Microbial and Antibiotic Resistant E. coli Contamination in Retail Eggs Produced by Alternative and Conventional Rearing Methods

The aims of this study were to determine: i) the presence of total mesophilic aerobic bacteria (TMAB), total psychrophilic aerobic bacteria (TPAB) coliform, E. coli, Enterobacteriaceae and Salmonella in retail eggs produced in different poultry rearing systems, ii) Enterobacteriaceae species diversity, and iii) antibiotic resistance profile of E. coli isolates. A total of 350 retail eggs produced by four different rearing systems [organic (n= 100), free-range (n= 100), barn (n= 50) and conventional-cage (n=100)] were collected and characterized microbiologically. Out of the 350 eggs tested, the eggshell surface samples were contaminated, with TMAB, TPAB, coliform, E. coli and Enterobacteriaceae at positive percentages of 100%, 100%, 49.1%, 18.6% and 38%, respectively. The positive percentage of coliform, E. coli and Enterobacteriaceae were statistically significant between rearing systems (P