Tetracycline residues in milk and beef from the Ugandan Cattle Corridor

Veterinary antibiotic residues in foods of animal origin (FOAO) are of public health concern because they can contribute to antimicrobial resistance, disruption of gut microbiota, hypersensitivity reactions and developmental effects following chronic exposure. This study investigated the occurrence of six veterinary tetracyclines (oxytetracycline, tetracycline, doxycycline, chlortetracycline, demeclocycline and methacycline) in FOAO from the Ugandan Cattle Corridor districts of Nakaseke and Nakasongola. Raw milk, muscle tissue, liver and kidneys were analyzed for tetracyclines using high performance liquid chromatography and liquid chromatography-tandem mass spectrometry. Districtwise analysis revealed a moderate prevalence of tetracycline residues in milk (5.3-42.1%) and beef (7.7-69.2%), with oxytetracycline being the most detected. Of these, 5.3-69.2% of the samples had oxytetracycline, methacycline and tetracycline concentrations exceeding their maximum residue limits established by the European Union Commission Regulation No. 37/2010. These results provide baseline data on the presence of tetracycline residues in marketed FOAO from the Ugandan Cattle Corridor. It emphasizes the need for strengthened antimicrobial stewardship, enforcement of veterinary drug withdrawal periods, and routine national antimicrobial residues monitoring in FOAO.