Monday, May 26, 2008

Cultured Meat

This post was crossposted to SCIFIRAMA.
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The aristocrat of Dorm Ten was Herrera. After ten years with Chlorella he had worked his way up – topographically it was down – to Master Slicer. He worked in the great, cool vault underground, where Chicken Little grew and was cropped by him and other artisans. He swung a sort of two-handed sword that carved off great slabs of the tissue, leaving it to the lesser packers and trimmers and their faceless helpers to weigh it, shape it, freeze it, cook it, flavor it, package it, and ship it off to the area on quota for the day.
He had more than a production job. He was a safety valve. Chicken Little grew and grew, as she had been growing for decades. Since she had started as a lump of heart tissue, she didn't know any better than to grow up against a foreign body and surround it. She didn't know any better than to grow and fill her concrete vault and keep growing, compressing her cells and rupturing them. As long as she got nutrient, she grew. Herrera saw to it that she grew round and lump, that no tissue got old and tough before it was sliced, that one side was not neglected for the other.
~The Space Merchants, Frederik Pohl & CM Kornbluth, 1952
On January 17, 1912, Nobel prize-winning physician Dr. Alexis Carrel placed a part of a chicken's embryo heart in a nutrient medium in a glass flask of his own design. Every forty-eight hours the tissue doubled in size and was transferred to a new flask. The cells derived from the original heart tissue were cultured for 34 years, at which time they were intentionally destroyed. The long-lived culture caught the public imagination - the New York World-Telegram even marked the culture's "birthday" each January. It's not so surprising, then, that the ever-growing slab of muscle tissue in The Space Merchants was derived from a chicken heart.

It's been nearly a century since Carrel began culturing his chicken heart. So why aren't we all eating meat grown in tanks? It turns out it's not quite as simple as tossing some muscle cells in a Petri dish.

First off, when we eat a nice juicy steak, we aren't just eating muscle cells - muscles are made up of large bundles of the cells or muscle fibers. Cells growing in a Petri dish form a sheet of cells rather than a structured muscle, and, as PZ Myers put it, is likely to "have the texture of slime and would not sell well in test markets". There is at least a partial solution: grow the cells on a nutrient-soaked scaffold that allows the developing muscles to be stretched, causing them to naturally bulk up (so to speak). Even using that methodology New Harvest, an organization devoted to the development of meat substitutes, notes that texture is still a significant obstacle to creating a replacement for animal-grown meat. Of course if you want a replacement for ground beef rather than a ribeye, then texture is probably not as much of a problem.

Then there is the issue of nutrients. Typical cell growth medium contains calf serum (or fetal calf serum), which obvious isn't ideal to use if you are trying not to involve actual animals. The growth factors and other components found in serum can be replaced with synthetic chemicals and plant and mushroom-derived products, but that is both more complex and more expensive than serum-based media.

That's not to say that it's an impossible task. In NASA-funded research at Touro College, Dr. Morris Benjaminson and colleagues demonstrated that chunks of goldfish muscle could grow in culture. They even cooked up the resulting tissue (with garlic, yum!), and it looked edible, but apparently no one was willing to actually taste it. Back in 2003 the Tissue Culture and Art Project cultured muscle from prenatal sheep and a still-living frog as part of their "Disembodied Cuisine" project, and actually ate the results (image to the left, and video). Neither project produced anywhere enough meat to be practical for commercial sale - nor even a complete meal.

Despite the technical limitations, commercially-produced cultured meat may become a reality in the near future. A January 2007 Times Online article reported that growing a kilo of meat cost $10,000, however at last month's In Vitro Meat Symposium, a report estimated that the meat could be grown as cheaply as $5200 per ton.

But that doesn't address perhaps the greatest obstacle to the adoption of cultured meat - the squick factor. As Wired reported, even the scientists involved in developing the technology aren't necessarily keen on eating what they produce:

For all the talk of high-tech meat production, attendees of the first In-Vitro Meat Symposium didn't put their stomachs where their mouths were. Instead of sampling early versions of in vitro meat, they stuck to local fare.

"We had some excellent Norwegian salmon, which was very tasty," Bennett said.

I like to think that I'd be more open minded if offered a sample.

For more science fictional examples of meat grown in vitro, check out Technovelgy and Wikipedia lists.

Top Image: Cultured chicken embryo heart cells (edu-graphics.com)
Middle Image: Prenatal sheep skeletal muscle cells cultured in a bioreactor on a biodegradable polymer scaffold to create "semi-living steak" as part of the "Disembodied Cuisine" art project.
Bottom Image: In the Eureka episode "E=MC...?" chicken parts grown from cultured cells were grown under conditions that caused them to produce a GABA blocker, so everyone who ate a piece becomes very dumb.
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1 comment:

Tony said...

Good Job! :)