# Biological and Technical Challenges Related to Cultured Meat Production
## 1 Introduction  
The current global population is approximately 8 billion, a number that is set to grow rapidly by 2050, when it is estimated that the number of people on Earth will reach 9-11 billion [1]. Such a significant population increase will lead to an exponential growth in the demand for food products, reaching 50% by 2030 and, doubling by 2050, at which point the demand will be difficult to meet without negatively impacting environmental health [2, 3]. Products subject to high demand are those of animal origin, especially meat and dairy products. In 2012, the Food and Agriculture Organization (FAO) estimated that the global demand for meat is expected to reach 455 million tons by 2050, a 76% increase from 2005. This trend also applies to fish farming, where the amount of fish obtained from aquaculture has increased from 4.7 to 66.6 million tons in just 32 years, and the global demand is expected to reach 140 million by 2054 [2, 4].  
Consequently, to meet the massive demand for animal products, intensive farming has been largely applied. Despite their success after the industrialization process of the 1960s, animal production systems have proven to be extremely fragile.  
Current industrial-scale breeding systems have been the subject of debate regarding animal welfare, environmental protection, and public health.  
Since the 1980s, intensive livestock farming has been the source of numerous public health crises, such as mad cow disease and, later, the contamination of farmed chicken, beef,port, milk, and salmon products with dioxin, and more recently, swine flu and poultry flu [2]. Another problem related to intensive livestock farming is the environmental impact. The intensification of livestock and agricultural production is involved in greenhouse gas (GHG) emissions, particularly methane (CH4) and nitrous oxide (N2O). As reported by [PERSON] et al., agriculture contributes 10-12% of all total emissions, while livestock production, especially ruminants, contribute a total of 14,5% [5; 6]. However, this statement is at odds with what [PERSON] and [PERSON] reported. According to these authors, while it is true that livestock has an environmental impact, especially in terms of CH4, N2O, and carbon dioxide (CO2) emissions, it is also true that the latter is the main source of emissions of in vitro meat due to the fossil energy consumed to ensure cell growth and proliferation [7]. In support of this contention, [PERSON] et al. confirmed how the impact of cultured meat will be minor only in the short term (within 20 years), but not in the long term (beyond 100 years), since CO2, unlike CH4, accumulates for long periods within the atmosphere [8].  
Moreover, although livestock, mostly ruminants, consume food not intended for humans, they occupy about 70% of global agricultural land and consume about 35% of agricultural crops, directly competing with the production of crops for human consumption and with potential alternative land uses, including nature conservation [9]. The agricultural sector is extremely resource-rich and continues to transform with population growth. Global food production is the largest user of freshwater and uses about 38% of the land. The remaining 62% of the global land area is estimated to be unsuitable for cultivation due to climate, topography, poor soil quality, urban development, or because it is covered by natural lands such as forests. Therefore, little arable land remains for agricultural expansion without a negative impact on environmental health [10].