How much would you pay for a hamburger? How about US$345,000? No, it's not wrapped in edible gold leaf and held together with a skewer made out of a diamond stick pin that you get to keep. It's an ordinary burger that doesn't include the bun, lettuce, pickles or onions. It isn't even super-sized. This may seem like price gouging on a monumental scale, but it's actually the cost price for this particular burger. That's because even though it is a real hamburger made from real meat, it doesn't come from a cow at all.

Dr. Mark Post, a vascular biologist at the University of Maastricht in the Netherlands, is one of a handful of scientists around the world working on the problem of cultivating meat artificially in a laboratory. The idea is to find a way to create the meat without the animal by growing it directly. Speaking to the Reuters news agency, Dr. Post estimates that, if he succeeds, his first burger will cost a staggering $345,000, but when the technique is perfected and scaled up to industrial levels, economies of scale should kick in and make lab-grown beef (or pork or chicken or fish) as cheap, if not cheaper, than its four-legged counterpart. He also believes that the advantages of in vitro meat, as it is called, are such that it will go a long way toward alleviating world hunger and saving the environment.

It may even give the phrase "factory farming" a whole new meaning.

A long predicted dish

The idea of growing meat in a vat without the animal middle-creature has been around longer than many people realize. The most famous prediction of the coming of in vitro meat was from none other than Winston Churchill. During his "wilderness years" of the early 1930s when he was out of political favor, Churchill passed the time by writing and one essay penned for Popular Mechanics magazine in March 1932 dealt with predictions of what life would be like fifty years ahead in far off 1982. In this he wrote - "We shall escape the absurdity of growing a whole chicken in order to eat the breast or wing, by growing these parts separately under a suitable medium."

Chicken heart

Growing a chicken leg bone and all wasn't even a remote possibility in the real 1982, but Churchill did have some basis for his prediction that this would come about within a half century. He probably based it on the work of Dr. Alexis Carrel, a French surgeon and biologist working in New York City in the first half of the 20th century. There at the Rockefeller Institute of Medical Research, Dr. Carrel conducted a unique experiment when in 1912 he cultivated tissues from an embryo chicken heart. By constantly bathing it in a nutrient solution, Dr. Carrel was able to keep the heart tissue alive and growing until 1942, when it died after a lab assistant forgot to feed it.

The "chicken heart" (actually, just a bit of tissue suspended on silk gauze) was Carrel's best known project and the heart was something of a minor celebrity with newspapers sending it birthday greetings every year. Carrel himself thought that the longevity of the heart pointed to the secret of immortality. Perhaps living cells freed from the burden of sustaining an entire organism could reproduce infinitely and live forever. This was in line with the thinking of the day and Carrel's work seemed to prove it. If this was indeed the case, then supplying the animal protein needs of the world might be as simple as raising mushrooms.

Certainly the public seemed to think so, since stories in the popular press talked about the chicken heart as being a large mass of flesh that grew so much that it was forever in danger of bursting from its container and needing to be periodically trimmed to keep it in check. In their 1952 science fiction novel The Space Merchants, Frederick Pohl and C M Kornbluth described a future farm where Carrel's chicken heart is grown into a lump of flesh weighing hundreds of tons and is serviced by butchers who trim off steaks from it with great flensing knives like those used by whalers. Radio author Arch Oebler took this a step further in his short radio play "Chicken Heart" where Carrel's experiment breaks loose and devours the entire United States. Comedian Bill Cosby claimed in his stand-up routine that he found this story so frightening as a child that he smeared Jell-O on the floor and set fire to the couch to keep the monster at bay. He said his father's reaction to this was for years after to call strangers into the house to see his "dumb kid".

So why didn't Carrel's experiment lead to a world of chicken heart fast food franchises? It was simply because the experiment was indeed unique-literally. After Carrel died in 1944, many scientists tried to duplicate his experiment, but none succeeded. In fact, as more was understood about the nature of living tissue, it became clear that Carrel's experiment should never have worked. Cells of the type Carrel used should only have reproduced a certain number of times and then die. They certainly shouldn't have kept on growing for decades. No one is certain what happened, but one theory is that Carrel's nutrient solution, which was derived from animal tissue, kept reintroducing fresh cells that replaced the ones that died. Whatever the truth was, the conclusion was that cultivating meat wasn't as simple as first thought.

Still, the idea remained. In the 1970s, the New Scientist magazine ran a satirical column about the fictitious and ethically-challenged DREADCO corporation that allegedly experimented on new ways to cultivate meat, such as genetically engineering alligators with salamander DNA so their huge, meaty tails fell off when grabbed with huge tongs or taking an elephant's trunk, hooking it up to a heart/lung machine and then hooking the other end to a machine that induced the trunk to grow by applying tension. The growing trunk would then be automatically wrapped in pastry and passed through an oven to produce a continuous stream of fresh, delicious elephant trunk pie. Meanwhile, on a more practical tack, food scientists in the wake of the food shortages after the Second World War often speculated on the possibility of manufacturing meat and NASA showed periodic interest in the idea as a way of feeding astronauts on extremely long space missions. In recent years, the animal rights organization PETA offered a $1 million prize for anyone who could come up with a commercially successful way of cultivating meat as a way to reduce livestock farming, which PETA regards as inhumane.

How to grow a steak

We hear so much about so many biomedical miracles - from mapping the thoughts in the human brain to transplanting entire cardiopulmonary systems - that we tend to think that growing meat in a lab must be easy. It isn't expected to be hooked up to someone's body. It just has to lie there and be cooked - preferably with a bit of rosemary and a dash of pepper. But, in fact, cultivating meat is in many ways as difficult as growing a transplant organ. In some very fundamental aspects, the two are identical. So difficult is the problem that it wasn't until the development of cloning and stem cell research that anyone took the idea of growing a steak seriously.

This is because meat is not simply a collection of cells. The chop on our plate was once part of a living organism-part of its skeletomuscular system, to be exact. It was what allowed the pig or the lamb or the cow to stand up, move around and generally do what animals do. If you were to take that chop (preferably before cooking) and examine it under a microscope, you would see a complex organization of tissues. There would be muscle cells, bone cells, cartilage, sinew, tendon, fat and blood vessels. Inside those blood vessels would be traces of blood, not to mention all the chemicals associated with a living organism ... what it ate and the life it lived. These make up the taste of the meat and are the sort that allows you to tell the difference between corn-fed pork raised on a farm and and wild boar meat brought down in a hunt.

And then there's the texture of the meat, which can have a significant effect. For example, another way of referring to the breast or leg of a chicken is as white or dark meat. White meat is what happens to poultry breast muscles when they aren't exercised because of wing clipping. They grow larger, but they remain white and tender. Leg muscles, on the other hand, get a daily workout, so they become tougher and darker. A similar process happens with all meat. A cow raised and pampered to become Wagyu beef will be very different from a steer that spent its life on the pampas of Argentina and the taste and texture shows this.

Cultivated in vitro meat has a huge challenge before it is to pass as a burger patty-much less a slab of hung, rare Argentine steak. This starts with the cell. To be specific, it starts with stem cells. In order to cultivate meat, it's necessary to induce cells to reproduce, but mature muscle cells, like most animal cells, are difficult to cultivate and only reproduce a fixed number of times before dying. Therefore, the meat cultivator has to take a biological step backwards to the precursor cells that become mature cells. This means working with stems cells and similar immature cells types that can be induced to reproduce regularly and coaxed into becoming the various tissues that make up what we call meat. Though it may sound simple as a statement, stem cell technology is still in its infancy. Obtaining and propagating stem cells and the like is relatively difficult, requiring very strict controls against contamination, and even though the end product is intended for the dining table, many of the problems are identical to those working on stem cell therapies for medicine.

But it isn't simply a matter of growing cells. A collection of beef cells grown in a flask wouldn't look remotely like anything you'd call meat. It would be more like a handful of wet whitefish run through a blender until it was pureed into a slurry. It wouldn't have the texture of meat, nor would it have the color and hardly any of the flavor. For all of that, the cells need variety and structure as well as a few added ingredients.

As of today, there are two major approaches to doing this. The first and more likely to produce cultured meat in the near future is called "scaffolding". In this, embryo cells, called myoblasts, that develop into muscle cells or immature muscle cells, called satellite cells, are grown and attached to a "scaffold" made out of a mesh of collagen or edible microbeads. This is then bathed in nutrients in a special container called a bioreactor, which is designed to provide the cells with a suitable growing environment. As the cells grow, they are coaxed to fuse together into tiny structures called myotubes. These then, if all goes well, are turned into simple muscle fibers called myofibers. Then end result resembles sausage meat or hamburger in texture, though having never had blood circulate through it, the meat has a color more like ground scallops. This can be cooked an eaten just like conventional meat, but it is literally anemic and a long way from what most people regard as "meat".

The second method is a bit more complicated. Called "self-organizing", in this technique thin sheets of muscle tissue are taken from a living animal. In recent experiments, these have usually been goldfish. When placed in a bioreactor with a suitable nutrient solution including muscle cells, the sheet is coaxed to grow. The advantage of this method is that such sheets contain the variety of cells required to give the meat more of its expected taste and texture. The disadvantage is that the sheets must be very thin. Muscles, like all animal tissue, are heavily dependent on blood vessels to provide the cells with nutrients and oxygen while carrying away waste products. If the sheets are very large or become more than a few cells in thickness, the cells inside the sheet quickly suffocate and die. Also, since most of the work has been done on tissues from relatively simple animals such as fish, there is the question of how well it would work with more complicated organisms. And, as with the scaffold meat, the results are not very appetizing. In the case of Dr Post's experiments, the end product are extremely thin sheets only about an inch (2.5 cm) wide. It would take approximately 3,000 of these sheets with some lab-grown fat tissue thrown in to make the first in vitro burger. Unfortunately, this must be done under laboratory conditions using very labor-intensive techniques, hence the staggering price tag of $345,000. And the result, admits Dr Post, looks like ground scallops.

Obstacles still to be overcome

In vitro meat has a long way to go before it's ready for the table. Since meat is muscle tissue, like all muscles it must be exercised or it has the consistency of tofu. Think of an old laying hen that has to be boiled for an hour before it's slightly less tough than an old boot and a battery hen that if boiled disintegrates into chicken pudding. To toughen up his in vitro meat, Dr. Post exploits the natural tendency of muscle tissue to contract by stretching the tissue strips between two Velcro bands. It's a crude system, but it points the way to a time when we may see factories of the future with vats filled with rows of roasts pumping away like something out of a Frankenstein film.

Another problem is how much the cells can reproduce. Theoretically, a single cell should be able to feed the entire planet, but no one knows how much cultured meat can grow before the process has to be restarted with fresh cell strains.

Then there is the fact that cells now can only be grown in thin sheets or tiny clumps to keep them from suffocating. To make larger pieces of meat, there has to be a way of getting nutrients and oxygen to every part of them. That means either growing blood vessels in the meat just like their natural counterparts or building some sort of artificial, yet edible, nanotube system. Without it, cultured meat would be available only as hamburger or in slices thinner than blowfish sashimi.

But, as mentioned, meat isn't just one kind of cell. It's made up of many different cells making up many different kinds of tissue and they go a long way toward defining what we think of as meat in general and what makes up a particular kind of meat. Fish is different from lamb, which is different from pork, but what they all have in common is that they are made up of a complex variety of tissues built into a particular structure. In order to be accepted as meat, the in vitro variety must mimic this at some level, which means having some of this variety included and a structure provided that allows the meat to be constructed along the same line as the four-footed, winged or finned variety. In other words, the meat must be designed.

Another factor is that growing meat will mean controlling its environment. Hormones and growth factors must be introduced and nutrients monitored to produce the desired outcome. Also, much of the color and flavor of meat derives from what an animal eats and the fact that blood is the tissues' nutrient solution. It's no good making something that on paper is meat, but tastes like the paper. That means all the things that provide the taste and aroma of meat, especially when cooked, need to be introduced. It's not impossible. Artificial meat made from soy protein can do all this by spinning soy like cloth and then introducing various flavorings, but that is on a much coarser level. In vitro meat has to do this at the cellular or even molecular level.

And then there is the nutrition and safety aspect. The meat has to be as least as nutritious, if not better, than the conventional version. More than that, it has to pass the strict regulatory eye of government that already takes a dim view of genetically modified crops-let alone meat made from as close to scratch as is possible without actually being a cow.

The advantages and disadvantages

Oddly enough, the last point is one of the advantages of in vitro meat. The necessity to maintain control over all aspects of the composition and environment of the cultivated meat means that the cultivators can engineer the meat to specifications. Low cholesterol meat can be grown or one free of allergens. It can be enriched with all manner of nutrients Theoretically, a food that the cultivator has absolute control over could be ideally tailored to the nutritional and health needs of the consumer. Imagine a Christmas dinner that leaves you feeling better than when you sat down to eat.

Obviously, the need to prevent contamination of the meat as it progresses from stem cells to table means that it is amazingly hygienic. E coli outbreaks from in vitro meat would be unheard of as would any other food-borne pathogen. Mad cow disease, trichinosis and any other disease could be easily excluded.

In would also be a far more humane way of raising meat. People who eat meat, especially city dwellers, don't care to think about what goes in in a slaughter house, however much the animal is kept from suffering, and having meat reduced to an unfeeling factory product would assuage many a conscience. Small wonder animal welfare groups such as PETA are so interested in in vitro meat.

However, some other advantages are more problematic. Supporters of in vitro meat make much of the greater efficiency of cultivating meat rather than growing it on the hoof. Dr. Hanna Tuomisto conducted a study into the relative environmental impacts of lamb, pork, beef and cultured meat and in an article published in the Environmental Science and Technology journal in 2011 concluded that if in vitro produces just the meat and not all the other bits that go into making an animal, it would use 35 to 60 per cent less energy than conventional livestock rearing and that there would be a similar savings in land and resources. Like similar estimates comparing a vegetarian lifestyle to a more conventional diet, these conclusions are debatable, as meat production in most parts of the world relies on free energy (sunlight) and often involves land and resources that would otherwise be wasted, such as grazing lands that are useless for crop cultivation or feeding animals on agriculture waste such as rapeseed cakes. At any rate, the question of energy savings as an advantage is the same as a reduction of green house gases, which proponents of meat cultivation also cite - unless in vitro turns out cheap enough to not just compete with conventional meat, but to replace conventional livestock on a massive scale to the point where livestock herds are actually reduced, then the savings are moot.

But how efficient in vitro meat production is raises other questions about its disadvantages. The use of a scaffolding to give in vitro meat structure means that some of the meat will be displaced and this must be compensated for with a greater density of protein. Also, the safety and nutritional quality of any scaffold material that remains in the finished meat must meet government standards.

Then there is the problem of scalability. Over the past half century, there have been any of a number of schemes to create food in the laboratory that looked like excellent candidates in tests, but when scaled up to industrial levels, minor problems became major obstacles. In the 1950s, the Charles Pfizer & Co laboratories and, later, NASA and the Soviet space program looked at algae as a high-protein alternative food that could be cultivated like any factory material. At first, it looked very promising. Algae is easy to grow. Known to most people as pond scum, it is high in protein and incredibly prolific. All you need is water, sunlight, carbon dioxide, sugar and a few additives and the simple little plant cells will grow and grow until you're harvesting 40,000 tons of protein per acre. Furthermore, it can be grown and processed just like an industrial chemical without ever seeing an ounce of dirt and artificial lights allow algae to grow 24 hours a day, 365 days a year.

It was brilliant-in the lab. On bench tops and in pilot plants, algae worked exactly as advertised, but when attempts were made to scale it up to industrial levels, problems suddenly appeared. Keeping the algae cells, carbon dioxide and nutrients in the proper concentrations was more difficult than first thought and getting enough light everywhere that algae grew in the processing vats or tubes was a real challenge. The algae proved very temperamental when it came to its growing conditions, didn't grow in efficiency as predicted and bacterial contamination was a real problem. Worse, it was discovered that the hard shell around the algae cells was more expensive to remove than first thought and the finished product was too high in certain nucleic acids for general human consumption. But what really put the nail in was that the cost of algae never came down enough in price with the end product selling at $1,000 per ton. This confined algae to the food supplements market.

Another thing that algae and in vitro meat have in common is public perception. Algae suffered from having its roots in pond scum and "test tube" or "Frankenfood" meat has a similar public relations problem. Advocates of cultivated meat tend to downplay this, but when consumers become set against something, it can be a real uphill battle to convince them otherwise. Many people are dead set against genetically modified crops and it does no good to point out that one modification merely causes corn to produce a protein that humans can digest, but parasites can't and thus kills them. Irradiation of meat and vegetables would save thousands of deaths every year from salmonella, but over half a century after it was introduced, the technique is restricted to little more than spices.

Where to from here?

Food is a very personal thing and plays a much larger role in people's lives than as a fuel to sustain life. Meals are a social function, a center of family life and a way of intimate sharing. It even acts as a form of identity, as anyone who has thrown a dinner party that mixed dedicated barbecue enthusiasts and militant vegetarians can attest. It's one of the things that has made NASA less enthusiastic about in vitro meat over the years. The space agency's idea was to make meat cultivation part of a 100 percent recycling system to turn wastes back into air, clean water and food, but astronauts have always shown a marked resistance toward "eating poo." That is what is known as an image problem.

The biggest disadvantage is, of course, cost. At $345,000 per burger, we're not likely to see in vitroburgers on our plates soon, but if this can be brought down, then it is possible. However, unless proponents are willing to settle for being a curiosity item on the menu like alligator or rattlesnake, that cost will have to not only come down to affordable levels, it will have to be competitive or even markedly cheaper than conventional varieties. That, however, is still a very big if.

The question is, where will in vitro meat sit on the food chain? Will restaurants serve lab-grown chops? Will we have fish fillets on our plate that never saw the sea or even a fish? Will fast food fried chicken receive the PETA seal of approval? Or will in vitro meat be like the processed meat that we see today in things like chicken nuggets? Maybe instead of a featured item on the menu cultured meat will be an ingredient that exists behind the scenes and we are only aware of if we read the list of ingredients on the package.

Or, perhaps, it won't even be something we eat. The story of synthetic foods has taken many odd turns and as the pioneer in the field Dr. Magnus Pyke pointed out in his book Synthetic Foods, many of the successes have nothing to do with creating new foods, but rather with creating substitutes for foods that were used for industrial purposes, such as animal fats going into soaps or proteins into adhesives. Every year, millions of tons of food that once would have been used for everything from fertilizer to squash rackets now feeds the hungry of the world while science creates substitute supplies for industry. Even today, over half of the United States corn crop goes to making ethanol, which shows how much food is used by industry. Perhaps the future of in vitro meat will be not to feed people, but to free up the food needed to free them.

Only time will tell, but in the meantime, scientists working on in vitro meat may need to tread carefully. Remember Cassel's chicken heart. One mistake and we won't be eating it, it will be eating us.