Determination of Aflatoxins M1, M2, B1, B2, G1, and G2 and Ochratoxin A in UHT and Powdered Milk by Modified QuEChERS Method and Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry

Abstract

A suitable method for routine analysis of aflatoxins M1, M2, B1, B2, G1, and G2 and ochratoxin A in milk by modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) sample treatment method and ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was developed and validated. Satisfactory recoveries ranging from 72 to 121 %, with relative standard deviation lower than 17 % were obtained for the target compounds. The limits of quantification for aflatoxin M1 were 0.017 and 0.25 μg kg−1 for ultra-high-temperature (UHT) milk and powdered milk, respectively. The validated method was successfully applied to the determination of mycotoxins in milk samples from local supermarkets in Rio de Janeiro, Brazil. Ochratoxin A and aflatoxins B1, B2, G1, and G2 were not detected in the analyzed samples. Aflatoxin M1 was found in 53 (74 %) of the powdered milk samples analyzed at concentration levels ranging from 0.08 to 1.19 μg kg−1. In UHT milk, aflatoxin M1 was found in 11 (69 %) of the analyzed samples at concentration levels ranging from 0.005 to 0.042 μg kg−1. The concentrations found for aflatoxin M1 in milk samples were lower than the maximum permitted level according to Brazilian regulation. Aflatoxin M2 was detected in 17 (24 %) of the powdered milk samples (>0.08 μg kg−1) and in 3 (18 %) of the UHT milk samples (>0.009 μg kg−1). The present study is the first report showing the incidence of aflatoxin M2 in milk in Brazil.