الفهرس 
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Abstract
7. ENGLISH SUMMARY
The present work studied the chemical and microbiological quality of some marine fish including sardine, seabream, and seabass (20 samples of each type) that were selected from among the commercially important species of harvested marine fish from retailed markets in Alexandria province. Examined fish samples were subjected to chemical evaluation through the determination of histamine content, Trimethylamine, and total volatile nitrogen; in addition to microbiological evaluation through determination of total bacterial count, Enterobacteriaceae count, and coliforms count, with isolation of some of the foodborne pathogens such as E.coli, Vibrio parahaemolyticus, and Salmonella species. Moreover, comparing positive samples with national and international standards and guidelines.
The obtained results summarized in the following items.
7.1. Chemical indices of different marine fish :
Mean values of histamine content in examined sardine, seabream, and seabass were 0.41±0.002, 0.44±0.02, and 0.19±0.01mg/100g, respectively. According to the Egyptian Organization for Standardization (3494/2005) (should not exceed 10 mg/100g). All the marine fish examined, including sardine, seabream, and seabass, were found to be within the acceptable limit set by Egyptian standards.
Mean values of Trimethylamine level in examined sardine, seabream, and seabass were 8.53±0.033, 18.03±0.27, and 12.92±0.45 mg/100gm. According to the Egyptian Organization for Standardization (3494/2005), (the level of TMA should not exceed 10 mg/100 g), As a result, 100% of examined sardine samples and 20% of examined seabass below the acceptable limit set by Egyptian standards, while 100% of examined seabream samples above the permissible limit.
Mean values of total volatile nitrogen in examined sardine, seabream, and seabass were 18.52±0.62, 19.61±0.29, and 17.64±0.13 mg/100g, respectively. According to the Egyptian Organization for Standardization (3494/2005), (the level of TVB-N should not exceed 30 mg/100g), All the examined marine fish, including sardine, seabream, and seabass, were found to be below the acceptable limit set by Egyptian standards.
7.2. Microbiological analysis of different marine fish :
Mean values of Total bacterial count in examined 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, with an incidence level of 100, 90 and 90%, respectively. The Egyptian Organization for Standardization (3494/2005) stated that the total bacterial count should not exceed 106 cells/g, All the examined sea bream, sea bass, and 75% of examined sardine samples were found to be below the acceptable limit set by Egyptian standards.
Enterobacteriaceae were detected in 100, 75, and 80% of examined sardine, seabream, and seabass fish samples with mean values of 5.8×104 ± 3.6×104, 3.1×103 ± 0.63×103 and 2.3×103 ± 0.54×103 cfu/g, respectively.
Mean values of Coliforms count in examined sardine, seabream, and seabass fishes were 2.2×103 ± 0.51×103, 8.1×102 ± 1.02×102 and 7.4×102 ± 0.8×102 Cfu/g with an incidence rate 100, 65 and 75%, respectively. According to the Egyptian Organization for Standardization (3494/2005), (stated that the total coliforms count should not exceed 100 cells/g ), as a result 95, 100 and 100% of examined sardine, sea bream, and sea bass fish samples were found to be above the acceptable limit set by Egyptian standards.
Escherichia coli was detected in 20% of examined sardine samples and failed to be detected in examined seabream and seabass.
Vibrio parahaemolyticus were detected in only one sample of sardine, seabream, and seabass, respectively with an incidence level of 5% in each fish type.
Salmonella was detected in 10% of examined sardine samples and failed to be detected in examined seabream and seabass.