The eight Tunisian players are said to have tested positive for the banned substance clenbuterol.
Neither the International Football Association Board (FIFA) nor the Tunisian Football Federation have commented on the information.
Clenbuterol increases muscle mass and reduces body fat.
It is a doping agent that is notorious, and is a muscle-building agent that is not available for human use but is used, for example, in Mexico and China to make meat animals grow large before they are slaughtered, says Åke Andrén Sandberg, medical expert in the Swedish Sports Federation's doping commission.
Baptized by meat
According to The Times, the players ingested the substance by eating contaminated meat at their World Cup base in Mexico.
It occurs in meat in Mexico, and the Swedish leaders know this, for example. So when Swedish sports teams go to countries like Mexico, China and Colombia, they don't eat their meat but bring their own. It's very well known, says Andrén Sandberg.
The Times reports that the levels of the substance are low, and that the risk of punishment is low.
Clenbuterol is banned in all doses, so they are declared doped, that's for sure. But if you can show that it was unintentional, they won't get any punishment.
Does not affect
Andrén Sandberg does not believe Tunisia was physically affected by the substance, either positively or negatively.
Anabolic steroids of this nature, it's something you build up over months, he says.
Tunisia lost all three group matches at the World Cup, including a 1-5 defeat by Sweden in the opening match, and conceded a total of twelve goals. The Netherlands and Japan were also in the group.
