摘要：The present study was conducted to evaluate the extent of β - lactam antibiotics residues in unprocessed market milk during the year 2006. Milk samples were randomly collected from Hyderabad city, Latifabad and Qasimabad. Microbial screening test ( Bacillus subtilus Field Disc Assay) and High Performance Liquid Chromatography (HPLC) methods were used to detect, identify and quantify the β-lactam residues in milk. A total of 137 milk samples were screened. Among these 63.50% were negative and 36.50% positive for β - lactam antibiotics residues. The zones size of positive samples appeared between 5.0 and 15.0mm (mean 8.91 ± 0.36mm). Residues level quantified between 0.4 to 400 µg/L for Penicillin G, between 1.0 to 190µg/L for Amoxicillin, between 0.5 to 141µg/L for Ampicillin and between 2.1 to 122µg/L (40.74 ± 10.59µg/L) for unknown antibiotics. The residues of Penicillin G (mean 59.53µg/L) in unprocessed milk was 14.9 and 11.9 fold, Amoxicillin (mean 36.11µg/L) 9.03 and 3.61 fold, Ampicillin (mean 46.91µg/L) 11.73 and 4.69 fold higher than (MRL`s) standards of EU (4µg/L) and FDA (5 and 10µg/L), respectively.
