(Reuters) -McDonald's was sued on Tuesday by consumers in a proposed class action stemming from the E.coli outbreak linked to onions in the fast-food chain's Quarter Pounders.

In a complaint filed in Chicago federal court, Amanda McCray and William Michael Kraft said they experienced many symptoms associated with E.coli infection after buying Quarter Pounders this month. They said they would not have bought their burgers had McDonald's disclosed the risk of contamination.

The lawsuit seeks damages for all people in the United States who bought Quarter Pounders contaminated with E.coli.