Beef Without Cows?

So, how can we have a nice juicy burger without killing cows? Well, you grow a cow outside of a cow, or more specifically, you grow the cells that make up the burger outside of a cow, in a lab. You might chuckle, thinking to yourself “how is that even possible?”. But it is being done using cellular agriculture, an emerging technology that combines the fields of tissue engineering, biotechnology, microbiology, and synthetic biology to create products that would otherwise come from traditional agriculture.

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In August, 2013, Professor Mark Post created the first cell-cultured hamburger that was cooked and tasted live for a whopping $325,000! There were a few problems including a lack of fat but the bite still felt like a conventional hamburger. This historical event paved the way for future research into this technology

There are two kinds of cellular agricultural products:

• Acellular products: made of organic molecules like proteins and fats and contain no cellular or living material — made from microbes such as yeast or bacteria that act as a “factory”
• Cellular Products: made of living or once-living cells (think meat, wood, and leather)

Source: New Harvest

Cultured Meat

Cultured meat is a cellular product that is made from animal cells, an alternative to killing animals. One muscle cell has the potential to turn into 1 trillion muscle tissue. The first step is gathering the stem cells, which is the essential building block used in the meat cultivating process. The second step is placing the stem cells in a medium that contains the nutrients and growth factors needed for the cells to reproduce. The third step is a scaffold which can be optional — if the resulting product is to be in a structured form, that is to have an overall structure or arrangement of cells (ie. steak). A scaffold is a mold to which cells are attached for them to achieve a certain shape. Finally, the cells, medium, and possible scaffold are put into a bioreactor which helps the cells to proliferate (reproduce more cells). Each of these steps is explained in a bit more detail in the section below.

Source: EatingWell

Step 1: Gather Stem Cells

Stem Cells are the foundation of the meat cultivating process. They are unspecialized cells with self-renewing capacity that differentiate into the different cell types called germ layers that are used to create cultivated meat.

There are 3 layers of cells, called germ layers:

• Endoderm: the inner layer
• Ectoderm: the outer layer, which gives rise to the nervous system and the epidermis among other tissues
• Mesoderm: the middle layer which gives rise to the muscle cells and connective tissue in the body

There are different types of stem cells that can be used in cellular agriculture, each with its own benefits and challenges and the ability to produce some or all of the germ layers. Here’s a brief summary of the types of cells that can be used to create cultivated meat:

Embryonic Stem cells (ESC): derived from embryos that develop from eggs that have been fertilized in vitro. These cells can differentiate into cells of all three germ layers.

Induced Pluripotent Stem Cells(iPSC): as an alternative to ESC, and is the result of cellular reprogramming to obtain these types of stem cells that maintain the desirable properties of ESC without being derived from an embryo. These cells can differentiate into cells of all three germ layers. Derived from adult skin or blood and reprogrammed to act as a stem cell.

Mesenchymal Stem Cell (MSC): multipotent adult stem cells, meaning they can differentiate into a limited number of cell types, usually within a single germ layer. They are isolated in different sources such as bone marrow, umbilical cord tissue, and fat.

Myosatellite Cell: multipotent stem cells found in adult skeletal muscle tissue. Obtained by taking a muscle biopsy from the animal, about the size of a pinhead, and then the cells are isolated.

Fibroblast: the most common type of connective tissue. They are used to synthesize the structural framework for animal tissues (classically, strictly allows for collagen and other ECM deposition as well as the formation of scar tissue).

The most successful method of obtaining a starting cell involves harvesting stem cells from cows via biopsy (myosatellite cell). The muscle tissue is harvested from the live animal in a harmless procedure. The tissue is made up of muscle and fat cells which are then separated. The muscle cells are then dissected and ready for the medium.

Step 2: Growth Medium

Stem cells will not grow on their own. They need to be put in a Medium to provide the necessary nutrients needed for growth. The cells are ‘bathed’ and ‘nurtured’ in nutrients consisting of amino acids, vitamins, and salts, and sugar that provides the growth and survival factors needed for the cells to reproduce or proliferate.

One of the most important parts of the culture medium is the growth serum. Fetal Bovine Serum (FBS) is the serum derived from the bovine fetuses of pregnant cows before slaughter. When a cell knows it’s in the wrong place, it will undergo apoptosis - programmed cell death. FBS stops suicidal cells by convincing the cells that they’re in the right spot, even though they are out of the body of the cow. It also contains all of the growth factors needed for a cell. FBS is good growth serum, however, there are a few problems that arise, making this an undesirable long term solution:

1. Ethics — the fetus’s heart is punctured without anesthesia, causing possible suffering to the animal
2. Price — very expensive, making mass production of cultured beef more expensive than current beef
3. Scalability — the supply of FBS won’t be able to keep up with the demand as its popularity grows
4. Reliability — there is significant batch-to-batch variations due to geographical and seasonal variation

There are no other reliable alternatives at the moment. However, being one of the biggest obstacles in the cellular agriculture industry, a great deal of effort is being put in to find a viable alternative. People for the Ethical Treatment of Animals (PETA) have a list of 74 potential cell culture alternatives, but most are cell-specific and have their own issues.

Source: Stem Cell Thailand

Step 3: Scaffold

At this point, if the cell and the medium are put into the bioreactor, the result would be unstructured meat, something like ground beef. To create structured meat such as steak, there is a need to utilize a scaffold. Cells grow in and around the scaffold to create the three-dimensional desired shape. Three-dimensional tissue engineering was first developed in the medical field for tissue regeneration and transplantation. Now, the cellular agriculture industry is pursuing suitable scaffolding materials to produce cultured meat products for human consumption.

Understanding the extracellular matrix (ECM) is key to tissue engineering which will help form structured meats. The ECM supports the cells in a tissue and has four key roles:

1. Controls communication between cells
2. Segregate tissues
3. Regulates cell processes such as growth
4. Migration and differentiation

Collagen plays a major role in building this network. Collagen proteins are modified with carbohydrates and once they’re released from the cell into the extracellular space, they assemble into long fibers called fibrils. They are then interwoven with a class of carbohydrate — bearing proteoglycans (proteins that are heavily glycosylated) which attach to a long polysaccharide backbone.

Source: openstax

Just as standard animal cells use collagen as the structure, a scaffold would play a similar role. Scaffold materials can be composed of synthetic or natural polymers which offer different properties such as high porosity, tailored pore sizes, biodegradation, mechanical strength dependent on their composition, structure, and arrangement of their constituent macromolecules.

Step 4: Bioreactor

In order for cells to reproduce they need not only the medium but the environment that will promote this growth. The cells, medium, and scaffold if being used are placed in an incubator (bioreactor) under strict conditions that mimic the same growth conditions that occur in animals and facilitates proliferation. The cells are exposed to a variety of different environmental cues within a controlled environment that encourages them to specialize into specific cells.

The two sequential cell culture phases of proliferation and differentiation form the foundation of the bioprocess design.

During the first step, the proliferation phase, the cells just multiply until they reach the desired concentration. The second step starts with differentiating the cells into muscle cells. After differentiation, they begin to merge and form myotubes that continue to grow into skeletal muscle tissue if the right conditions are provided. The structure of the meat product depends on the length and conditions of the production process. At the early stages of the differentiation phase, the cell culture consists of tiny and soft cell strands that require electric or mechanical stimulation to boost protein production, improve the structure and produce larger pieces of meat. In theory, it could even be possible to generate a steak-like structure but it would require a vascular system to deliver nutrients to the tissue.

Source: The Good Food Institute

Although the 3 or 4 steps to make cultured meat seem very complicated and on the surface would seem to take a long time to create meat, it takes 44 days to grow a single batch at scale.

Benefits

Cultured meat has a significant number of benefits and has the potential to change the world. Being able to grow meat without having to raise livestock, is much more environmentally friendly: less energy and land is used and less harm to the environment.

Being able to grow meat would also help to deal with food supply issues around the world, assuming the ability to mass-produce at a cost-efficient level is achieved. Creating meat in a lab would also avoid some health and safety issues that have occurred in natural settings such as mad cow disease.

Challenges

Although there are a lot of benefits to cellular agriculture and cultured meat, there are still a number of challenges that will need to be overcome before it will be able to replace the current animal product:

• Economic impact: producing meat in a lab vs on a farm will have a significant impact on the farming industry and likely result in a large number of job losses. But lab-grown meat isn’t the only pressure facing this industry - automation itself is a large factor.
• Perception: anything grown in a lab can sometimes be seen as unnatural. Cultured meat is not genetically modified (GM) meat - education will be key.
• Taste: cultured meat is still in its infancy stages so it is not fully known how the taste will compare with the real thing. With the potential of growing meat without fat or bones, will this change the taste and be acceptable?
• Cost: current costs of cultured meat is very high and not affordable for most people. The ability to mass-produce cultured meat to drive efficiencies in the process and reduce production costs is still years away.
• Animal Cruelty: cultured meat eliminates the need to slaughter animals, however, the most popular and successful medium currently in the process is the fetal bovine serum which has its own perceptions of cruelty to animals. Further development of alternative growth serums, particularly plant-based, will need to replace the fetal bovine serum to improve the acceptance of cultured meat.

The Big Question: Is it Meat?

The answer to this question is neither straightforward nor consistent and depends right now on who you ask.

Yes people: argue that cultured meat is created by painfully harvesting cells from living animals. These cells are fed and nurtured through scientific means so that they reproduce to create muscle tissue, which is the meat that we eat, therefore it is biologically the same as the meat tissue that comes from a cow — it is meat.

No people: argue that meat has to come from harvested livestock — if it doesn’t, it is not meat. The cattle industry has been big lobbyists against the use of the word meat by cultured meat companies so much so that in some states in the US there is now legislation banning it. In Canada, cultured meat companies are not able to use the word ‘meat’ in their marketing as the product does not come from slaughtered animals.

Fifty years hence we shall escape the absurdity of growing a whole chicken to eat the breast or wing by growing these parts separately under a suitable medium.

-Winston Churchill, 1931

Who knew that this would be a reality. This new emerging technology is just a part of the future of food, where it will be sustainable and easily accessible to billions of people around the world. I hope to see a cultured burger on the shelf of my local grocery store in the near future and bite into it, not being able to tell the difference between a normal hamburger.

Thank you for reading! Keep up to date with what I‘ve been working on by subscribing to my monthly newsletter. You can contact me via LinkedIn or email: tjawortley@gmail.com