Ninety random samples of fresh and frozen each of Tilapia niloticus, Mugil cephalus and Shrimp (15 of each) were
collected from different fish markets at Qaliuobia Governorate. All collected samples were bacteriologically examined
for determination of Aerobic Plate Count (APC), psychrotrophic count, Isolation and Identification of pseudomonas and
Aeromonas species. The bacteriological examination revealed the mean values of APC in the examined fish samples was
1.52×10⁶ ± 0.47×10⁶ and 3.08×10⁵ ± 1.31×10⁵ in fresh and frozen Tilapia niloticus, 7.14×10⁵ ± 1.84×10⁵ and 2.59×10⁵ ±
0.62×10⁵ in fresh and frozen Mugil cephalus and 7.81×10⁴ ± 2.07×10⁴ and 1.36×10⁴ ± 0.42×10⁴/g, in fresh and frozen
shrimp . The mean values of psychrotrophic count in fresh and frozen Tilapia niloticus were 2.67×10⁵ ± 0.45×10⁵ and
5.36×10⁵ ± 1.24×10⁵ cfu/g, respectively. 4.91×10⁴ ± 0.93×10⁵ and 1.72×10⁵ ± 0.46×10⁵/ gm respectively in fresh and
frozen Mugil cephalus. 7.81×104 ± 2.07×104 and 6.51×104 ± 1.80×104/g, in fresh and frozen shrimp. The incidence of
Pseudomonas species was 33.3% and 53.3%in the examined samples of fresh and frozen Tilapia niloticus, 46.7% and
60.0 %in fresh and frozen Mugil cephalu, respectively, 33.3 %and 40.0 %in fresh and frozen shrimp, respectively. The
incidence of Aeromonas species were 46.7 %and 33.3 %in the examined samples of fresh and frozen Tilapia niloticus,
53.3 % and 40.0% in fresh and frozen Mugil cephalus, respectively, 33.3 % and 40.0 %in fresh and frozen shrimp,
respectively