Using Real Time PCR an microbiology methods we analyzed several food samples expended in streets around Universidad Politécnica Salesiana, Sede El Girón in search for the bacteria Escherichia coli. We selected three fast food restaurants, which were identified as the most important and popular for the community of students from nearby universities. To achieve a reliable statistical analysis were analyzed approximately 15 samples for each food establishment using different products. We developed a protocol for the quantification of samples, using a standard curve for E. coli. Microbiological analyzes were performed by a conventional standard method for cultivation in specific media (EMB, McKonkey) and the real-time PCR with specific primers using the Kit FS LC DNA Master PLUS ˆ HY-Pb, 96 react. (Roche Diagnostics). Through real time PCR we isolated E. coli in all the samples (100 % sucess), whereas using the conventional method we detected E. coli in only 53.36 % of the analyzed food. Chi-square (χ 2 ) test showed statistical significance between both techniques. The molecular technique revealed a 100 % of positive E. coli cases in the analyzed fast food in all three establishments, whereas through the conventional method we identified E. coli in: 40 % of the hambuerguer samples, 66.7 % of the shawarma samples and 53.3 % of the skewers. We also observed differences in the speed each technique requires to show results: real Time PCR is much more sensitive, rapid and specific compared to the conventional method of cell culture. We quantified the amount of DNA in each sample through a standard E. coli curve.
CACES Knowledge Areas
- 215A Biochemistry