Tetracyclines are antimicrobial agents used in dairy cattle to treat infection diseases, as mastitis and also as additives in animal food to improve feed efficiency and growth. The use of tetracyclines can result in the presence of residue of these antimicrobials in the milk, especially if they are not used according to the label directions and if the minimum period of their elimination is not respected. The presence of antibiotic residues in the milk interferes in the dairy industrial process diminishing starter culture growth used in the yogurt and cheese production, causing strong economic loss. Antibiotic residue in the consumer milk may represent risk to the human health, allows allergic reactions in sensitive human beings, disorders of the intestinal flora damaging its local protection action and provides antibiotic resistance development. The objective of this study was to validate the multiresidue method to determine the oxytetracycline, tetracycline, chlortetracycline and doxycycline in milk by acidic desproteinization extraction and to identify and quantify them by high performance liquid chromatography with photo-diode array detector. The method presented detection limit and quantification limit respectively of 37,5 and 50 ng/mL, linearity from 50 to 1600 ng/mL and correlation coefficient of 0,9996, 0,9994, 0,9996 and 0,9996 to the oxytetracycline, tetracycline, chlortetracycline and doxycycline respectively;and recovery between 66,6 and 89,2%, with good precisions and accurancy.
Residues; Antibiotics; Tetracyclines; Milk; HPLC
