In vitro meat

In vitro meat, also known as laboratory-grown meat or cultured meat, is animal flesh that has never been part of a complete, living animal. As of May 2003, some scientists are experimentally growing in vitro meat in laboratories, but no meat has been produced yet for public consumption. Potentially, any animal could be a source of cells for in vitro meat.

As with most experimental products manufactured on the laboratory scale, the current cost of in vitro meat is prohibitive, but industrial production would be much cheaper. For in vitro meat, costs only apply to the meat production, whereas for traditional meat, costs include animal raising and environmental protection (meaning there are less negative externalities associated with in vitro meat). However, it is not yet known whether in vitro meat is possible to be made economically competitive with traditional meat.

In vitro meat should not be confused with imitation meat, which can be a vegetarian food product produced from vegetable protein, usually from soy or gluten. The terms synthetic meat and artificial meat are synonymous, as they may refer to either.

Process and patent
Meat essentially consists of animal muscle. There are, loosely, two approaches for production of in vitro meat; loose muscle cells and structured muscle, the latter one being vastly more challenging than the former. Muscles consist of muscle fibers, long cells with multiple nuclei. They don't proliferate by themselves, but arise when precursor cells fuse. Precursor cells can be embryonic stem cells or satellite cells, specialized stem cells in muscle tissue. Theoretically, they can be relatively simple to culture in a bioreactor and then later made to fuse. For the growth of real muscle however, the cells should grow "on the spot", which requires a perfusion system akin to a blood supply to deliver nutrients and oxygen close to the growing cells, as well as remove the waste products. In addition other cell types need to be grown like adipocytes, and chemical messengers should provide clues to the growing tissue about the structure. Lastly, muscle tissue needs to be trained to properly develop.

In 2001, dermatologist Wiete Westerhof from the University of Amsterdam and businessmen Willem van Eelen and Willem van Kooten announced that they had filed for a worldwide patent on a process to produce in vitro meat (patent number WO9931222). A matrix of collagen is seeded with muscle cells, which are then bathed in a nutritious solution and induced to divide. Jon F. Vein of the United States secured a patent (US 6,835,390 B1) for the production of tissue engineered meat for human consumption, wherein muscle and fat cells would be grown in an integrated fashion to create food products such as beef, poultry and fish.

Reduced animal suffering
In vitro meat may appeal to animal welfare advocates and others concerned about animal well-being. Replacing traditional meat with in vitro meat has the potential to reduce or eliminate food-animal suffering. Ethical vegetarians may consider it an acceptable part of their diet. However, some people may even see the duplication of cells donated from otherwise unharmed animals as abuse. See "Animals are still used", below.

Health
In vitro meat may be cleaner and less prone to disease than animals, provided that donor cells are not contaminated. With relatively simple isolation procedures, economically damaging culls could also be avoided. The in vitro meat would also be free from the growth hormones and antibiotics that are fed to many animals in intensive factory farming.

In part because the fat content of meats could be brought more fully under our control, and also because other chemical constituents could be altered to produce the best nutrient balance, meat could be made a healthier product than at present.

There is also the benefit that there are no bones involved in this form of production, which are often removed from real meat for convenience. This also reduces the risk of choking.

Environment
The negative environmental consequences of traditional meat production, such as nitrate contamination and methane production, are reduced. While there will be some byproducts in the process of creating the nutrients to grow the cells, the environmental demand should still be lessened. Less of the animal would be wasted.

Space food
On long space voyages or stays, in vitro meat could be grown alongside hydroponic vegetables.

Increase in consumer choice and reductions in cost of production
Many kinds of animals are far too expensive to produce by the conventional agribusiness industries, even through factory farming (lions, for example). In part, this is due to some of these animals being "secondary consumers" — this denotes an animal that generally relies on other animals for sustenance. The energy in the flesh of their prey comes from the vegetation it ate while living, which in turn came from sunlight. Each transfer of energy from one living being to another is inefficient; only a small fraction of the available energy is carried over. To farm these kinds of animals would mean farming enough vegetation to feed the primary consuming animals to feed the secondary consuming animals to feed us, which is expensive. Yet with in vitro grown flesh, it is possible to greatly increase the variety of flesh available on the market, since the energy is supplied directly via a "perfusion system", as described above.

For this and other reasons, it is predicted that in vitro flesh would cost much less to produce than factory or free-range farmed animal flesh, and the production industries would not need to be given the massive subsidies that are given to many agribusiness industries in the west today.

Animals are still used
Animals are still used as tools in multiple steps. For example, current cell and tissue culture almost always use calf or fetal calf serum (or other animal sources, such as pituitary extracts) to provide the growth factors the cells need to signal them to divide. However, animals would not have to be killed in the process, which greatly reduces the ethical implications of eating meat.

Artificiality
At least initially, many people will likely prefer meat grown in a natural rather than an artificial environment. Consumers whose preference is whole and unprocessed food may find such an interventionist high-technology approach to food production distasteful, for reasons aesthetic, cultural, or ethical. On the other hand, some may prefer the consumption of in vitro meat to the slaughter of live animals, and it may be argued that the current industrial meat production infrastructure is "unnatural" and puts a bigger strain on the planet's natural resources than does growing meat cells artificially. Moreover, a range of highly processed non-meat food products, such as textured vegetable protein, has been available to many Western consumers for decades.

Quality, safety, health
People may be concerned that in vitro meat is of lesser quality than traditional meat, and that there are unresolved health risks. However, like any food product, in vitro meat would be required to pass through many safety and health trials before it could be sold. Also, this question is one of the main focuses of scientists working on in vitro meat, and they aim to produce healthier meat than conventional meat, most notably by reducing its fat content and controlling nutrients. For example, most meats are high in the fatty acid Omega 6, which can cause high cholesterol and other health problems. With in vitro meat, Omega 6 might be replaced by Omega 3, which is more healthful.

Differences from traditionally produced meat
If in vitro meat is different in appearance, taste, smell, texture and other factors; this may reduce its appeal. The lack of fat and bone may also be a disadvantage, for these parts make appreciable culinary contributions. Many food items, such as surimi, designed to substitute for other ingredients (for reasons from morality to expense) have become independently sought out for their own properties.

Challenges
At the moment, hardly any serious research has been made on the subject of in vitro meat. There are several obstacles to overcome if it has any chance to succeed.
 * Proliferation of muscle cells: Although it is not very difficult to make stem cells divide, for meat production it is necessary that they divide at a quick pace. This requirement has some overlap with the medical branch of tissue engineering.
 * Culture medium: Proliferating cells need a food source to grow and develop. The growth medium should be a well-balanced mixture of ingredients and growth factors. Depending on the motives of the researchers, the growth medium has additional requirements.
 * Commercial: The growth medium should be cheap to produce.
 * Environmental: The production of the growth medium shouldn't have a negative impact on the environment. This means that the production should be energetically favorable. Additionally, the ingredients should come from completely renewable sources. Minerals from mined sources are in this case not possible, as are synthetically produced nutrients which use non-renewable sources.
 * Animal welfare: The growth medium should be devoid of animal sources, although they may initially be more useful than other sources.
 * Space travel: The growth medium should be almost completely created from the waste products in the space ship, if it is to be used in space travel.
 * Bioreactors: Nutrients and oxygen need to be delivered close to each growing cell, on the scale of millimeters. In animals this job is handled by blood vessels. A bioreactor should emulate this function in an efficient manner. The usual approach is the creation of a sponge-like matrix in which the cells can grow, and perfusing it with the growth medium.

Initiatives
Probably the first research into in vitro meat was performed by M. A. Benjaminson from Touro College. His research group managed to grow muscle tissue from goldfish in a laboratory setting with several kinds of growth media.

In 2004, a group of researchers started the non-profit organization New Harvest, with the goal of promoting research into in vitro meat. Among the founders are Jason Matheny and Vladimir Mironov.

In April 2005, a research project into cultured meat started in The Netherlands. It is carried out under the lead of Henk Haagsman at the University of Amsterdam, the Eindhoven University of Technology and Utrecht University, in cooperation with sausage manufacturer Stegeman. The Dutch government granted a two million euro subsidy for the project. In Amsterdam the culture medium is studied, while the University of Utrecht studies the proliferation of muscle cells and the Eindhoven university will research bioreactors.

Fiction

 * In The Space Merchants (1952) by Frederik Pohl and C.M. Kornbluth, artificial meat is grown in huge lumps tens of metres in diameter, workmen walking on top of it harvest slices with big knives.
 * In Stars in My Pocket Like Grains of Sand (1984) by Samuel R. Delany, the main character's culture uses vat-grown meat cultured from humans as the primary protein source. Interaction between this culture and cultures using 'natural' meat are (briefly) explored.
 * Claude Zidi's 1976 comedy film L'aile ou la cuisse starring Louis de Funès as top-notch gourmet and Julien Guiomar as the infamous Tricatel who secretly produces artificial food.
 * In Assimilating our Culture, That's What they're Doing!, one of Larry Niven's short stories set in the Draco Tavern, a man who visits the tavern is depressed by the fact that he has licensed his own genome to an alien race, who are mass-producing headless clones of him for the meat market on their home planet.
 * The Bob the Angry Flower strips, The Vegetarian's Dilemma and Meat Sheets.
 * In the short story collection "The State of the Art" by Iain M. Banks, one of the stories includes a party where the main course is vat grown meat from cells of notable human villains and meglomaniacs, with "stewed Idi Arman" and "Richard Nixon Burgers" among others.
 * In Margaret Atwood's Oryx and Crake, 'Chicky Knobs' were chickens with only a mouth and a digestive tract that were genetically engineered for meat products.
 * Although not called "in vitro meat", the creation of zombification in the Xbox 360 game Dead Rising was the result of US scientists trying to mass produce meat for consumption. The engineered wasps that were to facilitate this escaped from the Santa Cabeza complex and 'zombified' the populace, resulting in military intervention. One of the few survivors of that incident, Carlito and Isabella Keyes, started a new outbreak in Southwest town of Willamette in revenge, where the game takes place at the mall there.
 * A popular urban legend describes a genetically engineered vat-grown creature, dubbed "Animal 57", as the source of meat for various fast-food chains.
 * In Rudy Rucker Ware Tetralogy almost all of the meat was tank grown, including human meat.