(CNN) -- Reigning Tour de France champion Alberto Contador has rejected the findings of a positive dope test taken while the cyclist was competing in this year's race, blaming it on bad meat.
Contador was provisionally suspended from competitive cycling by the sport's governing body, the Union Cycliste Internationale (UCI), on Thursday following the results of the test.
The Spanish rider, a three-time winner of cycling's showpiece event, had traces of the banned substance clenbuterol in a test sample he gave on July 21 -- which was a rest day.
However, in a press conference held in the 27-year-old's home town of Pinto in Spain, which CNN attended, Contador said he was innocent.
"It is a food contamination case of which I am the victim." He added that the test result was due to bad meat he and several other riders had eaten the day before the test.
"When they confirmed to me what had happened the first thing I did was ask the UCI which of my fellow riders had passed the test.
"They said the only one who passed the control ... was Alexandre Vinokourov. [He was the only one of the riders] who did not eat the meat on that day." He concluded that truth was on his side.
Contador now faces a fight to clear his name after the UCI released a statement saying: "The UCI confirmed today that Spanish rider Alberto Contador returned an adverse analytical finding for clenbuterol.
"The rider, who had already put an end to his cycling season before the result was known, was nevertheless formally and provisionally suspended as is prescribed by the World Anti-Doping Code.
"This result was reported by the WADA accredited laboratory in Cologne to UCI and WADA simultaneously."
The UCI went on to explain the amounts of the prohibited stimulant found in the sample were low, so a second sample was also tested.
"In view of this very small concentration and in consultation with WADA (World Anti-Doping Agency), the UCI immediately had the proper results management proceedings conducted including the analysis of B sample that confirmed the first result."
Further analysis of the results will now be carried out by UCI and WADA, with no further comment being made until it has been concluded.
"The UCI continues working with the scientific support of WADA to analyze all the elements that are relevant to the case.
"In order to protect the integrity of the proceedings and in accordance with the World Anti-Doping Code, the UCI will refrain from making any further comments until the management of this adverse analytical finding has been completed."
Andy Schleck, who finished runner-up to Contador in this year's Tour De France, said he hoped the Spaniard would prove his innocence.
"I hope he is innocent and I think he deserves the right to defend himself now," Schleck wrote on the micro-blogging site Twitter. "What a crazy day in cycling with the news about Contador. I only heard about it in the press."
Cadel Evans, who finished second to Contador in the 2007 edition, said he wanted to find out the facts of the case before passing judgment.
''I just read some little things in the paper, I don't really know what the situation is. [But] if people are cheating and getting caught, that's a good thing. If people want to exaggerate the stories and ... claim cycling is a filthy sport, that's not such a good thing.
"I don't know exactly what the situation is, they're still waiting on further analysis. I'd like to see what facts come about Contador before I make an opinion.''
Daniel Friebe, features editor of Pro Cycling magazine, believes it is possible the Spaniard could have received the substance in food, and this case is not comparable to other doping scandals in cycling.
Friebe told CNN: "This really does sound like a legitimate excuse.
"It's well known that clenbuterol is used on cattle. This is an alibi that's been used before and it's been verified before. It doesn't sound impossible to me."
He said that people familiar with other incidents of doping in the sport will recognize that Contador has been unlucky.
"Most people who are au fait with how doping within cycling works will be fairly sure that this is quite different to other cases," he said.
Friebe also explained how taking clenbuterol would not make sense for Contador and it could possibly have a negative effect on his performance.
"He is well known for his climbing ability. This substance is a steroid, which will boost muscle mass and make him heavier. It's not really the kind of substance you would expect a rider like him to take."
Contador, who has just signed a contract with the Saxo Bank team, successfully defended his Tour title while riding for the Kazakhstan-based Astana team.
The Spaniard won his first Tour in 2007 and joined Astana in 2008 -- although he was prevented from defending his title that year as the team had been banned by race organizers for previous doping violations.
In 2006, Contador was linked to a Spain-based blood-doping ring known as "Operation Puerto" but was cleared of any wrongdoing.
The only previous winner of the Tour de France to be stripped of his title after being found guilty of using a banned substance was Floyd Landis.
The American was found to have taken testosterone while winning the 2006 race.