Canelo Alvarez tested positive for the banned substance Clenbuterol, but his highly anticipated rematch with Gennady Golovkin set for May 5 remains on.

That’s because the result included “trace levels of Clenbuterol consistent with meat contamination that has impacted dozens of athletes in Mexico over the last years,” according to a statement released Monday by Golden Boy Promotions, which guides Canelo’s career.

Tom Loeffler, who promotes Golovkin, couldn’t be reached for comment.

Indeed, Mexico has spurred many positive tests for Clenbuterol over the years, including claims from boxers Francisco Vargas, Luis Nery and Erik Morales, who say contaminated meat was the cause of the substance in their system.

The positive result was discovered by a test conducted at SMRTL, a World Anti-Doping Agency-accredited lab. Daniel Eichner, the director of SMRTL, said “these values are all within the range of what is expected from meat contamination.”

Clenbuterol is a powerful bronchodilator that is used to treat breathing disorders like asthma. It’s also used as performance-enhancing substance by athletes, mainly as a fat burning tool. The substances helps increase muscle mass and reduce body fat. It’s listed on WADA’s prohibited list, and is classified as an anabolic agent because it promotes muscle growth through anabolic properties.

Meat is often treated with Clenbuterol in order to create leaner meat with a higher muscle-to-fat ratio. It’s been banned in meat since 1991 in the United States, though it remains in Mexico.

Canelo, THE RING’s middleweight champion, moved his training camp from Mexico to California immediately, which he was planning to do anyway.

“I am an athlete who respects the sport and this surprises me and bothers me because it had never happened to me,” said Alvarez (49-1-2, 34 knockouts). “I will submit to all the tests that require me to clarify this embarrassing situation and I trust that at the end the truth will prevail.”

Alvarez and Golovkin (37-0-1, 33 KOs) put on a thrilling fight in September, one that ended in controversy with a majority draw. Many fans and media members alike felt Golovkin earned the nod, and each man has vowed to take the judges out of the equation in the rematch.

The fighters formally announced the fight at an event in Los Angeles last Tuesday to much fanfare.

Now, it remains to be seen what steps will be taken to ensure the fight is contested on an even playing field.

Mike Coppinger is the Senior Writer for RingTV.com. Follow him on Twitter: @MikeCoppinger