A drug with the potential to cause cancer in humans might have entered the food chain through horse meat slaughtered in UK abattoirs, Labour has claimed.
Shadow environment secretary Mary Creagh told the Commons she had evidence that "several" horses slaughtered in the UK last year tested positive for the carcinogen phenylbutazone.
Agriculture minister David Heath told the Commons the Food Standards Agency checks all meat to ensure it is fit for human consumption.
He told MPs:
Where positive results of phenylbutazone are found the FSA investigates and takes follow-up action to trace the meat.