UK retailer ASDA has said it does not know how tests for equine DNA on the same beef product came up with opposing results.

Last month it said tests had found the presence of horse meat in beef bolognese sauce provided by Greencore.

Greencore said the meat came from ABP's Nenagh factory.

Greencore said today that tests carried out on their behalf on the same batch of beef sauce revealed there was no equine DNA present.

It said multiple further tests on the same batch of product were carried out at two separate laboratories.

In response to queries from RTÉ, ASDA said it did not know how the tests came back with such divergent results.

A spokesperson said that because the tests carried out on their behalf came back positive they withdrew the product from sale.

“We don't have any concerns about the subsequent tests by Greencore or the original tests,” the spokesperson added.

Tests for horse meat were also carried out at the Bristol factory which made the bolognese sauce and at ABP's factory in Nenagh which provided the meat.

All were negative, according to Greencore.

In a statement, ABP welcomed the announcement by Greencore and said it confirmed their own findings that there was no horse meat in the samples.