Comparative study of bacterial load and organoleptic quality changes between lean fish and fatty fish in fresh, iced and non-iced state under laboratory condition

The study conducted in the laboratory conditions of Sylhet Sadar Upazila compared the bacterial load and organoleptic quality changes in lean fish (Oreochromis niloticus) and fatty fish (Pangasianodon hypophthalmus) across fresh, iced, and non-iced states. Preservation times of 6- and 8-hours intervals were examined, focusing on organoleptic quality changes and Total Viable Count (TVC). The evaluation of defect points and fish grading revealed that all fresh and iced Tilapia and Pangas samples were in excellent condition (Grade A) at 0, 6, and 8 hours, while non-iced samples at 6- and 8-hours intervals were in acceptable condition (Grade B). Notably, non-iced Pangas exhibited higher defect points than non-iced Tilapia at the same intervals. The bacterial load varied, with the highest observed in non-iced Pangas at an 8-hour interval in May and the lowest in iced Tilapia at a 6-hour interval in April. Compliance with International Commission on Microbiological Specifications for Foods (ICMSF) standards was noted in both fish types across all states. The temperature dependence of bacterial growth was evident, with the highest bacterial load at 35 ℃ in May and the lowest at 24 ℃ in April. Overall, the study suggests that fresh Tilapia and Pangas, whether iced or non-iced at 6- and 8-hour intervals, meet ICMSF standards, ensuring their safety for consumption and potential export.