The owners of a food processing factory in North Yorkshire are investigating how traces of horse meat ended up in their beef burgers which were sold in Iceland supermarkets.
The processing company says its suppliers in Europe may be responsible.
You can watch the report from Ben Chapman below.
A drug with the potential to cause cancer in humans might have entered the food chain through horse meat, Labour has claimed.
Traces of horse DNA have been discovered in a beef burgers sold in supermarkets across the UK. A Tesco burger was found to be 29% horsemeat
A list of the beef burgers, sold in UK supermarkets, that were found to contain traces of horsemeat.