McDonald's is naming the supplier believed to be responsible for causing an E. coli outbreak linked to the company's Quarter Pounders across 10 states, as the number of infected people climbed to 75 Friday.

Health officials say that recalls of onions — the suspected source of the contamination — would help lessen the risk to consumers. Other major fast-food chains have also stopped offering onions.

Seventy-five people across 13 states have fallen ill in an E. coli outbreak attributed to McDonald's Quarter Pounders.