The latest raids come a day after UK authorities arrested three workers at two meat plants, Farmbox Meats near Aberystywth and Peter Boddy Slaughterhouse in Todmorden, West Yorkshire.
Inspectors toured the plants Tuesday and suspended their permits to operate Wednesday, the agency said.
Meanwhile, authorities in northern England confirmed Friday that a dish had been pulled from 47 school kitchens after tests revealed horse DNA.
The ready-made cottage pie, or shepherd's pie, came from an external supplier, the Lancashire County Council said.
"This does not appear to be a food safety issue but I've no doubt parents will agree we need to take a very firm line with suppliers," councilor Susie Charles said in a prepared statement.
Authorities across Europe have been scrambling to get a grip on the crisis over rogue horse meat in beef products.
Fears of mislabeled meat also spread to the sky, where companies that provide in-flight catering in Europe initiated reviews of their suppliers.
LSG Sky Chefs said it has contacted all its meat suppliers in Europe and has asked for written confirmation that their products do not contain horse meat. Another major caterer, Gate Gourmet, is doing the same with its suppliers.
The European Union intends to begin testing meat across all 27 member states, it confirmed Friday.
It called for testing 10 to 150 samples per country and at least five tests per country for the presence of the drug phenylbutazone, also known as bute, which is approved for horses but is not allowed to enter the food chain because it can be harmful to humans.