This study was conducted to investigate the possibility of food poisoning bacteria isolated from local Egyptian markets. A total of 100 samples made up of five types of Egyptian food staff were isolated from different food sources [smoked beef salami, Ringa (smoked herring), Fesikh (un-gutted salted fish), Luncheon and Basturma (cured beef)] collected from different Egyptian local markets. The isolated bacteria species after biochemical and serological typing were Escherichia coli O157.The effects of bacterial endotoxin extracted from bacterial isolate on liver enzyme changes were investigated. Little information is available about the direct effect of bacterial endotoxin on the onset of liver impairment. In this work, 32 Sprague Dawley rats (males) were injected intraperitoneally with endotoxin derived from E. coli culture supernatant to induce impairment of liver functions. Study detected an obvious increase in ALT as well as AST values and reduction it with treated by oils as antioxidant. Study suggests that these alterations in liver functions could be related to the development of liver damage in response to significant dose of bacterial endotoxin.