Abstract
Fish has high consumer preference due to its inherent nutritive value, taste and easy digestibility. It is one of the most important sources of animal protein available and has widely been accepted as a good source of animal protein and other elements for maintaince of healthy body. The present study was planned to estimate the quality and heavy metal residues of the frozen fish fillet for that aim, a total of 50 frozen fish fillet samples from market retail from different origins in Kafr El-Sheikh Governorate. Bacteriological and Chemical analysis was done for frozen fish fillet. The results revealed that total bacterial count, coliform count and total psychtrophic count were 32.04x107 ± 5.75x107, 14.35x103±5.26x103 and 8.08x108±13.46x108 respectively. The Staphylococcus aureus were isolated from 23 samples (46%) detection of Staph. aureus enterotoxin by using multiplex PCR indicates that only 9 (39.1%) strains from the 23 isolates were positive for enterotoxin production, 6 (26%) isolates produce Sea; 2(8.7%) isolates produce Seb; one (4.3%) isolate Sec; and one (4.3%) isolate produce Sed enterotoxin.. On the other hand, E.coli was detected in 5 samples (10%) of the examined sample, and the serological identification of the obtained isolates revealed the presence of the following serotypes 1(0.2%) for EPEC (O153:H2), 2(0.4%) for ETEC (O126:H21) and 1(0.2%) for EHEC (O55:H7), 1(0.2%) for EHEC (O121:H7). While in heavy metal residues were found that mean values of Mercury, Lead and Cadmium were 0.5992±0.102, 0.1596±0.037 and 0.059±0.019 mg/kg respectively.
The obtained results indicate that consumption of frozen fish fillet may cause a public health hazard to the consumer. Measures to control the quality of frozen fish fillet during handling and processing should be taken.

Key words: fish fillets, microbiology, heavy metals.