WADA said it accepted FIFA's "compelling evidence" from the recent Under-17 World Cup in Mexico that the country has a "serious health problem" with meat contaminated with clenbuterol.
FIFA accumulated the evidence while working with the government of Mexico. "The studies conducted by FIFA showed the correctness of the footballers' claim that the positive samples were the result of meat they had ingested at a training camp ahead of the tournament," the governing body of international soccer said.
In June, Mexico won the Gold Cup despite the absence of goalkeeper Guillermo Ochoa, defenders Edgar Duenas and Francisco Rodriguez and midfielders Antonio Naelson and Christian Bermudez. It beat the United States 4-2 in the final.
Mexico's government has agreed to address the issue of farmers giving steroids to livestock, which is illegal, WADA said. "Already several arrests have been made pursuant to these laws and large amounts of clenbuterol seized. Investigations are to continue," WADA added.
WADA issued a warning to athletes traveling to Mexico to compete at the two-week Pan American Games, which open Friday in Guadalajara, that if possible they should eat in cafeterias designated as safe by event organizers and also try to eat in large numbers. "The state government in Guadalajara has taken steps to ensure the meat available to athletes at the Pan American Games will not be contaminated," it added.
This most recent case marks the second time this year that WADA has dropped an appeal after an athlete used a defense of contaminated meat to explain consuming clenbuterol.
German table tennis player Dimitrij Ovtcharov tested positive after competing in China, which also has long-standing issues with illegally feeding steroids to livestock. Three-time Tour de France winner Alberto Contador will use the same argument as part of his defense at CAS next month.
WADA and the International Cycling Union appealed to the sports court after a Spanish cycling federation tribunal accepted Contador's explanation that he inadvertently ate a contaminated steak during his 2010 Tour victory. Contador's four-day hearing is set to begin Nov. 21.