Chanos chanos) during ambient storage

Milkfish has not been implicated in histamine poisoning in the past but it was detected in smoked deboned milkfish collected from a local smoke fish producer. Histamine could have likely formed prior to smoke processing, where the fresh deboned milkfish could have been exposed to temperature abuse. The study evaluated the histamine accumulation and microbiological quality of deboned milkfish exposed to ambient conditions. Results revealed that initial histamine content (1.26±0.50 mg histamine 100 g-1 fish flesh) increased to 8.25±1.87 mg 100 g-1 on the 6th h, level beyond the allowable maximum limit (5 mg 100 g-1) to be considered safe. Potentially hazardous levels were present (58.8±10.67 to 111.9±11.73 mg 100 g1) on the 8th-12th h. Total viable count (TVC) and histamine-forming bacteria (HFB) generally increased through time, as influenced by temperature. Initial total viable count (3.94 log cfu/g) significantly increased to 5.53 (log cfu) on the 4th h, the maximum acceptable microbiological limit in food, while the initial HFB count of 1.80±0.68 (log cfu) increased to 5.70±0.11 (log cfu) on the 12th h. The study showed that histamine developed in deboned milkfish beyond the safe levels when exposed to ambient temperature for more than four (4) h and may pose health risks to consumers.