Abstract
Consumption of fresh fish especially is increasing on daily basis based in Nigeria; meanwhile Fish has been reported to capable of harbouring pathogenic bacteria and the level of its prevalence depending on many factors. The load of bacteria may results to diseases and cause biological and economical losses. The study investigated the total bacterial and enterobacterecea count in water, pond sediment, fish flesh, liver, kidney, intestine and gill from fish farms across large, medium, and small scale farms in the zone.The study was carried out in Oyo State, using Oyo state into agro-ecological segment by Oyo State Agricultural Development Programme (OYADEP). Farms in each zones were sub-grouped into Large, Medium and Small scales using stratified method. A total number of thirty-six (36) farms (5 Large, Medium and Small scales farms) were selected. Water (in a plastic bottles), soil, and fish (in a sterile polythene) samples were collected aseptically and examined for bacteria load.The total viable count (TVC) and total enterobacteriacea (TEB) were expressed in mean (cfu/g) and Log10CFU/g.The mean data were compared using one way analysis of variance (ANOVA) and Duncan Multiple Range Test.The results show that water samples from Ogbomosho zone had highest TVC and TEB and 5.73±0.29 Log10cfu/ml and 5.25±0.31 Log10cfu/mlrespectively. Evaluation of pond sediment shows that Ibadan/Ibarapa zone had highest TVC (5.89±0.26Log10cfu/g)and TEB and (5.53±0.25Log10cfu/g). Fish from Ogbomosho zone had highest TVC in gill (128.04±51.57cfu/g), liver (78.22±33.93cfu/g), kidney (66.07±31.01cfu/g), intestine (98.81±52.36cfu/g), skin (232.67±77.62cfu/g) and spleen (31.70±25.25cfu/g) while Saki zone had highest TVC in flesh (41.56±21.13cfu/g). TEB were highest in fish from Ogbomosho zone in gill (72.67±43.9cfu/g 5), kidney (45.04±29.14cfu/g), intestine (54.44±39.74), skin (110.41±65.41cfu/cm2) and spleen (31.70±25.25cfu/g) while TEB were highest in liver (35.82±17.81cfu/g) from fish from Ogbomosho zone and flesh from fish from Saki zone (21.19±12.16cfu/g). Fish from most of agro-ecological zone of Oyo State are contaminated with enterobacteria higher than the recommended values opining consumer health risk therefore, effort should be put in place to prevent culture system contamination throughout the value production chain

Key words: Enterobacteriacea, distribution, bacteria, Fish tissues