by Nina Planck
This ran in
The New York Times on September 21, 2006.
Leafy Green Sewage
Farmers and food safety officials still have much to figure out
about the recent spate of E. coli infections linked to raw
spinach. So far, no particular stomachache has been traced to
any particular farm irrigated by any particular river.
There is also no evidence so far that Natural Selection Foods,
the huge shipper implicated in the outbreak that packages salad
greens under more than two dozen brands, including Earthbound
Farm, O Organic and the Farmer's Market, failed to use proper
handling methods.
Indeed, this epidemic, which has infected more than 100 people
and resulted in at least one death, probably has little do with
the folks who grow and package your greens. The detective trail
ultimately leads back to a seemingly unrelated food industry -
beef and dairy cattle.
First, some basic facts about this usually harmless bacterium:
E. coli is abundant in the digestive systems of healthy cattle
and humans, and if your potato salad happened to be carrying the
average E. coli, the acid in your gut is usually enough to kill
it.
But the villain in this outbreak, E. coli O157:H7, is far
scarier, at least for humans. Your stomach juices are not strong
enough to kill this acid-loving bacterium, which is why it's
more likely than other members of the E. coli family to produce
abdominal cramps, diarrhea, fever and, in rare cases, fatal
kidney failure.
Where does this particularly virulent strain come from? It's not
found in the intestinal tracts of cattle raised on their natural
diet of grass, hay and other fibrous forage. No, O157 thrives in
a new - that is, recent in the history of animal diets -
biological niche: the unnaturally acidic stomachs of beef and
dairy cattle fed on grain, the typical ration on most industrial
farms. It's the infected manure from these grain-fed cattle that
contaminates the groundwater and spreads the bacteria to
produce, like spinach, growing on neighboring farms.
In 2003, The Journal of Dairy Science noted that up to
80 percent of dairy cattle carry O157. (Fortunately, food safety
measures prevent contaminated fecal matter from getting into
most of our food most of the time.) Happily, the journal also
provided a remedy based on a simple experiment. When cows were
switched from a grain diet to hay for only five days, O157
declined 1,000-fold.
This is good news. In a week, we could choke O157 from its
favorite home - even if beef cattle were switched to a forage
diet just seven days before slaughter, it would greatly reduce
cross-contamination by manure of, say, hamburger in meat-packing
plants. Such a measure might have prevented the E. coli outbreak
that plagued the Jack in the Box fast food chain in 1993.
Unfortunately, it would take more than a week to reduce the
contamination of ground water, flood water and rivers - all
irrigation sources on spinach farms - by the E-coli-infected
manure from cattle farms.
The United States Department of Agriculture does recognize the
threat from these huge lagoons of waste, and so pays 75 percent
of the cost for a confinement cattle farmer to make manure pits
watertight, either by lining them with concrete or building them
above ground. But taxpayers are financing a policy that only
treats the symptom, not the disease, and at great expense. There
remains only one long-term remedy, and it's still the simplest
one: stop feeding grain to cattle.
California's spinach industry is now the financial victim of an
outbreak it probably did not cause, and meanwhile, thousands of
acres of other produce are still downstream from these lakes of
E. coli-ridden cattle manure. So give the spinach growers a
break, and direct your attention to the people in our
agricultural community who just might be able to solve this
deadly problem: the beef and dairy farmers.
Nina Planck is the author of Real Food: What to Eat and
Why.