The first Irish studies on the potentially lethal E coli 0157: H7 in cattle found 11 per cent of beef carcasses sampled at the National Food Centre were contaminated with the pathogen.
Dr Alice Doherty, of the Teagasc National Food Centre in Dublin, told a conference yesterday that while her study sample was small, it had important implications for Irish beef production and processing.
She said the positive samples were found in four out of 36 carcasses sampled in July and August last year.
The bug normally spreads from the hide and intestines to carcasses.
She said a review of information from around the world would seem to indicate the Irish levels of the pathogen in live cattle were no higher than elsewhere.
She told the International Meat Conference in Malahide, Co Dublin, that younger animals were more frequent carriers of the bug than adult cattle.
This meant that animals of two years old, the typical age at which animals were slaughtered, were more likely to be carrying E coli: H7 than adult cows.
She gave details of recent research work at the National Food Centre which showed the ability of the organism to survive during the ensiling of grass which was treated with formic acid.
But, she said, when the grass was not treated with formic acid, the bug did not survive.
She said these studies, which were on-going, have important implications for the preparation of silage for animal feed.
The pathogen caused a number of deaths around the world when it was consumed in undercooked meat.
Recently, the head of the Food Safety Board, Dr Patrick Wall, said the pathogen is killed if meat is properly cooked and handled before cooking.