PESTICIDE RESIDUES IN COW MILK AND DAIRY PRODUCTS FROM THE MAJOR MILK PRODUCING AREA OF SRI LANKA

Abstract

Nuwara Eliya district is the leading fresh milk producing area in Sri Lanka. In the district, pesticides are widely applied for intensive cultivation of vegetables which leads to contamination of water and material used to feed cows. Contamination and health risk hazards of organophosphorus pesticide residues in milk and dairy products originated in the district were studied. Identification and quantification of eleven commonly used pesticides in 50 milk samples and 12 dairy product samples were performed using standard analytical methods and GC-MS technique. Results revealed that fresh milk contained residues of Prothiofos (0.0568±0.037 mg/kg), Diazinon (0.0378±0.009 mg/kg), Chlorpyrifos (0.0264±0.004 mg/kg), Profenofos (0.196±0.099 mg/kg), Fipronil (0.1906±0.188 mg/kg), Phenthoate (0.1012±0.110mgkg), Dimethoate (0.1196±0.201 mg/kg) and Tebuconazole (0.062±0.069 mg/kg) at higher levels than the recommended maximum residue levels (MRLs) of the World Health Organization. Sterilized milk (0.0115±0.000 mg/kg) and fermented milk (0.022±0.004 mg/kg) contained higher levels of Profenofos than the MRLs. Higher levels of Fipronil than MRLs were observed in pasteurized milk (0.086±0 mg/kg) and fermented milk (0.014±0.000 mg/kg) samples. Phenthoate at higher levels than MRL was reported in pasteurized milk (0.3645±0.402 mg/kg), sterilized
milk (0.1405±0.197 mg/kg) and milk powder (0.0055±0.000 mg/kg). Moreover, Dimethoate content in fermented milk (0.087±0.012 mg/kg) was higher than the MRL. Routine monitoring of the above pollutants in food items including fresh milk and value added milk products is essential to prevent, control and reduce the pollution and to minimize the health risks to consumers.