Slaughter-free meat is on its way to our plates. In California, the Netherlands and Japan, a handful of startups are already growing animal flesh in laboratories, outside of the bodies of animals. Their goal? To produce meat without needing to kill a single animal, cutting out the cruelty and huge environmental costs associated with meat production today.

But the clean meat industry has a messy problem. None of the major players have managed to grow meat without using animal serum – a blend of growth-inducing proteins usually made from the blood of animals. The most popular is foetal bovine serum (FBS), a mixture harvested from the blood of foetuses excised from pregnant cows slaughtered in the dairy or meat industries. FBS contains a cocktail of proteins that make it ideally-suited for helping all kinds of animal cells grow and duplicate. “That’s why it’s a miracle juice, it’s got a protein for everyone,” says Michael Selden, CEO of lab-grown fish startup Finless Foods. Other animal serums work for one or two cell types, but FBS is a natural all-rounder.

And it's absolutely key to growing meat in the lab. To create a lab-grown beef burger, you start by removing a small number of cells from a living animal, and transfering them into a petri dish, where they’re bathed in a liquid containing animal serum and all the other nutrients they need to grow and divide. Given the right food and conditions, those cells continue to duplicate and can be transferred to a bioreactor where they grow into something resembling real animal flesh. Eventually you can remove a portion of those cells, prepare them as you would any other burger, and eat them.


All the startups working in this nascent industry are doing is growing meat in roughly the same way that animals do, but without having a living body wrapped around it. “Everything animals eat is going to bone formation, blood formation, brain formation, and muscle,” says Selden. “This is a more streamlined way of bringing these nutrients into meat that people want to eat.” And, unlike plant-based meat alternatives, lab-grown meat doesn’t just taste like real meat. It is real meat.

But unless the clean meat industry can solve the serum question, not a sliver of lab-grown meat will ever make its way into our kitchens. “There’s absolutely no way you can have a viable product that has serum,” says Selden. “There’s no company that will ever do that, no matter how cold hearted and brutal they are – nobody would do it.” So now the clean meat industry is on a mission to brew up its own miracle juice.

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Then there’s the cost. A single litre of foetal bovine serum costs between £300 and £700, and the clean meat industry is getting through buckets of the stuff every day. Mark Post, co-founder of Mosa Meat and creator of the world’s first cultured burger, estimates that it takes 50 litres of serum to produce a single beef burger. It is the sheer cost of serum that makes clean meat so eye-wateringly expensive. That first cultured beef burger, made in August 2013, cost over £220,000 to produce. Post estimates that this is now down to around £4,400 per burger, but it’s still way off the price level needed to make clean meat a realistic alternative to conventional meat.


Part of the reason why serum is so expensive is that the industry producing it isn’t set up to supply the vast quantities that clean meat startups need. Most companies selling FBS are geared towards biomedical research, where they use tiny amounts of the serum, sometimes less than a millilitre at a time, to grow small clusters of cells. The clean meat industry, once it properly gets going, will be on a much, much bigger scale. In a paper published in Biochemical Engineering Journal, Liz Specht, senior scientist at the Good Food Institute, a non-profit that promotes animal-free food, estimates that eventually a standard 20,000 litre batch of cultured cells, which includes serum and other nutrients as well as the meat itself, would yield between 1,800 and 4,500 kilograms of meat.

“Right now the clean meat companies aren’t really buying large quantities of media,” says Specht. Growth media – media being the generic term for a liquid broth of nutrients – is another liquid full of amino acids, sugars and vitamins needed to keep growing cells healthy, and most of these are easy to synthesise artificially. “It’s not dissimilar to Gatorade,” says Selden, who knows one Japanese scientist using a sports drink as an alternative to conventional media. But ten to 20 per cent of media is made up of, you guessed it, animal serum.

Growing demand from the clean meat industry might be enough to tempt biotech firms to start producing serum at scale, says Post, who estimates that he is around three years away from growing commercially-available clean meat. “Mostly likely biotech is going to pick this up and realise that they are going to have to move from a small volume high value product to a huge volume and low value.”

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In September 2017, Finless Foods held a tasting of five carp-and-potato croquettes worth an estimated £150 each Finless Foods


Selden won’t say which animal serum Finless Foods uses in its labs – many startups keep the exact composition of serum and media tightly under-wraps – but the company has already cut its animal serum use in half since being founded last year. Cells can cope with small reductions in the amount of serum, Selden says, but if you cut out too much then it starts inhibiting the growth and development of the cultures.

Finless Foods is planning to go serum-free by the end of 2018 and release its first lab-grown fish paste by the end of 2019, but to pull off both those feats the startup needs to find an alternative source of growth protein. These could be made by microbial fermentation, the same process that is used to create vegetarian versions of the enzyme rennet, which is used in cheese production. Finless Foods is also considering algal or fungal extracts.

Just, a clean meat company that was previously called Hampton Creek, is going down a different route for its animal serum alternative. The company, which is building a database of different plants and analysing each one to find species that could supply the growth factors and other nutrients that dividing cells need. “From our perspective, the most technically challenging and critical thing here is nailing this media thing,” says Just CEO Josh Tetrick, who was left as the sole member of the company’s board last summer after the other four members quit as the firm struggled to meet deadlines and faced criticisms of dodgy science in its labs. But Tetrick already reckons he’s onto the next big thing.

He’s aiming to bring out a commercial clean meat product by the end of 2018, but he’s not sure what it’ll be yet. “We’re looking at chicken nuggets, we’re looking at sausages and we’re looking at chorizo,” he says. Ground meats like these are easier to grow because they don’t require much structuring, but each different meat requires a different set of growth factors, so creating a universal serum, like FBS, is mostly likely out of the question. “The challenge is that we’re going to have to have different formulations for different cell lines,” he says. Like Finless Foods, Just is committed to going animal serum free by the end of 2018.

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It’s also possible to artificially manufacturer growth factors using recombinant DNA technology, says Post. He has already tested cells in 400 different conditions to see how they respond to different growth factors and conditions, and thinks that soon enough we’ll see the growth of a specialised industry supplying the clean meat world with growth proteins. “It’s a matter of time, it’s just going through the alternatives that there are and optimising them,” he says.

Recycling the media used during the growing process is another cost-saving option being pursued by startups. While cells are growing and dividing, they release metabolites into the media, which is then thrown away. “It’s a wasteful system that we need to improve over time,” Post says. Selecting cells that are more better at converting media into growth would also increase the efficiency and lower the cost of the whole process.

Cost, after all, is the whole reason why these companies are putting so much effort into finding animal-free serum. Without drastically lower production costs, clean meat will never make it out of the lab. “It’s a waste of time and a fantasy if you can’t solve the media cost,” says Tetrick. “Ultimately, if we cannot get this kind of meat below the cost of conventional meat it is complete bullshit in my mind.”

Concept packaging for Just beef burgers. The company is also developing clean meat chicken and sausages. Just

For Just's first clean meat produt, Tetrick has set himself the goal of being within 30 per cent of the cost of a comparable meat product. To get there, however, he might have to fill out his lab-grown meat a little. One benefit of starting with ground meat is that you can pack them out with breadcrumbs, flour or other forms of starch, just like the real meat industry does for plenty of lower-end products. Combine a little filler with lower-cost media and the challenge of scaling clean meat suddenly becomes significantly easier.

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But Post is wary about filling out clean meat products with other things. Clean meat products should be 100 per cent meat, he says. “It’s essential to create a product that is exactly the same as the alternative.” This would narrow the ground between the two types of meat, and undercut criticisms that lab-grown meat is somehow an inferior product.

The meat industry is already gearing up to fight that battle. In February, the United States Cattlemen's Association filed a 15-page petition to the Department of Agriculture arguing that lab-grown meat companies should not be able to call their products “meat” since they won’t come from slaughtered animals. Post, who is Dutch, dismisses this as an achterhoedegevecht – a fight that will have no consequences in the future. He uses the example of the milk industry, where non-dairy milks now make up 10 per cent of the market. A name change there wouldn’t change the huge impact that milk alternatives have had on that market, he says.

Elsewhere, the meat industry is starting to cosy up to the clean meat world. In January, Tyson Foods, the world's second-largest producer of chicken, beef and pork, invested in Memphis Meats, the startup that many in the industry think is closest to producing commercially-viable meat. The startup has already managed to reduce the cost per pound down to around £1,700, and Specht says it still has a lot further to go. “It’s not hard for me to see how we can get in the region of a couple of dollars per pound,” she says. Serum, which costs hundreds of dollars per litre at the moment, could go as low as one dollar per litre once we’re able to synthesise it ourselves.

In the long run, Specht says the clean meat industry might make more of a foothold for itself by growing high-end cuts of meat such as steak or lamb chops. Since these cuts have more complex structures, with intricate arrangements of fat, muscle and connective tissue, they require some kind of scaffolding to make certain kinds of cells grow in different positions. Specht even thinks that clean meat could eventually bring the cost down of what are traditionally more expensive cuts of meat, while plant-based alternatives flood the lower end of the market.

But the immediate priority for the clean meat industry is finding a way to make sure those first burgers, chicken nuggets and crab sticks are sold at a price that people don’t find stomach-turning.

If they can work that out, they’ll be in with a chance of taking a slice of the £717 billion global meat industry, and with it reduce its huge environmental footprint. It takes 2,000 litres of water to produce one beef burger, but researchers estimate that clean meat would use between ten and 100 times less water as well as reducing greenhouse emissions and land use by the same amount.

The only way to achieve this is to convince normal meat eaters to switch to lab-grown meat, by putting the ethical arguments to one side and appealing to their pocket. “Luxury products are not going to save the environment,” says Selden. “You have to play the capitalism game.”

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