Discussion
These differences in the results could be contributed to many factors such as sample size, methodology used for identification, geographical variations, seasonal variation and hygienic precautions. Absence of E.coli O157 among isolated E.coli does not rule out other non-O157 shiga-toxin E.coli (STEC) which may be the main causes of food poisoning in our area and require investigation. Johnson and co-workers [21]reportedthat human are more exposed to non-O157 shiga-toxin E.coli from contaminated foods and environmental sources than to E.coli O157. According to the current results and results of the previous studies carried out in the area, E.coli O157 is very rare and warrant studies focusing on non-O157 STEC.