RESUMEN
Organochlorine pesticides have been used in agriculture as seed dresser, in sanitation and in livestock to combat ectoparasites. Their residues accumulate in lipid rich tissues due to their chemical stability and lipophilicity. In the body, they are slowly metabolized, deposit themselves in adipose tissue and excreted during lactation. In the present study one hundred and fifteen milk samples from different dairy farms as well as 119 samples of 7 major feed ingredients, were collected and analyzed for organochlorine insecticide residues using high performance thin layer chromatography. Results showed that the different materials contained low or negligible levels of chlorinated insecticides. Total DDT residues were generally the predominant contaminants detected in some samples of the animal feed ingredients together with low levels of gamma-BHC [lindane] akirin/dieldrin and heptachlor/ hepatochlor epoxide. The residues of these insecticides in bovine milk were [222.83 +/- 11.151, 133.72 +/- 18.61, 81.58 +/- 10.65 and 88.17 +/- 6.827] micro g /kg fat respectively. These levels were less than the codex tolerance limits. The examined samples of animals feed ingredients also contained trace organochlorines residues. More extensive monitoring of the residues in milk of some Egyptian governorates were carried out. The obtained data and desirability of tolerance limits of insecticides in animal feeds were discussed