I succumbed to peer pressure today...

Study flaws
The EFSA concluded that the researchers, led by Gilles-Eric Séralini of the University of Caen in France, failed to use enough rats in the study to draw statistically valid conclusions about whether the GM food or glyphosate they were fed caused extra cancers compared with control rats. Furthermore, says the authority, the researchers relied on strains of rats that frequently develop tumours spontaneously, especially in old age.

"Conclusions cannot be drawn on the difference in tumour incidence between the treatment groups on the basis of the design, the analysis and the results as reported," says the review of the study. The same conclusion was reached independently by six national food safety bodies also asked to review the study, from Denmark, the Netherlands, France, Germany, Italy and Belgium.

The EFSA and the panels say that Séralini used a fifth as many rats as would be required for standard, internationally accepted toxicology testing, making his conclusions statistically unreliable. "Given the spontaneous occurrence of tumours in Sprague-Dawley rats, the low number of rats reported in the Séralini publications is insufficient to distinguish between specific treatment effects and chance occurrences of tumours in rats," says the authority.

The EFSA found the NK603 maize strain to be safe in 2003. In its report this week, it declared that there is no need to re-evaluate the safety of the maize or the herbicide.

Séralini's backersclaim that he's the victim of a "covert war" orchestrated by supporters of GM technology to discredit criticism. "Behind the cohort of academic titles [of critics] that are listed is a hidden 'biotech sphere' which brings together biotechnology researchers, regulatory policy experts and representatives of industry," says a statement from CRIIGEN, the France-based Committee for Research & Independent Information on Genetic Engineering, which opposes GM crops and supported Séralini's study.

The study is the second in recent years by Séralini to assess the safety of NK603. His first study was also critised. New Scientist wrote at the time: "Independent toxicologists contacted by New Scientist said Séralini's analysis overplays the importance of minor variations that most experienced toxicologists would consider to be random background noise."