by Marion Nestle
Dec 2 2013

What’s up with the retraction of the Séralini feeding-GMO-corn-to-rats study?

The big news over the weekend was that the journal, Food and Chemical Toxicology, announced that it is retracting the paper it published last year by Séralini et al.

The Séralini paper claimed that feeding genetically modified corn to female rats, with or without added Roundup, caused them to develop more mammary tumors than rats that were not fed GMO corn.

As I discussed in a post at the time, I had my doubts about the scientific quality of the Séralini study.  The findings were based on a small number of animals, were not dose-dependent and failed to exclude the possibility that they could have occurred by chance.

In response to readers’ queries about my critique of the science, I added a clarification:

I very much favor research on this difficult question.   There are enough questions about this study to suggest the need for repeating it, or something like it, under carefully controlled conditions.

In science, repeating someone else’s study is common practice.  Retracting a published paper is not. The editors of Food and Chemical Technology say they are retracting the paper because its findings are inconclusive.

The low number of animals had been identified as a cause for concern during the initial review process, but the peer-review decision ultimately weighed that the work still had merit despite this limitation.  A more in-depth look at the raw data revealed that no definitive conclusions can be reached with this small sample size regarding the role of either NK603 or glyphosate in regards to overall mortality or tumor incidence. Given the known high incidence of tumors in the Sprague-Dawley rat, normal variability cannot be excluded as the cause of the higher mortality and incidence observed in the treated groups.

Hello.  Where were they during the peer review process?  Editors decide whether papers get published.  The editors chose to publish the study, even though they had just published a meta-analysis coming to the opposite conclusion: “GM plants are nutritionally equivalent to their non-GM counterparts and can be safely used in food and feed.”

Now, in response to a barrage of criticism (see letters accompanying the online version of the Séralini study), the editors have given its authors an ultimatum: withdraw the paper (which Séralini says he will not do), or they will retract it.

But the editor wrote Séralini:

Unequivocally, the Editor-in-Chief found no evidence of fraud or intentional misrepresentation of the data.

Then how come the retraction?  Guidelines for retracting journal articles published by the Committee on Publication Ethics (COPE) say:

 Journal editors should consider retracting a publication if:

  • They have clear evidence that the findings are unreliable, either as a result of misconduct (e.g. data fabri­cation) or honest error (e.g. miscalculation or experimental error)
  • The findings have previously been published elsewhere without proper crossreferencing, permission or justification (i.e. cases of redundant publication)
  • It constitutes plagiarism
  • It reports unethical research

The Séralini paper may be unreliable, but that should have been obvious to the peer reviewers and the journal’s editors.  Otherwise, the paper does not fit any of the established criteria for retraction.

The anti-GMO group, GM Watch, points out that Food and Chemical Technology is a member of COPE.  On this basis, it says the journal’s retraction of the study is ”illicit, unscientific, and unethical.”  It has a point.

This is a mess, with the journal’s editors clearly at fault.  At this point, they should:

  • Admit that the journal’s peer review—and editorial—processes are deeply flawed.
  • State that the journal never should have accepted the paper in the first place.
  • Announce immediate steps to correct the flawed review processes.
  • Apologize to Séralini et al. for having caved in to pressure and blaming him, rather than themselves, for the mess.
  • Publish all documentation about the paper on the journal’s website.
  • Call on the scientific community to repeat the Séralini study with populations of rats large enough to permit statistical analyses of the results.

About the documentation:

  • Séralini, according to a scathing account of this affair in Forbes, plans to sue Food and Chemical Technology for breach of protocol.  The Forbes piece finds ”

    The entire episode, including the oddly worded retraction statement…a black eye for the beleaguered journal and Elsevier [the publisher].”

  • GM Watch posted the “oddly-worded-retraction” letter (from the editor to Séralini) but then took it down.  While the link was still active, I took a screenshot.  I wish I’d copied the whole thing.  If anyone knows where to it, please send the link.

Screenshot 2013-11-28 10.29.58


  • Thanks to a reader for sending the entire letter from editor Hayes to Séralini.
  • Another reader sent this article suggesting that appointment of a Monsanto-connected editor to the journal may have led to the retraction.
  • Matt Ruscigno RD MPH

    Thank you for weighing in on this and explaining the whole fiasco.

  • mem_somerville

    Hello. Where were they during the peer review process? Editors decide whether papers get published.

    Do you think we should have an investigation here? And see if there was any conspiracy among the editor/reviewers to push crappy work through?

    You seem on board on the conspiracy about something that happened after. Why discount one before? Would you call for us to see all the editorial emails?

  • Claire Robinson

    Marion, the Hayes retraction letter is still on the GMWatch site, it’s pasted at the end of the GMWatch press release pdf at this link:

  • The editors and journal should be sued. However, not by Mr. Seralini, but by the people and scientists in countries like Kenya who used his flawed claims to institute bans and justify huge costs (both economic and humane) linked with the false cancer fear campaigns that ensued. Dr. Nestle is to be commended for her early criticisms of the Seralini claims; however, too many colleagues and influential voices like Michael Pollan, Mark Bittman and Gary Hirshfeld trumpeted Seralini as cause for alarm and action against plant biotechnology. They too should hold some accountability for their role in helping turn these claims – almost immediately debunked by the scientific community and experts like Dr. Nestle – into fodder for damaging policy decisions around the globe.

  • Novagene

    The Séralini paper is an engine of political propaganda and while there may not be a stated guideline for retracting his paper, science-as-propaganda is a good reason to do so.

    Why am I say that it was “science” as media-theater?

    • The prominent full color tumor-rat photos in the paper.
    • Contracted press blackout before media release.
    • Concurrent book released authored by Séralini.
    • Concurrent anti-GMO documentary release featuring Séralini.

    Plenty of shoddy papers are published through peer-review, why is another discussion, but typically they are rightfully ignored and forgotten. This is what would have happened with the Séralini study under normal circumstances, except that it’s purpose was that of a media weapon.

    If Séralini wants to play politics with science, then it’s fair for Food and Chemical Toxicology to play politics with him by retracting his paper with vague reasoning that offers that no one was at fault, but “no, thank you” to activist studies designed to grab Internet eyeballs in furthering a political agenda.

    Repeating the Séralini study for the sake of clarification is a waste of time and resources. The study conclusion is patently unsupportable and even if a properly executed follow-up study were released, it would do little to squelch cries of cover-up conspiracy from anti-GMO proponents.

    As for Séralini suing, which won’t be the first time he’s done so, I’m curious which scientists among the lists of Nobel laureates sued their way to receiving their scientific recognition.

  • Gesa

    Good comment on the review process, here is some more

    Who’s Afraid of Peer Review? A spoof paper concocted by Science reveals little or no scrutiny at many open-access journals.

    by John Bohannon

  • Allison Wilson, PhD

    A “must read” for anyone critical or supportive of the Seralini et al. research is the just published “Rat feeding studies with genetically modified maize – a comparative evaluation of applied methods and risk assessment standards” by scientists Hartmut Meyer and Angelika Hilbeck. Published in Environmental Sciences Europe, it is data-based (unlike so many of the critiques) with valuable tables and discussions and it is revealing of the double standards used in GMO risk assessment and of the overall quality of all GMO feeding studies, either those from Monsanto scientists or non-industry scientists. (It is available at

    For those interested in learning more about the antics of the Journal Food. Chem. Tox. that retracted the Seralini study, I also highly recommend reading “The Goodman Affair: Monsanto Targets the Heart of Science” (available at Things are never as simple as they may first appear, especially when industry has so much power over the science media and scientific publishing.

  • Novagene

    Both scientists who wrote the first paper are associated with The European Network of Scientists for Social and Environmental Responsibility (ENSSER). Founded in 2009, it is merely an anti-GMO activist organization. The Journal Environmental Sciences Europe was founded in 2010, hardly a longstanding journal. The publishing timing of the study review is also uncanny, December 1, 2013.

    Independent Science News founded in 2011, is another anti-GMO activist organization that attempts to mask itself as a credible and unbiased source.

    By contrast, the Food and Chemical Toxicology Journal has existed since 1963 and doesn’t just publish on the singular topic of genetic engineering of crops.

    Consider those sources “must read” if you like, but please acknowledge that the conclusion of such information will be heavily biased on the onset against genetic modification.

  • mem_somerville

    Oh, you are just spamming this comment around everywhere, eh? Then I’ll repost my response from where I saw it first:

    Yeah, it certainly shouldn’t have been accepted. But if it hadn’t gone there, it would have gone to some predatory/vanity publisher and come out anyway–and still been used as fodder by the anti-GMO shouters.

    The downside of the retraction is that it just goes into the conspiracy-theory bucket–as Allison and her team at ISN demonstrates conclusively.

    So it, like the Carman stuff, as you say is “worthless” to most people. But as science has shown us, to CTers it’s just more evidence of the CT.

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