The questions raised by 'horsemeat' burgers

The questions raised by horsemeat burgers Photo: PA

Nowadays people want to know what farm the beef in their burgers came from - even sometimes the name of the calf. But if you have bought frozen burgers from some big name supermarkets, you could have been buying meat from a different species.

That is after the Irish Food Standards authority revealed that burgers it tested (on sale until today in the UK too) contained traces of DNA from horses and pigs. Ten out of 27 burgers they tested were positive for horse DNA and 23 out of 27 were positive for pig DNA.

Most of the samples were contaminated with very small amounts of pig or horse DNA but in one, nearly 30% of the meat came from horse. The burgers were made in three factories, one in the UK, two in Ireland and were sold in Tesco, Lidl, iceland, Dunnes Stores, and Aldi. Tesco and Iceland told us tonight they'd removed them from their shelves.

There is no suggestion of any health hazard here - everyone agrees that. But Muslims and Jews would be dismayed to find they could have been inadvertently eating burgers contaminated with pig DNA.

And there are questions to be asked. Where did the horsemeat come from? The factories that made the burgers apparently do not make products from horsemeat. So how did horse DNA get into their burgers?

And what does all this say about the "trace-ability" of food that we hear so much about?