A total of 68 samples including ( raw minced meat, Luncheon, Pasterma, and sandwiches of cooked beef, cooked liver, cooked sausage, kofta and burger) were randomly collected from butchers, take away meals' markets and street vendors in different regions of Great Cairo (Cairo, Giza and Shobra El-Khema). The evaluation of microbial load of the collected samples revealed that, no samples contained Total Bacterial Count (TBC) more than the permissible limits, 26.5%, 10.3%, 10.3%, 5.9%, 35.4% and 86.8% of the examined samples contained Total Fungal Count (TFC), Total Coliform Count (TCC), E.coli (Faecal coliform count), Staphylococcus count, Salmonella and Bacillus cereus counts (BC) more than the permissible limits, respectively. The E.coli (Faecal coliform) positive samples (7) together with another 7 samples contained the highest cfu/g of TCC were selected to be tested with Standard (St) as well as Real Time (RT) PCR techniques to detect the presence of E.coli serotype O157:H7. The result of St Polymerase Chain Reaction (PCR) assay indicated positive results (specific bands) in 78.6% of the examined samples. On the other hand, by using specific RT PCR Kit for the detection and differentiation between E.coli O157:H7 and other E.coli serotypes, the obtained results revealed that, all St PCR positive samples showed a separate plateau differed from that obtained from the E.coli O157:H7 positive control sample, indicating that the present serotype (E.coli O55:H7 as clarified by the kit user manual) has nearly the same primer sequence as E.coli O157:H7 which led to false positive result using St PCR technique. This result indicated that, RT PCR is considered as an important, specific and accurate method for the detection and identification of food poisoning organisms.