A couple of my facebook friends are among the 755 people* who’ve shared this image, originally posted by the Maine Organic Farmers and Gardeners Association (MOFGA). It’s part of a broader campaign against Monsanto’s Bt sweet corn that’s starting to heat up because the first commercial crop is poised to debut in supermarket produce bins this summer.
Important disclaimer: I’m not a fan of Monsanto. I think they represent some of the worst tendencies of monopolistic, profit-driven enterprise. They bully farmers to buy their seeds every year and sue the ones who don’t if patented seed gets into their fields anyway, whether or not the farmers wanted it there (see: Food, Inc., The World According to Monsanto, Knight-Ridder/Tribune, Examiner.com). They risk their workers’ health and pollute the environment, often at great public cost (see: Wikipedia, Washington Post, Environmental Working Group). They have fired whistle-blowing scientists willing to talk to journalists about the potential health risks of their products (see: New York Times). Their PR is Orwellian in a way that strikes me as somewhere between darkly hilarious and seriously unnerving (see: their website**). They’d make an outstanding movie villain.***
In fact, Monsanto is so stereotypically evil that I totally understand why people are willing to believe that food grown from their seed is dangerous, that Monsanto could be aware of this but try to sell it to you anyway, and that the regulatory agencies who ought to stop them have probably been effectively bought off.^ However, that’s not what’s happening here. I’m reasonably certain that Bt sweet corn is totally safe for human consumption. If it’s not and Bt is a real threat, then no sweet corn you can buy is safe for human consumption because Bt insecticides have been used by organic farmers for over 50 years.
How Bt Works
What’s wonderful about Bt-toxin is that it’s only toxic to insect larvae. Rather than referring to Bt compounds as “toxins,” it would probably be more accurate to call them proteins.^^ Unless you happen to be a larval-stage weevil or gypsy moth, in which case the description of what happens in the ad is fairly accurate: it binds to your gut, ruptures your intestines and you die.
These larvae-killing proteins occur naturally in the spores of a soil bacterium called Bacillus thuringiensis. The proteins are activated by the digestive juices of vulnerable caterpillars, and here’s James McWilliams’ account of what happens next:
Precisely what happens with the Bt-toxin is, in its own way, a masterpiece of natural adaptation. Certain insects that ingest the bacterium cease processing potassium. As a result, they become paralyzed and die as their cells drown in a cascade of water. As so often happens with life down in the dirt, one organism’s demise is another’s meal ticket. Indeed, the besotted gut mucosa of the dead insect becomes a fertile breeding ground for millions of Bt spores, which proceed to grow exponentially, catch a gust of wind, and dust the topsoil with a layer of natural repellent. If anything can be called natural, this would seem to be it. (Just Food p. 87)
Bt insecticides are also highly specific. Each Bt strain is only effective against the larvae of a handful of species. They’re not even effective against the adults of those species, let alone other kinds of insects (including agriculturally-useful ones like bees). So it’s not true that Bt is designed to rupture the stomach of “any insect” that feeds on it. Nor does it matter if it breaks down before it gets to your dinner table, although it probably does because it breaks down pretty easily, especially when exposed to UV light (source: UCSD Aorian Laboratory).
According to the Environmental Protection Agency, Bt is so safe that the EPA has exempted Bt insecticides from its food residue tolerances, groundwater restrictions, endangered species labeling and special review requirements. Bt has no known effects on fish, birds, or mammals, with one exception: if you apply it directly to rabbits’ eyes, they get irritated. Researchers note that that may be caused by the formulation tested and not the Bt itself (source: UCSD Aorian Laboratory).^^^
So this isn’t some crazy, newfangled technology. We have no idea how old the bacterium is, although it probably evolved along with the larvae it attacks, which may have evolved along with the plants they target. It was first discovered in 1901 by a Japanese biologist. In 1911, it was independently discovered in Germany and identified as the cause of a disease affecting flour moth caterpillars. It’s been used to control insect pests since the 1920s and was first developed for commercial use in 1958. It’s not synthetic, doesn’t accumulate in the soil, and poses no threat to wildlife, water, or human health, so it has always been compatible with the current restrictions on pesticides approved for “organic” farming (sources: Wikipedia and UCSD).
Using GM seed as a delivery mechanism for the protein is newer, although that’s been happening for the better part of two decades with no apparent negative effects. In 1987, the gene that produces the insecticidal protein in the bacterium was successfully transferred to tobacco and cotton. Transgenic Bt food crops including commodity corn and potatoes have been grown in the U.S. since 1996. The only thing that’s new and different about Bt sweet corn is that it’s designed for immediate human consumption rather than cattle feed or high fructose corn syrup. Since there’s no reason to believe that Bt is bad for you, before or after it passes through a cow’s gut or refining plant, there’s no reason to believe that Bt sweet corn is some kind of strange, new, scary thing. Unless you happen to be an organic farmer who grows sweet corn, in which case you may be relying on the far-less-efficient process of applying Bt insecticides externally via spraying, which must be repeated at least half a dozen times throughout the growing season. Then, I imagine you might indeed feel threatened by farmers who can grow plants that produce the very same proteins themselves. Read more »