Risk assessment of antibiotic residues in raw cow's milk in Bangladesh

This study evaluated the presence of residual levels of commonly utilised antibiotics, including oxytetracycline (tetracyclines), ciprofloxacin, enrofloxacin, and levofloxacin (fluoroquinolones), in milk samples. Fifty raw milk samples were collected from five farms in Keraniganj, Dhaka. A validated RP-HPLC method was applied to detect and quantify antibiotic residues, demonstrating good linearity with coefficients ranging from 0.999 to 1.0 in the concentration range of 1.25-15.00 µg/mL. The study revealed that oxytetracycline was detected in 90% of the samples, followed by levofloxacin (66%), enrofloxacin (64%), and ciprofloxacin (62%). One farm showed the highest antibiotic prevalence, with oxytetracycline in all samples and levofloxacin, enrofloxacin, and ciprofloxacin in 80% of the samples. About 30% of the oxytetracycline-positive samples exceeded the MRL, while none surpassed the MRL for enrofloxacin and ciprofloxacin. Calculated human health risks appeared to be low, but children might face potential risks due to prolonged exposure.