d for a specific GM event as mass fraction (g/kg). IRMM verifies the purity of the two raw materials used for production with respect to the presence of the particular GM event that is certified. The CRMs are not certified for the absence or adventitious presence of other (contaminating) GM events.
The GMO CRMs can be used as positive controls for the certified GM event for instance to validate a screening method. However, the GMO CRMs should not be used as negative controls for any other GM event than the one certified. Also the blank material of each series is certified to contain less than the certified amount for a given GM event and the absence of this event can not be guaranteed.
For additional information IRMM has conducted a study to verify the GM composition of 33 raw materials used for the production of the GMO CRMs. Those raw materials have been tested by quantitative PCR for the presence/absence of 39 single GM targets known for 7 plant species. It needs to be noted that adventitious presence of other GM events is likely to be heterogeneously distributed over the batch of raw material and needs to be taken into account when comparing the results obtained so far. These results are summarised in this document
and provide an indication about possible adventitious presence.