Science in Society Archive

Cover-up over GM DNA in milk

Syngenta's GM maize linked to dead cows linked to GM DNA in milk and scientist involved in what appears to be a major cover-up on behalf of big dairy producer. Dr. Mae-Wan Ho

Campaign against GM animal feed

Greenpeace Germany began campaigning against GM animal feed in March 2005. Their main target is Mueller, one of Germany’s biggest dairy producers and also number one in Britain in yogurt sales. Greenpeace exposed Mueller’s use of GM soya to feed their dairy cows, which Mueller does not deny. But the company tried to stop Greenpeace’s campaign, and especially the use of the term “GE-milk” through the law court. The company claims it is scientifically demonstrated that no GM DNA could transfer into the milk, and produced a statement signed by six German scientists with the title, No transfer of genetically modified components from animal feed to milk. Greenpeace contacted me for help in producing a counter-statement. The counter-statement, Transfer of genetically modified DNA from animal feed to milk cannot be ruled out, and is a cause for concern, was eventually signed by Dr. Mae-Wan Ho, Dr. Arpad Pusztai, Dr. Susan Bardocz, Prof. Joe Cummins and Prof. Peter Saunders on behalf of the Independent Science Panel (

On 5 July 2005, the court of Cologne decided in favour of Greenpeace, refusing to grant Mueller an injunction. The court stated that as since Mueller is using genetically modified plants for animal feed, the products are connected with genetic engineering and therefore the term GE-milk is perfectly justified. Mueller claimed that GM-DNA fragments are not present in milk, but Greenpeace countered by saying it was not yet scientifically decided.
“The report of the ISP was vital to support our arguments!” says Greenpeace activist Ulricke Brendel. Unfortunately, that’s not the end of the matter. Mueller has filed a new case against Greenpeace, going for the highest court in Germany, to prevent Greenpeace from using the term, “GE-milk”, and also asking for €500 000 in damage compensation.

“For the next 3 to 5 years, that is as long it might take, we will keep arguing the case,” Ulricke added.
So what’s the current status of the evidence? Is there or is there not GM-DNA in milk?

Unpublished evidence kept under lock and key

There are several published studies on the transfer of genetically modified (GM) DNA from animal feed to milk, all of them methodologically flawed; nevertheless they indicate that it is possible for DNA from GM feed to transfer to milk. And this is confirmed in an unpublished study from the Weihenstephen Institute of Physiology and the Technical University of Munich.
Astonishingly, the lead author of the unpublished study from Weihenstephen Institute, which found positive evidence of GM DNA in milk - Prof. Rolf Espanier - is also the lead author of the statement on behalf of the company Mueller, claiming there is no transfer of genetically modified components from animal feed to milk.
Furthermore, that unpublished study was done on milk collected from dairy cows in a farm in Hesse Germany where, between 2000 and 2001, 12 cows died after eating Syngenta’s GM maize Bt 176 (Cow ate GM maize and died). No proper autopsies were carried out; while this crucial study dated 20 October 2000 remained under lock and key for more than three years before it was leaked to Greenpeace [1].

A handful of studies

The first study in the laboratories of Einspanier, Jahreis and Falchowsky [2] detected “faint signals” of the abundant plant chloroplast DNA in milk, but not the GM DNA. However, the limit of detection, i.e., the sensitivity of the detection method, was not reported. This would involve spiking the milk with increasing amounts of DNA from the GM feed until a positive signal is obtained.

A second study in another laboratory [3] failed to detect any GM DNA in milk. But the limit of detection was 30 ng GM soya DNA added to the milk, which is equivalent to 16 200 copies of the GM soya genome, or the same number of copies of the GM DNA insert, assuming there is a single insert in the genome. This is unacceptably high compared to the standard limit of detection of 10 copies or less; and it indicates that the method used was far from sensitive enough. A follow-up investigation [4] did detect plant chloroplast DNA, but not the GM DNA in milk. Chloroplast DNA outnumbers GM DNA by up to 50 000 copies to 1. The limit of detection in this study was still unacceptably high; it required the presence of 2 700 copies of the GM soya genome and 602 copies of the GM maize genome in 330 microlitres (about three drops) of milk. Another limitation of these studies was that the feeding trials [2, 3] were of short duration, lasting only several weeks.

The fourth published study [5] established the limit of detection as between 5 and 10 genomic copies of the GM DNA, but not by adding the GM plant DNA to milk, which is necessary, as inhibitors of the detection reaction are often present. Nevertheless these researchers found plant chloroplast DNA in high proportions, possibly all, of the milk samples from dairy cows: 86% positives while the rest were ‘indeterminate’. They claim to have found “no statistically significant” presence of GM DNA in milk. No information on the length of the feeding trial(s) was given.

Positive evidence for the transfer of GM DNA into milk was presented in the unpublished report [6] from Weihenstephen Institute referred to earlier. Two milk samples were analysed, and in both of them, positive signals for GM DNA were found.
These studies used a wider range of probes for different plant DNA:
Ubiquitin and zein (about 20 and 40 copies respectively in the maize genome); EPSPS, single copy gene specific for GM soya; rubisco gene in chloroplast genome (about 10 000 to 50 000 copies); and Bt (CrylA), single copy gene specific for GM maize
The first milk sample was probed for ubiquitin, rubisco and Bt; the second sample was probed for all five gene-sequences. The milk was separated by centrifugation into the cell fraction at the bottom, fat at the top and solution in between.
The first sample showed that ubiquitin DNA was present in all the cell and fat fractions, but not in solution. The chloroplast rubisco DNA could be detected in all cell and fat fractions. The Bt DNA was detected in all the fractions that were positive for chloroplast DNA, with a rather similar pattern.

The summary stated, “It was not difficult to prove the existence of general plant DNA (chloroplasts) in this milk. In addition, positive signals for the presence of Bt-maize fragments were obtained. This data indicates the presence of small quantities of Bt-maize gene fragments in the tank milk.” (emphasis added)

However, the authors made the unjustified assumptions that the Bt-maize gene fragments came from other sources than the animals producing the milk and that they have no biological significance, “The presence of Bt-maize material in the milk supplied is not necessary due to endogenous factors (i.e., via the animal itself). Thus, the presence of many different kinds of feed in the tank milk is likely and almost inevitable in spite of stringent hygienic conditions. The PCR analysis will also detect dust or aerosols from neighbouring feeding areas. On the basis of the biological knowledge available to us, the presence of the very small quantity of Bt-maize DNA identified has only analytical but no biological relevance whatsoever.”
In the second sample, not only was the Bt gene fragment from GM maize detected in milk, the EPSPS gene fragment from GM soya - contained in the animal feed - was also detected. The summary stated, “In this milk, it was possible to identify sporadic traces of general plant DNA (chloroplasts) as well as zein and EPSPS gene fragments. As well as this, slightly positive signals indicating the presence of Bt-maize fragments were also contained. This data indicates minor contamination with Bt-maize gene fragments in the tank milk.”

Again, this “contamination” was deemed to have “no biological relevance whatsoever.”

GM DNA in milk is a cause for concern

The presence of GM DNA in milk is a cause for concern, regardless of whether it originated in the animal producing the milk, or by contamination from “dust or aerosols” containing GM feed, which according to the authors of the unpublished report [6] “is likely and almost inevitable in spite of stringent hygienic conditions.”

GM DNA is unlike natural DNA in many respects [7]. It contains new combinations of genetic material that have never existed in billions of years of evolution, including genes sequences that are completely synthesized in the laboratory, differing significantly from their natural counterparts. GM DNA is designed with recombination sequences in order to break and insert into genomes; it also contains other changes to overcome genetic differences between species. GM DNA inserting into genomes causes mutational and other genome rearrangements including cancer. In addition, GM DNA contains a high proportion of viral and bacterial DNA, known to cause a range of immune reactions in human [8].

Another source of hazard from GM DNA comes from the gene products encoded, which have never been part of our food chain. For example, one study found that two-thirds of all the transgenes have similarities to known allergens [9, 10] and should be regarded as potential allergens until proven otherwise.

Article first published 26/07/05


  1. “Traces of genetic engineering detected in milk” 22 June 2004.
  2. Einspanier R, Klotz A, Draft J, Aulrich K, Poser R, Schwagele F Jahreis G and Falchowsky G. The fate of forage plant DNA in farm animals: a collaborative case-study investigating cattle and chicken fed recombinant plant material. Eur Food Res Technol 2001, 212, 129-34.
  3. Phipps RH, Beever DE and Humphries DJ. Detection of transgenic DNA in milk from cows receiving herbicide tolerant (CP4EPSPS) soyabean meal. Livestock Production Science 2002, 74, 269-273.
  4. Phipps RH, Deaville ER and Maddison BC. Detection of transgenic and endogenous plant DNA in rumen fluid, duodenal digesta, milk, blood and feces of lactating dairy cows. J Dairy Sci 2003, 86, 4070-8.
  5. Nemeth A and Wurz A. Sensitive PCR analysis of animal tissue samples for fragments of endogenous and transgenic plant DNA. J Agric Food Chem 2004, 52, 6129-35.
  6. Einspanier R and Klotz A. Reports on examination to determine plant and Bt-maize residues in cow milk – milk sample No. 14/160101/00 obtained 11.10.00 & 14/17121/00 obtained 11.10.00
  7. Reviewed in Ho MW. Living with the Fluid Genome, I-SIS & TWN, London & Penang, 2003.
  8. Bessis N, GarciaCozar FJ and Boissier M-C. Immune responses to gene therapy vectors: influence on vector function and effector mechanisms. Gene Therapy 2004, 11, S10-S17.
  9. Kleter GA and Peijnenburg Ad ACM. Screening of transgenic proteins expressed in transgenic food crops for the presence of short amino acid sequences identical to potential, IgE-binding linear epitopes of allergens. BMC Structural Biology 2002, 2:8
  10. Fiers MWEJ, Kleter GA, Nijland H, Peijnenburg Ad ACM, Nap JP and van Ham R CHJ. Allermatch TM, a webtool for the prediction of potential allergenicity according to current FAO/WHO Codex alimentarius guidelines. BMC Bioinformatics 2004, 5:133 23 March 2005

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