Monitoring of pesticide and antibacterial drug residues in animal products from two states in India by modified multi-residue analytical methods using GC–ECD and HPLC–DAD

The study aims to monitor pesticide and antibacterial drug residues in food of animal origin namely eggs, chicken, chevon and cow milk using two modified multi-residue analytical methods for simultaneous detection and quantification of thirteen pesticides with gas chromatography-electron capture detector (GC-ECD) and four antibacterial drugs with high performance liquid chromatography–diode array detector (HPLC-DAD). A total of 462 egg, 503 chicken, 575 chevon and 570 milk samples were collected from the local markets, dairy farms and households in twelve districts of West Bengal and four districts of Odisha, India. Samples were procured in summer and winter season. The validation of the method included the determination of limit of detection, limit of quantification, linearity, accuracy and precision and an inter- and intra-day assay of the method. Good linearity was obtained (r2 > 0.99), the recovery % ranged from 85.07 to 93.53% for antibacterial drugs and from 82.0 to 99.47% for pesticides, inter-assay and intra-assay variability were below 10 and 15% and repeatability was < 20% in both cases. The proposed modified methods thus proved reliable and were applied for monitoring pesticide and antibacterial drug residues in animal samples. The results revealed that 5.17% of the chicken samples were positive for delta-hexachlorocyclohexane, 11.33% for gamma-hexachlorocyclohexane and 11.93% for alachlor whereas 2.09% of the chevon samples were positive for alachlor and 1.57% for chlorpyrifos. However, all these values were within the maximum residue levels as set by European Commission and Codex Alimentarious Commission, suggesting no serious threat to public health.