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Since humans first established agriculture, livestock products including meat and dairy have constituted a major proportion of our diets. However, the consumption of alternatives to livestock products is becoming more commonplace; plant-based milks, dairy-free cheese, the infamous vegan sausage roll. This movement has partially been triggered by the revelation that food production puts an enormous strain on the environment.

According to the Food and Agriculture Organisation of the United Nations, the livestock sector is responsible for 14.5% of man-made greenhouse gas emissions. The projected impact of reducing meat intake is significant; in a 2018 Nature article, Springmann and colleagues calculated that if global red meat consumption was reduced to 1 serving a week and white meat consumption to 3.5 servings a week, agricultural greenhouse gas emissions would halve by 2050. Aside from meat, a 2018 study published in Science by Poore and Nemecek calculated that 200 mL of cows’ milk requires 120 L of water to produce, releasing 0.6 kg of greenhouse gas emissions in the process. Meanwhile in 2019, 9.4 billion eggs were produced in the USA in January alone. When paired with estimates from researchers at the University of Oviedo that 12 eggs carry a carbon footprint equivalent to 2.7 kg CO2, the environmental impact of this scale of industry must be considered.

Environmental awareness alongside animal welfare concerns have awakened movements towards animal-free eating. The Vegan Society reported that the number of UK vegans quadrupled between 2014 – 2019. However, many people struggle to envision life without meat or dairy. The sharing and enjoyment of food is a key element of the human experience, and inclusion of these food groups is considered essential in many cultures. What options are there for those who want to eat sustainably without having to radically change their diet? The answer may lie in the expanding field of food biotechnology, where scientists and start-ups worldwide have been working on producing livestock products such as meat, milk, and eggs without farming animals at all.

Perhaps the most famous example of this is cultured meat, where animal cells are isolated and grown in the laboratory to produce meat. Cultured meat gained media attention in 2013 when Professor Mark Post of Maastricht University unveiled the first cultured meat burger and cooked it live on air. The burger had been made with 20,000 strands of muscle fibres grown in the lab. Although some viewed it as a whimsical pursuit, cultured meat has since become a serious area of research.

According to David Hicks, Scott Allan and Moein Mir Fakhar, researchers working on cultured meat at the University of Bath in partnership with Cellular Agriculture Ltd., producing meat this way carries many advantages. 'Cultured meat production has the potential to offer a number of (...) benefits, including reduced land and water usage, reduced use of antibiotics, and the production of a highly specific end product with little waste or by-product formation' they say. However, progress in this field is highly dependent on the nature of the final product. For instance, Hicks and colleagues explain that producing cell powders for use as protein additives in food simply requires growing muscle cells in a bioreactor, which are then harvested and dried. In comparison, to make a product replicating the composition and texture of a cut of meat, the process is more complicated, involving multiple cell types grown on a scaffold. 'For a (...) product such as a full cut of steak, the challenge will be ensuring a favourable distribution of the two (or more) cell types throughout the chosen scaffold (...). Edible scaffolds have been tested, with the theory that these could be incorporated to lend their material properties, such as texture, to the end-product' they say. In spite of this, Hicks and colleagues mention that there is traction in the field of cultured meat. 'Many of the largest start-up companies in the field have said that they hope to have their cultured meat products in high-end restaurants and on supermarket shelves in the next 3-5 years'.

Whilst lab-grown meat has taken the centre stage as a futuristic alternative, other livestock products have been targeted for culinary mimicry. By combining molecular biology and chemical engineering, the USA-based company Perfect Day has developed 'synthetic' milk which they claim has the same texture, taste and nutrition as cows’ milk. They achieved this by expressing genes encoding milk proteins including whey and casein in culturable fungi from the Trichoderma genus. By growing the fungus in industrial fermentation tanks, large quantities of milk proteins are isolated and combined with vitamins, minerals, fats, and water to generate imitation cows’ milk. This reductionist approach of identifying the minimal elements of milk, producing them in-house and then mixing them into a synthetic milk cocktail means that troublesome components including lactose or cholesterol can be omitted and factors including fat content easily controlled. Whilst synthetic milk is not yet available for purchase, a campaign selling limited edition ice cream made using the fungus-grown milk proteins was highly successful, with all stock selling out. The company is also working on using its technology to make synthetic cheese and yoghurt. If their products taste as authentic as they claim then the replacement of cows’ milk could potentially be on the horizon.

Arguably, the most difficult livestock product to replace is the chicken egg, a versatile product with a complex composition. Further to their consumption alone, eggs have an array of uses, including binding, emulsification, thickening, and foaming. Developing a substitute that functions well in all of these areas is challenging. Some alternatives such as aquafaba — the liquid gathered from soaking chickpeas in water — can form foams and emulsions, but cannot be consumed alone in the same manner as an egg. To address this, Silicon Valley based company JUST developed a chicken-free egg substitute which they claim scrambles and tastes identical to eggs. They use mung-bean protein along with turmeric to create a yellow liquid akin to scrambled egg mixture. Meanwhile, other companies are attempting to replicate eggs entirely — even down to the shell. French entrepreneurs Philippine Soulères and Sheryline Thavisouk own a company called La Merveillœuse, which is set to release vegan eggs in mid-2020. Although their methods are proprietary, they have managed to recreate eggs with both whites and yolks, and are currently developing eco-friendly egg shells to contain them in.

A huge amount of creativity, money and scientific thought is being channelled into developing alternatives to livestock products that have been familiar to humans since agriculture was first established. Lab grown meat, synthetic milk, and a foray into replica eggs is only the beginning of what can be achieved in food science with technological advances. However, this will require a great deal of investment as well as support from the public as there is little use in developing alternatives if no-one wants to consume them. There is also the question of the necessity of such alternatives, especially considering the wide range of plant-based products that are already available. Some would argue that all that is required for more sustainable eating is a recalibration of our expectations and habits — eating a little less meat, consuming less dairy, sourcing food responsibly — without the need for developing like-for-like alternatives. Nevertheless, the expansion of this area of food science demonstrates that some of these products may become familiar items in our supermarkets in coming years.

Ruby Coates is a 2nd year Microbiology PhD student at Darwin College. Artwork by Hinze Ho and Alexandra Pinggera