Tesco has became the latest firm to drop a major supplier after discovering a range of spaghetti ready meals contained more than 60% horse meat.
The supermarket giant said that tests on its frozen Everyday Value Spaghetti Bolognese, withdrawn last week as a precaution, showed some had high levels of contamination.
It followed frozen food firm Findus and Aldi in finding the meat in products made by French firm Comigel, and joined them in dropping the company as a supplier.
The announcement came as Environment Secretary Owen Paterson told the House of Commons it appeared that "criminal activity" had been at the heart of the scandal.
Tim Smith, Tesco's group technical director, said the spaghetti bolognese should have contained only Irish beef from its suppliers and that it was sorry for letting customers down.
The supermarket was forced to issue a public apology last month after tests discovered traces of horse in burgers from an Irish supplier.
"Of the positive results, most are at a trace level of less than 1% but three showed significant levels of horse DNA, exceeding 60%," he said.
"We have carried out further tests to ensure that there is no danger to health through the presence of potentially harmful bute. The test for bute was clear.
"The source of the horse meat is still under investigation by the relevant authorities. The level of contamination suggests that Comigel was not following the appropriate production process for our Tesco product and we will not take food from their facility again."
The National Beef Association (NBA) called for more precise labelling of products in the wake of the scandal affecting products made by Comigel, including own-brand lasagne for Findus and Aldi, that would add the words "United Kingdom origin" to packaging to prevent "further cheating" by suppliers.