Background: This series contains brief reports on each of the "600 studies" held on the GENERA database, published at Bifortified.org, in the order in which they were listed on 18 Sept 2013. The general purpose is to counter the extraordinary claims that the entries on this list demonstrate the human food safety of GM crops. See the Introduction to this series [link].
The Ash et al 2000 entry appears to be an advance abstract for the same body of work finally published in Ash et al 2003.
This is a lightweight 'digestive fate of GM protein' study in what the authors self-described as a "brief field trial". They seemed to be using a commerically available testing strip for identifying GM protein from Monsanto's Roundup Ready Soy in not only the feed but the digesta, body and products of laying hens. With brief descriptions of method, limited information on or verification of feed, nor (seemingly) validation of the diagnostic tools in the complex testing matrices (such as egg) it was unlikely to make findings outside those for which the simple diagnostic tools were specifically designed.
This is not a study that can provide information on the human health and safety of GM crops.
A brief comment on the detection of GM DNA and proteins...
Food sourced DNA can and has been detected in body tissues of animals, their products, and also within humans. The detection of DNA proceeds in a very different manner to methods used in the detection of GM proteins. By specifying a short lengths of DNA, fragments of various sizes or whole genes may be detected.
In contrast, protein detection is generally conducted with the use of antibodies to the proteins. Amongst other things...
- depending on the exact amino acid sequence/s and/or conformation of the protein (its folded shape) used at the time of the raising of the antibodies in animals;
- depending on which antibody/s is/are selected for subsequent use, from the many different antibodies animals may produce;
- depending on changes in the state of the GM protein at the time of testing;
- depending on the presence of other confounding substances within the testing media;
the antibody may never recognise fragments or different conformation of the protein. For example, a protein may unfold slightly due to warming and the antibody may not recognise it. Part of a protein may be lost such that the antibody does not recognise the protein, yet the residual protein may nonetheless still be present and functionally active. Antibodies may bind to proteins other the one they are targeting, or may themselves be denatured in the testing media and unable to recognise their target. A positive detection may indicate the presence of a protein or fragment (that may require other methods of verification for certainty), but an absence of detection does not mean the protein or active fragments are not present. Many circumstances related to antibody recognition are discussed in the European Food Safety Authority's "Scientific Opinion on the assessment of allergenicity of GM plants and microorganisms and derived food and feed" [link]
As a further confounding factor, it seems likely that the independent development of GM protein detection methods are not allowed without the permission of companies such as Monsanto. When US public sector scientists were developing agreements for research they were allowed to undertake without specific approval, Sappington et al 2010 [pdf link] noted amongst other things that
- Development of methods for detecting the presence or absence of patent-protected traits in seed
- Use of non-commercial methods to detect the presence or absence of patent-protected traits in seed
were not addressed by the statements at that time. Thus it seemed that researchers were limited to detection tools provided or approved by the GM crop developers. I have wondered how this could have affected detection outcomes over the years.
These simple diagnostic tools can be unhelpful when used out of validated context. The authors did not detect the GM "CP4 EPSPS" protein in hens eggs using such tool in this study. However one of the authors, lead authoring another study in concert with Monsanto (Scheideler 2008) [pdf link], reported detections of a different GM protein (Bt-inspired Cry3Bb1) in every single egg they tested, and in eggs subsequently purchased from a supermarket. While the Monsanto-supported authorship decided that an interfering substance must be present in the eggs, with results therefore inconclusive, such findings did not preclude the possibility that the GM proteins were present in some or all of the eggs and being detected by the antibodies. I didn't see a report that the authors had attempted to identify proteins (interfering and/or GM) captured by the antibodies.