Changes in Scomberotoxin (Histamine) and Volatile Amine (TVB-N) Formation in Longtail Tuna (Thunnus tonggol) Stored at Different Temperatures

Abstract

Changes in histamine and volatile amine (TVB-N) formation was studied in longtail tuna (Thunnus tonggol) captured in the Sea of Oman and stored at different temperatures. Based on sensory analysis, longtail tuna maintained shelf life for 1, 4, 15 and 300 days at 0, 8, 25 and -18 oC, respectively. Histamine and TVB-N increased with time, but the rate of change varied with storage temperature. Histamine formation was suppressed significantly at lower than the FDA limit of 5 mg/100 g at 0 and -18 oC but not at 8 or 25 oC. TVB-N did not reflect the quality index at 0 or 8 oC even though the samples were rejected by sensory evaluation. No correlation was observed between histamine and TVB-N values except at 25 oC and assessment of TVB-N was not sufficient for estimating the degree of histamine-related health hazard. Poor correlation was found between sensory score and pooled TVB-N value compared to histamine, and the correlation was closer at 8 and 25 oC than at the lower temperatures.