Science in Society Archive

Approval of Bt11 Maize Endangers Humans and Livestock

Dr. Mae-Wan Ho explains why the European Commission's decision to approve Syngenta's GM maize is illegal and criminal based on existing scientific evidence.

The European Commission ended 6 years of de facto moratorium on GM authorization by approving Syngenta's Bt11 sweet corn for food use in Europe on 19 May 2004 (see Box 1). That, despite the fact that voting by experts last December in the EU's Standing Committee on Food Chain and Animal Health was an even 6-6 country split with three abstentions. Finland, Sweden, Ireland, UK, Netherlands, and Spain voted in favour; Greece, Denmark, France, Austria, Luxembourg, Portugal voted against; and Belgium, Italy and Germany abstained. The same split happened at the Council of Ministers on 27 April, but this time Italy voted in favour, while Spain abstained.

Box 1

History of Bt11 maize approval
An official dossier was submitted to the European Union in 1996 and approved under the old Directive for deliberate release into the environment (90/220/EEC) for import and processing since 22 April 1998.

Two notifications for cultivation were submitted in 1996 (to France) and 1998 (to Spain). The Scientific Committee on Plants (SCP) gave a favourable opinion for these two notifications, although Syngenta has since withdrawn the latter. The 1996 notification was updated in 1998 and 2002, and finally in 2003, additional information was supplied as required by the new Directive for deliberate release 2001/18/EC. The French competent authority concluded that, in this respect, Bt11 "does not present a greater risk to human health or the environment than any other variety of maize". Approval is still pending.

In February 1999, a request was submitted under Regulation (EC) 258/97 for placing sweetcorn from GM maize line Bt11 on the market for food use (fresh or processed). On 17 April 2002, the Scientific Committee on Food gave its opinion that Bt11 sweetcorn is as safe for human food use as its conventional counterparts.

The vote in the Standing Committee on Food Chain and Animal Health, December 2003, resulted in an even 6-6 country split with three abstentions. A similar split ratio in the Council of Ministers 27 April 2004 led to a stalemate. The European Commission broke the deadlock by deciding in favour of approval.

Belgium's scientists first expressed concerns over the safety of Bt11 when they subjected Bt11 to molecular characterisation, as required by Europe's current Directive for deliberate release. These concerns were strongly reinforced by French and Austrian scientists.

According to an article in Le Monde published 24 April, two scientific evaluation committees, in France and Belgium, have refused to give their approval for food use of Bt11 sweetcorn. On 22 April, AFSSA (French Agency of Food Sanitary Security) opposed the authorization of Bt11 sweetcorn for the third time, after having refused it twice before, in 2000 and 2003, on grounds that the scientific results were insufficient.

In a brief note published 22 April, implicitly replying to the European Commission statement on 5 February that "the results supplied by Syngenta…are in accordance with the criteria and rules defined in the recommendation 618/97/EC", AFSSA said it "maintains its previous opinion which concluded that to rigorously evaluate the impact of regular consumption of a maize carrying the Bt11 event, toxicity/tolerance experiments on rats must be carried out… Such toxicity/tolerance experiments are not required by the actual regulation, though they might be advisable … because the sweetcorn is the only one to be consumed by humans."

The Belgian Council for Biosafety had already refused to give its approval for the Bt11 maize on 1 April 2004.

Dr. Mae-Wan Ho and Prof. Joe Cummins from I-SIS and the ISP (Independent Science Panel) have objected strongly to the approval of a range of GM crops; and called for the withdrawal of approval already granted, most probably for the same reasons as the Belgian and French scientists: the GM inserts in all these crops were found to have rearranged since characterised by the company. That is a sign that the GM varieties are unstable, and hence contrary to requirement laid down by the current European Directive for deliberate release (2001/18/EC). Furthermore, there is evidence that some GM varieties are non-uniform, also contrary to the requirement of the current European Directive. Thus, the European Commission is contravening its own laws in approving Bt11.

Ho and Cummins have referred to this as both "illegal and criminal"; criminal because transgenic instability is a key safety issue, and there is already evidence suggesting that GM food and feed are far from safe, even though very few feeding trials have been carried out, and toxicological tests on natural Bt toxins are thoroughly inadequate to predict the much altered GM toxins incorporated into GM crops (see "GM food and feed not fit for "man or beast"). In short, approval of Bt11 sweetcorn is endangering livestock and human beings.

Belgian scientists characterised the GM insert in Bt11 and reported, that "rearrangements, truncations and unexpected insertions" have taken place (see Box 2), that further inserts may be present, that the insert has landed in what turns out to be suspected "megatransposons" involved in exchanging segments between chromosomes, and that further it is contaminated with Bt176, a GM variety that has just been withdrawn from cultivation in Spain.

This is a damning indictment of the European Commission's decision.

Box 2

Molecular characterisations by Belgian Council for Biosafety

The plasmid used for making Bt11 contains a synthetic truncated crylAb sequence isolated from soil bacterium Bacillus thuringiensis kurstaki HDI, and a synthetic pat gene, isolated from Streptomyces viridochromogenes, another soil bacterium. Both coding sequences are driven by a 35S promoter sequence derived from cauliflower mosaic virus (CaMV) 35S promoter and the 3' untranslated region of the nopaline synthase (nos) gene from a third soil bacterium Agrobacterium tumefaciens. In addition, the promoter sequences of the pat and cry1Ab gene were combined with respectively intron Int II and Int VI derived from maize alcohol dehydrogenase adh1S gene to enhance expression.

The company's dossier claimed a single copy insert with the structure:

p35S-Int II-pat-tnos-p35S-Int VI-crylAb-tnos

But analyses by the Belgian Council for Biosafety revealed "primary insert with rearrangements, truncations and unexpected insertions", and "it is not certain if only one copy of the insert is present". Furthermore, 1.1kbp of the plasmid sequence was present at the 5' end of the insert, followed by plant DNA with homology to 180bp knob specific repeat sequence. At the 3' end, the plasmid sequence is again present followed by plant DNA with homology to the 180dp knob specific repeat sequence.

Although not discussed by the study, knob specific sequences are present in many maize chromosomes, and are suspected to be "megatransposons" involved in exchanges of whole chromosome segments in the genome. If so, the insert has landed in a megatransposon, and has the potential to spread uncontrollably over the entire genome.

Another worrying finding is that PCR primers for Bt176 amplify sequences from both Bt176 and Bt11, suggesting that Bt11 may have been contaminated by Bt176. Bt176 has been linked to the death of 12 dairy cows in Hesse Germany between 2001 and 2002; and approval for growing Bt 176 has just been withdrawn in Spain on grounds that it has an antibiotic resistance marker gene that the European Food Safety Authority recommends should not be present in GM crops placed on the market.

The Belgian Council for Biosafety concluded: "There are still uncertainties concerning the molecular data provided in the dossier C/F/96/05-10; rearrangements in the insert and truncations of parts of the insert might have occurred. Therefore, the sequence of the insert should be further checked together with the number of inserts."

Article first published 24/05/04


  1. Ho MW and Cummins J. GM food and feed not fit for "man or beast". I-SIS Report, 7 May 2004
  2. "European Union lifts GM food ban" BBC News World Edition 19 May 2004.
    Report of the molecular characterisation of the genetic map of event Bt11
    (June 2003)
  3. Ananiev EV, Phillips RL and Rines HW. A knob-associated tandem repeat in maize capable of forming fold-back DNA segments: are chromosome knobs megatransposons? Proc Natl Acad Sci USA 1998, 95, 10785-90.
  4. "AFSSA Does not Approve a GMO Which Brussels Wants to Authorise"
    Herve Kempf. Le Monde (France). 24 April 2004.

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