Mexican football authorities say the five players dropped from its Gold Cup squad after testing positive for clenbuterol have now tested negative for the banned substance.
The Mexican football federation said on Tuesday that results from a University of Los Angeles, California laboratory test performed on June 10 are negative for all five, including goalkeeper Guillermo Ochoa and PSV Eindhoven defender Francisco Rodriguez.
The federation said in a statement the five - which also includes defender Edgar Duenas, and midfielders Christian Bermudez and Antonio Naelson - have now requested a backup "B'' test of the initial samples taken May 21 that tested positive.
The players and some officials blamed the positive results, which occurred during a pre-tournament training camp on the outskirts of Mexico City, on contaminated meat. Tour de France champion Alberto Contador also has blamed contaminated beef for his positive test for clenbuterol last July.
Mexican agriculture officials have put that reason in doubt, saying very few cases of contamination exist.
Despite the loss of its players, Mexico has easily advanced to the Gold Cup quarterfinals as the top team from Group A, with 14 goals so from the tournament.