Investigation on Salmonella enterica, Escherichia coli, and coliforms in beef from Ethiopian abattoirs: A potential risk of meat safety.

ABSTRACT

The aims of this study were to determine the prevalence of Salmonella enterica (S. enterica) antimicrobial resistance based upon phenotypic assessment, and level of sanitation indicator organisms from 150 beef carcasses collected from three representative abattoirs in eastern, central, and southern Ethiopia. Samples were screened for S. enterica prevalence following the U.S. Department of Agriculture Microbiology Laboratory Guidebook (MLG) and confirmed by real-time PCR. The S. enterica isolates were phenotypically evaluated for susceptibility to a panel of 13 antimicrobials using disk diffusion method as described in Clinical and Laboratory Standard Institutes guidelines. In addition, the coliform, total coliform, and generic E. coli populations were quantified by plating onto E. coli/coliform petrifilms. A total of 45 isolates of S. enterica were confirmed using real-time PCR. The overall prevalence of S. enterica at the carcass level was 22.7% (95% CI, 16.0-30.0). However, based on the sampling points, S. enterica prevalence detected on hides was 13.3% (95% CI, 8.0-18.7), pre-evisceration was 12.0% (95% CI, 7.3-17.3), and post-evisceration was 4.7% (95% CI, 1.3-8.0). The prevalence of S. enterica was significantly lower on post-evisceration as compared to hides (p = .009) and pre-evisceration (p = .022). No differences were detected for the prevalence of S. enterica between abattoirs (p = .346). Finally, the prevalence of S. enterica was highest during the wet season (p = .011). The overall mean log CFU/cm2 ± SD of generic E. coli, coliform, and total coliform counts were 4.55 ± 0.99, 4.91 ± 1.13, and 4.98 ± 1.09, respectively. About 20% of S. enterica exhibited phenotypic multidrug resistant. The most frequently detected resistance was to Tetracycline (28.9%), followed by Streptomycin (22.2%) and Sulfisoxazole (20.0%). The data from this study highlight the need to implement interventions on improvement of sanitary practices in abattoirs.