MICROBIAL EVALUATION OF RAW BEEF AND ANTIBIOTIC RESISTANCE PROFILE OF SALMONELLA AND ESCHERICHIA COLI ISOLATES FROM SELECTED ABATTOIRS IN SOUTHEAST NIGERIA

Abstract

Meat contamination during slaughter and processing remains a major public health concern due to microbial proliferation that compromises safety and nutritional quality. This study assessed the bacterial quality of raw beef and the antibiotic resistance profiles of Salmonella spp. and Escherichia coli isolated from selected abattoirs in Southeast Nigeria. A cross-sectional survey was conducted from January to May 2025 in abattoirs located in Owerri (Imo State), Umuahia (Abia State), and Nsukka (Enugu State). A total of 324 samples; raw beef, table swabs, and floor swabs (108 per abattoir) were collected using systematic random sampling based on slaughter output. Total viable bacterial counts (TVBC) and total coliform counts (TCC) were determined using standard microbiological procedures, while isolation and confirmation of E. coli and Salmonella spp. followed established cultural and biochemical protocols. Data were analyzed using ANOVA and Chi-square tests. Mean aerobic plate and coliform counts were significantly higher (p < 0.05) on table and floor surfaces than on beef, indicating poor hygiene and cross-contamination risks. Antimicrobial susceptibility tests showed high resistance (80-100%) to amoxicillin/amoxiclav, streptomycin (79-100%), and tetracycline (76-100%) in both pathogens. Moderate resistance was recorded for neomycin (41-62.5%), ciprofloxacin (33-53.8%), and nitrofurantoin (41.6-58%), while lower resistance occurred with sulphamethoxazole-trimethoprim (12.3-47%), doxycycline, and gentamicin (11.730.8%). The presence of multidrug-resistant Salmonella and E. coli, alongside elevated microbial loads, highlights major sanitary lapses in the studied abattoirs. Strengthening hygiene practices, routine microbial surveillance, and prudent antibiotic use is critical to improving meat safety and protecting public health.