MADRID -- Alberto Contador was stripped of his 2010 Tour de France title Monday and banned for two years after sport's highest court found the Spanish cyclist guilty of doping.

The Court of Arbitration for Sport suspended the three-time Tour champion after rejecting his claim that his positive test for clenbuterol was caused by eating contaminated meat on a 2010 Tour rest day.

The three-man CAS panel upheld appeals by the International Cycling Union and World Anti-Doping Agency, which challenged a Spanish cycling tribunal's decision last year to exonerate Contador.

"The presence of clenbuterol was more likely caused by the ingestion of a contaminated food supplement," CAS said in its ruling in Lausanne, Switzerland.

CAS backdated Contador's ban and he is eligible to return to competition on Aug. 6. The ban means Contador will miss the Giro d'Italia, the Tour de France and the London Olympics, but he would be eligible to ride in the Spanish Vuelta, which begins Aug. 18.

Contador had no immediate comment and is expected to hold a news conference Tuesday. He can appeal the verdict to Switzerland's supreme court.

WADA president John Fahey described the court's judgment as "an appropriate decision ... which represents the effective nature of the World Anti-Doping Code."

"It is regrettable there was some political interference at the first instance process from Spain which inevitably led to the appeal," Fahey said Monday.

The ruling on Contador came just three days after U.S. federal prosecutors dropped a doping investigation involving seven-time Tour winner Lance Armstrong. The American was a teammate of Contador during the Spaniard's 2009 Tour victory. The revised list of champions shows Armstrong and Contador combined to win nine of the 11 Tours from 1999 to 2009.

Contador is one of only five cyclists to win the three Grand Tours -- the Tour, the Giro and the Vuelta. He also won the Tour de France in 2007 and 2009.

Contador becomes only the second Tour de France champion to be disqualified and stripped of victory for doping. The first was Floyd Landis, the American who lost his 2006 title after testing positive for testosterone.

Andy Schleck of Luxembourg, who finished second at the 2010 Tour, stands to be elevated to victory.

"There is no reason to be happy now," Schleck said in a statement issued by his team, RadioShack Nissan Trek. "First of all I feel sad for Alberto. I always believed in his innocence. I battled with Contador in that race and I lost."

Contador blamed steak bought from a Basque producer for his high reading of clenbuterol, which is sometimes used by farmers to fatten their livestock.

To avoid a doping ban, he needed to prove how the anabolic drug entered his body and convince the panel he was not to blame.

Luxembourg's Andy Schleck, right, who finished second at the 2010 Tour de France to Alberto Contador, stands to be elevated to victory. Joel Saget/AFP/Getty Images

CAS said both the meat contamination theory and a blood transfusion scenario for the positive test were "possible" but "equally unlikely."

"The Panel found that there were no established facts that would elevate the possibility of meat contamination to an event that could have occurred on a balance of probabilities," CAS said. "Unlike certain other countries, notably outside Europe, Spain is not known to have a contamination problem with clenbuterol in meat. Furthermore, no other cases of athletes having tested positive to clenbuterol allegedly in connection with the consumption of Spanish meat are known."

CAS secretary general Matthieu Reeb said the doping offense was "not contested," only the explanation for how the clenbuterol got into Contador's system.

"It is just the application of the rules, the fact that there was a positive test," Reeb told reporters. "In the end, it is not so spectacular. There is a clear decision based on a positive test. There was no reason to exonerate the athlete, so the sanction is two years."

Contador kept racing after his positive test on a 2010 Tour rest day. He will be stripped of all results from races in which he participated since Jan. 25, 2011 -- the day the Spanish federation proposed a one-year ban. That period includes his Giro d'Italia victory last season.

"This is a sad day for our sport," UCI president Pat McQuaid said. "Some may think of it as a victory, but that is not at all the case. There are no winners when it comes to the issue of doping: Every case, irrespective of its characteristics, is always a case too many."

CAS said it would rule later on a request by UCI to fine Contador $3.25 million.

Tour de France director Christian Prudhomme said he was relieved a resolution was reached, though the case had revealed many of the sport's problems in dealing with doping cases.