INSECTICIDE RESIDUES IN MILK AND INFLUENCE OF HEAT TREATMENTS AND BACTERIAL FERMENTATION AS SAFEGUARD AGAINST THESE POLLUTANTS

Sixty eight buffaloe's milk samples were collected from the major production farms of Alexandria and Behera governorates over summer months during the period of pesticides application in agriculture and veterinary purposes. The samples were analysed for some organochlorine and organophosphorus insecticide residues using gas liquid chromatography. The obtained results revealed the presence of organochlorine insecticide residues in analysed milk samples at percentages of 86.76, 79.41,91.18, 88.24 & 52.94% for p.p DDT, p.p DDD, p.p DDE, Lindane and Dieldrin with average values of 0.093+0.023, 0.101+0.018, 0.1380.089, 0.042+0.013 and 0.095+0.0.030 p.p.m respectively. On the other hand determination of organophosphorus insecticide residues in investigated milk samples revealed that 33.82 , 9.25 & 19.12% of the samples were polluted with Diazinon, Malathion & Dursban residues with mean values of 120.8+27.9, 0.1100.039 and 0.059+0.019, p.p.m respectively. However all analysed milk samples were free from detectable amounts of Aldrin, Lannate, Dimethoate and Parathion. The results were evaluated according to International Standards of WHO and FAO. The results indicated that presence of Diazinon residues above the permissible limit in some milk samples, may act as health hazard for man consuming such milk. It has been found that both pasteurization and boiling of milk were effective in minimizing the insecticide residues. The reduction percentages of p.p. DDT, P.p. DDE, Diazinon, Malathion and Dursban
residues were 29.79, 21.11, 70.54, 51.94 & 44.68% respectively in response to pasteurization. While values of 71.28, 70.35, 78.1, 56.11 & 55.32 respectively were resulted by boiling. In contrast, residues of p.p DDD were increased while Lindane and Dieldrin were relatively constant under used temperature. On the other hand the processing of milk into yoghurt has a significant role in degradation of the insecticide residues in milk. The reduction percent for each DDT, Lindane, Diazinon, Malathion and Dursban residues was 65.83, 56.1, 51.27, 47.37 & 61.22% respectively while it was 8.2% for Dieldrin residues. The public health importance of insecticide residues in milk and the suggestive measures for minimizing or eliminating the milk pollution and safeguard the consumers against the dangerous effect of these pollutants were discussed.