Mad Cow Madness

On December 23, 2003, The USDA announced that a Holstein cow in Washington state was diagnosed with BSE, or bovine spongiform encephalopathy (so-called "mad cow disease"). Since that time, media reports have presented a dizzying array of facts and opinions. This short article will give you some of the facts about BSE and its potential effects on humans. I'll also discuss how you can minimize your risk of exposure to BSE and far more common food-borne diseases like E. coli O157:H7 and salmonellosis.

BSE is a disease in cattle that affects the central nervous system and the brain. BSE may be transmissible to humans as something called vCJD, or variant Creutzfeldt-Jakob disease. The Centers for Disease Control's own data (www.cdc.gov/ncidod/diseases/cjd/cjd.htm) suggest that, in the UK, 143 cases of vCJD occurred after over a million cattle infected with BSE may have entered the food supply. There seems to be however, a "substantial species to species barrier" (according to the CDC) to transmission to humans. In other words the chances you'll get vCJD from eating a single commercially-produced hamburger are considerably lower than being struck by lightning or winning the lottery.

All of the 143 cases of the UK cases of vCJD in humans occurred where the patients had some substantial psychiatric or physiological condition of their central nervous systems before being exposed to BSE multiple times. One additional study suggested that the 143 British victims of vCJD shared a genetic predisposition to vCJD. Even if BSE reached outbreak proportions in this country, the chance that a normal person will develop vCJD are infinitesimally small. Although some U.S. cases of vCJD occur in humans, these have been linked to a single defective gene or to infection by other means, not to ingesting infected meat. These are not new diseases in cattle and sheep, but have been reported for hundreds of years. That an outbreak of a human equivalent has never been reported should be reassuring.

There is currently no immunization or treatment for the disease. It is invariably fatal and has a long incubation period, perhaps three to six years. BSE is caused by a prion (PREE-on). A prion is a protein - not a virus or bacterium, but a simple protein - that varies from a normal protein in how it's physically configured. This prion is ingested by the animal and makes its way to the animal's brain, where it causes lesions (tiny little holes). Unlike most diseases, the prion cannot be "killed" by heating, either. Enough of the lesions eventually affect the animal's ability to move normally. A similar condition occurs in sheep, where it's called scrapie; in deer and elk, where it's called chronic wasting disease, and in other animals as well. Sheep and cattle can become infected by ingesting tissues that contain the prion from infected animals.

Those facts themselves might be frightening, but there's more to the story you might not have heard yet.

First, let's look at how BSE is transmitted from animal to animal. An uninfected animal has to eat animal-based feed from infected animals to be exposed. In the United States, feeding animal-based feed to cows has been banned since 1997. Before 1997, the USDA banned imports of live ruminants like cattle and sheep from countries where BSE had been found. Even if the animal is exposed, there's no guarantee it will develop BSE.

I hope those facts help you breathe easier about minimizing your risk of vCJD. While it's true that the only way to reduce your risk effectively to zero is not to eat any meat at all, for some of us that's not possible, or we simply choose to eat meat. For those of us who eat meat, this episode is a way for us to step back and look at what circumstances have made possible this discovery of a BSE-infected cow in the U.S. In order to do that, let's turn to commercial slaughtering and processing practices. (It may be a little graphic for some, but if you're eating it, you should know how it got to your plate.)

The USDA is charged with ensuring the safety of meats (and milk, eggs, and cheese) in this country. Until recently, the USDA allowed for several practices that might have allowed BSE to spread. First, the USDA must test "suspect" meat, but until last week, the suspect meat was allowed to enter the food chain before the testing results were known. Suspected pathogens might be BSE, or they might be the far more prevalent E. coli O157:H7 that sickens thousands of people per year. The USDA has since amended this rule to keep suspected meats out of the food supply until the meat (or product) has cleared testing.

Another practice the USDA allowed until recently was the introduction of 4-D animals into the human food supply. 4-D animals include those dead, diseased, downed, or dying. These animals are no longer allowed for use as human food, a change that's virtually unenforceable, and they must be tested and cleared before inclusion into animal feed.

Closing these loopholes may afford us greater protection. However, there's one more loophole that still exists.

Although animal-based feed that contains blood, bone marrow, spinal tissues or brain cannot be fed to ruminants in this country, blood-based formula is still fed to weaned calves as a common "bridge" food supply high in protein. It's unclear whether BSE can be transmitted by blood products, but the CDC suggests that it's likely, since the prion does occur in bone marrow.

Finally, there's a long-standing commercial slaughtering process called MRA, or maximum recovery of assets. This is a practice where as much of the meat on the animal is removed from the carcass as possible before the remainder is sent to animal-feed rendering plants. In this practice, tissues known to contain both BSE and E. coli - spinal tissues, brains, intestines and bone marrow - frequently contact other uncontaminated meats and may, in this way, make their way into the human food supply.

So what's a meat-eater to do? Well, you can choose to give it up, or you can choose products that minimize your risk of any food-borne pathogens. For example, choose USDA-certified organic meats, milk, eggs, and cheese, where no animal-based feed is given to the production animals. There's no guarantee that labels like "free range" or "grass-fed" mean anything in the conventional marketplace. The Wedge actively investigates its meat vendors like Cedar Summit Farms, which has entirely-grass-fed animals and is in the middle of the organic certification process. All the farms that claim to be "grass-fed" that sell at the Wedge are certified by outside organizations.

Although this is not a marketing piece, but a piece about the science of your meat supply, I must close by plugging The Wedge's meat department - and the meat departments at the other Twin Cities Co-ops. Small operations, like those that supply the Wedge, typically take longer to raise their animals, because they don't rely on animal protein supplementation. Their animals are slaughtered by small houses that slaughter and process animals humanely. The cattle producers charge the cost of raising those cattle, so they earn a fair market price. We consumers pay the full cost of our food - not an artificially subsidized one. Despite this, I've noticed that the price I pay for local, grass-fed meat and milk is about the same as commercially-raised milk and meat at discount grocers. You're worried about your food supply? So am I. But I'm also worried about getting hit by a drunk driver, so I buy auto and disability insurance. The little extra I pay each month for my food has always seemed like a great deal for all the environmental, social, economic and political reasons. Now I find out I'm getting my money's worth for health insurance, too.

Editors Note: Anne-Marie Hoskinson is no fanatic. She's a hard-core scientist. She eats only organic meat or meat from Cedar Summit farm. She makes no exceptions - not even for eating out. She also eats only organic dairy and eggs and has for 13 years.