Biogenic amine formation and microbiological profile in Asian seabass and short-bodied mackerel during refrigerated storage

Biogenic amines (BAs) are key chemical indicators of fish spoilage and potential food safety hazards. This study investigated the formation of four common BAs-histamine, cadaverine, putrescine, and tyramine-and monitored microbial populations in Asian seabass (Lates calcarifer) and short-bodied mackerel (Rastrelliger brachysoma) stored at 0°C and 4°C for 7 days. Total viable bacteria, staphylococci, and Enterobacteriaceae were enumerated using culture-based methods, while BA concentrations were quantified by high-performance liquid chromatography (HPLC). The results revealed that microbial growth was significantly higher (p<0.05) in both fish species stored at 4°C when compared with those stored at ice temperature (0°C). The counts of total viable bacteria, staphylococci, and Enterobacteriaceae of short-bodied mackerel stored at 4°C reached 5.32-6.47 Log CFU/g after 7 days. Histamine levels in short-bodied mackerel stored at 4°C reached 292.67±1.53mg/kg by day 7, exceeding the Codex safety limit of 200mg/kg. Cadaverine, putrescine, and tyramine levels were also increased to 615.00±1.00, 461.67±1.53, and 731.67±1.53mg/kg, respectively. In contrast, histamine remained undetectable in Asian seabass under the same storage conditions. However, cadaverine, putrescine, and tyramine were detected in Asian seabass at 17.67±1.53, 17.00±2.65, and 8.33±2.08mg/kg, respectively. These findings provide essential reference data for assessing spoilage in marine fish species commonly consumed in Thailand and highlight the need for strengthened seafood safety standards on histamine. They further emphasize the critical role of effective cold chain management in traditional markets and local distribution systems.