FIFA president Sepp Blatter says five Mexico footballers who tested positive for clenbuterol did so because they ate food that was ''definitely'' contaminated, and he says he backs the decision of the Mexico Football Federation to exonerate the players.

Blatter is in Mexico for Sunday's final of the under-17 World Cup.

The Mexican federation said Friday it would not punish the five players, who tested positive during a training camp in May.

Tour de France champion Alberto Contador also blamed contaminated meat for his positive test for clenbuterol last July.