The study of Escherichia coli contamination rate in meats of chickens without antibiotic and conventional

The residue of antibiotics and other chemical compounds in chicken meat is one of main concerns in consumers of this protein source. In this research, for study of correlation between antibiotic consumption and chicken meat contamination, in summer of 2014, 10 chicken farms in Isfahan province that reared under conventional condition and 5 chicken farms that reared broilers under without antibiotic consumption were monitored from start of growing period. At end of growing period, in slaughter stage, one piece of breast muscle and cecum content were sampled. The percentage of carcass contamination and number of Escherichia coli (E.coli) in cecal content were determined in chickens reared under conventional and without antibiotic condition. Also, the shigatoxogenic E.coli was examined by PCR.Furthermore, the carcass contamination and E.coli colony count in cecal content in chickens with or without colibacillosis background were determined. The results showed that the chicken meat contamination to E.coli and the E.coli population in cecal content in chickens reared under conventional condition were not significant different from chickens reared without antibiotic, while these indices in chickens with colibacillosis history were significant higher than chickens without colibacillosis history. In this study the shigatoxogenic E.coli was not detected. In overall, this study revealed microbial infection in chicken farms that lead to antibiotic consumption could decrease hygienic quality of chicken meat. Therefore, in addition to controlling of withdrawal time for antibiotic consumption, the withdrawal time for infections incidence must be observed for decrease the risk of transmission of pathogens along the food chain of human.