Total of 500 samples from triceps, gluteal and diaphragm muscles, kidney, and liver, were obtained randomly from beef carcasses of a slaughterhouse in Tabriz. We measured oxytetracycline, tetracycline, and chlortetracycline (TCs) residues by high performance liquid chromatography (HPLC) method. Seventy four percent of samples (380 samples) had detectable TCs residues. The mean amounts of oxytetracycline, tetracycline, and chlortetracycline residues in all samples were 52.2, 33.8, and 125.2 µg/kg, respectively. The mean amounts of total residues of TCs in all meat samples, triceps, gluteal and diaphragm muscles, kidney, and liver were 131.0, 163.1, 63.4, 166.7, 408.1, and 254.9 µg/kg, respectively. Five percent of kidney and liver samples and 21.7% of all samples contained residues more than the maximum residue limits (MRLs) of the World Health Organization (WHO). This study indicates presence of different levels of tetracycline residues in the various edible tissues. Regulatory authorities should ensure proper withdrawal period before slaughtering of the animals.

Total of 500 samples from triceps, gluteal and diaphragm muscles, kidney, and liver, were obtained randomly from beef carcasses of a slaughterhouse in Tabriz. We measured oxytetracycline, tetracycline, and chlortetracycline (TCs) residues by high performance liquid chromatography (HPLC) method. Seventy four percent of samples (380 samples) had detectable TCs residues. The mean amounts of oxytetracycline, tetracycline, and chlortetracycline residues in all samples were 52.2, 33.8, and 125.2 µg/kg, respectively. The mean amounts of total residues of TCs in all meat samples, triceps, gluteal and diaphragm muscles, kidney, and liver were 131.0, 163.1, 63.4, 166.7, 408.1, and 254.9 µg/kg, respectively. Five percent of kidney and liver samples and 21.7% of all samples contained residues more than the maximum residue limits (MRLs) of the World Health Organization (WHO). This study indicates presence of different levels of tetracycline residues in the various edible tissues. Regulatory authorities should ensure proper withdrawal period before slaughtering of the animals.