A review of a paper linking herbicide tolerant maize to tumours in rats has been castigated as poor science

The European Food Safety Authority (EFSA) has sharply criticised a recent paper claiming that a strain of genetically modified maize and its accompanying herbicide increase the risk of tumours and organ damage in rats. The agency said the paper ‘is of insufficient scientific quality’ to reach such conclusions.

The paper, published online last month, describes a study of the potential toxicity to rats of the herbicide glyphosate – sold under the trade name Roundup – and of glyphosate-tolerant GM maize NK603. In a statement released yesterday, EFSA said ‘the design, reporting and analysis of the study, as outlined in the paper, are inadequate’. EFSA therefore will not ‘re-examine its previous safety evaluation’ of NK603, nor use the paper in its ongoing assessment of glyphosate.

EFSA listed nine problems with the paper that need to be resolved before the study could be described as ‘well-conducted and properly-reported’. These include using rats that are particularly prone to developing tumours, using too few animals to generate statistically significant results and not measuring how much herbicide the rats ingested. EFSA has contacted the paper’s lead author to give the team ‘the opportunity’ to provide additional documentation on those issues by 12 October.