In the study, mice fed with the NK603 x MON810 sweetcorn variety over a period of 20 weeks showed a smaller litter size and lighter offspring than mice fed with non-engineered maize. 

The differences "were statistically significant in the third and fourth litters," according to an abstract of the study led by professor Juergen Zentek and commissioned by Austria's Environment Ministry. 

Although in an alternative set-up of the study the differences between the groups of mice were found to be less pronounced and statistically not significant, the environmental organization Global 2000 said this meant that further long-term tests were needed. 

Austria has long resisted calls by the European Commission to allow the use of genetically modified food, but it finally had to lift its ban on MON810 maize as animal feed last year. 

However, Austrian feed companies have so far agreed to a self-imposed ban on MON810.

 The tested corn breed is a cross of MON810 and another variety and is designed to be resistant against herbicides and insects. 

An expert panel of the European Food Safety Authority (EFSA) found in 2005 that the hybrid was "safe for human and animal health." 

Following the release of the study at a conference in Vienna, Global 2000 and Greenpeace criticized EFSA's approval of the variety and called for a ban of genetically engineered maize.

"It is now vital to keep animal feed in Austria free of genetically engineered maize, and an immediate ban on the use of genetically engineered maize MON810 in Austria is the order of the day," Global 2000 spokesman Jens Karp said.

From the November 24, 2008, Prepared Foods e-Flash