Determination of Quality of Iced Freshwater Species Based on Total Volatile Base Nitrogen (TVB-N) and Microbial Contents Test

The following two types of freshwater fish species {tilapia hybrid Oreochromis niloticus x Oreochromis aureus and the Common Carp Cyprinus Carpio were purchased from aquaculture farm and assessed for quality changes during 13 days postmortem of ice storage. The total volatile basic nitrogen TVB N and microbial contents of iced freshwater fish species were assessed as indices of spoilage t 0, 3, 5, 7, 10 and 13 days postmortem. all fish species under investigation had pH value higher than 6.8. Tilapia fish had higher TVBN values than carp fish. Tilapia and carp reached their maximum TVBN content on the 7th and none of them reached the rejection limit 30 mg 100 g during the storage period. In this study TVBN of freshwater fish species ranged from 18.67 to 20.07 and from 19.13 to 23.80 mg 100g muscle during the storage period for carp and tilapia respectively. The total plate counts for microbial growth of freshwater fish species were similar for all fish species under investigation. Bacteria grew rapidly between day 1 and 10. However, Tilapi had the lowest initial TPC and the highest TPC at the end of the storage period 10 days . Bacteria grew progressively on freshwater fish species to reach a high count of 6.5, 5.7 and 6 log 10 CFU g fish for tilapia and carp respectively. None of freshwater fish species reached the maximum microbiological limit set by ICMSF 1978 . psychrotrophic counts increased rapidly and tended to reach their maximum counts at the end of the storage period, and were 2.6 and 3.3 log 10 CFU g fish for tilapia, and carp respectively. Total coliform counts were 1.3 and 2.3 log CFU g fish and increased with extended storage to reach their maximum values of 4.1and 3.5 log CFU g fish for tilapia and carp respectively..Proteolytic counts of all fish species increased with extended storage reaching their maximum count on the last day of storage period. The average proteolytic counts of freshwater species were 1.9 and 3.0 log CFU g reaching a maximum values of 3.9 and 4.8 log CFU g at the end of storage period for tilapia and carp respectively. Ahmed Rashed Al-Najada "Determination of Quality of Iced Freshwater Species Based on Total Volatile Base Nitrogen (TVB-N) and Microbial Contents Test" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29795.pdf Paper URL: https://www.ijtsrd.com/biological-science/microbiology/29795/determination-of-quality-of-iced-freshwater-species-based-on-total-volatile-base-nitrogen-tvb-n-and-microbial-contents-test/ahmed-rashed-al-najada