An equine drug that can harm humans has been found in horse carcasses exported from Britain to France and may have entered the human food chain, British agriculture minister David Heath said Thursday.
But the drug phenylbutazone was not found in tests on products made by Findus, the frozen food giant embroiled in a Europe-wide horsemeat scandal, Heath told parliament.
The Food Standards Agency (FSA) tested the carcasses of 206 horses slaughtered in Britain for traces of the painkiller, also known as "bute", which in rare cases can cause a serious blood disorder in humans.
"Eight have come back positive. Three may have entered the food chain in France. The remaining five have not gone into the food chain," Heath said.
"FSA are working with French authorities in an attempt to recall the meat from the food chain."
He added: "The results of bute testing in withdrawn Findus food products have come back negative."
However, the FSA gave a higher number, saying six horse carcasses were sent to France "and may have entered the food chain".
Supermarkets across Europe have pulled millions of frozen ready meals off the shelves after tests revealed that meat labelled as beef contained large quantities of horsemeat.
Some Findus lasagnes on sale in Britain were found to contain 100 percent horsemeat.
British officials stressed that it was extremely unlikely that eating horsemeat containing traces of bute could cause people serious harm.
"At the levels of bute that have been found, a person would have to eat 500 to 600 100-percent horsemeat burgers a day to get close to consuming a human's daily dose," said Sally Davies, chief medical officer for England.
"And it passes through the system fairly quickly, so it is unlikely to build up in our bodies.
"In patients who have been taking phenylbutazone as a medicine, there can be serious side-effects but these are rare. It is extremely unlikely that anyone who has eaten horsemeat containing bute will experience one of these side effects."
Horsemeat is widely eaten in parts of Asia and Europe, including in France, but is considered taboo in Britain.