A catering giant that supplies food to schools, care homes and the armed forces has withdrawn beef from its UK sites after a frozen product tested positive for horse DNA.
Sodexo, which provides services at 2,300 outlets according to its website, said the situation was "totally unacceptable" and the products were being recalled "with immediate effect".
In a statement, the firm said: "Sodexo has had a proactive programme in place to ensure that there is no horsemeat in its supply chain. We demanded written assurances from across our supply chain that the products we purchase did not contain horsemeat, and additionally implemented an internal sampling programme.
"Despite repeated guarantees from our suppliers, our sampling has identified a frozen beef product which tested positive for equine DNA. This situation is totally unacceptable.
"We felt the only appropriate response was to withdraw not only this product but all frozen beef products. We will only re-admit into our catering operations products that have affirmatively passed DNA testing, pursuant to laboratory test criteria."
The company has launched an investigation into how beef products were contaminated with horse. Sodexo said its Tillery Valley Foods business, which supplies meals to the healthcare sector, was not affected.
It is the latest company to announce that its products have tested positive for equine DNA. Earlier on Friday, Birds Eye said it was withdrawing three beef ready meals from sale in the UK and Ireland. The move follows tests that found 2% of horse DNA in a chilli con carne dish sold by Birds Eye in Belgium.
Birds Eye's spaghetti bolognese, shepherd's pie and lasagne are made by the same Belgian manufacturer, Frigilunch N.V., and are being withdrawn "as a precautionary measure".
The Food Standards Agency released the latest tranche of test results submitted by the food industry. They showed that out of 1,133 meat products checked, only six - including Sodexo's - were positive for horse.
In the second wave of tests, the products linked to samples showing horse DNA were Asda's chilled beef bolognese sauce, Sodexo's beef burgers, minced beef and halal minced beef, and a Whitbread Group lasagne and beef burger.