Pesticide residues in organic and conventional pasteurized milks

Abstract

The production of organic milk has been gaining attention due to global market demand for ecological products. However, data about this product are still very limited in Brazil. The aim of this study was to investigate the chemical residue contamination of organic and conventional pasteurized milk sold in three brazilian states. Five certified brands of pasteurized organic milk and five conventional milk brands were analyzed. The samples were subjected to the determination of 88 compounds (79 pesticides and 9 veterinary drugs). For the extraction of the analytes we applied the modified QuEChERS method and for the identification and quantification of the residue we used Liquid Chromatography Coupled to Mass Spectrometry in Series (LC-MS/MS). Results showed that both organic and conventional milk presented only pesticides contamination. Of the 56 samples, five (8.9%) contained pesticides residues. Three of them being samples of organic milk; two of which, were positive for clomazone and one for chlorpyrifos. In the conventional milk positive samples, one showed monocrotophos the other presented chlorpyrifos. Although there was a low frequency of positive samples and three of the pesticides detected were below the limit of quantification, there is concern regarding these results since the use of monocrotophos has been prohibited in Brazil, and chlorpyrifos showed concentrations above the maximum limit residue, indicating irregularities. Our results reaffirm the importance of monitoring pesticide programs and chemical contaminants in milk, since milk is one of the most consumed animal food in the country. Moreover, our findings showed that the organic milk production is not in compliance with current legislation.