In ten states, the Centers for Disease Control and Prevention have so far documented 49 cases of sickness. In ten incidents, people were admitted to the hospital, and one person lost their life.
According to the CDC, western and Midwest states accounted for the majority of instances of E. coli, a type of bacteria that can cause significant stomach problems.
Other large food firms have also said that they are pulling onions from the US market until health regulators continue to look into the outbreak’s cause.
The CDC said that an infected child is in hospital with a condition known as hemolytic uremic syndrome (HUS), which can cause kidney failure.
The first confirmed outbreak case was reported on 27 September, but McDonald’s said authorities only notified the company of their concerns late last week.
As of Wednesday, about a dozen of the people interviewed had identified eating a quarter pounder before contracting the illness.
