The European Union Reference Laboratory for Genetically Modified Food and Feed (EURL GMFF) organised a comparative test (CT) for National Reference Laboratories (NRLs) to support the official controls on food and feed in line with Regulation (EC) No 882/2004. Other official control laboratories were allowed to participate on a voluntary basis.
Two test items were distributed: a soya milk powder spiked with soybean GM event DAS-444Ø6-6 (Test Item 1, T1) and a maize flour containing maize event VCO-Ø1981-5 (Test Item 2, T2). Participants were required to screen T1 and T2 for the presence of three GM soybean events and three GM maize events, respectively, and to quantify those events identified. The results had to be reported in GM mass/mass %.
Eighty-three participants from 38 countries participated to this CT round, including 55 NRLs, of which 33 are designated in line with Regulation (EC) No 882/2004 (NRL/882) and 22 are nominated in Regulation (EU) No 120/2014 to support the EURL GMFF on method validation (NRL/120).
The qualitative results, i.e. the correct identification of the GM events, were evaluated and scored as correct or incorrect. The assigned value for the 44406 soybean mass fraction in the soy milk material was derived as the robust mean of the data provided by NRLs, while for VCO-1981, the certified value was set as the assigned value. z and ζ scores were calculated to assess laboratory performance.
The results reported indicate that all NRLs identified the correct GM events in both test items and most of the quantitative results were satisfactorily. Five laboratories, including one NRL/882, obtained an unsatisfactory z score for the quantification of 44406 soybean in soya milk powder. All z scores for VCO-1981 maize content in maize flour were satisfactory. A total of 19 and 7 unsatisfactory ζ scores were obtained for events 44406 and VCO-1981, respectively. At least for a number of laboratories this was the due to an underestimation or overestimation of the measurement uncertainty or a failure to report it.
A root-cause analysis will be requested from NRLs having reported unsatisfactory results in this CT round and will be followed-up.