Tesco has announced the Everyday Value Spaghetti Bolognese it withdrew on a precautionary basis last week has been found to contain large amounts of horsemeat.

Tesco took the product off shelves after concerns emerged that Findus frozen beef lasagne – made by Comigel, the same French supplier also used by Tesco – may have been adulterated with horsemeat. The meat content of the Findus product was later found to be between 60% and 100% horse instead of beef.

Following tests on its Everyday Value product, Tesco announced on Monday evening that it, too, had found horse, with three samples containing more than 60%. It added other samples of the spaghetti meal had contained trace amounts of horse of less than 1%.

Tesco group technical director Tim Smith said Comigel had been instructed to use only 100% Irish beef from approved suppliers for Tesco’s Everyday Value Spaghetti Bolognese. “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,” he added.

A spokeswoman for Tesco later clarified this did not mean Tesco had dropped Comigel as a whole but that it had delisted the specific Comigel factory in Luxembourg where the spaghetti meal was made. She added the Everyday Value spaghetti Bolognese was the only Comigel-made product that had been on sale in Tesco.

Tesco’s decision to delist the specific Comigel site rather than the entire company mirrors how it reacted to the discovery of horsemeat in one of its Everyday Value frozen burgers in January – it delisted the factory that made the burger, Silvercrest, but continues to work with Silvercrest’s parent company, ABP Food Group.

Earlier on Monday, Aldi announced it would also no longer use Comigel following the discovery of horsemeat in two of its frozen readymeals. The company has also been dropped by Findus.

The discovery of large amounts of horsemeat in Tesco’s Everyday Value frozen spaghetti meal comes after one of the retailer’s Everyday Value frozen burgers tested positive for 29.1% horse in a survey by the Food Standards Authority of Ireland published in January.

Tesco also blamed its supplier – Silvercrest – at the time, saying the company had failed to adhere to Tesco’s sourcing spec and gone to unapproved suppliers for raw material.

Smith apologised to Tesco customers for the latest adulteration problem. “We set ourselves high standards for the food we sell, and we have had two cases in recent weeks where we have not met those standards,” he said. “Our DNA testing programme is underway, and will give us and our customers assurance that the product they buy is what it should be.”

The recent discoveries of undeclared horsemeat in frozen foods sold in the UK have prompted fears consumers may have been exposed to phenylbutazone or bute – a commonly used veterinary medicine which is not allowed in the food chain.

However, Smith stressed Tesco had tested its frozen spaghetti for bute and not found any.