The health authorities of Mexico are cracking down on cattle merchants who use the banned substance clenbuterol to make the meat from livestock less fatty.

The measure was launched after clenbuterol turned up in the urine of 109 players from various countries taking part in the Under-17 soccer world championship, an event hosted by Mexico in June and July.

“Steps taken by the Mexican government have reduced the number of cases of such contamination from 555 in 2005 to 89 in 2010,” Mikel Arriola, director of the Federal Commission for Protection against Health Risks, said in a conference call to Mexican Soccer Federation headquarters.