The Burger King Corp. said it's taking measures to improve food safety after Washington health inspectors found hamburger patties at some restaurants were undercooked.
The company said Wednesday that it's inspecting its systems on the West Coast to determine what changes need to be made.
No illnesses have been reported.
The state Health Department sent Burger King a letter on Sept. 1 calling undercooked patties a disturbing trend, with violations at fast-food restaurants in seven counties -- King, Pierce, Kitsap, Whatcom, Grays Harbor, Adams and Benton.
Most of the undercooking was due to problems with a flame broiler and employees failing to discard undercooked patties.
Susan Shelton, environmental health specialist for the Benton Franklin Health District, said the district's inspectors identified problems at a local Burger King in Kennewick about two years ago.
The restaurant was one of the first in the nation to have the new flame broiler equipment installed.
Shelton said the problem in a nutshell was one of being unfamiliar with the new technology.
"It wasn't cooking to temperature because there were a lot of controls," she said. "When we started working with them, it was resolved."
The health district received no complaints about undercooked food or illnesses, and no lab samples were positive for bacteria or other illness-causing contaminants, she added.
The district continues to inspect the restaurants multiple times each year, but that isn't unique to Burger King, Shelton said.