CDC investigating E. coli outbreak linked to McDonald’s in 10 states, including Oregon KGW.comE. coli Outbreak Linked to McDonald’s Quarter Pounders CDCMcDonald’s provides update on E. coli breakout as shares drop amid scandal Yahoo FinanceMcDonald’s, Food Safety Officials Scrutinize Onions in E. Coli Outbreak The Wall Street JournalWhat we know about the McDonald’s E. coli outbreak investigation CNN