Can science build a better burger?

There’s more than one way to cook up tomorrow’s meat

impossible burger

TOMORROW'S BURGER? Two groups of scientists, for similar reasons, are exploring opposite ways of changing how meat is made. One approach grows just the edible parts of the animal; the other tries to simulate meat with plants (meatless Impossible Burger, shown).

Impossible Foods Inc.

This isn’t as extreme as if the federal government had decided to regulate time travel. But it’s almost as surprising. The U.S. Food and Drug Administration is taking the first step toward rules for growing nutritious, delicious, juicy meat in labs, not farms.

The notion of growing, say, just the beef instead of the whole cow has been floating around since at least the 1890s. This sci-fi fantasy got a bit more real at a 2013 televised tasting of a lab-grown hamburger, though the patty cost about as much as a Rolls-Royce.

In July, the movement passed a new milestone: In a packed auditorium in suburban Maryland, the FDA convened the first public hearing (the U.S. Department of Agriculture is jumping in too) to discuss federal regulation of food grown from cells — no hooves or fins or feathers in sight.

What to call such fare is a point of contention. Enthusiasts suggest “clean meat” or “cultured meat.” But calling this stuff “meat” doesn’t sit well with traditional farmers. “They’re hijacking our brand,” Montana rancher Maggie Nutter testified on behalf of the United States Cattlemen’s Association. Meat is harvested from a real animal. Period. (Yet the cells to start a meat-growing culture come from a real animal too.)

Whatever it’s called, cultured meat is one of two high-science endeavors to get animals, at least in the traditional sense, out of agriculture.

The other camp wants to take every bit of the animal out of agriculture and make “meat” from plants. These dreamers, including Patrick O. Brown of Impossible Foods in Redwood City, Calif., do not want to make another veggie burger. (Brown goes icy at the v-b label.) Instead they want to focus the full glory of molecular biology on identifying the proteins or other molecules that give meats their seductive flavors and textures. Then, sourcing each vital component from some nonanimal origin, these pioneers want to build plant “meat” so delicious that die-hard carnivores will sigh happily and take another bite.

“Animals happened to be the technology that was available 10,000 years ago” for making meat, Brown says. “We stuck with that same technology, and it’s incredibly inefficient by any measure — and destructive.”

Brown is convinced that science can come up with something better, for the sake of the environment, food security and animal welfare. He’s going the plant path, but says if the clean meat scientists can make their dream financially viable, “I’ll be their biggest fan.” The looming questions for both of these approaches, however, may arise from the not-so-scientific swerves of human desire.

Brave new meat

Many people like meat the way it is. Yet they may not always grasp what technological change could look like, says Bruce Friedrich, executive director of the Good Food Institute based in Washington, D.C. In another sign that the alternate-meat movement may be gaining traction, he and Brown were on a panel in June explaining their visions of future meat to a meeting of international economists at the headquarters of the World Bank.

On the panel, Friedrich conjures another weighty gathering. “It’s 1898. The world’s first-ever urban planning conference is convening.” The focus: “175,000 horses on the streets of New York … laying down 50,000 tons of horse excrement every month.” Failing to come up with a solution, the planners “go home despondent,” Friedrich says. “Ten years later Henry Ford introduces the Model T.”

Cars and other horseless vehicles caught on quickly, and within a decade, horse-drawn carriages were clop-clopping their way to the shrunken status of tourist attraction. What most people had really loved about equine transportation was not the workhorse itself so much as its speed, convenience and capacity. People still raise horses for pleasure, but when cars offered speed without manure, horse transport was history.

Likewise, most people don’t love modern industrial animal agriculture itself, Friedrich contends, with its high-density animal facilities and its greenhouse gases (SN: 7/7/18, p. 10) and other environmental consequences (SN: 11/28/15, p. 22). What people do love is the beef, pork, chicken and eggs that make current agriculture seem inevitable. Change, he argues, will take the Model T of meat.

Call it a Model M

That Model M will have to be affordable, but maybe more importantly, it has to deliver on flavor, a formidable challenge.

Meat scientist Hannah Laird runs a sensory evaluation lab at Texas A&M University in College Station. She recruits beef lovers to spend six months to a year learning to pick out and score some 40 flavors and aromas that can show up in ground beef. For two hours a day, trained panelists sniff, taste and rate beef samples against reference foods on characteristics such as “brown/roasted” (beef suet ranks an 8) and “metallic” (Dole canned pineapple juice, 6).

Raw beef is bland, Laird says. It provides mainly an aroma and flavor known as “bloody/serumy” with a few other components such as “overall sweet.” Cook it though, and oh my. Brown/roasted! Fatlike! Umami! Maybe smoky-charcoal (or, perhaps, smoky-wood), cocoa, salty, buttery, cumin, floral. For a less-than-perfect patty, testers could report “barnyard.”

The sensory experience of cooked ground beef is so embedded in American culture and so singular that one flavor is called “beef identity.” Cooked beef exerts such pull on its devotees in large part because of its sheer beefiness.

Laird is finishing a project probing for changes in this intense culinary romance. “People say they want low-fat ground beef,” she says. But in blind taste tests, they’ll choose the 20 percent fat over the 10 percent fat almost every time.

Taste preferences start forming in the womb, says Gary Beauchamp, who studies food preferences at Philadelphia’s Monell Chemical Senses Center. Tests there have detected an influence of mom’s diet during pregnancy on baby’s food preferences. But preferences can change. In Beauchamp’s own work on salty flavors, he finds that people who switch to low-salt diets are often miserable at first, but months later, these dieters rate a taste of their once-beloved foods as too salty. It would be daunting to predict what might happen with meat preferences, he says. “The complexity of something like a hamburger is astounding.”

Why try?

To displace that juicy cultural icon under the lettuce, tomato and special sauce will take some doing, but a range of thinkers argue that it’s important to try.

“Meat production is one of the most important ways in which humanity affects the environment,” population biologist Charles Godfray and colleagues wrote in the July 20 Science. By a variety of measures, animal agriculture leaves big environmental hoofprints, the University of Oxford researchers noted.

Greenhouse gases emitted during animal agriculture account for about 14.5 percent of humankind’s total, according to a 2013 report from the U.N. Food and Agriculture Organization.

Judging the hypothetical environmental footprint of cultured meat is tricky at this stage. A 2015 estimate in Environmental Science & Technology suggests that cultured meat could be less of a contributor to climate change than normal beef and require nowhere near as much land. Yet the lab processes might demand even more energy than conventional beef. The researchers are careful to call their results “possible future scenarios rather than predictions.”

Worries about the environment, however, don’t inspire people to change their diets as effectively as concerns about personal health, several surveys show. The health consequences of eating a lot of meat need a long and thoughtful story of their own. U.S. residents consume an astounding amount of beef, chicken and pork, according to the Paris-based Organisation for Economic Co-operation and Development: 79 grams (retail weight) per day. That’s triple the worldwide average. Many people are miles away from what the American Heart Association recommends: limiting meat to four or five 6-ounce (170 grams) servings of lean beef, skinless chicken or seafood per week.

The health consequences of eating cultured meat aren’t clear, since there are no products on the market to test. Plant-based foods can avoid many of the saturated fat problems of meats as long as people don’t doll them up with saucy, cheesy extravagance.Yet the Impossible Burger and the Beyond Burger, a meat-mimicking competitor, are not low fat.

Beyond art

For Friedrich, a big reason to move away from meat made from whole animals is waste. “Throwing food away is a horrible idea,” he says. “But that’s basically the relationship all of us enter into every time we choose to eat meat.” To get one calorie of meat from a chicken means putting in nine calories of feed. And chicken is one of the more efficient meats. Why not create just the pieces of an animal that people could eat?

Scientists have already proved that this is, sort of, possible. The first lab-cultured burger publicly unveiled, in 2013, required hand assembly of some 20,000 individual muscle cells at Maastricht University in the Netherlands. Producing and testing cost donor and Google cofounder Sergey Brin 250,000 euros.

The flavor was “surprisingly close” to regular ground beef, says the first person to taste cultured beef in public, food trend researcher Hanni Rützler of Vienna. It might have tasted more burgerlike, she says, if its scientist-creators had allowed the chef to mix in some onions and discernible seasoning. Beet juice was permitted for pinkness (that early burger hadn’t grown enough of the protein myoglobin, which gives meat its color).

Possibly the world’s most famous lab-grown hamburger patty (left), unveiled in 2013, was hand-assembled from thousands of individual cow muscle cells. Pinked up with a touch of beet juice, the burger was served well-done. David Parry/PA Wire
Possibly the world’s most famous lab-grown hamburger patty (left), unveiled in 2013, was hand-assembled from thousands of individual cow muscle cells. Pinked up with a touch of beet juice, the burger was served well-done. David Parry/PA Wire

That televised tasting, however, represented a leap forward from an earlier public tasting of lab-grown meat, in this case, frog legs. At the 2003 closing of an art installation in Nantes, France, a dinner party of tasters picked up their forks before an audience to try frog leg muscle fibers that artists Oron Catts and Ionat Zurr of the art group SymbioticA had been culturing on display.

Three tasters spit it out. The flavor was fine — lemon butter and garlic from a very good sauce, Catts says. The muscle fibers, however, hadn’t been exercised as they grew on their mesh support, nor did the mesh have time to soften during the relatively brief gallery show. Thus the meat’s texture was disconcertingly like “jelly on fabric,” he says. As its cocreator, he felt an obligation: “I swallowed it.”

Custom-making bits of living animal tissue for biology has been flourishing for decades. Medical teams have implanted lab-cultured bladders in people, and experimental lung tissue has survived several weeks in pigs (SN: 9/15/18, p. 8). These approaches, however, are very different from churning out gastronomically pleasing hamburger meat by the pound. Changing science experiments into food production takes so much more than just nicking a tiny pip of cells from a cow’s muscle and dropping them into a sciencey soup.

A muscle fiber cell that has matured into its full elongated glory can’t divide into two fibers. To grow muscles, researchers need to start with cells that still retain a lot of flexibility. There are trade-offs among the options. What are called pluripotent stem cells can turn into anything and divide many times, yet they can be trickier to control than cells already on their way to becoming a muscle. These cells, called myoblasts, naturally appear in animal muscles ready to repair damage. Collecting them could make for easier control, but they don’t divide as many times as stem cells. So meat growers may have to go to their cell banks more often.

A tasty morsel of meat contains more than muscle fiber cells. Connective tissue holds those fibers in place, and fat cells, a big component of flavor, power the fibers’ exertions. One of the big challenges for tissue culture, edible or simply research-based, has been trying to get blood vessels to reach into meat. Without vessels to supply oxygen and food to inner cells, a scrap of muscle cells can’t develop much thickness. Thus, clean meat projects so far tend to produce ground beef instead of a porterhouse.

Lowering the bar from steak to ground meat and growing jumbles of cells is still complex. “We know that many of these cells don’t really like … to be isolated,” says cell biologist Chris Dammann, cofounder of cellular aquaculture start-up BlueNalu in San Diego. As normal tissue forms, cells communicate with their neighbors and “know exactly where they are,“ he says. When a scientist pulls out cells for culture, the cells “get a little bit confused,” he says. Without orienting inputs, an isolated cell can devolve into its built-in suicide program.

To coax disoriented cells into growing neighborhoods, researchers are exploring various scaffolds. On this and other details, however, start-ups are not willing to share.

Andrew Pelling, a biophysicist at the University of Ottawa, will talk. He turned to the produce aisle for scaffold inspiration. His lab stripped the living innards of cells out of apple segments. On the remaining fine mesh of cellulose, he grew human cells (not for food). The nonprofit New Harvest foundation in New York City has provided money for similar scaffold experiments planned for Asian pears, carrots, rose petals, asparagus and mushrooms.

Cells also need nutrients and compounds that give them the normal body signals that regulate growth. Biomedical lab scientists often enrich their nutrient culture medium with what’s called fetal bovine serum, plasma collected from calf fetuses. A liter can cost hundreds of dollars, which is a serious drawback for the clean meat industry, cautions Jean-François Hocquette. (Alternatives exist for medical tissue, but suitable edible options have been a long-standing challenge.)

Hocquette is a Paris-based researcher with the French National Institute for Agricultural Research who starts a Skype call with a cheerful smile and a warning: He doesn’t see how the cultured meat industry is going to become financially viable, and not just because of the serum.

There’s the scaling up of the bioreactor, the chamber where the cells grow, which needs to mimic an animal body in temperature and in making sure cells get the nutrients and signals they need. Erin Kim, New Harvest’s former communications director, says that the foundation funded the development of a bioreactor prototype, about the size of a portable space heater. It was “a short, little project,” she says. However, it created a much bigger sensation in the field than she would have expected for a problem that every company must have been working to solve. “We were bombarded by people wanting to pick our brains.” Her conclusion: Bioreactor design may not be that far along.

Regardless of the uncertainties, the push to grow meat or other animal products without whole animals is growing, says food scientist Liz Specht of the Good Food Institute. In 2016 she knew of six companies chasing this dream. Just two years later, she knows of at least 20. Even established giants of food production, such as Tyson Foods and Cargill, are investing.

Plans for cultured products include beef, pork, seafood, poultry, egg whites without eggs, milk without cows, fois gras and pet food. Beyond food, there’s leather and spider silk.

The plant path

Meanwhile, Impossible Foods’ Brown and some like-minded pioneers are taking a leap of faith in the opposite direction: trying to re-create genuinely meaty eating from plant ingredients.

“When I go to meetings that are basically nothing but ardent environmentalists, they’re pretty much all having meat for dinner, and they know very well what the issue is. It’s not that they’re bad people,” he says. “It’s just that it’s very difficult for people to change their diets.”

Brown is trying anyway. The molecular biologist, an award-winning developer of the ubiquitous lab tool called a DNA microarray and a member of the National Academy of Sciences, ditched a wunder-kind science life at Stanford University to — of all the job swerves in the world — start a burger business.

“I loved what I was doing,” Brown says of his academic days. Yet he realized “the most important scientific problem in the world was figuring out what makes meat delicious — and how to make that same experience sustainably from plant ingredients. I’m not kidding.”

To woo the true carnivores in ways that current veggie burgers don’t, Brown has assembled a research team to search for underappreciated molecules that give meat its allure. “There’s a lot of interesting stuff there,” he says.

He launched Impossible Foods in 2011 and is convinced that he’s found “the magic ingredient that makes meat taste unlike anything else on Earth.” It’s the structure called heme, he says, basically a molecular cage of nitrogen surrounding an iron atom. Heme is a powerful catalyst forming the business end of human blood hemoglobin as well as plenty of other compounds. It often plays a role in extracting energy from food, a major part of animal life.

Therefore, heme as part of the distinctive meat taste makes sense to Brown, and he’s found a plant version, leghemoglobin, in soybean roots. Instead of harvesting roots, though, the burger makers put leghemoglobin genes into yeast and brew the magic ingredient much the way insulin and rennet (for making cheese) are grown: in vats.

An early attempt at a plant-based burger tasted like “rancid polenta,” one taster reported, but Brown’s project has made much progress since then, he says. The team is still tinkering with the flavor and the process of their plant-based technology for making burgers, but Brown doesn’t seem disturbed.

“However good it is today, the next day it will be better,” he says. “The cow is not improving at all.”

Historian Gabriella Petrick in Boston has not yet tried one of Brown’s burgers, or one from competitor Beyond Meat. She studies technology and food systems, and she points out that the world-changing Model T was far from the first horseless carriage. (Nicolas-Joseph Cugnot, a French military officer, demonstrated his three-wheeled, steam-powered vehicle, getting it up to 4.8 kilometers an hour briefly in 1771, though it proved impractical for towing artillery and was sidelined.) Ford’s car was more practical and, a vital point, affordable.

Likewise, some of the big innovations in food, such as canning or freezing, took at least a generation to catch on, Petrick says.

She can, however, think of one encouraging counterexample in which all the supporting pieces for change, such as consumer demand, shipping infrastructure and refrigeration technology, lined up. It wasn’t long before 1930s Northeasterners moping for fresh greens in winter embraced a funny-looking oddity recently available from California’s Salinas Valley: the now-ubiquitous iceberg lettuce. Just maybe, the next iceberg will be the burger itself.

This article appears in the September 29, 2018 issue of Science News with the headline, “Dreaming up tomorrow’s burger: Can science make the meat without the moo?”

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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