To identify the positive and negative claims about the contributions of technological solutions to social inclusion in food systems, the selected literature in ‘Food Science Technology’ (see Section 2.2) was further analyzed by a researcher with technical expertise. The hybrid process of inductive and deductive thematic analysis (Fereday and Muir-Cochrane, 2006) was performed with assistance of Citavi. The deductive coding scheme (see Section 2.1) was used to sensitize the researcher to claims about social impacts. The emerging insights were regularly discussed with a social scientist to ensure the consistent use of the coding scheme. A few additional categories emerged from the data in an inductive way, related mostly to specific reasons for social exclusion. The review took place between April 2022 and May 2023. It identified some claims about social effects of technologies but also revealed technologies of which social impacts were not discussed in the literature.

As the above search strategy (see Section 2.2) was aiming at the maximum variety of technological solutions for production of cultivated meat, there was a possibility that some articles focused on impacts were overlooked. To address this shortcoming, another search strategy was performed in the Web of Science database. First, a search string which aimed to identify papers focused on inclusion was used: (“cultured meat” OR “cultivated meat” OR “cell-cultured meat” OR “in-vitro meat” AND inclus*). Only one document was identified. The search string was then broadened to social impacts: (“cultured meat” OR “cultivated meat” OR “cell-cultured meat” OR “in-vitro meat”) AND “social impact*.” Only two documents were identified. Subsequently, the search string was broadened to capture papers that address various impacts: (“cultured meat” OR “cultivated meat” OR “cell-cultured meat” OR “in-vitro meat”) AND ((social OR political OR environmental OR health OR economic) AND impact). The searches were executed between December 2022 and May 2023 and yielded 133 publications, which include the search terms in title, abstract or keywords. All abstracts were reviewed, and 98 articles were selected for a full text analysis. The papers were analyzed by researchers with technical or social science expertise, as appropriate. Most papers referred to environmental impacts and to cultivated meat in general, rather than to specific production technologies.

Given the limited literature about social impacts of various technological solutions, 11 expert interviews were conducted between December 2022 and May 2023. Experts are believed to understand the “causal mechanisms” or to be the mechanics behind the “causal mechanisms” and hence expert interviews are suitable to gain insights into how “x and y interact” (von Soest, 2023). This provides insights into how technological choices and social impacts are related to each other.

Researchers and entrepreneurs with expertise relevant to production of cultivated meat were identified using the aforementioned secondary sources and were invited to an interview. The selected experts have either extensive expertise in this field or have expertise on technologies for which the social impacts could not be identified in the literature (see the interviewee list in Table 2). In advance of the interview, experts were provided with information about the project, the data management policy and an interview consent form. The interviews were conducted online by two researchers with expertise in social and technical sciences and lasted 1–2 h. One interview took place in person. Experts were asked how different technological solutions relate to food affordability, food acceptability, health, and social relations. The interview recordings were transcribed using an automatic transcription software and were verified manually. The anonymized interview transcripts were numbered I1 to I11, uploaded to Citavi, analyzed by a social scientist and consulted with the scientist with technical expertise. As in the case of literature analysis, the hybrid process of inductive and deductive thematic analysis (Fereday and Muir-Cochrane, 2006) was performed to analyze the interview transcripts and identify positive and negative claims about the contributions of technologies to social inclusion.

Meat is composed of muscle fibers, connective, adipose, vascular and nervous tissue (Listrat et al., 2016). For cultivated meat, skeletal muscle cells, fat cells and cells of the connective tissue are considered (Post et al., 2020; Jara et al., 2023). Muscle cells make up the largest proportion and are rich in proteins. The fat cells serve as flavor carriers while the connective tissue cells contribute to the tenderness and texture (Weston et al., 2002; Li et al., 2020a; Jara et al., 2023). Additional requirements for cell selection are the capacity for replication and for the development into a specific cell type, also called differentiation (Post et al., 2020). The long-term capacity of replication allows a continuous production process which enables to lower the overall costs of cultivated meat production (Specht et al., 2018). The following paragraphs will therefore focus on different approaches to sourcing cells and cell innovations for production of cultivated meat.

Technological solutions for sourcing and optimizing cells for cultivated meat production are expected to have various impacts, which with the use of the coding framework (see Table 1) can be categorized as positive or negative claims about the barriers to social inclusion. The overview of impact claims is provided in Table 3 and is displayed on the innovation radar (see Figure 3).

Some people could be excluded from consumption when ESCs are used because they would find it difficult to understand the production (I4) (cognitive barrier is expected = negative claim) or consider it unethical (Zehorai et al., 2023) (cultural barrier is expected = negative claim). However, those following kosher diets would be included in consumption as ESCs are expected to be compatible with Jewish dietary laws (I4) (lack of religious barrier is expected = positive claim). Further, ESCs could improve inclusion in production as the cost barrier would be lowered given the reduced need for biopsies taken from animals and reduced costs for cell isolation and analytics. Positive claims about inclusion in health are exemplified by expected increases in food safety and security (Zehorai et al., 2023) (food contamination not expected = positive claim).

The use of adult stem cells harvested by biopsies could raise concerns about animal welfare (I2) - for some it would create a cultural barrier to consumption (negative claim). But biopsies could be replaced by necropsies (Gstraunthaler and Lindl, 2013), which could lower such cultural barriers (positive claim).

An alternative to stem cells are primary cells but as they require frequent biopsies, they are expected to raise not only concerns about animal welfare but also production costs (I4), that is cultural barriers to consumption and cost barriers to production (negative claims). Should the primary cells be harvested by necropsies, experts raise concerns about production costs and additionally see the need for new safety procedures to manage the risk of contamination (I3) (expected extra costs to production = negative claim). However, as mentioned above, necropsies allow cells isolation without hurting animals and could be positively perceived by consumers (I3) (no cultural barrier to consumption = positive claim).

Primary cells can be immortalized without genetic modification (GM), leading to an enhanced replication which lowers the production costs (Zehorai et al., 2023) (positive claim). Those cells can be used continuously without harming animals (I2) - they create no cultural barriers to consumption (positive claim). However, the immortalization process without GM is more expensive, longer, and less reliable compared to immortalization using GM (I2), resulting in increased production costs compared to immortalization with GM (negative claim about cost barrier). The techniques used for immortalization can be misunderstood or not allowed (Soice and Johnston, 2021) (negative claims about cognitive and regulatory barriers to consumption). Further, only a few firms in the world can immortalize cells without GM (I2) (expected capability barrier = negative claim).

Primary cells can also be immortalized through GM. The cells are affordable for producers and researchers (I2) and offer a good replication capacity further lowering the production costs (Zehorai et al., 2023) (positive claims about the cost barriers). However, the use of GM can be seen as unacceptable to consumers (I2, I4) (expected cultural barriers = negative claim) and the technologies used for immortalization can be misunderstood by them (Gaskell et al., 2000; Hubalek et al., 2022) (expected cognitive barriers = negative claim). It is further unclear if selling in the EU would be approved for cultured meat if GM is used (I2, I4) (expected regulatory barriers = negative claim).

iPSCs come without the need for frequent biopsies, have neither the donor-to-donor variability that primary cells suffer from (Hubalek et al., 2022), nor the ethical issues connected to embryonic stem cells (Rosselló et al., 2013). These are positive claims about the lack of cultural barriers to consumption and lower costs barriers to production. However, the regulatory approval and public acceptance for iPSCs cells is seen as uncertain, e.g., in the EU, as their stem cell-like properties are induced with GM methods (I3, I2, I4), (Gaskell et al., 2000; Soice and Johnston, 2021; Su et al., 2021). Such claims about cultural barriers and regulatory barriers are negative.

The natural microenvironment of the cells is often mimicked by the scaffold. Its microstructure ensures the efficient transport of oxygen, nutrients, and waste products to and from the cells (O'Brien, 2011). The production techniques can be divided into bottom-up and top-down approaches. For bottom-up approaches smaller building blocks such as tubes, sheets, spheres or other microstructures seeded with cells are built together to reconstitute the meat cut. Whereas for top-down approaches, a prefabricated scaffold is used to seed cells, which grow inside the 3D-Structure and mature into tissue (Nichol and Khademhosseini, 2009; Bomkamp et al., 2022).

The following paragraphs will present the current scaffolding innovations. Until now, the main consideration was the structure and the scale up of scaffolds but social impacts have not been considered so far. Currently, six innovative approaches exist for scaffolding: hydrogels, microcarriers, porous scaffolds, fiber scaffolds, 3D-printing and decellularization (Bomkamp et al., 2022; Chen Y. P. et al., 2022).

Literature was analyzed and interviews were conducted to understand if scaffolding technologies are expected to make the production and consumption of cultivated meat inclusive. The results are summarized in Table 4 and used for the creation of the innovation radar in Figure 3.

Scaffolds can influence the organoleptic properties by creating structures that resemble the structure of conventional meat. Furthermore, scaffolds may have an impact on costs and on scalability of the process by enabling to suspend cells that need to attach to a surface in a bioreactor (Bomkamp et al., 2022).

Microcarriers that are food grade and remain in the final product, lower the production costs (positive claim), since the cells do not need to be separated from the scaffold, which results in higher cell yields (Bodiou et al., 2020; Zernov et al., 2022; Yen et al., 2023). It is possible to enhance the nutritional value of the final product when using microcarriers, for example, by encapsulating nutraceuticals (Yen et al., 2023) (enhancing food properties = positive claim). Additionally, the color of the final product can be influenced (Chen L. et al., 2022; Chen Y. P. et al., 2022; Yen et al., 2023) leading to greater consumer acceptance, (expected low cultural barriers = positive claim). Yen et al. (2023) incorporated oleo gels into microcarriers, which had similar properties to beef fat with enhanced nutritional values (enhanced food properties = a positive claim). Others produced microcarriers out of by-products of the food industry, such as turkey collagen and eggshell membrane (Andreassen et al., 2022). Those components are low in cost, have a high nutritional value and are biocompatible for the cells (enhanced food properties = positive claim). However, they are not vegetarian/vegan, thus there could be cultural barrier for some consumers (negative claim). One main advantage of microcarriers is that they are simple to control and monitor compared to the other scaffolds, which can result in enhanced quality, consistency and cost reduction (Moslemy et al., 2023) (expected lower production cost = positive claim).

When using hydrogels for scaffolding some of the ingredients, such as alginate, are already widely used in the food industry and therefore represent and affordable solution for cultivated meat producers (Seo et al., 2023) (expected no cost barriers = positive claim).

For porous scaffolds plant proteins represent a suitable scaffolding ingredient due to their affordability, high nutritional value, and compatibility with cells (Ben-Arye and Levenberg, 2019; Ben-Arye et al., 2020; Lee et al., 2022). These positive claims refer to low cost barriers for producers and food properties that are conducive to consumer health. Using extrusion to produce porous scaffolds allows for the use of side streams, for example from the oil industry, increasing the sustainability of the process (Ben-Arye et al., 2020). Even though further steps need to be taken to increase the functionality of extruded scaffolds, this technology represents a promising approach due to its scalability, affordability, and consumer acceptance (I4) (Levi et al., 2022). It is thus associated with reduction of cost barriers for producers and lowering of cultural barriers for consumers (positive claims).

Electrospinning is a cost-effective and simple process and already widely used in the textile industry and tissue engineering (Levi et al., 2022), (expected low cost barriers for producers = positive claim). However, products made by electro-spinning are not considered tasty (I4) and therefore the technology is associated with cultural barriers to consumption (negative claim).

3D-bioprinted cultivated meat could lead to more consumer acceptance due to the possibility to precisely mimic the structure of conventional meat (Handral et al., 2022; Levi et al., 2022) (expected low cultural barriers = positive claim). Furthermore, it could offer appealing food by bringing it into desired shapes for elderly people who might have chewing or swallowing problems (Portanguen et al., 2019; Handral et al., 2022) (food properties enhancing inclusion in consumption = positive claim). Including antioxidants as a scaffolding component during 3D-bioprinting allows to enhance the nutritional value of the final product (Dutta et al., 2022) (food properties conducive to consumer health = positive claim).

Decellularized scaffolds are low in cost, sustainable, contain the vascularization and have the potential to be scaled up in a bioreactor (Levi et al., 2022; Singh et al., 2023). These positive claims refer to lowering the cost barriers for producers. However, the composition of the scaffold might not be as easy to enhance compared to the other scaffolds. The nutritional value of the final product would be influenced directly by the growth of the cells (I5) (no possibility to enhance food properties = negative claim).

Cell culture media is the major cost driver when considering large scale cultivated meat production (Post et al., 2020; Pajčin et al., 2022). It is estimated to make up to 99% of the total cultivated meat production cost (Stout et al., 2021; Yang et al., 2023). Therefore, it is important to ensure that a medium enables efficient proliferation and differentiation of cells while maintaining food safety of the final product (Guan et al., 2021). The media contains nutrients and oxygen for the cell culture and influences the characteristics of the final cultivated product (Post et al., 2020). Efficiency of the cell culture is impacted by the composition of the medium and each cell type has its unique requirements. Therefore, adjusting the medium based on the specific needs of the cell type is crucial. Finding appropriate concentrations of growth factors and proteins is essential to prevent inefficient nutrient uptake and excessive buildup of metabolic compounds (Hubalek et al., 2022).

As for the other technological areas, literature was analyzed and interviews were conducted to understand if various approaches to production of cultured medium are expected to help make the production and consumption of cultivated meat inclusive. The results are summarized in Table 5 and further used for the creation of the radar in Figure 3.

The serum-based media using FBS are expected to have a high batch to batch variation and be more expensive than serum-free media (I11) (Gstraunthaler and Lindl, 2013; Post et al., 2020). These claims relate to production cost and are negative. Moreover, the serum-based media are expected to be seen by consumers as unethical (I4, I6, I11) (Gstraunthaler and Lindl, 2013; Post et al., 2020) and incompatible with vegetarian diets due to animal welfare concerns (I4, I5, I6) (expected cultural barriers to consumption = negative claims). Including FBS or other animal components in the medium poses a food contamination risk (Gstraunthaler and Lindl, 2013; Post et al., 2020) and large-scale decontamination process is yet to be developed (I3) (enhanced risk for consumer health = negative claim). However, it is expected to be easier to get regulatory approval for serum-based media compared to the other alternatives (I4) (expected low regulatory barriers = positive claim).

The expectations about media using animal components other than FBS, such as blood from slaughtered animals, are mixed. Some experts expect costs to be lower than in case of chemically defined medium and the acceptance to be high among meat eaters (I3) (lower cost for producers and low cultural barrier for consumers = positive claims). Others expect the same ethical concerns as for FBS-based medium would affect the general public acceptance but also stop vegans and vegetarians from consumption of cultivated meat (I3, I5) (expectation of cultural barriers to consumption = negative claims). These positive and negative claims about cultural barriers concern people with different eating habits.

Similarly, in the case of media with plant components, some experts expect high batch-to-batch variations (increased costs = negative claim) and possible exposure to high concentrations of pesticides or herbicides to pose problems (risk of food contamination = negative claim) (Su et al., 2021; Messmer et al., 2022). However, media with plant components are expected to be cheaper than chemically defined medium (I3) (lower costs barrier for producers = positive claim).

Should GM plants be used for production of medium, experts expect that crop farmers could participate in the emerging value chains for cultivated meat by doing what they already know for example producing crops but with higher added value (I2) (no capability barrier for producers = positive claim). The use of GM crops for medium production is also expected to allow scale-up and lower the production costs (I2) (lowering cost for producers = positive claim). However, one expert noted that regrettably it is unclear if sales of cultivated meat would be allowed in the EU when the GM crops are used in culture medium (I2) (risk of regulatory barriers to consumption = negative claim).

Medium with ingredients obtained by precision fermentation is expected to be 75–85% cheaper compared to serum-containing medium when produced at scale (Stout et al., 2021) (expected lower cost for producers = positive claim). However, the scale-up is currently not possible (I2) (Stout et al., 2021; Hubalek et al., 2022) (capability barrier for producers = negative claim). Moreover, it is unclear if sales of cultivated meat would be allowed in the EU when GM microorganisms are used to produce components of the culture medium used in the production of cultivated meat (I2, I4) (regulatory barriers to consumption = negative claim).

Medium recycling is expected to mitigate the problem of eutrophication of water bodies, which would arise if wasted media, containing nitrogen and phosphorus, is released into water (Mattick et al., 2015b) and could put public health at risk (risk of water pollution is reduced = positive claim). Furthermore, the recycling would lead to more effective use of the media lowering the production cost (Haraguchi and Shimizu, 2021; Haraguchi et al., 2022; Hubalek et al., 2022) (lower cost barrier for producers = positive claim). In circular cell culture the use of the medium would be more effective and the use of FBS not necessary (Haraguchi et al., 2022) further lowering cost barrier for producers and cultural barrier for consumers (positive claims).

Bioreactors are needed to scale-up the production of cultivated meat, which represents further challenges. The scaling effects on animal muscle cells is not yet fully known and the use of different bioreactor types needs yet to be explored (Li et al., 2020b). Only a few proof of concept publications using microcarriers and/or spinner flasks for the cultivation of meat at a bigger scale exist (Verbruggen et al., 2018; Hanga et al., 2021; Zhang et al., 2021).

The choice of bioreactors depends on the cell type during proliferation and maturation phase, the scaffold and the product characteristics that need to be achieved (Specht et al., 2018; Allan et al., 2019). Even though the bioprocess design for cultivated meat can rely on the expertise of other industries, the cultivation of mammalian anchorage dependent cells continues to face difficulties for large scale production (Allan et al., 2019). The cells used for meat cultivation have lower shear limits compared to prokaryotes used in fermentation processes, wherefore the stirring and agitation rate in the process plays a crucial role to preserve the viability of the cells (Hu et al., 2011; Pajčin et al., 2022). Further the surface area to volume ratio of the scaffold used in the cultivation process has an impact on the size of the bioreactor. Additionally, the choice of the scaffold has an influence on the bioreactor seeding efficiency, the passaging requirements, downstream processing, the bioreactor fluid dynamics, the mass transfer, and the costs (Allan et al., 2019).

Operation modes to cultivate cells in a bioreactor are batch, fed-batch, or perfusion. The batch process allows no additional feeding throughout the process and is the simplest method. However, only limited control of the growth rate of the cells are possible. Fed-batch is the most frequently used operation mode, here the nutrients are added in a controlled manner to the bioprocess. It allows good control of cell growth and thus results in higher productivity (Meyer et al., 2017). The perfusion mode allows the cultivation of higher cell densities. Here the medium is continuously cycled through a porous structure containing attached cells. This allows to provide nutrients and oxygens to the cells and to discard metabolic compounds. The perfusion is limited by the cell growth in the structure (Humbird, 2021).

Cell proliferation and differentiation are the two key stages that need to be considered for bioprocess design (Pajčin et al., 2022; Roy et al., 2023). For proliferation purposes the cells can be grown on microcarriers in dynamically mixed bioreactors such as stirred-tank bioreactors, air-lift reactors or rocking bed reactors. Differentiation of cells is supported by static bioreactors including scaffolds such as packed-bed bioreactors or hollow fiber bioreactors (Zidarič et al., 2020). The conditions present in those bioreactors mimic the in vivo conditions of the cells and supports differentiation (Specht et al., 2018; Pajčin et al., 2022). Finally, the bioreactor choice influences the structure of the final product since some bioreactors support two-dimensional growth of cells, while others support three-dimensional growth of cells (Pajčin et al., 2022). Bioreactors for unstructured cultivated meat products are stirred-tank bioreactors, wave or rocking bed bioreactors and air-lift bioreactors, while the packed- or fixed-bed and the hollow fiber bioreactors allow the cultivation of more complex structures (Specht et al., 2018; Pajčin et al., 2022; Roy et al., 2023).

Stirred-tank bioreactors are often used for mammalian cell cultivation. Stirrers in those bioreactors are used to ensure a homogeneous distribution of the nutrients, oxygen, and cells. This can lead to high shear stresses acting on the cells, which has an impact on their viability (Marks, 2003). Since most cells are anchorage dependent, they can either be grown on microcarriers or in aggregates. Microcarriers provide a large surface to grow on and are suitable for bovine muscle cells (Verbruggen et al., 2018; Bodiou et al., 2020). Different cell types such as modified iPSCs, ESCs from mice and human and mice muscle cells can be grown in aggregates (Fok and Zandstra, 2005; Abbasalizadeh et al., 2012; Chen et al., 2012; Aguanno et al., 2019; Post et al., 2020). However, mice muscle cells showed the characteristics of dormant cells when grown in aggregates, which make them unsuitable for cell expansion (Post et al., 2020). More research is needed for cell aggregates in the cultured meat domain to investigate the relevancy of this process (Djisalov et al., 2021).

Wave or rocking bioreactors are a low-shear-alternative compared to the stirred-tank bioreactor and are as well commonly used for cell cultivation (Cantarero Rivera and Chen, 2022). The cells are suspended in aggregates or on microcarriers in a bag or container, which is mounted to a rocking platform (Cantarero Rivera and Chen, 2022). Both bioreactor types, stirred-tank and wave or rocking, can be used as single-use bioreactors, which has multiple advantages such as easier sterilization, lower contamination risk, lower energy and sensor cost and allows to shorten the downtimes between batches. Further, single-use bioreactors allow to lower the water and energy usage, reducing the environmental impact compared to traditional reusable stainless-steel bioreactors (Chen L. et al., 2022).

The mixing in air-lift bioreactors is carried out without mixing units but through integrated air streams or the stream of other gases and special components that force a circulating flow. This is advantageous because it can lead to less inhomogeneity, less shear stress and lower power requirement due to less energy dissipation compared to stirred-tank bioreactors (Merchuk, 1990).

Packed-bed or fixed-bed bioreactors consist of two vessels: one contains the porous or fibrous scaffold for the cells to attach to while the other contains the culture medium. Both vessels are connected to each other through a circulating loop. The medium is pumped from the medium vessel through the scaffold containing the cells and brought back to the medium vessel. Operation modes are batch, fed-batch or perfusion mode. At a larger scale a radial flow is needed to overcome potential oxygen limitations (Pörtner et al., 2007).

As mentioned before hollow fiber bioreactors are considered for the differentiation phase of cells. The bioreactor consists of semipermeable hollow fibers, which allow the artificial circulation of nutrients and oxygen. Cellulose and polyethersulfone are most commonly used for the hollow fibers (Pajčin et al., 2022). Tuomisto et al. (2022) recently calculated the life cycle assessment of a bioprocess design using hollow fiber bioreactors. The bioreactor used for research consisted of polystyrene fibers that were used as scaffolds and further allowed the proliferation and differentiation of the cells. It was possible to produce a cell slurry that could later be incorporated in a product. However, the production of whole-cut meat involves other design challenges, which were not addressed in the work (Tuomisto et al., 2022). If cells must be detached from the fibers it can cause problems, since the reagent might not be able to penetrate all cell layers (Kirsch et al., 2023).

Due to high media and cell costs, scaling of the cultivated meat production process is very expensive leading to lacking data of scaled bioprocess designs (Li et al., 2020b). Therefore, the data present for bioprocess design is based on assumptions, small-scale experiments or simulations. As explained above, the choice of the bioreactor will influence the structure/texture of the final product, which either raises or lowers cultural barrier for consumers (Specht et al., 2018; Pajčin et al., 2022; Roy et al., 2023). Further, the operation mode of the bioprocess is directly related to the capital costs (Humbird, 2021), hence it relates to the cost barrier for producers. More data is needed to specifically determine the impact of the different innovations possible in the field. The claims about impacts of technologies on inclusion in production or consumption are analyzed below and summarized in Table 6, the results are further used for the creation of the radar shown in Figure 3.

Humbird (2021) estimated the costs for cultured meat bioprocesses running in fed-batch and perfusion. He assumes that achieving a price of cultured meat at $50 per kilogram in supermarkets, which relates to the price for premium cut meat, might result in the replacement of traditional meat with cell-cultured alternatives. Running the bioprocess in fed-batch could potentially allow to meet the 50$ price mark if low-cost hydrolysates could be used in the media. However, perfusion exceeds the price mark due to the increased capital cost and capital-dependent costs. These claims refer to financial barrier for consumers. In both cases the price would be equal or higher to premium cut meat, which is not affordable for many (hence these claims are negative).

The advantage of stirred-tank bioreactors is a good scalability of the cultivation process (Moritz et al., 2015; Post et al., 2020). Additionally, stirred-tank bioreactors allow for a better quality control compared to hollow fiber and fixed-bed bioreactors which lead to lower production costs (Bodiou et al., 2020) (positive claim). Hanga et al. (2020) demonstrated the cultivation of bovine adipose cells on microcarriers in a 3 L-single-use stirred-tank bioreactor. This approach was specially developed for the cultivation of meat. A negative aspect of stirred-tank bioreactors is the need for higher media volume in comparison to other bioreactors (Allan et al., 2019; Bellani et al., 2020; Thyden et al., 2022), which raises the production costs (negative claim).

The scale up of wave or rocking bioreactors is limited since the bags can only be operated at 50% of their capacity to guarantee homogeneous mixing (Cantarero Rivera and Chen, 2022). Further, to be used in the cultivated meat production, the single-use bioreactors need to be more affordable (Chen Y. P. et al., 2022). The limited scale-up and high costs of single-use bioreactors constitute cost barriers for producers (negative claim). However, compared to fixed-bed bioreactors and hollow fiber bioreactors, the use of microcarriers in stirred-tank and wave bioreactors is advantageous since it allows to control and monitor the culturing process. This results in a more consistent quality and reduces the costs (Bodiou et al., 2020) (expectation of lower cost barrier = positive claim).

Packed- or fixed-bed bioreactors allow the cultivation of more complex, structured cultured meat products (Pajčin et al., 2022). Such products are expected to be more acceptable to consumers (lower cultural barriers = positive claim). The reduction of the cultivation medium and the operational costs might be possible due to the large surface area of the scaffold which allows for a high cell concentration and therefore circumvents the need for frequent passaging. This lowers cost barriers for producers (positive claim). Meuwly et al. (2004) analyzed the effect of the perfusion rate in the fixed-bed bioreactor while cultivating Chinese Hamster Ovary cells. A reduction of 25% media perfusion on a pilot scale allowed to maintain the productivity while reducing the costs for media, material, and human resources (Meuwly et al., 2004). However, high cell densities also lead to concentration gradients in nutrients and oxygen, which impacts the cellular behavior (Kumar and Starly, 2015). As mentioned above controlling and monitoring the culturing process is more complex compared to stirred-tank and wave or rocking bioreactors (Bodiou et al., 2020). This complexity creates a barrier for producers who lack advanced controlling and monitoring capabilities (negative claim about capability barrier).

Hollow fiber bioreactors may allow for the cultivation of a continuous piece of tissue allowing to grow more complex structures (Specht et al., 2018; Roy et al., 2023), hence meeting the cultural expectations of consumers (positive claim about cultural barriers). However, the bioreactors allowing to produce more complex meat structures such as the packed-bed or the hollow fiber bioreactor allow less quality control compared to the wave or stirred-tank bioreactor (Bodiou et al., 2020) and require higher capabilities from producers (capability barrier = negative claim).