Effect of cooking methods on tetracycline residues in pig meat

Tetracyclines (TCs) are widely used for disease control in the livestock and poultry industry due to their broad spectrum of activity and affordability. However, some residues have been found to remain in the animals during slaughter and subsequent consumption. The potential of different cooking methods as strategies to reduce TC residues in pork were therefore investigated. Samples of pig muscles containing oxytetracycline (OTC), TC, chlortetracycline (CTC) and doxycycline (DC) residues were subjected to boiling, deep-frying or microwaving and the residues were extracted in a mixture of McIlvaine buffer-ethylenediaminetetraacetic acid (EDTA)/methanol (75:25, v/v), and then analyzed by high performance liquid chromatography (HPLC)-diode array detection on a XBridgeTM C18 reverse phase chromatographic column. Results show that TC residues in muscles were reduced by 45.35 to 67.05% after boiling for 9 min, 38.17 to 65.74% after deep-frying for 9 min and 38.17 to 48.47% after microwaving for 1 min. It can therefore be concluded that from a safety and toxicological point of view, reduction of TC residues in pig muscle is an additional advantage of cooking as a food processing method and it is recommended that more studies in other kinds of meats be done.   Key words: Tetracyclines, pig muscle, cooking effects, antibiotics residues.