This study was conducted to determine quality parameters of Nile tilapia (Oreochromis niloticus) and grey mullet (Mugil cephalus) which were collected from different local markets in Alexandria city, Egypt during 2015. According
to the overall sensory scores, the Nile tilapia and mullet samples collected from the different local markets could be classified into three categories of quality grade as follows: High quality grade (score between 8 to 10), acceptable grade (score between 5 to 7.9) and unacceptable grade (less than 5).
The TVB-N values in the different samples were below the maximum value of 30 mg N/100g flesh (upper limit according to E. O. S. Q. C., 2005, ES: 3494). The TMA-N value of Nile tilapia and grey mullet collected from the different markets were within the recommended standard limits for acceptability.
The pH values of Nile tilapia varied from 7.01 to 7.38. The data obtained showed significant differences (P< 0.05) among the samples. Further, Hanuvil market samples had the highest value of pH, while samples collected from El Wardian market had the lowest value of pH, with no significant differences between El Wardian, Alqsy and Bab Omar Pasha market samples. It was found that the pH values of grey mullet samples ranged from 6.74 to 7.18. Hanuvil samples followed by El Amreya samples were recorded to have the highest value of pH with no significant difference between them. On the other hand, Bakkous samples followed by Zananiri samples showed the lowest value of pH with no significant difference between them.
The results indicated that the psychrophilic bacterial count of Nile tilapia and grey mullet collected from different
markets were higher than mesophilic bacterial count. All Nile tilapia and grey mullet samples had high quality considering that the microbiological upper limit for fresh fish proposed by E. O. S. Q. C. (2005, ES: 3494) not exceed 106 CFU/flesh.