The number of E. coli cases linked to onions used by McDonald’s has cracked 100. The Food and Drug Administration said in an update that the number of people sickened by the fast food bacteria outbreak has climbed from 90 to 104.

The source of the outbreak was likely slivered onions on McDonald's Quarter Pounder burgers, health officials have said.

Officials have confirmed that more than 100 people were infected by a severe E. Coli outbreak linked to slivered onions on McDonald’s Quarter Pounders, Forbes reported. The infections sent 34 people to the hospital and left four with a potentially life-threatening kidney condition called hemolytic uremic syndrome.