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March 6, 2018


In safety assessments a large number of non-target effects  has to be analysed statistically. A recent paper published in the Journal of Agricultural and Food Chemistry advocates an approach which leads to over-optimistic conclusions. In a recent Correspondence to this journal the concerns about the misapplication of methodology are explained. See: Safety Assessments and Multiplicity Adjustment: Comments on a Recent Paper, available on the Journal of Agricultural and Food Chemistry website at http://pubs.acs.org/doi/abs/10.1021/acs.jafc.7b03686.

1 March, 2018


On April 16, 2018 G-TwYST organises a conference on general conclusions and recommendations from three scientific projects: G-TwYST, GRACE and GMO90+. Registration for this conference is compulsory and can be done by completing the registration form at the G-TwYST website. Registration is open until April 6, 2018.

More information, including a preliminary programme, is available on the G-TwYST Final Conference webpage.

Researchers from the French GMO90+ project published results of metabolomics analyses of field-grown harvested grains of two GMO maize events -MON810 and NK603- and feeds derived from them and compared them with non-GMO samples. The majority of statistically significant differences in grain composition could be attributed to the combined effect of genotype and environment. In comparison, transgene and glyphosate effects remained limited in grain for the compound families studied. Some but not all compositional changes observed in grain were also detected in grain-based diets formulated for rats.

Bernillon, S., Maucourt, M., Deborde, C. et al. Metabolomics (2018). Characterization of GMO or glyphosate effects on the composition of maize grain and maize-based diet for rat feeding. Metabolomics, March 2018.

22 February 2018

The preliminary programma for the G-TwYST stakeholder consultation workshop on March 28 and 29 in Antwerp is available now and can be downloaded here.


This workshop, which is open for interested stakeholders, will focus on the draft results of a 90-day feeding study with 50% inclusion rate of GM maize NK603, as well as a combined chronic toxicity and carcinogenicity feeding study and the overall draft conclusions. Also included in the scope would be proposed quality criteria for whole-food animal feeding studies, and preliminary conclusions on the scientific value of such studies for GMO risk assessment. An additional agenda item will be insights from an analysis of scientific controversies around animal feeding studies including the GMO case.



Registration for the workshop is compulsory. To prepare for the consultation, documentation will be provided in advance of the stakeholder meeting to registered parties. An electronic registration form is available at the G-TwYST website. Registration is possible untill March 14, 2018.


Non Disclosure Agreement

Since the documentation will contain unpublished information that will be used for publication in a peer reviewed journal at a later stage, we also require all participants to sign a Non Disclosure Agreement (NDA). The NDA can be downloaded from the G-TwYST website. Please fill in your name, affiliation, address and signature and send it to .


Written comments, including from interested parties not able to attend, are welcome, and should be submitted before 6 April. Please, note, due to the tight schedule of the final phase of the project, this will be a firm deadline.


January 22, 2018

The G-TwYST project includes a stakeholder consultation procedure on the results of the feeding studies and their interpretation in terms of quality criteria and their scientific value for GMO risk assessment. Registration for a written consultation in the course of February 2018 and stakeholder workshop on March 28-29, 2018 in Antwerp is open for registration now. More details about the consultation procedure and registration are available at the G-TwYST website

Scientists form the GRACE consortium evaluated gene expression in rat intestinal tissues based on mandatory 90-day rodent feeding studies with 33% GM maize (MON810) or near-isogenic control maize.


No biological response to the GM-diet was observed in male and in female rat tissues. Transcriptome wide analysis of gene expression by RNA-seq confirmed these findings. Nevertheless, gene ontology (GO) analysis clearly associated a set of distinctly regulated transcripts with circadian rhythms. Differential expression of circadian clock genes was confirmed using RT-qPCR and immunoassays for selected factors, thereby indicating physiological effects caused by the time point of sampling.



Prediction of potential unintended effects of GM-food/feed by transcriptome based profiling of intestinal tissue presents a novel approach to complement classical toxicological testing procedures. Including the detection of alterations in signaling pathways in toxicity testing procedures may enhance the confidence in outcomes of toxicological trials. In this study, no significant GM-related changes in intestinal expression profiles were found in rats fed GM-maize MON810. Relevant alterations of selected cellular pathways (apoptosis, DNA damage and repair, UPR) pointing toward intestinal toxicity of the diets were not observed. Transcriptomic profiles did not reveal perturbations of pathways associated with toxicity, underlining the study results revealed by classical OECD endpoints.



The publication is available at the website of Frontiers in Genetics.

In October 2016 ARTE broadcasted "OGM - Mensonges et vérités" (GMOs - Lies and truths) on French and German Television. In this 100 minutes long documentary Frédéric Castaignède sheds light on genetically modified crops, the impact on farmers, biodiversity and human health. We have selected and translated a fragment in which G-TwYST project leader Prof Pablo Steinberg presents the results of the 1-year feeding study with MON810 maize in the GRACE project.


The documentary provides a ‘snapshot’ of the GRACE final Conference which took place on November 9-10 2015 in Potsdam, Germany. We refer to videos on the GRACE Youtube channel  for a full account.


An open access paper describing the statistical approach for equivalence testing in G-TwYST has now been published in Food and Chemical Toxicology. The method was tested on data from the GRACE project, as described in this paper. We will now progress by applying the method in the statistical analyses of the G-TwYST feeding trials, to be reported first in the statistical reports as project deliverables.


  • An equivalence testing method is proposed to assess the safety of regulated products
  • We combine data from a current study with test and control, and historical studies with assumedly safe reference products
  • The method is illustrated with animal feeding studies using genetically modified and reference maize varieties
  • A high statistical power of the equivalence test is the basis for the equivalence criterion
  • Generalized fiducial inference is used to integrate uncertainties from the historical and the current data


van der Voet H, Goedhart PW, Schmidt K (2017). Equivalence testing using existing reference data:  an example with genetically modified and conventional crops in animal feeding studies. Food and Chemical Toxicology, 109: 472-485. https://doi.org/10.1016/j.fct.2017.09.044

15 February 2017


The G-TwSYT team completed a publicly available Interim report with information about the progress that has been made in the first 1.5 years of the project. The report can be downloaded here.

17 January 2017


In 2013 the Dutch Commission on Genetic Modification (COGEM) published a topic report on alarming studies on the safety of GMOs. COGEM pointed out that while repetition of ‘alarming studies’ is sometimes the only way to reject or confirm the results, stakeholder participation during investigation may increase its social robustness.

In a letter sent to the Secretary of State of Infrastucture and Environment on January 11, 2017 COGEM adds some reflections on the value and possible pitfalls of stakeholder participation based on experiences in and results of the GRACE project.

The COGEM letter states that the involvement of stakeholders in this project has been meticulous and transparent and has finally contributed to the validity of the results also from a broader social perspective. However, COGEM also noticed that some stakeholders were too fixated on their own arguments and vision, that reflection and interaction became difficult. According to COGEM this situation significantly hampered the achievement of broadly supported conclusions. On the basis of this experience COGEM also proposed some guidelines for improving such processes.


Read the full letter >

28 November 2016


So far, we have received comments on the proposed scientific quality criteria from the Federal Office of Consumer Protection and Food Safety, Germany (BVL) on October 5th, 2016. The comments can be downloaded here.


The G-TwYST research team responded to the BVL comments on November 28th, 2016. The response can be downloaded here.

11 October 2016


A number of GRACE team members published a new paper published in Archives of Toxicology: Variability of control data and relevance of observed group differences in five oral toxicity studies with genetically modified maize MON810 in rats. They analysed the data of four 90-day feeding trials and a 1-year feeding trial with the genetically modified (GM) maize MON810.


Firstly, the data obtained from the groups having been fed the non–GM maize diets were combined to establish a historical control data set for Wistar Han RCC rats at the animal housing facility (Slovak Medical University, Bratislava, Slovakia). The variability of all parameters is described, and the reference values and ranges have been derived.


Secondly, the consistency of statistically significant differences found in the five studies was analysed. In order to do so, the body weight development, organ weight, haematology and clinical biochemistry data were compared between the studies. Based on the historical control data, equivalence ranges for these parameters were defined, and the values measured in the GM maize–fed groups were compared with these equivalence ranges.


Thirdly, the (statistical) power of these feeding studies with whole food/feed was assessed and detectable toxicologically relevant group differences were derived. Linear mixed models (LMM) were applied, and standardized effect sizes (SES) were calculated in order to compare different parameters as well as to provide an overall picture of group and study differences at a glance. The comparison of the five feeding trials showed a clear study effect in the control data. It also showed inconsistency both in the frequency of statistically significant differences and in the difference values between control and test groups.

On October 12, 2016,

ARTE broadcasted "OGM - Mensonges et vérités" (GMOs - Lies and truths) and "Vorsicht Gentechnik?" (Take care, Genetic Engineering?) on French and German Television. In this 100 minutes long documentary Frédéric Castaignède sheds light on genetically modified crops, the impact on farmers, biodiversity and human health. The goals, design and results of GRACE and G-TwYST are pictured between 1:02:00 - 1:18:15.


The documentary provides only a ‘snapshot’ of the GRACE final Conference which took place on November 9-10 2015 in Potsdam, Germany. We refer to videos on the GRACE Youtube channel  for a full account.


The documentary was discussed in both the Frankfurter Rundschau and Le Monde.


Providing a link to the documentary does not mean that the project team shares the view of the documentary.

September 21st, 2016


Members from the GRACE and G-TwYST research teams recently published “Proposed criteria for the evaluation of the scientific quality of rat and mouse feeding trials with whole food/feed derived from genetically modified plants” in Archives of Toxicology. We cordially invite all stakeholders to contribute to further developing these criteria by sending comments.

As one of its tasks G-TwYST developed and proposes criteria to evaluate the scientific quality of 2-year feeding trials. These criteria are now being published in order to trigger a broader discussion in the scientific community an among GMO risk assessment stakeholders. These quality criteria have been developed based on the experience and standards in other toxicity assessment contexts.


Proposed criteria

In a Letter to the Editor recently published in Archives of Toxicology in June 2016 a number of scientists involved in the GRACE and G-TwYST projects propose 9 scientific criteria:

  1. The design of the feeding trial is based on internationally recognized test guidelines, but adapted for specific needs of whole food/feed studies and non-targeted testing.
  2. An analysis of the plant materials and diets including, among others, macro- and micronutrients, biological and chemical contaminants as well as the identification and quantification of the event, is performed.
  3. The highest level of the plant material that can be incorporated in the animal diets without leading to a nutritional imbalance is tested.
  4. A non-GM line with a comparable genetic background is used as a control.
  5. Specific aspects regarding the choice and housing of the laboratory animals used in the feeding trials are considered.
  6. Appropriate randomization techniques are applied.
  7. A reliable and appropriate sample collection and processing strategy is implemented.
  8. The staff performing the feeding trial and the analysis of the plant materials, diets and animal samples is “blind” with respect to the identity of the diets.
  9. Appropriate statistical methods are applied to evaluate the power of the study and to analyse the obtained results.


Possibility to comment

Comments to this and other recently published GRACE papers (http://link.springer.com/article/10.1007/s00204-016-1798-4, http://link.springer.com/article/10.1007/s00204-014-1374-8) can be sent either:

  • to for publication on the GRACE/G-TwYST website. These comments will be put without further peer-review or editorial polishing on our websites. Depending on the nature of the comment, The GRACE and G-TwYST teams will opt for a response at the project website, if deemed necessary. Offending or discrediting comments will not be accepted for publication,
  • directly to Archives of Toxicology for publication in the "Letters to the Editor" forum* . These comments will be answered by the respective project team in form of a Letter to the Editor, if deemed necessary and according to the publication policy of the journal.


*The "Letter to the Editor" forum is independent of the editors' opinions and contributions are published as soon as technically possible (online publication within 3 weeks), to stimulate a lively debate on cutting-edge topics in toxicology. Authors are free to present their opinions on articles recently published in the journal or those published in other journals that would be of general interest to readers. Letters and guest editorials represent personal opinion and will therefore not be peer-reviewed. Nevertheless, the editorial board ask that the submissions adhere to the following standards:

  • They should be sound, scientifically-founded and of general interest.
  • Critical contributions are welcome; however, ad hominem reasoning must be avoided.
  • They should be no more than 1 printed page long, without an abstract, figures or tables. The journal accepts a maximum of three references, and asks for short affiliations only (institute and country, no address).

Comments can be submitted online at https://www.editorialmanager.com/atox/default.aspx

22 July 2016


The results of GRACE's 1-year feeding trial with a GM maize MON810 variety, its near-isogenic non-GM comparator and an additional conventional maize variety are published in the online edition of Achives of Toxicology. The feeding trials were performed by taking into account the guidance for such studies published by the EFSA Scientific Committee in 2011 and the OECD Test Guideline 452. The results obtained show that the MON810 maize at a level of up to 33 % in the diet did not induce adverse effects in male and female Wistar Han RCC rats after a chronic exposure.


Detailed results are freely available through the CADIMA website.


26 February 2016


The G-TwYST team's responses to written comments provided by stakeholders were published today. Seven stakeholders representing industry, civil society, science and competent authorities filed more than 100 written comments to the G-TwYST draft study plan. Comments and responses were split in 8 categories:

  1. General comments
  2. Cultivation
  3. Feed production and plant analysis
  4. Feed quality
  5. Design of the feeding trials
  6. Data collection
  7. Statistical analysis
  8. Other issues

The full report (PDF) is available here.

18 December 2015


The Conclusions and Recommendations from the GRACE project on animal feeding trials and alternative approaches and on the use of systematic reviews and evidence maps for GMO impact assessment have been published on the GRACE homepage today.

24 July 2015


Hanno Charisius, independent journalist, writes in Krautreporter, a journal for investigative journalism, about genetically modified crops. This time he reports on the first G-TwYST stakeholder workshop that was held shortly before Christmas in Vienna. Charisius interviewed a number of attendees of the workshop. The article is in German and is available at the Krautreporter website.

G-TwYST Workshop1.jpg11 June 2015


On 16-17 December 2014 41 stakeholders from 14 Member States, USA and Norway participated in a workshop in Vienna to discuss G-TwYST's draft study plans. A full report of this Stakeholder Workshop on Planning Stage Issues of 2-Year Animal Feeding Trails with GM Maize is available now. This report includes written comments submitted by a number of stakeholders after the workshop.


More detailed information on how stakeholder comments have been processed and which of them have been adopted will be available soon.

FinalStudyPlan1 copy 1.jpg11 June 2015


Based on the valuable comments and input from various stakeholders -scientists, industry, Competent Authorities and Civil Society Organizations-, taking into accounts constraints in time, lab space (the number of animals we can house at the same time) and funding, the G-TwYST team decided to amend the original study plan with 5 major changes



GRACE scientists now published their first study findings  of a 90-day feeding trial on rats in Archives of Toxicology. The animals were given two different varieties of MON810 GM maize. The control groups were given the non-GM parent variety or one of four conventional maize varieties as part of their diet.



G-TwYST has started a LinkedIn Group where events, publications and other items concerning long term safety evaluation of GM plants in food and feed can be posted and discussed. This group will be moderated by the G-TwYST Stakeholder Consultation and Communication team. Subscription is free to all.



G-TwYST website 1.jpg06-10-2014


Today the G-TwYST website was put online. This website is a major tool in achieving maximum transparency in all research, consultation and communication activities of the project.

G-TwYST logo1 copy 1.jpg18-11-2014


Registration for the G-TwYST Stakeholder Workshop on 2-Year Animal Feeding Studies with GM Maize which will take place on 16 and 17 Dec 2014 in Vienna, Austria, has now been closed. Any questions regarding participation and registration can be directed to the G-TwYST Stakeholder Participation and Communication team by email.

2 October 2014


In a letter to the editor of Archives of Toxicology the coordinators of the EU funded projects GRACE and G-TwYST and the French GMO90+ project explain how these projects are related and how they will co-operate by sharing methodologies, materials and data. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.