By Charlie Dunmore
BRUSSELS (Reuters) - A French study linking a type of genetically modified corn to health risks in rats was of insufficient scientific quality to draw any conclusions on the safety of such crops, an initial review by the EU's food safety watchdog has found.
Last month, researchers at the University of Caen said rats fed on Monsanto's NK603 GM corn or exposed to its top-selling Roundup glyphosate weed killer were at higher risk of suffering tumors, multiple organ damage and premature death.
The study led Russia to temporarily ban imports of NK603, which can be found in internationally traded animal feed, and is designed to be grown in conjunction with use of glyphosate to control weeds.
France's government said it would also ban imports if the findings are confirmed, but other experts have questioned the study's methods and Monsanto said it felt confident its products had been proven safe.
"Considering that the study... has unclear study objectives and given its inadequate design, analysis and reporting, EFSA finds that it is of insufficient scientific quality for safety assessments," the European Food Safety Authority (EFSA) said in a statement on Thursday.
Among other criticisms, the panel of EFSA scientists that reviewed the paper said the authors had failed to establish appropriate control groups as part of the study, and had chosen a strain of rat that is prone to developing tumors during its normal lifespan.
"Therefore, EFSA concludes that the study as reported does not impact the ongoing re-evaluation of glyphosate and does not see a need to reopen the existing safety evaluation of maize NK603," the panel concluded.
Monsanto said EFSA's findings confirmed the positive safety assessments that its products had received by regulators worldwide.
"Monsanto's products are subject to detailed scrutiny and safety testing. It is appropriate that claims like those made in the publication... should be scrutinized in the same way," the company said in a statement.
The safety watchdog said it would ask the authors to provide full details of the study's design and procedures, ahead of a final review due by the end of the month.
But the study's lead author, Gilles-Eric Seralini, said he would only make further information publicly available if EFSA published all the data from its 2003 safety assessment of NK603, which concluded that it was as safe as non-GM corn.
"To play fair they can't keep their data secret. The authorization of these products is based in our view on data and a methodology that are even more faulty," he said.
Campaign group Friends of the Earth accused EFSA of putting the interests of biotech firms ahead of public safety concerns.
"For the past decade, EFSA has consistently sided with the biotech industry and disregarded health or environment concerns about genetically modified crops. Instead of picking holes in peer-reviewed research, they should take public concerns seriously," said food campaigner Mute Schimpf.
But Cathie Martin, a scientist at the John Innes plant research centre in Britain, said: "EFSA do not take their responsibility towards food safety lightly."
Martin said if this maize were toxic it would be important to make that public, but she added the EFSA analysis shows the Seralini paper "offers no useful information on toxicity of Roundup or herbicide resistant crops."
"I hope that the journal and the team behind the original work will take notice of this and cooperate in providing all the additional information required to support their claims, or retract the paper," she said.
Consumer resistance to GM foods remains strong in Europe, with the most recent European Union survey showing 57 percent of people oppose the technology compared with 27 percent in favour.
Only one GM crop, MON 810, is currently grown on a commercial scale in Europe - a pest-resistant corn variety also produced by Monsanto - which covers about 115,000 hectares of farmland, mainly in Spain.
That compares with about 160 million hectares of GM crops grown worldwide, including varieties of cotton, soybeans and maize.
While there is virtually no demand for GM foods in the European Union, the bloc imports millions of tonnes of GM animal feed each year from major growers including the United States, Argentina and Brazil.
(Additional reporting by Marion Douet in Paris and Chris Wickham in London; Editing by Anthony Barker)