Canelo Álvarez has tested positive for trace levels of the performance-enhancing drug clenbuterol ahead of his 5 May bout with Gennady Golovkin, the boxer’s promoters Golden Boy Promotions have announced.

Golden Boy have moved to attribute the result to meat contamination, with support from the laboratory that conducted the tests. The Mexican fighter attended a voluntary drugs test before his rematch with multiple world middleweight champion Golovkin, which is still scheduled to take place as planned.

“As part of the voluntary testing programme that Canelo Álvarez insisted on ahead of his 5 May fight, one of his results came back positive for trace levels of clenbuterol, consistent with meat contamination that has impacted dozens of athletes in Mexico over the last years,” read a statement from Golden Boy Promotions.

“As Daniel Eichner, director of SMRTL, the Wada-accredited lab that conducted the tests stated in his letter (on Monday): ‘These values are all within the range of what is expected from meat contamination’. Upon receiving this information, Golden Boy immediately notified the Nevada State Athletic Commission and Golovkin’s promoter, Tom Loeffler.”

Wada has previously issued warnings to athletes travelling to Mexico over the risks of eating meat. UFC fighters Brandon and Augusto Moreno both avoided suspensions after claiming positive tests for clenbuterol came from contaminated meat. Another, Francisco Rivera, was given a four-year suspension after Usada rejected his version of events.

Clenbuterol, often used by asthmatics, has fat burning properties and athletes have been known to use it to help them drop body fat and weight quickly. Among those who have tested positive for it are baseball players Raul Mondesi and Guillermo Mota and cyclist Alberto Contador.

Golden Boy said Álvarez will immediately move his training camp from near Guadalajara in Mexico to the United States and will submit to any number and variety of additional tests. The promoters added that the 27-year-old has tested clean dozens of times over the course of his previous 12 fights.

Álvarez said: “I am an athlete who respects the sport and this surprises me and bothers me because it had never happened to me. 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.”