Ireland's Agriculture Minister Simon Coveney blamed a lone meat processor in County Monaghan, on the border with Northern Ireland, for the horsemeat find, which he called "totally unacceptable." Coveney told state broadcaster RTE that an imported additive used to make the burger appears to have been packed with horsemeat.
The additive was "either falsely labeled, or somebody made a mistake, or somebody was behaving recklessly. That allowed some horsemeat product to come into the system that shouldn't have been here," he said, adding that veterinarians had been dispatched to the meat processor and other factories to conduct more tests.
"A mistake has been made here, it has been flagged by our systems as it should have been, and we will take the appropriate action to ensure it doesn't happen again," Coveney said.
U.K.-based Tesco PLC apologized for its horsemeat-heavy burger and said it was pulling Tesco-brand burgers from stores in Britain and Ireland as a precaution. The find is unwelcome news for the world's fourth-largest food retailer, known in the United States under its Fresh & Easy brand.
"The presence of illegal meat in our products is extremely serious," the company said in a statement. "Our customers have the right to expect that food they buy is produced to the highest standards. ... We understand that many of our customers will be concerned by this news, and we apologize sincerely for any distress."
But the bad news wasn't just for Tesco.
The Food Safety Authority of Ireland also said Tuesday that it had found traces of pig DNA in 85 percent of the burger products it tested in Irish supermarkets, including those operated by British frozen food specialist Iceland, German discounters Lidl and Aldi, and supermarket giant Spar. Irish stores, including Dunnes the country's largest domestically owned supermarket chain also carried beef with horse or pig DNA.
Many of the brands affected, like the Oakhurst Beef Burgers carried by Aldi, carried both DNA from both creatures, but most of the traces were miniscule. For example, the authority said it found 0.1 percent horse DNA content in Iceland's own-brand quarter-pounder patties.
The watchdog says the unusual animal DNA in Ireland's burgers isn't a threat to anyone's health but does "raise some concerns."
"In Ireland, it is not in our culture to eat horsemeat and therefore, we do not expect to find it in a burger," said Alan Reilly, the authority's chief executive. "Likewise, for some religious groups or people who abstain from eating pig meat, the presence of traces of pig DNA is unacceptable."
Meat exports are big business in Ireland, and opposition politician Eamon O Cuiv warned that the news "could have a damaging effect on the Irish agriculture sector if not dealt with quickly and comprehensively."