Beefburgers made by the Burger Manufacturing Company in Powys, Wales, are being withdrawn from cafes, restaurants, hotels and other outlets as well as wholesalers after three of nine samples ordered by the Food Standards Agency tested positive for at least 1% horsemeat.
Much of the meat used by the company was supplied by Farmbox Meats near Aberystwyth, which was raided by police and FSA officials investigating the horsemeat scandal on Tuesday last week.
The latest burger withdrawal from wholesalers and caterers coincided with evidence that some supermarkets have raised prices on meat-free products.
Asda accused rivals of seeking to benefit from consumers' switching from meat.
Labour, meanwhile, stepped up pressure on the government to speed up checks for horse adulteration in beef products used by caterers, including those supplying schools and hospitals.
The FSA said further work was being carried out to establish exactly how much horsemeat the BMC products contained and to test for the presence of the veterinary medicine phenylbutazone, also known as bute.
Mark Cornall, sales and marketing manager for BMC, in Builth Wells, said the firm was withdrawing all products using Farmbox meat.
"We are absolutely devastated. We have been market leaders when it comes to quality," Cornall said: "If we survive is questionable at the moment."
The average price of Tesco's meat-free products, including meat-free burgers and lasagnes, rose from £2.45 before the scandal first broke to £2.61 days later, after tests by Irish authorities meant they became one of the first supermarkets shown to have burgers with horse DNA.
A Tesco spokeswoman explained half-price promotions had come to an end and there had been price increases from suppliers.
The figures emerged as Asda boss Andy Clarke accused rival supermarkets – without naming Tesco – of cashing in on the scandal, claiming some had increased the price of meat-free meals.
"Consumers are switching, so vegetarian meals and meat-free products have taken a lift."
Mary Creagh, Labour's food and environment spokeswoman, has written to Owen Paterson, the environment secretary, expressing concern at an apparent two-speed approach to testing, with supermarkets generally reporting more quickly than catering companies and others.