By SHAWN POGATCHNIK
DUBLIN (AP) -- Horsemeat might not be bad for you to eat, but it's definitely bad for sales of products labeled as beef.
But Ireland's surprise discovery of horsemeat traces in many factory-produced burgers is boosting business for one trade: Forensics labs able to use DNA fingerprinting to tell pig from fowl.
Until now, supermarkets and food processors have not employed DNA testing of their meat products to confirm whether there are traces of other species in products marked as chicken, pork, beef, lamb or fish. That's because such findings have no bearing on food safety, only the integrity of labeling.
But a string of food processors and retailers say they're planning to introduce such testing after the Food Safety Authority of Ireland -- determined to confirm whether food labels on meat and fish are honest and accurate -- has used DNA testing to show that "pure" processed meat products often contain traces of other animals slaughtered in the same facilities or carried in the same vehicles.
Worse, the agency's testing found that bargain-brand burgers produced at the Silvercrest food processing plant for sale by British supermarket king Tesco contained up to 29 percent horsemeat, a revelation that government and Silvercrest officials eventually pinned to a powdered "filler" ingredient imported from Poland.
Tesco, which saw its shares slump following the news, announced Wednesday it will become the first supermarket chain to perform DNA tests on its meat products.
"These checks will set a new standard," Tesco, the largest grocer in both Britain and Ireland, said in a statement. "We want to leave customers in no doubt that that we will do whatever it takes to ensure the quality of their food and that the food they buy is exactly what the label says it is."
Industry analysts expect other supermarket chains in Britain and further afield to follow suit, because the cross-contamination detected in Ireland is likely to happen in processed meat products worldwide.
"This sort of species testing simply has not been done in other nations. It looks like that's going to change," said Patrick Wall, the professor of public health at University College Dublin and former chairman of the Food Safety Authority for the 27-nation European Union.
Beef is Ireland's No. 1 food export, and Tesco is Ireland's No. 1 customer, accounting for nearly one tenth of the country's annual ¤1.9 billion ($2.5 billion) in beef exports.
Silvercrest supplied most of the supermarket chains in Ireland and Britain. After the Irish findings that more than one third of its burgers contained horsemeat traces below 0.1 percent -- and one batch of Tesco burgers contained 29 percent horsemeat -- Silvercrest withdrew about 10 million burgers from those stores. It suspended operations once a second round of DNA tests found more horsemeat traces in recently produced burgers.
In a statement Silvercrest's parent company ABP Foods said it understood Tesco's decision and said it had already decided to begin its own practice of random DNA testing of products at all its facilities in Ireland and Britain. Other Irish processors say they, too, plan to follow suit.
Food policy experts say meat labels may eventually be changed in many countries to reflect the kind of warnings already familiar for people allergic to nuts: This beef product may contain traces of other animals.
Wall said consumers shouldn't be unduly unsettled by the Irish findings, which included results showing that most cheaply produced "beef" burgers also contained minute elements of pork. He said such molecular transfers were almost impossible to prevent though, until now, they hadn't been measured.
"People need to understand how sensitive these DNA tests are," Wall said. "This thing will pick up molecules. So if horsemeat traveled in a refrigerated lorry one day and beef was carried in it the next day, molecules would travel over. If horsemeat was boned out on a premises, and if beef was subsequently boned out, you could get carry-over of molecules."
Copyright 2013 The Associated Press.