COWS which eat bracken produce milk containing a potent carcinogen absorbed from the plant, according to new scientific research. The carcinogen, ptaquiloside, cannot be destroyed by pasteurisation, according to a leading British expert.
The Irish Farmers' Association and the Department of Agriculture have assured consumers that Irish dairy cows do not eat bracken.
Ptaquiloside is well known for causing tumours by damaging DNA, the basic genetic material of all cells, according to Mr Alan Heyworth, of the Bracken Advisory Committee in the UK.
A team of scientists in New Zealand and Venezuela has discovered that almost 10 per cent of the chemical eaten by cows is passed on in milk, a statistic the team describes as "a cause for concern".
The research, published in Nature, the scientific journal, found ptaquiloside is excreted in milk almost four days after feeding stops.
The Department of Agriculture said yesterday its experts would be examining the report in Nature and would be in touch with the New Zealand team.
"It is not relevant here, however, because our dairy herds are fed on grass and silage and hay and are not normally found in areas were ferns are growing," a spokesman said. The Department of Health referred queries to the Department of Agriculture.
Mr Liam Foley, chairman of the IFA's National Dairy Committee, said most Irish farmers kept their land free of bracken and fenced animals away from it.