The number of known mycotoxins, their precursors and metabolites has been steadily increasing over the past years. The European Commission puts special emphasis on the need to monitor the co-occurrence of mycotoxins of various families at levels that allow for a sound risk assessment, taking into account possible additive or synergistic effects. Prior any regulatory action is taken for mycotoxins for which a health concern has been expressed (e.g. enniatins and beauvericin) valid data on their prevalence in food is required. LC-MS-based multi-mycotoxin methods have the potential of streamlining and widening the monitoring work carried out by the official control laboratories. Although many practical advantages have been recognised, such methodologies have not been adopted by all routine laboratories and only a handful of such methods are just on the verge to become standardised. It is of great interest to assess how well laboratories using diverse sample preparation methodologies and determination techniques perform. Therefore, a proficiency test was organised by the European Union Reference Laboratory (EURL) for Mycotoxins for this purpose. The focus was the assessment of the measurement performance of EU Member States laboratories regarding the determination of aflatoxin B1, deoxynivalenol, zearalenone, fumonisins B1 & B2,T-2 & HT-2 toxins, enniatins B, B1, A, A1 and beauvericin in two test materials (corn and oat) using single- or multi-mycotoxin methodologies. Fifty-three laboratories, among them thirty-six National Reference Laboratories for mycotoxins in food and feed from the 28 EU Member States and 17 Official Control Laboratories, participated in the PT. For the regulated mycotoxins, 83.7 % of the results were rated with satisfactory z-scores. The performance of the laboratories was best for AFB1 (94 %), followed by DON (91 %), ZON (89 %), FB1 (87 %), FB2 (78 %), T-2 (75 %) and HT-2 (64 %). Additionally, 11 laboratories submitted results for all enniatins and beauvericin. LC-MS/MS is gaining much preference as it allowed for the determination of all the proposed analytes (12) in the test materials. Nevertheless, the results provided by multi-mycotoxin methodologies did not differ statistically from those produced by singleanalyte procedures. Many participants uphold the will to implement a methodology to analyse enniatins and beauvericin in the near future, while other laboratories' methods require improvements in the extraction efficiency and sensitivity.
