production of animal proteins by cell systems - New Harvest

4. Tissue engineering of muscle fibers. In the absence of blood flow that provides
oxygen and nutrients to the cells and removes metabolic end products, the possibility to
form a 3-dimensional structure of cells is restricted. The in vitro culturing of cells is
limited to only a few layers of cells, which would represent tissue of a thickness of less
than a millimeter at maximum because limitations in nutrient diffusion. This problem also
has to be addressed by those who pursue tissue engineering for biomedical purposes.
Culturing of cells on biological or synthetic scaffolds may provide a solution to this
problem. In this way the scaffold would provide shape and structure to the engineered
tissue. In the case of cultured meat, the scaffold should be either edible or
biodegradable. A more straightforward solution would be the processing of thin layers of
cells into a (meat-like) product.
5. Industrial bioreactors. Production of sufficient numbers of muscle cells for the
generation of edible products will require large-scale culturing. Since stem cells and
skeletal muscle cells require a solid surface for culturing (in contrast to, for instance,
blood cells that can be cultured in suspension) a large surface area is needed. Culturing
should be performed in large bioreactors containing many sheets of printed cells, cells
grown on scaffolds, or cells cultured on microspheres that can be kept in suspension.
In a model for mammalian muscle cells in a 3-D matrix, cells are supported and supplied
within the bioreactors such that the natural tissue builds ‘self-organizing constructs’,
where the 3D self-organization of tissues allows the provision of the nutrient supply,
aeration, waste removal etc. (one of the models from the in vitro meat economics study;
see supplementary materials). This subsequently allows cell, and consequently, tissue
growth. It was concluded from this study that several areas require further development:
(1) the mechanism for cell support and growth within the bioreactor; (2) the mechanism
for harvesting; (3) the need for pharmaceutical grade cleanliness and ability to sterilize;
(4) instrumentation and process control.
6. Food processing technology. Depending on the starting material (suspensions of
small myotubes, myofibers on scaffolds, microspheres, etc.) new technologies need to be
developed to make attractive products. It is expected that at first small pieces of cultured
muscle fiber will be produced that serve as raw materials for making a wide variety of
products (‘cultured meat inside’).
7. Consumer preferences and adapted marketing strategies. Why would a
consumer prefer cultured meat if meat from animals is available? If it is because of
sustainability or animal welfare issues, why not eat less meat and instead, more plant
proteins? Many questions can be asked and many factors determine consumer
preferences. Studies are required to determine the preferences and, consequently, the
marketing strategies. Interesting in this respect is the summary from a workshop on
cultured meat held on December 3 rd , 2008 as part of an NWO application (see boxes).
This workshop was organized by scientists from Wageningen University (Dr. Cor vd
Weele and Dr. Hilde Tobi) and Utrecht University (Prof. dr. Henk Haagsman and Dr.
Bernard Roelen).
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