Abstract

A total of 163 milk samples (200 ml) human breast milk and (500 ml each) of cows, ewes, goats, buffaloes and camels were collected randomly at weekly intervals (10 samples/week) from Baghdad governorate. Among the total milk samples (138) milk samples were examined during two climatic periods from the beginning of September 2016 to the end of the February 2017 were tested for the occurrence of DMT residues by using the HPLC technique. Besides that, some of the selected positive samples were subjected to one of the commercial heat treatments such as 63°C/30 min, 80°C/5 min and 100°C/5 min to evaluate the efficiency of heat exposure on the degradation of deltamethrin and bifenthrin residues in milk. The results pointed out that milk samples containing the higher fat percentage exhibited significantly (P<0.05) the highest concentration of deltamethrin and bifenthrin in summer highest than in winter, increased the fat percentages of milk was being associated with an increased level of deltamethrin residues due to the lipophilic nature of the deltamethrin and bifenthrin pesticide. The current results revealed that milk samples that were collected from buffaloes, ewes and cows recorded the highest deltamethrin and bifenthrin residues in summer season where their mean levels that exceeded the accepted MRLs of 0.05 ppm to milk samples of goats, camels and breast milk the lowest mean levels of deltamethrin and bifenthrin residues. There was a seasonal variation of the deltamethrin and bifenthrin concentrations in milk samples for each animal species where all the milk samples that were collected from buffaloes, ewes, cows, goats, camels and breast milk had higher mean levels of deltamethrin and bifenthrin residues in summer season than in winter season. Data illustrated revealed that there was a seasonal variation in the mean levels of deltamethrin and bifenthrin residues in human breast milk samples for each district village where all the milk samples that were collected from AL-Sader and AL-Karada districts had highest mean levels values in summer than in winter season.