by Marion Nestle
Apr 25 2012

What’s up with mad cow?

You have to feel sorry for the beef industry.  First pink slime, now a mad cow.

Here’s what we know about the latest mad cow scare (the USDA has a page devoted to mad cow disease, so does the FDA, and I wrote about it in my book, Safe Food: The Politics of Food Safety).

  • Mad cow is the common name for bovine spongiform encephalopathy (BSE), a fatal disease caused by abnormal proteins (prions) in the brain and nervous system.
  • The disease affected 37,311 cows in Great Britain in 1992.
  • In 2011, there were only 29 cases worldwide.
  • No human case has been seen in the U.S., except for one in a woman who moved here from England at the time.
  • The affected cow found in California is only the fourth in the U.S. since the testing program started a decade ago.
  • The USDA tests about 40,000 cows a year out of the 34 million slaughtered. 
  • This one was evidently high risk.  It died and was sent to a rendering plant.  It either looked suspicious enough to be singled out for testing or was picked up on routine testing.
  • When the test came back positive, authorities impounded the carcass.
  • It never entered the food supply for either people or pets.
  • How it got the disease in the first place is either unknown or undisclosed.  The most likely possibility is that the disease developed spontaneously (as it does occasionally in older cows).

According to the Wall Street Journal,

The disease was detected on a cow carcass taken in for rendering last Wednesday at an animal-rendering plant in Hanford, Calif., said Dennis Luckey, vice president of Baker Commodities Inc., a Los Angeles-based processor of animal byproducts that operates the facility.

Mr. Luckey said the cow had died at a dairy he couldn’t immediately identify, saying that information was in the hands of the USDA.

The plant renders cows that have died to make commodities such as “high-protein ingredients for poultry feed and pet food,” according to Baker’s website.

During the British mad cow scare of the 1990s, people eating beef and cats eating cow byproducts got the disease, but dogs did not. 

The USDA is issuing assurances that the system is working since mad cow prions from this cow did not get into the food supply for people or pets.

My assessment: The risk of you getting this disease from eating beef is extremely small.

You don’t find this reassuring? Eat your veggies!


  • Elisa Trimble
  • April 25, 2012
  • 11:33 am

I’d like to ask Marion if we actually solved the mad cow problem in the UK by requiring that cows be slaughtered no older than 24 months–or are we just covering it up? ie do cows younger than this have the disease in a subclinical way, that may yet result in them passing it to humans?

  • Jill
  • April 25, 2012
  • 11:55 am

Thanks for clarifying about the pet food – my immediate thoughts were that it was used for animal/pet food because it wasn’t addressed in the press release (at least not what I saw).

  • jay jay
  • April 25, 2012
  • 1:08 pm

Eat your veggies! Ha!

It’s ironic how much buzz mad cow generates, with its miniscule number of deaths, compared to the thousands who die each year from eating contaminated vegetables.

Yes, eat your veggies, but cook them first!

  • Charlie L
  • April 25, 2012
  • 5:49 pm

I’ve been making a concerted effort to buy local grass-fed beef in bulk so I know exactly where it came from, who raised it (i.e. small family farmer, not some faceless corporate “farmer”), how it was raised, and how fresh it is. Plus, more humanely raised animals just taste better on my dinner plate! =)

  • Ana
  • April 25, 2012
  • 7:20 pm

The sister of my husband’s best friend died from a variant CJD (Mad Cow Disease in humans) around 2004. She was 25 years old. She was born in England, where she contracted it, and moved to South Florida when she was 12 years old. She wasn’t diagnosed with it until 2001. I never met her before her health started to decline, but I have heard the stories of the changes she went through and saw her at the very end of her life.

Even though the number of deaths of this disease is relatively low, it doesn’t make it any less serious or grave. Like many other diseases, this is one is just as devastating.

  • Erin
  • April 26, 2012
  • 10:44 am

I agree, if you’re uneasy about the beef issues, don’t eat it. I’m not buying the bull the USDA’s public relations and higher-ups are spewing. My main concern is that the amount of cows tested in the US is EXTREMELY low (see stats in Ms. Nestle’s article) — so what kind of guarantee the food is “safe” is that?

  • Jack Everitt
  • April 26, 2012
  • 4:58 pm

RE: “the USDA tests about 40,000 cows a year out of the 34 million slaughtered” – so you’re saying that testing 1 out of 850 cows, on average, is enough to determine that the chances of getting this disease is very small?

  • Bong Kim
  • April 26, 2012
  • 7:00 pm

Testing only 0.1% of slaughtered cows, and a BSE case detected once about every 3~4 years. If someone has any expertise in statistics, please let us know the statistically derived number of BSE cows slaughtered undetected.

  • Tom
  • April 26, 2012
  • 7:10 pm

The cow died at a dairy. Is there a chance the Food Politics BSE passed into the milk?

  • Margeretrc
  • April 27, 2012
  • 1:23 pm

Eat grass fed beef if you’re worried about mad cow and don’t want to just “eat your veggies.” That’s what I do. I will occasionally eat beef out that most likely isn’t grass fed, but never buy it for home consumption.

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  • Eric Esterling, MS RD
  • April 29, 2012
  • 5:08 pm

@Margaretrc: grass fed beef does not assure that the cows won’t have BSE. It arguably reduces risk since BSE can be transmitted in feed. But grass fed is not a a sure thing.

@Tom: It is not believed that BSE can be transmitted through milk. See the FDA page that Ms. Nestle linked to in the post:

@Elisa Trimble: Using younger cattle significantly reduces, but does not eliminate the risk of consuming infected cattle. Rather, other methods are used to reduce the risk. Primarily the elimination of “specified risk material” from the food supply. See:

[...] reading Whats Up With Mad Cow on, I could not help but feel a little bit happy with our American food [...]

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