Table 3.

Tetracycline residues in commercial milk samples(μg/kg)

	Number of positive samples	Minimum	Maximum	Meana	Each drug ratio to the total TETs concentration
Oxytetracyclin	37	197.65	2137.27	945.90	86.71
Tetracycline	2	<LOD	241.45	28.71	2.63
Chlortetracycline	5	<LOD	288.19	71.93	6.59
Doxycycline	2	<LOD	206.13	44.283	4.05
Total residues in positive samples	37	220.93	2452.06	1090.83	100
Total residues in total samples	187			252.41b

^aThe average concentration in the positive samples

^bMean concentration of TET residue in the whole sampled population was calculated as an average of 1090.83 μg/kg for positive samples (20 % of the total share), 100 μg/kg (maximum residue level) for 15 % of the total share and 25 μg/kg for the rest (65 %) which appeared negative in the screening test