Milk contamination by organophosphorus and carbamate residues present in water and animal feedstuff

In Brazil, the legal requirements regarding the quality control of raw milk are restricted to microbiological, physico-chemical and antimicrobial research. However, pesticides can be detected in milk after exposure of dairy cows to these agents. The present study aimed to search for the presence of organophosphorus (OPP) and carbamate (CB) pesticides in samples of water and feedstuff supplied to dairy cattle and also in the milk produced by these animals. All samples were analyzed by gas chromatography with nitrogen phosphorus detector (GC-NPD). Residues of OPP were detected in 5 (16.67%) out of 30 raw milk samples, all bellow maximum residues limits (MRL). CB residues were not detected in milk. Pesticide residues included in the research were not detected in water samples. Within the 98 samples of the diet’s components of the animals analyzed, OPP were detected in 28 (28.57%) samples, CB in 18 (18.37%), while both pesticides were detected in 1 sample (1.02%). In 3 dairy farms it could be noted milk contamination by the same active ingredient of OPP that were detected in animal feed. High levels of animal feed contamination detected in this study raise concerns to the absent control in animal feed production and may represent an important source of milk contamination by these compounds.