FIFA have revealed more than 100 players at the Under-17 World Cup in Mexico tested positive for stimulants due to contaminated meat.
Jiri Dvorak, chief medical officer for world football's governing body, announced on Monday that samples provided by players from 19 of the 24 squads at the tournament - that ended in July - tested positive for banned substance clenbuterol.
After four players at the youth competition tested positive, FIFA opted to analyse all 208 urine samples collected, with the steroid found to be present in more than half of them.
Suspicions were aroused by the fact five players from Mexico's senior squad for the CONCACAF Gold Cup had previously tested positive for the same substance in May.
The players were later deemed to have unwittingly ingested the drug through tainted food consumed on a training camp in Mexico.
The Mexican government has since launched a crackdown on the illegal use of steroids in the country's meat industry.
According to Dvorak, the amount of clenbuterol ingested by the Under-17 athletes was not harmful to the players.
"FIFA was very alarmed and it was highly surprising to see something like this – I had not seen anything like it in my 20 years in this post," Dvorak said.
"My first question was: 'Could any harm have been done to the players?' and I was assured by the different medical specialists the answer is no."
Cyclist Alberto Contador tested positive for clenbuterol during his victorious 2010 Tour de France campaign.
He blamed contaminated meat and was cleared by the Royal Spanish Cycling Federation (RFEC).
The RFEC's exoneration of Contador is the subject of a World Anti-Doping Agency appeal, set to be heard by the Court of Arbitration for Sport in November.