A Spanish consumer rights organisation has found horse DNA in fresh burgers sold in Spanish supermarkets.

The Organización de Consumidores y Usuarios (OCU) said it tested 20 fresh, chilled beef burgers on sale in Spanish supermarkets, and found equine DNA in two of them.

A spokesperson for OCU said the products affected were an Eroski Basic burger sold in Eroski supermarkets and an Alipende burger sold in Ahorramas supermarkets.

The DNA tests carried out by OCU were qualitative only, meaning the goup knows it has found horse DNA but cannot say in what quantities.

OCU initially carried out the tests to check burgers for additives and preservatives, but decided to add in a DNA test on horse following the revelations about horse DNA being found in burgers sold in Ireland and the UK.

The OCU said there was no food safety concern about the two burgers that tested positive for horse but – as the horse content was not declared on product labels – consumers were being misled about the true contents of their meat products.

The group said it had approached Spain’s food safety regulator AESAN, the ministry of agriculture and local authorities to demand an urgent investigation into its horse DNA findings.

Spain was initially suspected as one possible source of the horse DNA contamination in burgers sold in Ireland and the UK, but on Saturday the Irish government said the source was, in fact, an imported ingredient from Poland.

The name of the Polish supplier has not been disclosed.