McDonald's halted sales of bulgogi burgers at 440 branches in Korea on Saturday over a food poisoning scare.
The decision came after seven elementary schoolchildren and their teacher complained of food poisoning symptoms after eating the novelty burgers at a branch in Jeonju, North Jeolla Province on Aug. 25.
One of the children had to be treated in hospital.
Health authorities have started investigating. The Korea Centers for Disease Control and Prevention on Saturday took stool samples from the victims and launched an investigation to find out if there are other customers who experienced similar symptoms after eating burgers there.
In early August, the Korea Consumer Agency tested 38 kinds of burgers and found McDonald's bulgogi burger was contaminated with staphylococcus aureus, which causes food poisoning. The level of the bacteria in the burger was 3.4 times higher than permissible.
"We sell 100,000 bulgogi burgers a day and 36 million a year nationwide. There had been no problem for the last 20 years," a McDonald's spokesman said. "We will do our best to identify the exact cause of the illness."
Pedestrians pass by a McDonald's branch in Seoul on Sunday.