Comparative quality assessment of wild and cultured Nile tilapia [Tilapia niloticus] stored at 4°C

ABSTRACT

Sixty Nile [Tilapia nilotica] fish of about 200 -250 gm [30 wild and 30 aquacultured] were collected alive and transported directly to the laboratory surrounded by ice bags in an ice box. Organolyptic, bacteriological and chemical examination to estimate the freshness rating and the quality parameters were carried out directly after fish arrival to the laboratory and periodically during chilling storage at 4°C. The mean [ +/- St. Error] Demerit scores of wild and aquacultured [Tilapia niloticus] fish were 0.0 +/- 0.0 and 0.0 +/- 0.0 at zero time and increased gradually during the storage time till it reaches 16.8 +/- 1.37 and 18.2 +/- 1.41 respectively at the end of the storage period. The mean [ +/- St, Error] Aerobic bacterial counts of wild and aquacultured [Tilapia niloticus] fish were [<102 and 0.4X10[2] +/- 0.13X10[2]] and [<3 and <3] respectively at zero time and increased gradually during the storage time till it reaches [6.8X10[5] +/- 7.85X10[2] and 6.1X10[6] +/- 9.70 X 10[2]] and [0.85 X102 +/- 0.12 X10[2] and 0.94X10[2] +/- 0.14X10[2]] respectively at the end of the storage period and there was a significant difference [P> 0.05] between the means of both aerobic plate counts and coliforms counts of the wild and aqua-cultured [Tilapia niloticus] fish during all storage period. The mean values [ +/- St. Error] of Total Volatile Bases - Nitrogen [mg/100g] and Thiobarbituric acid number [mg Mal./ Kg] of the wild and aquacultured [Tilapia niloticus] fish samples were [3.16 +/- 0.05 and 3.58 +/- 0.07] and [0.036 +/- 0.003 and 0.081 +/- 0.009] respectively at zero time and increased gradually during the storage time till it reaches [32.83 +/- 1.17 and 33.72 +/- 1.21] and [2.164 +/- 0.168 and 2.535 +/- 0.195] respectively at the end of the storage period and there was no significant difference [P> 0.05] between the means of both TVB-N and TBA of the wild and aquacultured [Tilapia niloticus] fish