Abstract
A total of Sixty random samples of marine fish, including sardine, seabream, and seabass (20 of each), were chosen from the commercially significant species of harvested marine fish from retail markets in Alexandria province for chemical and microbiological assessment. The study revealed that the average values of histamine, Trimethylamine (TMA), and total volatile nitrogen (TVN) in the analyzed samples of sardine, seabream, and seabass were as follows: for sardine, the values were (0.41±0.002, 0.44±0.02, and 0.19±0.01mg/100g); for seabream, the values were (8.53±0.033, 18.03±0.27, and 12.92±0.45 mg/100g); and for seabass, the values were (18.52±0.62, 19.61±0.29, and 17.64±0.13 mg/100g). The average total bacterial count in the analyzed samples of sardine, seabream, and seabass were 17.8×105±2.6×105, 3.2×105±0.61×105, and 1.95×105±0.49×105 Cfu/g, respectively. The Enterobacteriaceae count in the same examined samples were 5.8×104 ± 3.6×104, 3.1×103 ± 0.63×103, and 2.3×103 ± 0.54×103 cfu/g, respectively. Additionally, the mean values of coliforms were 2.2×103 ± 0.51×103, 8.1×102 ± 1.02×102, and 7.4×102 ± 0.8×102 Cfu/g, respectively. E.coli and salmonella were detected in 20 and 10% of examined sardine sample, and both organisms failed to be detected in seabream and seabass, respectively, While Vibrio parahaemolyticus were detected in only one sample of examined sardine, seabream, and seabass with an incidence level (5% of each type). In conclusion, Sardine had the highest level of contamination with pathogenic organisms such as E.coli, V. parahaemolyticus and salmonella, therefore, conduct regular audits and inspections of fish processing facilities, fishing vessels, and storage areas to ensure compliance with hygiene and safety standards.

Key words: Marine fish, histamine, TVN, TMA, E.coli, V. parahaemolyticus, salmonella.