* EU Commission wants DNA tests to assess scale of problem
* Aim to determine level of horsemeat in processed beef
* Affair undermining confidence in EU food chain -minister
By Charlie Dunmore and Adrian Croft
BRUSSELS, Feb 13 (Reuters) - The European Commission has proposed increased DNA testing of meat products to assess the scale of a scandal involving horsemeat sold as beef that has shocked the public and raised concern over the continent's food supply chains.
"The tests will be on DNA in meat products in all member states," European Union Health Commissioner Tonio Borg told reporters after a ministerial meeting in Brussels to discuss the affair.
The initial one-month testing plan would include premises handling horsemeat to check whether potentially harmful equine medicine residues have entered the food chain, Borg said, with the first results expected by mid-April.
The scandal erupted when tests carried out in Ireland revealed that meat in products labelled as beef was in fact up to 100 percent horsemeat. Operators in at least eight EU countries have since been dragged into the affair, raising fears of a pan-European labelling fraud.
Officials have said no risk to public health from the adulterated foods has been identified at this stage but testing for horse medicine in meat is being undertaken to be sure.
The suspected fraud has caused particular outrage in Britain, where many view the idea of eating horsemeat with distaste, and exposed flaws in food controls.
"This is impacting on the integrity of the food chain, which is a really significant issue for a lot of countries. Now that we know this is a European problem, we need a European solution," Irish farm minister Simon Coveney told reporters before the meeting.
At the urging of ministers, Borg said the Commission would accelerate work on potential changes to EU labelling rules that would force companies to state the country of origin on processed meat products.
Currently the requirement only applies to fresh beef, and is expected to be extended to fresh lamb, pork and poultry from December 2014.
But EU officials have warned privately that the complexity of supply chains would make the requirement almost impossible to implement in practice.
EU and national authorities are still trying to uncover the source of the suspected horsemeat fraud.
"All those countries through which this meat product has passed of course are under suspicion," Borg told a news briefing earlier on Wednesday. "By the countries, I mean the companies in those countries which dealt with this meat product."
He added that it would be unfair at this stage to point the finger at any organisation in particular.
NOT JUST HORSE?
On Jan. 15, routine tests by Ireland's Food Safety Authority found horsemeat in frozen beef burgers produced by firms in Ireland and Britain and sold in supermarket chains including Tesco, Britain's biggest retailer.
Concerns grew last week when the British unit of frozen foods group Findus began recalling packets of beef lasagna on advice from its French supplier Comigel, after tests showed up to 100 percent of the meat in them was horse.
The affair has since implicated operators and middlemen in a range of EU countries, from abattoirs in Romania and factories in Luxembourg to traders in Cyprus and food companies in France.
German supermarket chain Real, part of the world's fourth largest retailer Metro, said tests revealed traces of horsemeat in frozen lasagna on Wednesday. Real, which operates more than 300 stores across Europe's largest economy, said it had already removed the ready-meal from its shelves on Friday.
The first evidence that the labelling scandal could go beyond horsemeat also emerged when the upmarket British grocer Waitrose said its testing found that some of its frozen British beef meatballs might contain pork.
The firm, part of the John Lewis Partnership, has withdrawn the product from sale.
Horsemeat is traditionally prized by many consumers in EU countries such as France, Italy and Belgium.