Survey of antibiotic residues in raw milk samples in Qazvin (2012)

  Background: Use of food products of animal origin containing antibiotics residues has led to much concern in consumers.   Objective: The aim of this study was to determine the antibiotic residues in raw cow milk in Qazvin province.   Methods: In this cross sectional study, 200 raw cow milk samples were randomly collected from industrial dairy farms in Qazvin province during the warm and the cold seasons in 2012. All samples were examined by Delvo test and specific ELISA kits for enrofloxacin , gentamicin , tetracycline , tylosin , chloramphenicol and sulfonamides residues . Data were analyzed using ANOVA and Tukey’s test.   Finding: 86 milk samples (43%) were positive for antibiotic residues to Delvo test. The highest mean values were related to sulfonamides (20.40±12.99 ng/ml) and gentamicin (20.06±14.92 ng/ml) and the lowest mean value was related to chloramphenicol (0.13±0.07 ng/ml) by specific ELISA kits. ​​ The mean values ​​of antibiotic residues were significantly higher during the warm season compared to the cold season. Chloramphenicol residues were above the Maximum Residue Limits (MRL) (0 μg/l) in all positive samples. Sulfonamides residues were above the MRL (25μg/l) in 25.39% of milk samples .   Conclusion: With regards to the results, extensive and careful monitoring of the production and supply of food products of animal origin, especially milk and evaluation of drug residues are essential.