Antibiotics abundant use in veterinary medicine may result in the presence of their residues in. animal products for human consumption, especially in milk at unsafe concentrations that increase the potential health risks to consumers due to their adverse effects. The aim of the current study was carried out to detect the effect of two thermal treatments including, boiling
and microwaving on oxytetracycline residues in raw cow's milk using ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technique. One hundred of raw cow's milk samples were collected from different markets and retail dairy shops in various districts of Damietta governorate. Oxytetracycline residues extraction was carried out by solid phase extraction method. From analytical check performed by HPLC, it was confirmed that 5% of total raw cow's milk samples had different values of oxytetracycline residues ranged from 35.5 to 112 ppb. Referring to the maximum residual level (MRL) that 100 µg/kg for oxytetracycline in milk, only 1% of analyzed samples has been confirmed with
value higher than this limit. The observed oxytetracycline residual levels in milk samples were reduced after application of the thermal effect by boiling and microwaving up to 80.5% and to 92.5%, respectively. The obtained results revealed absence of possible transformed metabolites of oxytetracycline because of boiling or microwaving of positive samples
concluding 4-epioxytetracycline (4e-OTC), α-apo-oxytetracycline (α-apo-OTC) and β-apooxytetracycline (β-apo-OTC). Moreover, boiling and microwaving on oxytetracycline residues in raw cow's milk do not guarantee a full elimination but it can reduce its quantities largely. Consequently, will discuss the findings, health risks and economic importance, and those must be recommended.