Contador pleaded his innocence after he was provisionally suspended by the International Cycling Union (UCI) in the latest doping affair to rattle the world of professional cycling.

Contador, repeating a statement which he issued earlier for the Spanish press, told a news conference in his hometown near Madrid that the test result was "a clear case of food contamination" and called the UCI's suspension "a true mistake".

He claimed the contaminated meat was brought across the border from Spain to France during a rest day at the Tour.

He said there were complaints about the food at the hotel where the team was staying.

The UCI announced Contador’s provisional suspension, saying a doping test the rider took in July found traces of clenbuterol, a banned anabolic agent.

A statement on the UCI's website said the case would require further investigation before any conclusion could be drawn and that a final decision could take more time.

The UCI said that the "adverse analytical finding" of clenbuterol, was detected in a urine sample taken during the second rest day of this year’s Tour de France.

A very small concentration of the doping agent prompted a second analysis that confirmed the initial result, the UCI said.