In the 1960s, several companies began development of Single Cell Protein (SCP) as a protein source for human and animal feed. SCP refers to protein produced by microorganisms, such as bacteria, yeasts and unicellular algae. This was not a new concept and can be traced back at least as far as 1936.
My first job was as a fermentation experimental officer at ICI in the UK, helping to develop the ICI Single Cell Protein Process. Several other companies were developing SCP for human and animal consumption. ICI intended to produce 1m te/yr by the 1990s; Shell was working on producing SCP as a by-product of gas oil dewaxing. Several other processes were based on mycoprotein from Fusarium sp.- ‘Quorn’, and algae. These projects involved very significant effort and investment; it has been estimated that by 1983, the main players had invested in R&D a staggering $US 2.9 x 108 in today’s terms.
Image shows the ICI production fermenter for SCP. 60m tall with a capacity of 3,000m3. I do not own the copyright of this image.
The new processes were beset with problems. Bacterial cells contain relatively large amounts of RNA, which can result in gout and kidney stones in consumers, as purines increase plasma uric acid, so RNA reduction was required. Some products had undesirable taste, and considerable downstream processing was required to produce acceptable texture and mouthfeel. Consumer acceptance of food made from bacteria was also difficult to achieve. However, one of the greatest hurdles was the scale of operation required and the resulting cost of the product. Most of these processes, while being technological marvels, were not commercially successful. In fact, as far as I am aware, the only product now on the market is Quorn.
Against this background, we see in vitro meat (IVM) or cultured meat, being developed as a sustainable food. It is also referred to as ‘Lab-grown meat’, illustrated by lumps of tissue apparently grown in Petri dishes, though this is perhaps somewhat misleading, as the scale of operation to produce sufficient product to be economically viable would require a facility similar in size to a modern dairy plant. To produce IVM, stem cells are collected from living animals and cultured in a reactor, using suitable culture media, which must be made up of food-grade components. Typically, vitamins, antibiotics, growth factors, such as calf serum, horse serum and chicken embryo extract are included, (though I have seen a recent report stating that calf serum is not necessary). The stem cells will differentiate into muscle cells under the influence of certain hormones. Obviously, strict sterility must be maintained, or contaminating bacteria will grow in the highly nutritious medium. The developing cells will require a supply of oxygen, carbon dioxide will be produced in the metabolic processes, and heat will have to be removed.
Merely getting the muscle cells to grow is only part of the process - Since consumers want something that resembles meat as closely as possible, some form of three-dimensional scaffolding is usually required for the cells to fuse together to form organised tissues.
For many people, the decision to purchase IVM will come down to taste, texture, appearance and cost. Estimates suggest that IVM will be twice the price of farmed meat. I saw recently a report that a burger pattie could cost around $11.35 I will be happy to eat IVM, but not if the product costs a lot more than my favourite grass-fed beef fillet steak.
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