We would like to express some comments on two publications related to genetic stability of MON810 published in this Journal (Aguilera et al. 2008, 2009). In the first publication (Aguilera et al. 2008), it is reported that “Twenty-four out of the 26 analyzed varieties met the expected stability features. One variety gave negative results in all assays, and one variety contained the necessary genetic elements for expressing CryIA(b) protein although giving negative results for the long PCR product. To our knowledge, this study is the first post-marketing stability analysis performed on GM commercial seed varieties”. In the second publication (Aguilera et al. 2009), it is also reported that “Global results assessed and guaranteed the genetic intactness of the transgenic integration per haploid genome for 24 out of the 26 commercial varieties studied, which showed no significant differences between 2(-Delta Delta CT) values respect to the calibrator value. Conversely, two varieties showed no intact transgenic insert in their genomes. This validated analytical method was suitable for MON 810 detection and quantification purposes.”

Upon our request, the authors informed us that the Spanish Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (www.inia.es) provided the JRC with 26 MON810 maize varieties, without however providing details of the respective batch numbers. We can confirm that the two deviating results are not related to intact transgenic insertion as reported by the authors. After investigation, the conclusions were that the two varieties (entry 2 and entry 5) were in fact not MON810 maize. Variety CGS4540 (entry 5) was a Bt176 maize hybrid, and we do not understand why the seed were provided as MON810. With regard to entry 2 (designated as Aristis Bt), we requested the Spanish Ministry to send a sample of Aristis Bt to its official Spanish laboratory CSIC for testing. The results were positive for MON810, as expected. However, the material that was provided to the JRC was most likely Aristis, the conventional counterpart of Aristis Bt (MON810). The authors were not able to provide a correct chain of custody for the samples used in their analyses allowing to resolve the origin of these deviating results.

The industry has invested significantly to provide quality products to the marketplace, which includes selling compliant and stable products. Traits are tested for presence and stability for many generations prior to release to the market place. We are of the opinion that there is no scientific evidence for MON810 instability.