Science in Society Archive

GM food safe?

Recent incidents and scientific findings cast grave doubts over the safety of GM food and feed. We shall be circulating a selection of the following reports.

  1. Cows Ate GM Maize & Died
  2. Transgenic DNA and Bt Toxin Survive Digestion
  3. Bt Toxin Binds to Mouse Intestine
  4. Syngenta’s Spanish GM Trojan Horse
  5. Liver of Mice Fed GM Soya Works Overtime
  6. Animals Avoid GM, for Good Reasons

Cows Ate GM Maize & Died

GM maize and dead cows

Twelve diary cows died after being fed GM maize and silage. This happened on a farm in Woelfersheim in the state of Hesse, Germany.

According to the report by Greenpeace Germany, "common errors in feeding and infections had by and large been ruled out as the cause of death", and the farmer involved, Gottfried Glöckner, a supporter of GM crops, now suspects that Syngenta's GM maize Bt 176 is to be blamed.

Bt 176 contains multiple complex traits, including insect resistance - conferred by a toxin from the soil bacterium Bacillus thuringiensis - and tolerance to the herbicide glufosinate. It was produced initially by the company Ciba-Giegy in 1994, and acquired subsequently by biotech giant Syngenta.

Glöckner has been growing Bt 176 increasingly in his fields since 1997, and in 2000 and 2001, switched over entirely to GM maize. Shortly thereafter, five of his cows died within four months in 2001, and another seven in 2002. The rate of milk production decreased in some of the remaining cows and others had to be slaughtered because of unknown illnesses.

Syngenta obtained a European license to market GM maize Bt 176 in 1997 and is currently growing 20 000 hectares commercially in Spain. The US license for the crop expired in 2001 and was not renewed. Austria, Luxembourg and Italy have banned its cultivation.

In Germany, safety concerns were raised in early 2000, causing the German Robert Koch Institute to announce " the suspension of the authorisation for putting the maize line 00256-176 and its derivatives on the market, unless it is cultivation for research or trial purposes."

In November 2001, Glöckner reported the demise of his herd to Robert Koch Institute in Hesse, who were regulating the GM trials on behalf of Syngenta Corporation. In 2002, he was awarded compensation of 40 000 euros by Syngenta for five dead cows, decreased milk yields and vets bills. In February 2002 he decided to stop feeding his cattle GM maize altogether, but by October 2002 a further seven cows had died. The distraught farmer, who by this time was over 100 000 euros out of pocket called upon Syngenta and the Robert Koch Institute to conduct a proper investigation.

Cause of death unknown

The Robert Koch Institute impounded neither the dead cows nor the GM feed from the farm and carried out no comprehensive tests on the soil from the farm or any dung samples from the cows in question. What investigations they made on the GM maize feed from the farm ended in December 2002 with inconclusive evidence as to what caused the death of the cows. This was backed up by the local district council in Giessen who issued a statement in August 2003 that "the cause of the incidents referred to could not be determined."

But only one of the five dead cows in 2001 was examined at the pathology institute at Giessen. Additional tissue samples were sent to the University of Göttingen, "where they vanished in unexplained circumstances", according to Greenpeace's report.

The regulatory maze surrounding another Syngenta Bt maize

Further concerns are being raised over another Syngenta GM maize, Bt 11, destined for human consumption in 2004, if approved by the European Council of Ministers, because it contains the same protein that according to Syngenta, was in the Bt176 maize fed to the German cows.

Despite the UK Food Standards Agency's recommendations to the Standing Committee of the Foodchain and Animal Health in December 2003 that GM maize Bt 11 is safe for human consumption, the five-year old de-facto moratorium remains in place in Europe, thanks to other member-countries who voted against approving Bt 11.

However, the approval process for Bt 11 as food is being processed under the Novel Food Regulation, which is not as strict as the new GM Food and Feed Regulation. The new legislation provides for approval under the old rules, if the application received a final scientific assessment before the new rules apply, as in the case of Bt 11. Nevertheless, Bt 11, if approved, will be subject to the new labelling and traceability legislation. Indeed Bt 11 sweet corn will fail to meet new EU food safety criteria, which clearly state that short term and long term effects of food safety on future generations must be taken into account, according to Article 14 (4) of EC Regulation 178/2002 (the general legislation on food law and food safety, not the Novel Food Regulation).

"Poison protein" in Bt maize?

A chief suspect for the death of the cows in Hesse is the Bt protein contained in Bt 176, which Syngenta says is Cry1Ab, the same as in Bt 11.

Studies conducted in Japan in 2003 clearly showed that undigested Bt toxin Cry1Ab is present in calf stomach, intestine and dung after being fed Bt 11 maize; and these results have been replicated in further experiments in pigs. Both transgenic DNA and toxin protein fragments were detected in pigs fed Bt 11 maize (see "Transgenic DNA and Bt toxin survive digestion", this series). Both normal and transgenic DNA break down much more slowly in vivo than Syngenta previously assumed.

The Austrian Government is putting up a valiant fight to resist the introduction of GM products into the food chain, and has issued a report questioning the validity of Syngenta's evaluation of GM maize Bt 11 for human consumption. Their report concludes that Syngenta has based the safety of Bt 11 on assumptions rather than scientific evidence.

To date there are no scientific studies on the long-term effects of eating Bt 11 and no toxicological testing on the whole GM maize plant. Tests for allergic reactions to Bt 11 were insufficient and relied on theoretical argument rather than scientific evidence.

Farmer Glöckner now fears that his pastures are contaminated with the Bt 176 toxin by decomposing dung from his cows leaching into the soil where it can bind with the minerals in the clay, and remain harmful to many organisms. He has called upon Greenpeace to lobby Robert Koch Institute and Syngenta to re-open the investigation into the death of his cows.

Bt 176 worse than it appears

But worse is in store. Molecular analysis recently carried out suggests that the toxin in Bt 176 may not be Cry1Ab, but Cry1Ac, and that Bt 11, which is engineered with Cry1Ab, may be contaminated with Bt 176, so it will have Cry1Ac and well as CrylAb (see "Unstable transgenic lines illegal", this issue).

Molecular analysis has recently been carried out both by French and Belgian government scientists.

Their results revealed that the Bt gene in Bt 176 showed 94% similarity with a synthetic construct of crylAc gene, but only 65% homology with the native cry1Ab gene of Bacillus thuringiensis subsp. kurstaki strain HD1, from which it was supposed to have been derived. This suggests that the company has misreported or misidentified the transgene present. This is extremely serious.

Syngenta is maintaining that Bt toxin can only deleteriously affect certain insect larvae, thus bestowing insect resistance to their GM maize. But many Bt toxinx are potential allergens and immunogens. A study in 2000 found that the Cry1Ac protein is a potent immunogen and does bind to the intestinal wall of mice, causing significant changes in the gut cells. Bt 176 expresses very high levels of the toxin (see "Bt toxin binds to mouse intestine", this series).

Many Bt transgenes are synthetic, including the one in Bt 176. They are hybrids of multiple toxins. That means Bt transgenes not only risk killing more species of insects than intended, but may also contain previously unknown toxicities for other animals and human beings (see "Regulatory sham on Bt crops", this issue).

Bt 176 is also the worst GM crop in terms of stability and uniformity. There are multiple transgenic inserts, the number of inserts depending on the source. This makes it very difficult to pin down the precise problems with the GM crop. There may be more than one problem with Bt 176 from different sources, or due to continuing instabilities in one seed lot, depending on where the unstable inserts have landed in the plant genome.

The transgenic inserts of Bt 176 have undergone rampant rearrangements - since characterised by the company - many involving the well-known recombination (fragmentation) hotspot, the cauliflower mosaic virus (CaMV) 35S promoter.

The CaMV 35S promoter, as I-SIS has repeatedly warned, is a very powerful promoter active in all species including humans. It leads to over-expression of genes downstream from it. Over-expressing of certain oncogenes are involved in cancer.

Transgenic DNA containing the CaMV 35S promoter is an invasive DNA, capable of inserting into all genomes, including those of animal cells, and hence carries the risk of triggering cancer.

The molecular analysis of Bt 11 reveals that it may be contaminated with Bt 176, and we have warned various European governments as well as the European Food Safety Authority's Scientific Panel on GMOs against its market approval.

Public enquiry needed

Greenpeace is demanding an immediate ban on Bt 176 and a full scientific investigation into the death of the cows at Woelfersheim in Hesse.

It is clear that farmers who support GM run the risk of being under-compensated for their livestock and harvests should anything go wrong. It appears that environmental risks and hazards on the farm even during field trials are not something that GM companies accept full liability for.

Syngenta has been growing Bt 176 in Spain at low levels since 1997, and is relying on that as a showcase of how GM and non-GM crops can co-exist in Europe (see "Syngenta's Spanish GM trojan horse", this series). It has been kept at 4-5% of the total maize acreage, and all of it has been mixed with conventional maize that's not specifically labelled GM-free, which is mostly fed to cattle. The Woelfersheim experience shows that increasing the level of GM feed may end in disaster. Furthermore, contamination of Spain's organic maize has already been found, which can destroy the growing market for this commodity.

The cows at Woelfersheim are by no means an isolated case indicating that GM feed is far from safe. It must be seen in the light of already existing evidence in the scientific literature that GM feed had adverse effects on laboratory rats and mice (see "Liver of mice fed GM soya works overtime", this series), largely corroborating the findings of the much maligned senior UK scientist Arpad Pusztai and his collaborators. To that must be added a host of anecdotal reports by farmers and others that animals avoid GM feed, if given the choice, and if force-fed GM, fail to thrive (see "Animals avoid GM food, for good reasons", this series).

Apart from a full scientific investigation into the safety of GM food and feed, we demand a public enquiry into the serious abuse of scientific evidence by our government's scientific advisors, which have allowed GM crops to be grown commercially (in some countries) and GM food to go on sale in our markets.

Article first published 29/01/04


  1. Henning Strodthoff and Christoph Then. Is GM maize responsible for deaths of cows in Hesse? Greenpeace Report, Greenpeace e.V. 22745 Hamburg. 12/2003.
  2. Chowdury EH, Shimada N, Murata H. et al. Detection of CrylAb protein in gastrointestinal contents but not visceral organs of genetically modified Bt11-fed calves. Vet Human Toxicol 2003, 34, 72-5.
  3. Cummins J. Regulatory sham on Bt crops, I-SIS report, 1 December 2003
  4. Friends of the Earth Press release: GM sweet corn may get green light in Europe December 5th 2003.
  5. Ho MW. Transgenic lines proven unstable, I-SIS report, 23 October 2003
  6. Ho MW. Unstable transgenic lines illegal, I-SIS report, 3 December 2003

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