LONDON – British supermarket giant Tesco recalled its private-label frozen meatloaf after tests revealed the products contain up to 5 percent horse meat, according to news reports. Tesco Simply Roast Meatloaf is the fourth Tesco product to test positive for horse meat contamination.

Tim Smith, Tesco Group Technical Director, said in a statement on the company's web site that Tesco tested more than 500 products identified as being most at risk of containing horse meat.

"Today we have withdrawn from sale a product which has tested positive for between 2-5 percent horsemeat. The product is a frozen Tesco Simply Roast Meatloaf 600g," Smith said. "The product tested was manufactured between October 2012 and January 2013 at Eurostock in Craigavon, Northern Ireland. Tests on 15 other lines from the same manufacturing site were clear of horse meat.

"Our investigation to thoroughly understand the source of the contamination has started and we will complete our investigation before deciding whether to continue using the supplier," he added.

The positive test follows a March 1 announcement from the British Retail Consortium that supermarkets and other food businesses had completed 100 percent of tests on processed beef products. The tests were negative for horse meat contamination.

"The UK's major supermarkets, and a number of other BRC-member food businesses, have now tested all existing processed minced beef products" said Andrew Opie, British Retail Consortium Food Director, in a March 1 statement on the BRC web site. "The reassuring news is that another intensive week of testing has produced no new positive results. And, since this testing program started in mid-January, just a third of one percent of products have tested positive."

The BRC also listed the following statistics:

• Total number of DNA tests for horse meat carried out by BRC members between 20 January and 28 February, 2013: 1,889

• Proportion of processed minced beef product lines now tested by the UK's largest supermarkets (and a number of other BRC member food businesses): 100 percent

• Proportion of processed minced beef product lines now tested by BRC food member businesses as a whole: 95 percent

• Number of products that have tested positive for horsemeat against the FSA's one percent threshold since 22 February: 0

• Proportion of products testing positive since testing began on 20 January: 0.3 percent