Naturally occurring aflatoxin M1 in raw bulk milk from farm cooling tanks in Argentina

The aim was to carry out a survey of aflatoxin M1 (AFM1) in raw whole milk from bulk tanks. The sample collection was performed in farms located in one the most important milk-production zones in the centre of Argentina. A total of 94 samples of milk from 47 dairy farms were analysed. AFM1 analysis involved the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) with prior purification of the extracts using immunoaffinity columns. AFM1 incidence in raw milk was high as 63.8% and levels were between not detected to 0.07 mu g l-1. Several contaminated samples (39%) were over the European Commission limit for infant milk (0.025 mu g l-1), although none of samples were above Argentine legislation. Estimates of AFM1 intake were assessed for different age populations. The average AFM1 estimated daily intakes were 1.6, 0.5, 0.17 ng kg-1 body weight day-1 for 4-year-old babies, young children, and adults, respectively. All tested farms used pastures and silages at similar composition. Even though some farms (13) employed high-risk supplementary feeds, such as peanut pod and/or cotton seed, no statistically significant differences were observed between groups. Information from AFM1 levels in milk in Argentina is limited. A systematic AFM1 monitoring programme must be performed by means of accurate and reliable analytical techniques as a strategy for protecting milk consumers.