Ever since Jo Robinson wrote Why Grass Fed is Best! in 2000, we’ve known there were many sound reasons to choose grass-fed beef instead of the far more common corn-fed beef found in most stores and restaurants.
Beef from animals raised entirely on their natural diet of grass has much less fat, which is good for our hearts and our waistlines. It’s also better for the environment than crowding cattle onto feedlots, which causes serious problems with air and water quality. Unfortunately, what we’re suddenly becoming more attuned to is another point Robinson makes about feeding cattle corn: This unnatural grain-based diet is producing toxic E. coli bacteria.
E. coli 0157:H7, the toxic strain that caused the recent outbreak of food poisoning from bagged spinach, is a fairly recent discovery; it was unknown before 1982. Today, it is common in cattle and in their manure, and it’s also now found in healthy goats, sheep and deer. But humans have a tough time with this bug. If we consume even a tiny speck of this new E. coli — even just 10 bacteria — it can make us very ill. Usually we recover, but a few will die or suffer permanent kidney damage.
One of the reasons this new strain makes us sick is that it is more acid-resistant than other forms of E. coli, so it can pass through our stomachs unharmed into the intestines, where it produces a toxin that causes diarrhea and organ damage. So, how did an acid-resistant strain of E. coli develop? Most outbreaks have been linked to cattle, and one major change in beef production in recent decades has been the confinement of cattle to feedlots where they are fed high-grain diets. It is now clear that forcing cattle to eat an unnatural high-grain diet, rather than their natural diet of grass, isn’t good for the cows, or for us. Here’s how Michael Pollan explains it in his brilliant new book, The Omnivore’s Dilemma:
“A concentrated diet of corn can give a cow acidosis. Unlike our own highly acidic stomachs, the normal pH of a rumen is neutral. Corn renders it acidic, causing a kind of bovine heartburn that in some cases can kill the animal, but usually just makes him sick. … Over time the acids eat away at the rumen wall, allowing bacteria to enter the animal’s bloodstream. These microbes wind up in the liver, where they cause abscesses. … In this new, man-made environment new acid-resistant strains of E. coli, including 0157:H7, have evolved … by acidifying the rumen with corn we’ve broken down one of our food chain’s most important barriers to infection.”
E. coli 0157:H7 can persist in soils for months, and it moves in runoff from feedlots to contaminate our waterways, where it can be carried into produce fields by flooding. Research also has shown that this deadly bacteria can even be taken up by lettuce and spinach roots and move into the leaves of the plants. In short, because many beef producers have chosen to use this unnatural, inhumane practice, this deadly new bacteria has emerged and now threatens the health of everyone. Yet again we discover too late: It’s not nice to fool with Mother Nature.
To learn more, including how this issue connects to larger topics of food production and government farm policies, we highly recommend The Omnivore’s Dilemma, and Jo Robinson’s newest book, Pasture Perfect.