Ricco's positive test is the third to hit this year's Tour de France
Tour de France organisers believe Italian Riccardo Ricco's failed test proves that cycling is winning the battle against doping.
Ricco is the third rider at this year's event to test positive for the banned blood booster erythropoietin (EPO).
"We're getting closer to an acceptable situation," said Patrice Clerc, president of Tour organisers Amaury Sport Organisation (ASO).
"This is a message of hope which means we're winning the game against doping."
He added: "We are building the foundations for a new professional cycling and we're closer than ever to achieving it.
"We're winning because we're kicking these people out of cycling."
Ricco, who won two mountain stages of this year's Tour and was sitting ninth in the overall standings, follows Spanish riders Moises Duenas Nevado and Manuel Beltran in failing a test.
The 24-year-old Saunier Duval rider tested positive after the fourth stage last week, the same stage as Duenas Nevado's failed test, and was detained by French police after being removed from the Saunier Duval team bus ahead of Friday's stage 12.
Following the announcement of Ricco's positive test his team decided to withdraw from the Tour.
And the news of Saunier Duval's withdrawal will come as a blow to veteran team member Leonardo Piepoli, who won Monday's tenth stage.
"We've decided to suspend all cycling activities until we find out what has happened," team spokesman Matxin Fernandez said.
"Ricco is not just any rider, he's a top rider. So for the sake of our team and the Tour de France we have made this decision.
"We can't act as though nothing has happened, we have to accept the reality."