Manure, my favorite topic of conversation (particularly at parties), is pretty awesome. It has been a staple crop fertilizer virtually since humankind began cultivating its own food. It's everything synthetic fertilizer wishes it could be: Chock full of nutrients, it is — assuming you raise animals — produced for free and delivered at no charge straight to the farm. Particularly for organic producers, whose fertilizer options are limited, manure is gold.
It should not surprise us, then, that the factory livestock industry, having already ruined so many other good things (meat, rural economies, clean air and water), would go and ruin manure, too.
Last week, an article in Environmental Health News covered two studies by a team of researchers at the University of Minnesota and set the sustainable food & ag world abuzz with horror. The studies aren't new - one was written in 2005 and the other in 2007 — but the shock of their findings stings just as bad as it did the first time. In a nutshell: As many Ethicurean readers know, in industrial livestock operations, it's common practice to feed animals subtherapeutic doses of antibiotics (literally, doses that are smaller than what you'd give an animal to cure it of illness — low doses that act as growth promoters, or keep the animals from getting sick). As much as 90% of the antibiotics that animals consume are not absorbed, but are instead excreted in their waste. That waste may hang out in lagoons and leach into water sources, but much of it gets applied to cropland as a fertilizer.
What the Minnesota researchers discovered is that when certain vegetables are planted in soil that's been mixed with said manure, the plants take up the antibiotics, and traces of antibiotic residue are detectable in the part of the plant that you eat.
In other words, there may be antibiotics in your veggies. Even, just maybe, your organic ones. And that's why all the emails and blog posts are flying. Pissed? Read on.
Attack of the superbugs
That concentrated animal feeding operations (CAFOs) overuse antibiotics is not news. According to the Union of Concerned Scientists, as much as 70% of all antibiotics used in the United States are fed to animals that aren't sick. Many of the drugs they're fed are the same ones that doctors rely on to cure human illnesses; penicillin, for example, is one of the more widely used antibiotics in the livestock industry. Over 95% of the antibiotics fed to hogs in the United States are human-use drugs. Damn.
Recent attention to the antibiotic issue has focused on the role CAFOs play in breeding antibiotic-resistant bacteria that can spread to the human population. When bacteria are exposed repeatedly and over long periods of time to the antibiotics that are fed to animals, they evolve to be resistant to them. Then they breed rapidly. Finally, they hitch a ride to Planet Human on workers, farm families, or the wind. The result? A growing number of illnesses that didn't used to kill humans, back in the day when antibiotics worked, now do. (For background, see my previous post from the American Public Health Association conference here or check out the Pew Commission report here.)
The research coming out of UMN adds a new twist to the already depressing story. Both the 2005 study and the 2007 study found that vegetables — corn, cabbage, green onions, potatoes and lettuce — planted in a mix of soil and antibiotic-laced manure take up small amounts of the antibiotics. The more recent study found that only about 0.1% of the antibiotics in the manure are absorbed by the plants, but researchers worry that if humans eat those low doses repeatedly over long periods of time, they could serve as another breeding ground for antibiotic-resistant bacteria. That means faster evolution of superbugs.
How many fruit and vegetable producers use manure from CAFOs to fertilize their crops? There's no way to tell. Farmers have traditionally been hesitant to take manure from CAFOs because the nutrient content is inconsistent and because it often contains nasty stuff like heavy metals, hormones, and (ahem) antibiotics. But CAFO manure is becoming a more attractive option as synthetic fertilizer prices rise; see this article from the Environmental News Network.
Before you start freaking out, remember that these were two studies performed in a controlled laboratory environment. More research is needed to determine how things play out in real-life conditions. The author of the EHN article told me that the UMN scientists will soon begin a new study in which 11 crops are grown for a full season in a field environment to see which take up antibiotics and to determine which antibiotics are most likely to be absorbed. So wait for their results, and in the meantime, take a deep breath.
Now let it out in the form of a loud, piercing scream directed at the industrial livestock industry. The industry's overuse of antibiotics isn't just compromising our strongest line of defense against certain illnesses, though it is certainly doing that, and doing it in the name of pumping out more meat in shorter amounts of time. It may also be exposing many of us to low doses of drugs via a food category that we thought was making us healthier: Produce.
And what's more, the industry's drug addiction could be compromising some organic farms. Organic producers rely heavily on manure as a fertilizer because synthetic fertilizers are off-limits. Many won't be using manure from CAFOs that are feeding their animals antibiotics, but some may not know the origin of all of the manure they apply to their land or the feeding practices of all their suppliers. The authors of the study suggest that organic farmers may need to start testing all of their manure for antibiotics, since the drugs are prohibited in organic production.
If I may offer my humble opinion: THIS SHOULD NOT BE THEIR RESPONSIBILITY.
Parents should not be charged with testing every can of their baby's formula for melamine, and organic producers shouldn't have to pay to defend their farms from a drug that animals shouldn't be shitting out in the first place. (And while we're at it, it shouldn't be a non-GM farmer's responsibility to put up barricades to GM pollen from his neighbor's farm. Seeing a trend?)
The only real solution is banning subtherapeutic use of antibiotics in livestock production. If that means that CAFOs can't maintain business as usual, too bad. This industrial solution to their industrial problem, just like in so many other areas, is just passing the shit off on the rest of us.
For more information on how to channel your outrage productively, see Keep Antibiotics Working.