The impact of seasonal variation on organochlorine pesticide residues in buffalo and cow milk of selected dairy farms from Faisalabad region

Two hundred milk samples from 20 randomly selected dairy farms were screened for the incidence of organochlorine pesticide residues to evaluate the safety of milk in Faisalabad region. The results revealed that overall buffalo milk samples in winter (85 %) and in summer (78 %) were more contaminated as compared to cow milk samples 83 and 75 % in respective seasons. The residues of cyhalothrin were found only in summer season in milk of both species. Permethrin residues were detected at higher levels than perfinofos while DDT and methamedophos were found undetectable. The mean levels of permethrin were 0.042 and 0.033 mg kg−1in buffalo milk samples and 0.045 and 0.043 mg kg−1 in cow milk in winter and summer season, respectively. Perfinofos residues were found to be the least contaminated pesticides with mean values of 0.0006 and 0.0013 mg kg−1, respectively in winter season, and 0.004 and 0.0025 mg kg−1 in summer season. All analysed pesticide residues in milk samples in both seasons were below the maximum residual limit (MRL) values as described by European Union (EU) but milk samples contaminated with α, β-endosulfan and endosulphate exceeded their respective Food and Agriculture Organization’s (FAO) established MRLs both in winter and summer.