Gennady Golovkin plans to go ahead with his rematch against Canelo Álvarez on 5 May, even after Álvarez failed a doping test last month. But Golovkin also believes Álvarez is a cheater whose attempt to blame the test on bad meat is a joke and a symptom of more extensive corruption in boxing.

“Again with Mexican meat? Come on,” Golovkin said on Tuesday, after Álvarez said he had eaten contaminated meat while on a visit to his home country.

“I told you, it’s not Mexican meat,” Golovkin added. “This is Canelo. This is his team. This is his promotion. ... Canelo is cheating. They’re using these drugs, and everybody is just trying to pretend it’s not happening.”

Golovkin (37-0-1, 33 KOs) spoke pointedly about Alvarez (49-1-2, 34 KOs) before a workout at his high-altitude training camp in southern California. For the first time, the unbeaten Kazakh middleweight champion repeatedly said he believes Álvarez has used banned substances for previous fights, including their first bout last September.

“You should take a look at the photos and ask a doctor,” Golovkin said. “Ask any doctor. Let him explain what those [muscles] are. It’s better even to use the lie detector. Then there wouldn’t be any silly questions about meat or fruits or chocolate.”

Golovkin also accused Oscar De La Hoya, Álvarez’s longtime promoter and a former six-division champion, of doping. “I can talk about Oscar De La Hoya, too. He is also not clean. He’s dirty.”

Álvarez tested positive for clenbuterol in mid-February in the fighters’ voluntary anti-doping program, and the results were revealed two weeks ago. Eric Gomez, the president of De La Hoya’s Golden Boy Promotions, responded sharply to Golovkin’s comments.

“He doesn’t sound like a confident fighter,” Gomez said. “GGG is trying to find a way out. If he doesn’t want the fight, he should just say so. Just last week he said the exact opposite. His remarks about needle marks, Oscar and every other lie are outrageous, false and defamatory, and we will deal with them appropriately.

“As for Canelo, he is focused on his training. He didn’t need any more motivation, but now he has it.”

The Nevada Athletic Commission still hasn’t announced whether it will level any disciplinary action against Álvarez, or even when it might hold a public hearing about its decision.

Golovkin is still upset about the verdict in his first bout with Álvarez. Golovkin and his camp felt they comfortably won the bout, which was ruled a draw.

“He’s always been the favorite, always had benefits,” Golovkin said. “I don’t think I would have the same amount of benefits as he has. That’s why I never use any drugs, because I know there won’t be any preferences to me.”

If the Nevada commission postpones the rematch, promoter Tom Loeffler echoed Golovkin’s interest in booking a middleweight title unification bout with Britain’s Billy Joe Saunders, who holds one of the four major belts.