Brazil’s state-controlled oil giant Petróleo Brasileiro SA, or Petrobras, has made the changes that were necessary to get past the corruption scandal that has shaken the country over the past year, President Dilma Rousseff said Thursday in a visit to Rio de Janeiro state.

Petrobras “has cleaned up what needed to be cleaned, throwing out the people it needed to get rid of that had taken advantage of their positions to enrich” themselves, Ms. Rousseff said in a ceremony at a government housing project.

Brazilian prosecutors allege that former executives of the oil company and some of Brazil´s largest construction firms colluded to inflate contract prices, kicking back a portion of the gains to lawmakers and other officials to fund political campaigns.

Ms. Rousseff, who served as Petrobras’s chairwoman for seven years, hasn’t been implicated in the scandal. The allegations have nevertheless become a big problem for the president, who needs popular support to get unpopular fiscal measures approved and get the country´s finances in order.

On Thursday the president praised Petrobras for producing oil from the deep-sea deposits known as the pre-salt area, and said the company is ready to move on.

“Petrobras has overcome this phase, now it will follow its path,” Ms. Rousseff said.

Petrobras, whose debt has already been downgraded to junk status by Moody´s Investors Service, could suffer more downgrades in the near future. The company has yet to release audited third-quarter financial results, and any fourth-quarter earnings figures, as it tries to find a way to measure the impact of the corruption scandal.

Analysts say Petrobras could release its earnings as soon as next week, but the company recently said it hasn’t yet set a date and will have results out as soon as possible.

On Thursday, Ms. Rousseff´s Workers´ Party Treasurer João Vaccari Neto testified before a congressional committee investigating the alleged corruption at Petrobras. He said that donations to his party were all legal and approved by the country’s electoral court.