Three horse carcasses that tested positive for the equine drug bute may have entered the human food chain in France, the British government said Thursday.

Environment Minister David Heath told the House of Commons that eight horses from British abattoirs had tested positive for bute, and "three may have entered the food chain in France. The remaining five have not gone into the food chain."

Heath said frozen lasagna sold under the Findus label in Britain had tested negative for bute. The product was removed from store shelves last week after tests found some of the meals contained more than 60 percent horsemeat.

Horsemeat itself is not dangerous to eat. But bute, or phenylbutazone, a painkiller and anti-inflammatory used on horses, is considered harmful to human health if ingested.

Authorities across Europe are testing for the drug after horsemeat was found in food products labeled as beef.