Five Mexico players suspended from the Concacaf Gold Cup after failing a doping test had eaten contaminated meat and should be cleared after a second test, according to Mexican FA sources.
The Mexican Football Federation said on Thursday that the players had all tested positive for the banned substance clenbuterol from tests carried out in Mexico on May 21.
Clenbuterol can be used to speed up and increase muscle mass in animals. A number of athletes, including three-time Tour de France champion Alberto Contador, have blamed their positive test results on eating meat adulterated with the steroid.
Hector Gonzalez, the Mexican football federation's (Femexfut) director of national teams, said the players had eaten tainted meat at Mexico's High Performance Centre where the team were preparing for their defence of the Gold Cup.
"Unfortunately, by accident, these players ate beef contaminated with the substance clenbuterol," he told a news conference following Mexico's 5-0 win over Cuba in Group A.
Gonzalez said Mexican farming officials were looking into beef supplies at the centre.
"We're confident that with the investigation that is being carried out we'll be able to clarify (the situation) and reach a happy conclusion," he added.
Femexfut general secretary Decio de Maria earlier named the players as goalkeeper Guillermo Ochoa, defenders Francisco Rodriguez and Edgar Duenas, and midfielders Antonio Naelson 'Sinha' and Christian Bermudez.
De Maria said the players, who face bans of up to two years, had all been suspended from the tournament.
Gonzalez said the players would fly to Los Angeles on Friday for another test at the University of California Los Angeles's certified laboratory which would "surely be negative."
"We will ask also for the B samples (of the original tests) to be opened and we will await the results," he added.
Mexico had only 17 players available for their match against Cuba, a second successive 5-0 victory saw them qualify for the quarter-finals. Defender Ricardo Osorio left for home earlier in the week due to illness.
Gonzalez said Mexico had appealed to be allowed to call up five replacements, a request that would be dealt with by the organisers at a meeting on Friday.
He added that tournament rules stated the team could not be docked the points of their win against El Salvador on Sunday because the results of the doping tests were unknown when the match was played.
El Salvador's Uruguayan coach Ruben Israel said he hoped the Mexicans had not obtained Sunday's victory through cheating and he did not want to make a premature judgment.
"It's a tremendously delicate matter that touches the morals of the (Mexican) players and national team," Israel said after his team's 1-1 draw with Costa Rica in an earlier Group A match.
"I'm sure my federation will come down with all their might on this issue if it's confirmed (that Mexico faced us with doped players)," he said.
De Maria earlier said there was a health alert in Mexico because of food contaminated with clenbuterol.
Mexico denied in April that its beef contained clenbuterol days after Germany's anti-doping agency advised athletes not to eat products from Mexico because it might increase the risk of involuntary positive doping results.comments