QUALITATIVE AND QUANTITATIVE ASSESSMENT OF ß-LACTAM ANTIBIOTIC RESIDUES IN UNPROCESSED MARKET MILK IN LAHORE, PAKISTAN
Keywords:antibiotic residue, Bacillus subtilis, β – Lactam, HPLC, milk
Present study was conducted to evaluate the extent of ?- lactam (Penicillin G, Ampicillin, and Amoxicillin) antibiotic residues in unprocessed market milk during the year 2013 from four different zones of Lahore city. Two zones (Mall road and Canal road) are located in center of city while other two zones (Multan road and Ferozpur road) exist near to periphery. A total of 120 samples (30 each from 4 zones) were collected from shops selling raw (unprocessed) milk. Qualitative assessment of ß-lactam antibiotic residues was done by Bacillus subtilis Qualitative Field Disc Assay. Milk samples producing zone of inhibition were considered having antibiotic residues. Quantification of these drugs residue in positive milk samples was done by High Performance Liquid Chromatography (HPLC). Antibiotic residue was detected in 23% samples on the basis of disc assay. The maximum inhibition on B. subtillis was 14 mm while minimum observed was 3.5 mm. Zone wise distribution of positive samples was 5 (17%), 3 (10%), 9 (30%) and 11 (37%), respectively. All 28 positive samples quantified through HPLC showed that ampicillin, amoxicillin and penicillin were present in 32 % (9/28), 85% (24/28) and 89% (25/28) of positive samples, respectively. About 68% (19/28) of the positive samples, were unfit for human consumption having residues higher than maximum residual limit (MRL’s) standards of EU (4?g/L) and FDA (5 and 10?g/L), respectively. Overall percentage of samples with more than MRL’s was 16 (19/120).