You might have watched some of the coverage of the Tour de France in recent years, if only to see whether former seven-time champion Lance Armstrong could complete an improbable comeback at age 38.

He didn’t, and in fact, his short-lived return to professional cycling had about as much drama as Michael Jordan’s equally unremarkable comeback with the Washington Wizards basketball team a few years back.

And unless you’re a hardcore cycling fan, you probably haven’t even heard about the doping allegations swirling around the defending Tour de France champion, Spanish star Alberto Contador. But his story is worth reviewing because it puts meat-eating and livestock production back on the front burner, media-wise.

And not in a good way.

Contador, the world’s top cyclist and one of only five riders to win the sport’s premier stage races—the Tour de France, the Giro d’Italia and the Spanish Vuelta—is a three-time Tour titleist who’s no stranger to doping allegations. He was unable to defend his first title in 2008 after his entire Astana team was banned for doping.

Then last July, Contador tested positive for a minute amount of clenbuterol during the 2010 Tour. Clenbuterol, well-known to the beef industry as an anabolic—and illegal—steroid that stimulates lean carcass growth in cattle, is a banned substance in athletics. In cattle, it increases lean carcass weight. In humans, it adds muscle mass and burns off fat, two very valuable assets for professional cyclists, who generally tip the scales at a buck-fifty or so.

When the positive test was announced, Contador claimed that a Spanish butcher had personally supplied special steaks for he and his teammates to enjoy at a rest day meal during the Tour, and that the clenbuterol must have come from tainted beef. Since the World Anti-Doping Agency, the governing body for Olympic sports, has a zero tolerance policy for clenbuterol, any amount whatsoever—even the 50 trillionths of a gram found in Contador’s system—is considered a violation.

Pumped full of drugs

So is Contador’s story plausible? As sportswriter Jim Caple put it when the Spanish Cycling Federation cleared Contador of any blame yesterday, “Apparently, Alberto Contador was able to convince Spanish cycling authorities that clenbuterol is simply one of the ingredients in Heinz 57 steak sauce.”

That’s likely the attitude of many casual sports fans: Professional cycling is rife with all sorts of doping allegations, and several of the sport’s prominent stars in recent years have openly admitted to using various performance enhancing drugs. At the end of the day, cycling is but a minor blip on the American sports scene, so who cares if some Spanish guy gets banned or not?

On the other hand, there are far more people who now find reinforcement for the notion that cows are routinely “pumped full of steroids and antibiotics,” as anti-industry activists’ favorite phrase categorizes beef production. And that’s where the problem lies.

Personally, I’ll confess to being a passionate cycling fan, and I’ll admit that many of the superhuman mountain climbs and time trial results the sport’s top athletes routinely produce are difficult to imagine that they occurred with training only. Moreover, I’m loathe to believe that clenbuterol is appearing in beef steaks in sufficient quantities to trigger a positive drug test, especially in Europe, which has banned the use of synthetic hormones in livestock production.

But hold on.

The German Sports University lab in Cologne, which is accredited by the World Anti-Doping Agency, claims that people can indeed inadvertently ingest clenbuterol from eating contaminated meat. A recent investigation by the lab discovered that 22 out of 28 travelers returning to Germany from China tested positive for low levels of clenbuterol.

“Those figures are most probably due to a food contamination problem, potentially caused by misuse of clenbuterol as growth promoter in stock breeding,” lab officials said in a statement. And in China, clenbuterol’s illegal use in livestock production is fairly well documented.

Plus, Contador isn’t the only athlete who floated the “my steak must have been contaminated” defense. Italian cyclist Alessandro Colo received a one-year earlier this year ban after an Italian tribunal accepted his argument that tainted beef caused his positive clenbuterol test. German table tennis player Dimitrij Ovtcharov used the same defense after testing positive for the drug, and the German governing body didn’t sanction him. And dozens of Chinese athletes have tested positive for clenbuterol in the past three years and received bans, despite their claims of beef contamination.

The German labs’ findings appear to offer the strongest proof yet that athletes can test positive inadvertently from contaminated food.

“One thing is clear: I am not going to ingest any more meat,” Contador said after being cleared of doping charges.

That may be a smart PR position on his part, but it’s a disturbing commentary on beef production.

Cycling certainly doesn’t have any broad appeal among Americans. But beef-eating definitely does, and this sad saga darkens the image of that all-American pastime far worse than any lingering effects the Contador case might have on professional cycling. □

Dan Murphy is a veteran food-industry journalist and commentator