Survey on microbial contamination, characteristics of E. coli bacteria in pork samples collected in Dien Bien province

Abstract

This study was carried out to determine the prevalence of aerobic bacteria total and E. coli in pork selling in some markets of Dien Bien province. A total of 90 pork samples collected randomly at 3 local markets in Dien Bien province from June, 2016 to April, 2017 were analysed to determine the bacterial contamination in pork. The studied result showed that 98.89% of samples were positive with aerobic bacteria total. Of which, 48.89% of samples were contaminated with aerobic bacteria total over the limited level; 75.56% of samples were contaminated with E. coli. Of which, 30 - 53.33% of samples were contaminated with E. coli over the permitted level of food safety, with the bacterial numbers ranging from 1.03x102 CFU/g to 5.23x102 CFU/g. The highest infection rate and intensity of E. coli in pork were in the central market. The prevalence of E. coli in pork was gradually increased and proportional to the time after slaughter and also increased in summer - autumn rather than in winter - spring. The isolated E. coli strains carried all the bio-chemistry characteristics of the E.coli bacteria and caused poison for human. The antibiotic susceptibility test of 68 E. coli strains showed that 67.65% - 91.18% of the isolated strains were susceptible to enrofloxacine, norfloxacine, gentamycine and spectinomycine. The isolated E. coli strains were strongly resistant to tetramycine (80.88%), streptomycin (77.94%), oxacillin (66.18%) and erythromycin (42.65%). All (100%) of the isolated E. coli strains were virulent, killing the experimental guinea pigs within 8 to 48 hours.