Evaluation of enniatins A, A1, B, B1 and beauvericin in Portuguese cereal-based foods.

Sixty-one samples of Portuguese cereal-based foods were analysed for the occurrence of emerging mycotoxins called enniatins (A, A1, B and B1) and beauvericin. Samples were extracted with a mixture of acetonitrile/water (85/15, v/v) using an Ultra-Turrax homogeniser, and mycotoxins were detected with liquid chromatography coupled to a mass spectrometer. This method was validated and adequate values of recovery (70-103%) and relative standard deviation (<15%) were obtained. Signal suppression/enhancement was studied and matrix-matched calibration used to minimise this effect, but no additional clean-up step was necessary. The mass spectrometer was operated in selected reaction monitoring (SRM) mode and with selected transitions for each compound to quantify and to qualify them. Fifty-nine per cent of samples were contaminated. The percentages of enniatins were 53%, 49%, 44% and 16% for A1, B, B1, and A, respectively, and for beauvericin it was 1.6%. For the total samples, the mean contamination was 30, 24, 15, 2.1 and 0.1 ng g⁻¹ for enniatins A1, B, B1 and A, and beauvericin, respectively. The wheat-based samples showed higher levels and greater prevalence than any other cereals monitored. These results were used to estimate the daily intake of ENs from wheat-based cereal by the Portuguese population. At the same time, the usefulness of this method in the analysis of other important mycotoxins (aflatoxin B₁, ochratoxin A, deoxynivalenol, T-2 toxin, fumonisin B₁ and zearalenone) was evaluated.