Prospects of edible insects as sustainable protein for food and feed – a review

Abstract


Introduction
Over the past seven decades, the global population has experienced a remarkable surge, rising from 2.6 billion to 7 billion, with projections indicating a further increase to approximately 10 billion by 2050 (Guiné et al., 2021;Sebatta et al., 2018).This population growth poses a significant challenge to food security, as it is expected to intensify the demand for food and animal feed (Okello et al., 2022).Surprisingly, about 2.37 billion people in the modern world lack basic food security insurance (FAO et al., 2021).To meet the growing demand for protein ingredients like soybeans, fish, and meat, it is projected that there will be an increase by 2050 (Sebatta et al., 2018;Smetana et al., 2021).Consequently, this would also result into more tons of food thrown away with direct environmental impacts on natural resources and biodiversity including food waste and loss (Rumpold and Langen, 2020;Siddiqui et al., 2022a), and the greenhouse gas effect (Skrivervik, 2020).In essence, the population increase has led to elevated food and feed consumption, resulting in increased food waste and loss (Hellwig et al., 2022).
The continuous growth of global meat production has contributed to deforestation, as forests are converted into grasslands to support beef production, while also increasing greenhouse gas emissions that harm the environment (Mishyna et al., 2020).This trend in the food system presents a challenge in terms of sustainability.Figure 1 illustrates recent demand trends and highlights the potential of alternative protein sources, such as insects, for food and feed industries due to their nutritional value and projected environmental sustainability (Hellwig et al., 2022).Currently, large-scale animal, fish, and plant production are economically viable but come at high environmental costs.Any attempt to further increase production in these areas would necessitate more feed and cropland (Hellwig et al., 2022;Skrivervik, 2020).Given the inability of the current food system to adequately satisfy rising demand, there is a growing need for alternative protein sources that can address this demand sustainably with minimal environmental impact (Smetana et al., 2021;Tanga et al., 2021).Insect farming present enormous prospects to meet the rising demand for protein products in an environmentally friendly manner.
In recent years, edible insects have gained increasing interest as an alternative protein source for food and feed.Evidence suggests that incorporating edible insects into the food system has the potential to provide a sustainable solution to global food and feed challenges, while also addressing developmental setbacks in developing countries (Ismail et al., 2020;Liceaga, 2021).In Africa, Asia, and Northern America, insect markets are experiencing huge acceptability (Lähteenmäki-Uutela et al., 2021;Penedo et al., 2022;Spartano and Grasso, 2021;van Huis, 2013).However, despite these potentials and acceptability in some regions, barriers related to disgust and sensory preferences towards insects persist in some part of Western world (Siddiqui et al., 2022b).
Acceptability of insects as feed for livestock and other animals is another important consideration in the development of the insect rearing industry.Research conducted by van Huis (2013) demonstrated that feeding insects to poultry did not negatively affect the sensory characteristics, including appearance and texture quality, of the meat.Similarly, a study by Al-Qazzaz et al. (2019) found that replacing fish meal with insect-based meal in the diet of Nile tilapia had no adverse effects on fish growth or carcass appearance and texture quality.
Circular economy could be one of the biological benefits of edible insects that can effectively convert lowvalue food waste into high-quality proteins, amino acids, and vitamins that can help to increase the productivity of alternative protein production, which will further improve the sustainability of the food system (Wilkinson et al., 2018).In this context, a partial or total replacement of protein ingredients with insects will significantly reduce the environmental impact associated with food and animal feed production, increased animal welfare, and reduce food waste with no or little greenhouse effect (Spartano and Grasso, 2021).Additionally, insects can be intensively reared in a vertical style, which may substantially optimize the less space used for their rearing with much less water compared to other animals (Penedo et al., 2022).As a result, rearing and using insects as food and feed is economically viable with limited or no greenhouse gas emissions (Penedo et al., 2022).This review aims to identify the future prospects of insects as food and feed and their environmental impact assessment.Even though this study focuses on the prospects of insects, the review also looks into regulations and scaling up farming.The results of the review may thus be relevant for the wider adoption of insects as food and feed.

Consumer acceptance
Numerous studies have shown that the production of the majority of food, including beef, chicken, pork, fish, and plant derived products (such as wheat and soybean) are not environmentally friendly (Perez-Martinez et al., 2018;Siddiqui et al., 2022b;van Huis, 2018) because of the current growing practices typical for industrial farming.Thus, alternative protein sources are now becoming more popular to feed the growing global population (Janssen et al., 2017).Insects have been proven to be very nutritive and to be excellent providers of energy, proteins, vitamins, fats and essential minerals (Madau et al., 2020;Rumpold and Schlüter, 2013).Moreover, it has been shown that a large fraction of essential amino acids is present in several insect species (Anankware et al., 2021).About 2,100 different types of insects are eaten as food worldwide, especially in tropical regions (Jongema, 2017;Nikkhah et al., 2021).Currently, some of the common edible insect species are African palm weevil (Rhynchophorus phoenicis), house cricket (Acheta domesticus), yellow mealworm (Tenebrio molitor), domesticated silkworm (Bombyx mori), mopane worm (Gonimbrasia belina), and honeybee (Apis mellifera) (Tang et al., 2019).Insects serve as food source with a low environmental impact since their production generally requires less water and arable land compared to livestock (Oonincx and de Boer, 2012;Siddiqui et al., 2023a;Veldkamp et al., 2012).
The appearance and texture of whole insects, which are major factors contributing to consumer acceptance, can be improved by transforming them into other forms such as powders, flakes, or pastes.This conversion is essential for reducing rejection and making insects more appealing to consumers (Guiné et al., 2021;Wendin and Nyberg, 2021).Cultural negative attitudes towards insects as food, prevalent in many Western cultures where insects are often associated with dirt and disease, contribute to their natural aversion.Additionally, the presence of insect body parts, such as legs or antennae, and the unfamiliar textures of whole insects can be unappetizing to some individuals (Hartmann and Siegrist, 2017).By incorporating insect-based ingredients into food products like energy bars or protein shakes, these factors can be mitigated.Marketing these products as healthy and sustainable alternatives to traditional snacks or supplements can help increase consumer acceptance (Megido et al., 2014).
DESTEP analysis can help the insect industry identify key factors that can affect its operations and develop strategies to address these factors.The DESTEP method is a useful tool for a systematic analysis of external factors.It gives abroad analysis of macro factors that may impinge upon an organization's business and operations.DESTEP stands for: demographic, economic, social, technological, ecological and political.The effectiveness of DESTEP methos was proved by van  navigate the dynamic and complex business environment it operates in.When applying DESTEP analysis to the insect industry, the following factors must be considered: 1.
Demographic factors: The acceptance of insectbased products as a food source varies across cultures and countries, with some societies showing a higher level of aversion towards insects as food.
Therefore, demographic factors such as age, gender, and ethnicity can influence the potential market for insect-based products (Tan et al., 2015).For example, a study by Wilkinson et al. (2018) shows that Asian ethnic consumers were usually try eating different of insects compared to than other consumers from different cultural backgrounds.In Czech Republic, Kouřimská et al. (2020) evaluated baked crickets involving a total of 98 assessors.Among the participants, 81.6% were female, while 18.4% were male.The age range of the assessors varied, with 88.8% falling between 18 and 25 years old, and 11.2% between 26 and 45 years old.
The findings revealed that 69.4% of the assessors expressed their willingness to try baked crickets after evaluating their appearance.

Economic factors:
The cost-effectiveness of insect farming and processing can impact the profitability of the insect industry.Economic factors such as inflation, interest rates, and economic growth can also affect the demand for insect-based products (van Huis, 2013).Halloran et al. (2017a) showed that when promoting insect farming, economic sustainability must be considered.(Tan et al., 2015).Brunner and Nuttavuthisit (2019) showed willingness to eat insects in a study with 542 respondants.They agree with the sustainability and health arguments.Highly educated consumer scored low on the food neophobia scale and show high nutritional knowledge and read about entomophagy in the media.4. Technological factors: Advances in technology related to insect farming, processing, and packag-ing can enhance the efficiency of insect production and improve the quality of insect-based products.The use of technology can also increase consumer trust in insect-based products and enhance their marketability (Payne et al., 2016).Technological advancements, such as automated insect farming systems and improved feed formulations, are increasing efficiency and scalability in the production of edible insects (Melgar-Lalanne et al., 2019).Orsi et al. (2019) showed that out of 393 accessors, 66% were willing to eat product containing whole insects or processed by Snack Insects.Similarly, Biró et al. (2019) also showed that buckwheatpasta enriched with 10% silkworm powder were highly accepted by consumer compared to the insect-free product. 5. Ecological factors: Insect farming has been proposed as a sustainable alternative to traditional livestock farming due to its lower environmental impact.However, ecological factors such as climate change, pollution, and habitat destruction can affect the availability and viability of insect farming as a sustainable food source (van Huis, 2013).Insect farming require less water, land, and feed and produce fewer greenhouse gas emissions.6. Political/legal factors: Regulations and policies related to food safety, labeling, and animal welfare can affect the production and distribution of insect-based products.Additionally, trade regulations and tariffs can influence the international market for insect-based products (Halloran et al., 2017a;Payne et al., 2016).For example, the EU are developing or updating regulations to address the growing edible insects industry, including food safety guidelines and labeling requirements.

Economic feasibility of insects as a future source of protein
The food economy faces difficulties as a result of social and demographic shifts, as well as the steadily decreasing amount of arable land (Żuk-Gołaszewska et al., 2022).As the global demand for protein rises, insects have been suggested as a potential replacement in the evolution of food systems.Although insects have long provided humans with sources of cultural, religious, and economic inspiration, their use as a food source has been crucial to the evolution of the human species (Jansson et al., 2019).Edible insects are typically considered to be a rich source of vital nutrients, protein, vitamins, fats, and minerals that may be grown on lowvalue feeds and have a small carbon impact (Gasco et  2021).In addition to providing protein, insects also give calories, lipids, vitamins, and minerals that are suitable for human consumption (Toxqui et al., 2021).
Despite the increasing relevance of the sector, there are several works focused on the economic aspects of insect farming for feed and food production, showing uncertain economical effectiveness.Gahukar (2016) analysed the economic convenience of insect cultivation and reported that insect farming is currently not as cheap as many researchers declare.The main cost is represented by the raw materials used for feeding insects and, today, the price related to the formulated feed is quite high (e.g.US $18 for 25 kg of feed for cricket breeding).The same trend is set by Chia et al. (2019) who described inclusive business models involving smallholder insect farmers.However, the market price for edible insects can vary depending on the geography, the type of insect, and the production method used.While the prices in the European Union (EU) may not be competitive with other protein or lipid sources, other geographies may have different market conditions and consumer preferences that make edible insects a viable and cost-effective protein source.Here are a few examples: 1.
Asia: In many parts of Asia, insects have long been a traditional part of the diet, with a sustained demand for them.The FAO et al. (2021) has reported that insects are widely consumed in countries like Thailand, Cambodia, and Japan.These edible creatures offer an affordable and accessible protein alternative to many consumers in these regions.These prices are generally fair in these countries, making insects an affordable protein alternative for many consumers (van Huis, 2022).The current estimation for Thailand's edible insect and insect protein industry in 2018 is valued at US $24.2 million.It is projected that the industry will experience significant growth, reaching an estimated value of US $56.8 million by 2023.This represents a Compound Annual Growth Rate (CAGR) of 18.6% from 2018 to 2023 (Reserch and Markets 2018).2. Africa: Insects are also a common food source in many African countries, and they are often harvested from the wild rather than farmed (Guiné et al., 2021).Mopane worms, a type of caterpillar, are highly valued in southern Africa (Guiné et al., 2021), while grasshoppers are a popular choice in Kenya (Alemu et al., 2015).The availability and affordability of these wild-harvested insects make them a valuable protein source, particularly for people living in rural areas with limited access to other protein-rich foods (Raksakantong et al., 2010).3. North America: Although insect consumption is less common in North America compared to Asia or Africa, the market for edible insects is steadily growing.The global market for edible insects was valued at a significant amount in 2020 and is projected to experience substantial growth in the coming years.In the United States, products like cricket flour, made from ground-up crickets, are gaining popularity (Delgado, 2019).The sustainability and environmental benefits associated with edible insects are attracting consumers who are willing to explore alternative food sources.The costs of insect production are associated with investments in infrastructure (spaces, containers, equipment), labour, as well as resources, including electricity, water, wrapping materials and feed substrates.Mancuso et al. (2019) publish a sales price of e10,850, e15,800 and e17,000 per tonne of different fresh insect biomass production in Europe.According to Kooistra (2020) a future scenario is that the price would probably decreaseto around e3,000 to e3,500 per tonne.The motivation for this scenario is the increase in automation and supply in combination with a difficult market combined limited demand growth.Reducing labour costs will be important to limit the production costs.Another possible reason of cost decrease can be the increase in publicity for this product which will lead to more adoption and therefore more demand and higher volume of production.Higher volume of production can be provided also by a cooperative model for different smaller farms which is quite an expected trend in the near future Kooistra (2020).

Economic factors that can influence the feasibility of insect farming
One of the major challenges in insect farming is the labour-intensive nature of the process.Unlike largescale automated livestock operations, insect rearing often requires manual labour, which can affect production costs (Guiné et al., 2021;Wilkinson et al., 2018).Training and managing a workforce proficient in insect handling and maintenance can be a significant factor in determining the economic feasibility of insect farms.
The willingness of consumers to embrace insects as a food source plays a crucial role in the economic success of insect farming (Alemu et al., 2015;Alemu and Olsen, 2020;Siddiqui et al., 2023a).Overcoming cultural biases and creating effective marketing strategies to educate Journal of Insects as Food and Feed 0 (2023) 1-27   Downloaded from Brill.com 12/29/2023 12:58: and promote the benefits of consuming edible insects are essential steps in building market demand (Siddiqui et al., 2023a).Developing a robust market and generating steady revenue may require time and efforts to shift consumer attitudes and preferences (Kornher et al., 2019;Siddiqui et al., 2023b).Competition from other protein sources, such as plant-based alternatives, may impact the economic feasibility of insect farms (Amrul et al., 2022;Gahukar, 2016), and the relative cost and market perception of insects compared to alternative protein sources can influence consumer choices and market dynamics (Madau et al., 2020).
While small-scale insect farming operations have been successful in certain contexts, scaling up to meet larger demand can present economic challenges.Increasing production capacity while maintaining quality control and cost-effectiveness requires careful planning, efficient processes, and potential investments in automation and technology.Establishing suitable facilities for insect production (Meyer-Rochow et al., 2021), including temperature-controlled environments (Halloran et al., 2017a), waste management systems, and processing units, can involve significant upfront investments (van Huis and Dunkel, 2017;Kim et al., 2021;Boakye-yiadom and Ilari, 2022).These costs need to be carefully considered when assessing the economic feasibility of insect farming.

Global trade of edible insects
Global trade of edible insects has become increasingly popular in recent years due to their high nutritional value and low environmental impact (van Huis and Dunkel, 2017).Insects and insect-based products are consumed in various forms worldwide, including being eaten whole or processed into flour or powder.Some of the most commonly consumed insects include beetles, caterpillars, bees, wasps, ants, grasshoppers, crickets, locusts, cicadas, leafhoppers, planthoppers, scale insects, and true bugs (Rumpold and Schlüter, 2013).The selling of edible insects in traditional markets has played a vital role as part of human nutrition in many rural households in African or Asian regions, and is sometimes the only income source for rural households in Africa or Asia (Raheem et al., 2018).Beetles are the most common and widely eaten insects, making up approximately one-third of global consumption.Caterpillars (Lepidoptera, 17%), as well as bees, wasps, and ants (Hymenoptera, 15%), grasshoppers, crickets, and locusts (Orthoptera, 13%) and cicadas, leafhoppers, planthoppers, scale insects and true bugs (Hemiptera, 11%) are the insects that are also frequently consumed worldwide (Jongema, 2017).
Crickets one of the most globally recognized edible insects are considered easy to rear at farms with a very large number of farmers, approximately 20,000, with a total of 7,500 tons/year in Thailand.The economic growth of cricket production in Thailand has been accompanied by a rapid increase in demand for human consumption (Khan, 2018).Insect meals are also more common in aquafeed because of the modulatory effects they have on aquatic animals' immune systems and the harmony of their gut microbiota (Huyben et al., 2019).The nutritional and energy content of some edible insects have been extensively reviewed, as they have become more widely recognized as a sustainable food source (Rumpold and Schlüter, 2013;Tang et al., 2019).Insect consumption is slowly gaining popularity in local markets in various parts of the world, with some countries such as Thailand and Mexico already incorporating insects into their diets.However, there are still some challenges in incorporating insects into the global food system, including regulatory barriers and cultural attitudes toward insect consumption (van Huis and Dunkel, 2017).
Edible insects have gained popularity as a sustainable food source, with their consumption potentially offering significant health and environmental benefits.However, regulation and legislation around the world have not kept pace with the growing demand for edible insects, which is a limiting factor in their global trade.In the EU, the Novel Food Regulation (EU) 2015/2283 applies to food products that were not consumed to a significant degree before 15 May 1997.This regulation requires companies to submit an application and undergo a safety assessment before they can sell a new food product, including edible insects, within the EU market (European Commission, 2015).In the United States, the Food and Drug Administration (FDA) has categorized insects as a "food additive" under the Federal Food, Drug, and Cosmetic Act, meaning that any food product containing insects must be approved by the FDA before it can be sold (FDA, 2018).In Canada, the sale of edible insects is regulated by the Canadian Food Inspection Agency (CFIA).Insects are categorized as "novel foods," and companies must provide evidence of their safety and nutritional value before they can be approved for sale (CFIA, 2016).These regulations and legislation, while necessary for ensuring the safety of food products, can create barriers to the global trade of edible insects.Companies must navigate the different regulatory requirements in each country, which can be costly and time-consuming.

The current industrial trend for insect protein
The use of insects as protein sources for both human consumption and as ingredients in the production of feed and food is on the rise (Veldkamp et al., 2012).According to IPIFF (2020), the market of insects as food is segmented to several segments, that are changing from prelevance of whole insect to processing of insects biomass to food ingredients (Figure 2).
At the same time, numerous companies sell insects for biocontrol, medical research, and the pet trade have seen exponential growth all over the world (Ortiz et al., 2016).Advanced technology for rearing, processing, and marketing of edible insects has successfully been developed over the years in a bid to meet the high demand (Mariod et al., 2020) with numerous companies involved in the insect food industry.Table 1 shows key companies in product development using insects as raw materials.Most of these companies have seen an increase in their operational funds mostly due to the acceptability of their insect-derived products in the market.For example, Ynsect, an international insect meal manufacturing company based in France has seen a growth in its operational capital since its establishment in the year 2016.The company manufactures Ynmeal from T. molitor.Also, Hexafly in Ireland produces insect oil, fishmeal, and insect frass using H. illucens.The development of the insect protein market has been aided by government funding and the existence of important manufacturers.To meet the demand for edible insects, it is essential to scale up production to meet the industrial and market sector and satisfy the anticipated future needs.

Revenue from insect protein
Mass production of insects for food and feed has seen record growth over the decade (van Huis and Oonincx, 2017).It is predicted that the market for edible insects would grow from $US 83.4 billion to US $130.3 billion by 2024 (Cheseto et al., 2020).In terms of revenue, Asia, led by Thailand, China, and Vietnam, held a 41% share in 2019 followed by Europe (22%), Latin America (21%), North America (13%), and the Middle East and Africa (3%) (Mancini et al., 2022).According to reports, southern Africa had a commercial trade in mopane worms Gonimbrasia belina of roughly 16,000 metric tons in 2012, valued between US $39 million and US $59 million (Mariod et al., 2020), but in 2015, the market for this worm expanded to US $85 million (Kelemu et al., 2015).The prices of edible insects such as grasshoppers and palm weevils are often higher than those for meat products (van Huis and Oonincx, 2017).Although the market for edible insects was valued at US $770.96 million in 2021 less than US $867.3 billion for animal meat, Figure 1 indicates that the market will increase rapidly by 28% by 2023 (Vinci et al., 2022).
In recent years, the use of insects as a food source has gained attention as a potential solution to address the growing demand for protein, particularly in developing regions.Below are some challenges to overcome in different regions other than the EU regarding revenue from insects: 1.
North America: In the United States of America (USA) and Canada, there is a lack of regulatory frameworks that define insects as food products, which can hinder the development of insect-based food businesses.Additionally, there is a perception among some consumers that insects are unappetizing or culturally unacceptable as food (Payne and van Itterbeeck, 2017).2. Asia: While insects have a long history of being consumed as food in many Asian countries, there are still significant barriers to scaling up the production and commercialization of insect-based products.These include issues related to food safety and quality control, as well as limited access to financing and markets for small-scale insect farmers (Gahukar, 2016).3. Africa: Insect farming has the potential to provide a low-cost source of protein and income for smallscale farmers in many African countries.However, there are several challenges to overcome, including a lack of infrastructure and technical expertise, limited access to markets and financing, and the need for more research to identify the most suitable insect species for farming in different regions (van Huis, 2013).4. Latin America: In many Latin American countries, insects are already a part of traditional diets and are readily available in local markets.However, there is a need to develop new processing and packaging techniques to improve the shelf life and quality of insect-based products, as well as to establish regulatory frameworks to ensure food safety and quality control (Ramos-Elorduy, 2009).equivalent amount of energy to 100 g of meat.Also, the protein content (35% to 60% based on the dry matter) of edible insects ranges higher than that of vegetable protein sources (Kim et al., 2019).Insect proteins are comparable to animal proteins (Tang et al., 2019).In terms of the production cycle, insects have a shorter production cycle compared to other protein sources (Table 2).For example, while it takes between 20-24 days to produce larvae of B. mori, it takes up to 243 days to produce a kg of beef.It takes more than ten production cycles (520% protein equivalent) for B. mori to produce 92% of beef, making it more feasible and sustainable to produce insect protein than beef.

Characterization of insect protein
Insect proteins are not only comparable in terms of protein content to other animals, but they also contain a similar range of essential amino acids (EAAs), making them a complete protein source.EAAs are amino acids that cannot be produced by the human body and must be obtained through the diet.The essential amino acid composition of insects varies depending on the species, but most insect proteins are rich in lysine and have good levels of other EAAs, such as methionine, threonine, and tryptophan (Rumpold and Schlüter, 2013).In terms of digestibility, insect proteins are lower digestible in comparison to animal proteins.However, several studies have reported that insect proteins have a high protein digestibility corrected amino acid score, which is a mea-sure of protein quality that takes into account both the EAA content and digestibility (Dong et al., 2017;Oonincx et al., 2015;Rumpold and Schlüter, 2013).For example, a study comparing the digestibility of cricket, mealworm, and beef proteins found that cricket and mealworm proteins had a similar digestibility to beef protein (Payne et al., 2016).However, the digestibility of insect proteins can vary depending on the species and life stage of the insect.A study comparing the digestibility of cricket and mealworm proteins found that both were highly digestible, but the cricket protein was more easily digested than the mealworm protein (Stull et al., 2018).Another study comparing the digestibility of grasshopper and silkworm proteins found that the grasshopper protein was more digestible than the silkworm protein (Yang et al., 2012).Insects are a promising source of protein that can provide a complete range of EAAs and have a high digestibility, making them a potential alternative to traditional animal sources.

The benefit of insects as feed
When it comes to broiler chicken nutrition, a meal made from soybean is usually substituted with Tenebrio molitor.The fatty acid profile of breast muscle and the expression of particular genes, such as GIMAP5 and APOA1, which control hematopoietic integrity, lymphocyte homeostasis, and phenotypic fatness variability,   (Kierończyk et al., 2018).Also, broiler chicken diets made with Musca domestica larvae give similar or better growth rates compared with conventional poultry feed (Sánchez-Muros et al., 2016).The use of insects as a feed source for animals, including poultry and livestock, has gained attention as a potentially sustainable and cost-effective alternative to conventional protein sources such as soybean meal and fishmeal.Insects have a rich nutritional value including protein, amino acids, and other essential nutrients such as vitamins and minerals.For example, the larvae of the black soldier fly H. illucens have been found to contain approximately 60% protein and a favorable amino acid profile that meets the requirements of poultry and livestock (van Huis, 2013).Several studies have reported improved growth performance, feed conversion efficiency, and weight gain in animals fed insect meals as a partial replacement for conventional protein sources (Makkar et al., 2014a;Rumpold and Schlüter, 2013).The use of insect meal as a feed source may help reduce the need for antibiotics in animal production, as insects have been found to contain natural antimicrobial peptides that may improve gut health and disease resistance in animals (Siciliano et al., 2019).Insect farm-ing requires less land, water, and feed compared to conventional animal farming, and produces less greenhouse gas emissions and waste (Oonincx and de Boer, 2012).
Table 3 provides additional information about the life stage of the insects used in the studies.This information is important because different insect species may have different growth and nutrient utilization characteristics at different life stages, and therefore may have different effects on the farmed animals they are used to feed.For example, the studies on house cricket Acheta domesticus found improved feed conversion and growth performance in chickens when using pellet made from whole (adult) insects (Makkar et al., 2014a), and improved growth performance and feed utilization efficiency in Nile tilapia when using pellet made from adult insects (Gasco et al., 2019).These findings suggest that adult insects of this species may be a good feed source for different types of farmed animals.The studies on pellet larvae of H. illucens found improved growth performance and carcass yield in chickens (Barroso et al., 2019) and pigs (Newton et al., 2005).This suggests that larvae of this species may be more suitable for feeding chickens and pigs.Similarly, the studies on T. molitor found improved feed conversion and growth performance in broilers when using whole (larvae) insects (Abdel-  et al., 2019), while the studies on M. domestica found improved growth performance and feed efficiency in poultry when using whole (larvae) insects (Khusro et al., 2020).These results suggest that larvae of different insect species may be effective feed sources for different types of farmed animals.Also, the study on B. mori was found to improve growth performance and nutrient utilization in pigs when using pellet (larvae) insects (Liu et al., 2020).This suggests that larvae of this species may also be a suitable feed source for pigs.

Regulations of insect protein as food and feed
Traditionally, insects have been harvested and consumed in many countries across the globe without detailed regulations (Lähteenmäki-Uutela et al., 2021).However, the recent regulations allowing the mass production and selling of edible insects have allowed companies from developed and developing countries to go into the global trade for insects as food and feed (Berger et al., 2020).Insect regulations as food and feed are intended to assure consumers that insects are pure and wholesome, safe to eat, and produced under hygienic conditions (Lásztity, 2009).Recently, global, national, and regional food safety bodies have started reviews and discussions on the regulation of insects.The EU has approved the safety of defatted house cricket powder as a novel food, concluding that the powder is safe for food.As also shown in Table 4, the EU also allows T. molitor as aquaculture feed and further added silkworms as aquaculture, poultry, and pig feed.The EU also introduced a list of low and medium-income countries that were authorized to export insect products to the EU.These low and medium-income countries are to comply with Regulation (EU) No 2017/893 while exporting their insect products.Europe permit the use of insects destined for human food that are not to be collected in the wild and thus must be reared in approved insect farms.The regulation that permits the use of insects as food for human consumption in Europe is the Novel Food Regulation (EU) 2015/2283.This regulation defines novel foods as those that have not been consumed to a significant degree within the European Union before May 15, 1997, and establishes the procedures for the authorization of these foods.

4
Insect farming: as food and feed

Insect farming system
Insect farming generally requires less construction material, less temperature control (except tropical species) and electricity, and a cheaper cost of transportation of feed as compared to livestock (Halloran et al., 2017a).Insects' metabolism always varies due to fluctuating temperatures.Insect production times for different insects are also highly dependent on temperature.Different ranges of temperatures may be considered optimal for different insects in terms of rapid development, taking physiological parameters like mortality, weight loss, and weight gain into consideration (Halloran et al., 2016).When compared with other animals, insects have a restricted capacity to metabolically maintain core temperature since they are poikilothermic (coldblooded), meaning that their core temperature changes with external conditions (National Research Council (NRC), 2011).Normally, insects with shorter life cycles may need a lower input, such as water and feed, while those with longer life cycles require a greater demand for inputs (Halloran et al., 2016).Most insect farming requires relatively cheaper rearing facilities and breeding materials.For example, cricket farming requires a breeding container in a breeding nursery for egg incubation and hatching which usually occurs within 10 days under a stable controlled temperature and humidity (Hanboonsong et al., 2013).Insect farming may sometimes require enclosing insects in a mosquito net to avoid predators.Because farmed insects (such as the black soldier fly, cricket, etc.) are good bioconverters, the substrate for feed production is usually from organic waste from agricultural and food by-products.While the feed requirement for insect production is 1.7 kg, chickens, pigs, and beef cattle are 2.5, 5, and 10 kg, respectively, for producing 1 kilogram of live weight (Gahukar, 2016).Insect farming requires relatively low consumable inputs such as water compared to livestock.Compared to 454 g (1 lb) of beef, which would require 12.5 times (11.35 kg) more feed and 2,900 times (10,962 L) more water, 454 g (1 lb) of cricket requires 908 g (2 lb) of feed and 3.78 L (1 gallon) of water (Gray, 2014).Low water input in insect farming means efficient use of energy which is to the advantage of the farmer.
It is important to note that an increase in global agriculture production means an increase in waste generation.Insect-based bioconversion has been suggested to be a viable approach to managing organic waste (Siddiqui et al., 2022a).Insects such as A. domesticus, H. illucens, M. domestica, and T. molitor have been identified as effective organic waste bioconverters (Surendra et al., 2020).Furthermore, being an environmentally friendly alternative source of food and feed, and bioconverter, insects serve as an important source of secondary products such as natalamycin, rose-  oflavin, chitin, carotenoids, ferulic acid, etc. (Kang et al., 2016;Zhou et al., 2021).In many regions of the world, the use of insects as medicine is an important alternative to modern therapy (Seabrooks and Hu, 2017).Bioactive compounds discovered in insects have health-promoting antioxidant properties, angiotensinconverting enzyme inhibitors to treat high blood pressure and effects on hyperlipidemia and fat reduction in humans (van Huis et al., 2020).

Prospect to scale up insect farming
Production systems for most insect farms are mass production.To meet the demand for edible insects, it is essential to scale up production and processing.Rearing and processing edible insects to feed the mass population requires the application of modern technology.Automating insect rearing, harvesting, and processing is a crucial step in improving the viability, and competitiveness of insect mass production (Mariod et al., 2020).To meet the market needs and satisfy anticipated future demand, it is essential to scale up the production of edible insect production to a sustainable level.The technological processes make production more attractive, have higher yields, and are more cost-effective.Rudimentary operational monitoring, which involves basic observation and record-keeping of production activities, may not be adequate for insect farming because it may fail to capture critical parameters necessary for optimal production (Tomberlin and Sheppard, 2002).Insect farming, like other forms of animal production, requires careful monitoring of several factors, including temperature, humidity, light, ventilation, feed, and water quality, among others.These parameters play a critical role in the growth, development, and overall health of insects (Makkar et al., 2014b).According to a study by Wang et al. (2020), environmental factors such as temperature and humidity have a significant impact on the growth and development of crickets, one of the commonly farmed insects.The study found that crickets raised under optimal conditions had higher growth rates and better feed conversion rates than those raised under suboptimal conditions.Similarly, a review by dos Santos et al. (2020) highlights the importance of proper feeding and nutrition for the growth and development of insects.The study emphasizes the need for accurate monitoring and control of feed quality and quantity to ensure optimal production.Therefore, rudimentary operational monitoring may not be adequate for insect farming as it may fail to capture critical parameters that impact production.To ensure optimal production, it is essential to adopt more sophisticated monitoring and To maximize the potential of insect farming as an environmentally friendly alternative source of protein, the application of advanced technology such as internet of things (IoT) sensors in monitoring key things such as light intensity, ammonia levels, and optimal breeding conditions are crucial.An alternative approach is developing small-scale inexpensive operations that can be used by subsistence farmers, family-owned organic and conventional farmers, hobby farmers, etc.Also, the application of biotechnology for mass breeding is needed for scaling up insect farming.The associated environmental benefits of switching from the current livestock systems to insect farming methods are frequently questioned (van Huis and Oonincx, 2017).Despite the fact that insect farming is more environmentally friendly than other animal farming, which corresponds firstly to small farms, when scaling a small production or designing a large-scale production, an additional assessment of the environmental impact is necessary.To address some of these concerns, detailed environmental impacts assessments such as life cycle assessment (LCA), feed conversation ratio (FCR), and benefit assessments are needed to predict future scenarios of large-scale insect farming.LCA analysis can be used to measure the economic performances of insectderived food and feed production systems.For LCAs to be comparable, they must use identical delimitations within the systems and use equivalent definitions of the system boundaries for the alternative production systems.

Sustainability of insects as food and feed
The World Population Prospect's most recent estimates indicate that the world's population is constantly increasing and will reach 10.9 billion by 2050 (Vinci et al., 2022).Even though food supplies are at a 50year low, by 2030, demand is predicted to rise by 50% (Gahukar, 2016).To help European firms and consumers make the transition to a stronger and more circular economy where resources are used more sustainably, the European Commission has proposed an ambitious new Circular Economy Package (European Commission, 2020).This package includes a plan to support the circular economy at every stage of the value chain (Veldkamp et al., 2012).Insect-derived products can help create a circular economy and increase food security in a market (Veld-kamp et al., 2012).Moreover, insects can act as a link to close the loops in the product lifecycle, ensuring the long-term viability of the food chain and an environmentally friendly source of protein (van Huis, 2013).Because of their potential to address some of the most pressing environmental issues, insects used as food and feed are recently gaining adequate attention.
Figure 3 provides the scheme of LCA analysis of insect production.The choice of the sceme of LCA analysis of insect production determines the factors and data that will be obtained for the LCA (Nikkhah et al., 2021).Some common impact assessment methodologies include Eco-Indicator 99, ReCiPe midpoint, IMPACT 2002, CML, IPCC, CML-IA baseline, EDIP 2003, EDP 2013, and ILCD 2011Midpoint (Nikkhah et al., 2021).The LCA process starts with first identifying the goals and scope of the assessment followed by conducting inventory analysis to measure the impact of the assessment.The purpose of the research must be specified as clearly as possible during the goal and scope phase of an LCA (ISO 14040: 2006 andISO 14044:2006).This entails specifying the study's objectives as well as often the product or service alternatives that will be contrasted (Halloran et al., 2016).The products must perform the same function, which is specified and quantified in the functional unit, to be comparable.A system model is built in the inventory phase of an LCA to simulate the emissions and resource consumption at each step of the product's life cycle (ISO 14040: 2006 andISO 14044:2006).Building of structures, feed, production (temperature, energy use, feed conversion ratio, greenhouse gas emissions, and water), transport, processing, and storage waste management, nutrient recycling; and recommending modeling of the insect production system and life cycle impact assessment.Varied environmental impact assessment techniques may also produce different results for LCAs (Notarnicola et al., 2015).Results from the impact assessment are then interpreted under damage and impact categories (i.e.climate change, ecosystem quality, resources, human health).

Environmental impact assessment of insect farming
Around 80% of agricultural land is utilized for the production of livestock feed, although only 15% of the total energy in the world's human food comes from this source (van Huis and Oonincx, 2017).Livestock accounts for 25% of the total protein that people eat, making animal food an important source of dietary protein.Due to population growth and rising affluence, the demand for meat products is anticipated to increase from present levels by more than 75% in 2050 (van Huis and Oonincx, 2017).Concerns about the environment and biodiversity that are related to the traditional production of foods are growing (Raven and Wagner, 2021) leading to the search for alternative protein sources especially those found in insects (van Huis, 2013).For example, livestock alone contributes to about 12% of total anthropogenic CO2 emissions.Interestingly, pork contributes 21-53 kg CO2eq/kg, chicken contributes 18-36 kg CO2eq/kg, lamb contributes 20-44 kg CO2eq/kg, and beef 75-170 kg CO2eq/kg of greenhouse emissions (Vinci et al., 2022).In the United Kingdom (UK) and the EU, reducing these products' consumption by half would result in about 65% reduction in greenhouse gas emissions (Westhoek et al., 2014).
The utilization of insect-based protein is promising for significantly enhancing food sustainability and environmental safety, taking into account that they often contain essential nutrients and high protein content (Vauterin et al., 2021).Also, insect production has less environmental impact (Table 5) than conventional cattle because it uses less land and water and emits fewer greenhouse gases like carbon dioxide compared to plant or animal protein sources (Salomone et al., 2017).For example, insect farms only need 1 ha of land to produce the same amount of protein as pork farms, which need between 2 and 5 ha (Alexander et al., 2017).
Compared to T. molitor, cattle need between 8 to 14 times more land and around five times as much water to produce a gram of usable protein (van Huis and Oonincx, 2017).Furthermore, the global warming potential of 1 kg of protein produced by Protaetia brevitarsis larvae (15.93 kg CO2eq) was lower than that of traditional meat sources like chicken (18-36 kgCO2eq), pork (21-53 kgCO2eq), and beef (75-170 kgCO2eq) (Nikkhah et al., 2021).Moreover, many insects have high feed conversion efficiency when compared with livestock production (Vinci et al., 2022).While poultry raised on optimal diets converts 33% of food protein to edible body mass, yellow mealworms use 22-45%, black soldier fly larvae use almost half (43-55%), and Argentinean cockroaches use 51-88% of dietary protein (van Huis and Oonincx, 2017).
In general, the majority of researchers use a variety of impact categories and characterization factors to analyze the environmental impact of insect rearing, for instance, LCA (Smetana et al., 2021).LCA is a globally defined methodology for evaluating the effects of a product or service on the environment and human health.(Vinci et al., 2021).It involves the analysis of a product or service's effects over its full life cycle, from the extraction of raw materials (cradle) to manufacture, usage, and eventual disposal or other end-of-life options (Smetana et al., 2021).Because LCA is a sophisticated methodology that deals with concepts and guiding principles connected to environmental impact, it necessitates a high level of understanding.Until recently, the main source of edible insects was largely harvested globally from the field/wild, but now situation is changing (Raheem et al., 2018).For example, in Thailand, nearly 2,000 recognized farms engage in insect farming, and 217,529 rearing pens generate nearly 7,500 tons of cricket, grasshopper, and weaver ant eggs annually.Families earn the equivalent of US $5,000 per year from this activity as opposed to US $2,200 from agricultural production (Gahukar, 2016).Thailand has some of the most advanced cricket (A.domesticus and G. bimaculatus) farming practices which many rural farmers depend on for their livelihood (Halloran et al., 2017a).In addition to being an alternative protein source, some farmed edible insects can transform lowgrade biomass into beneficial feed and food ingredients (Jansson et al., 2019).A range of wastes, such as animal carcasses, food scraps, fruit and vegetable waste, and human excrement, can be bioconverted to an extent of up to 70% (Lalander et al., 2019).Cricket farming alone generates a total annual quantity of 26,414.5 kg of biofertilizer from feed (Halloran et al., 2017a).In comparison to open composting, an insect-based waste treatment facility uses less energy (electricity and diesel) and generates fewer hazardous gases (CO2, CH4, and N2O) (Mertenat et al., 2019).

Life cycle assessment studies on insect farming
The LCA method of some insect production has been extensively reviewed by Smetana et al. (2021).System boundaries assessment (amount of resources and wastes included in the analysis) and functional unit (the relative amount of the product, which performs a specific function) are two key concepts of LCA (Smetana et al., 2015).LCA has been used in various studies to evaluate the environmental impact of food and feed (Table 6).Using LCA, Nikkhah et al. (2021)   that P. brevitarsis larvae production has beneficial environmental effects on various impact categories due to the utilization of bio-waste to feed insects.Although LCA is considered the benchmark for product impact assessment, it has its limitations (Halloran et al., 2016;Smetana et al., 2015).

Prospects of environmental impact assessments of insects
Evaluating the effects of increased water and land use, as well as the potential for pollution and other negative impacts on local ecosystems associated with smallholder rearing of insects can be a complex process.1.
Water use: Insect rearing can require significant amounts of water, particularly during the produc-

Opportunities for the insects as food and feed
A significant number of insect species has been placed on the environment and conventional energy supplies due to the world's rapid population and economic expansion, increased need for energy efficiency, and higher living standards.Insects raised on organic wastes and fed to livestock can boost their protein content while lowering greenhouse gas emissions.The nutritional value of some bioconverters, including H. illucens, M. domestica, T. molitor, Z. morio, Locusta migratoria, and Schistocerca gregaria, has been reported to be an alternative protein and fat source in various animal feeds (Mudalungu et al., 2021;Wang and Shelomi, 2017).
In addition, insect-rearing systems have lower levels of environmental impact because they have a relatively lower carbon footprint and use less land and water than crop or animal protein production systems (Vauterin et al., 2021).

Future prospects for sustainability assessment of insects as food and feed
The market of edible insects by the end of 2023 will amount to approximately US $ 1.2 billion, which is a 200% increase in the market volume of five years ago (Figure 4).Thus, over the past 5 years, the market has grown by about 25% per year.However, in the long term, the dynamics of market growth may reach 100% per year, since the predicted market volume in 2030 may amount to about US $ 8 billion (Guiné et al., 2021).At the same time, the largest market growth potential is expected in North America and Europe (Żuk-Golaszewska, 2022).Cultural diversity, food processing methods, farming systems and various consumption standards will continue to contribute to the expansion of the world market for edible insects in the future.Nevertheless, it cannot be denied that eating insects has enormous potential to improve human health worldwide.People who adhere to a healthy diet may be interested in consuming insects, often more useful than traditional livestock products.Once edible insects become a commodity on world markets, they may, like soybeans, serve as livestock feed rather than food for humans, and therefore may not benefit vulnerable groups of the population.Therefore, the potential socio-economic benefits of insect breeding to increase food security in low-income countries require detailed study.On the other hand, the main obstacle to the inclusion of insects in the human diet is consumer perception in developed countries (Lange and Nakamura, 2023).The formation of consumer preferences towards the acceptance of insects as a food source can be carried out through educational exhibitions, a combination of educational conversations and insect eating experience, gastronomic events related to the inclusion of insects in restaurant menus, as well as the publication of scientific and popular scientific materials on the benefits of edible insects (Lange and Nakamura, 2021).Global consumer acceptance of insects as food and feed will limit the excessive demand for farm animal meat and at the same time ensure the necessary protein intake.Consumer readiness will be the most important factor for shaping the future of edible insects as a practical option for eating (Siddiqui et al., 2023b).
Despite the wide range of potential benefits of insect consumption, the idea of edible insects as a solution to many problems is misleading.Various problems may be associated with the sustainable production of edible insects.Although in the past they were considered an inexhaustible natural resource, some insect populations are now threatened with extinction due to their collection by humans (van Huis and Oonincx, 2017).Thus, the collection of insects is already becoming a technogenic factor leading to disruption of ecosystem functions.Therefore, the sustainable development of the insect market can only be associated with the creation of large cultivation farms (van Huis, 2013).Processing of insects exclusively grown in farm conditions is also mandatory from the point of view of ensuring the functioning of the management system and the safety of their processed products.In the future, it is still necessary to create and optimize new methods of LCA analysis of insects as food and feed in order to understand whether the expansion of the scale of production of edible insects with the provision of the necessary amount of feed, energy, space, resources, processing technologies, packaging and transportation, to unforeseen environmental costs and whether it will actually be more sustainable, than traditional cattle breeding.Sustainability in this context will be considered within the framework of mass production.Therefore, future research is needed to compare the sustainability and environmental impact of large-scale breeding of edible insects with existing methods of livestock processing.
Thus, in the future, many questions concerning the use of edible insects as a sustainable food source have yet to be answered.The future sustainability and environmental impacts of large-scale cultivation, harvesting and production of edible insects are largely unknown and need to be studied in more detail so that comparisons can be made with traditional methods of livestock breeding and farming.Currently, knowledge about food safety in relation to insects for human consumption and about the potential dangers associated with eating insects is still limited.Like other animal and plant products, edible insects can be associated with various health risk factors, such as allergens, anti-nutritional compounds, food pollutants (e.g.mycotoxins, pathogens) and chemical residues (e.g.pesticides, heavy metals) (Lange and Nakamura, 2021).This requires further consideration and research.

Conclusions
Insects are nutritionally rich and easy to rear due to their rapid life cycle time and high protein content.
Insects have been demonstrated to have significantly higher protein than meat.However, digestability of insects protein remains lower than in animal-based protein.Insect production on a large scale requires a fraction of the land, water, or energy than the other methods of farming protein.The ability of insects to be raised on food waste is their most significant benefit for food and feed, and they have demonstrated a high potential as a good alternative protein source for the future in terms of sustainability, environmental impacts, and food security.Insects' ability upcycles organic waste to produce low-cost protein making them generate up to 90% few greenhouse gases and freeing more land for the cultivation of food compared to the destructive impacts of livestock on our land, waterways, and climate.Insect production for food and feed must be controlled to ensure safety.To create a worldwide regulatory framework for insects as a component of sustainable food systems, efforts are underway to develop policy frameworks and regulations that can support the production of edible insects.
In conclusion, the outlook on the environmental impact of insect farming is positive, as it is believed to have several potential benefits over traditional livestock farming.Insect farming requires significantly less land and water resources than conventional livestock farming, as well as emitting fewer greenhouse gases and generating less waste.Insects also have a much higher feed conversion efficiency, meaning they require less feed to produce the same amount of protein as traditional livestock.However, like any farming practice, insect farming does have its potential environmental risks, such as the use of pesticides, the potential for invasive exotic insect escape, and the need to manage waste and byproducts.These concerns can be mitigated through careful planning, regulation, and monitoring.

Figure 1
Figure 1 The global demand in tons for plant-based and animal-based proteins vs insect-based proteins.Source: Food and Agriculture Organization of the United Nations (FAO) (2013); Transparency Market Research (TMR) (2021).
der Voort et al. (2013) who determined and analized external topics (drivers) that can influence the priorities for policies about energy efficiency in agriculture considering all suggested factors.By considering demographic, economic, sociocultural, technological, ecological, and political/legal factors, the insect industry can effectively Journal of Insects as Food and Feed 0 (2023) 1-27 Downloaded from Brill.com 12/29/2023 12:58:50PM via Open Access.This is an open access article distributed under the terms of the CC BY 4.0 license.https://creativecommons.org/licenses/by/4.0/ 50PM via Open Access.This is an open access article distributed under the terms of the CC BY 4.0 license.https://creativecommons.org/licenses/by/4.0/

Figure 3
Figure 3 Scheme of LCA analysis of insect production.

Table 1
Key players in the insect as food and feed industry (according to Fortune BusinessInsights, 2022) ⁎ EnviroBug = dried black soldier fly larvae products from oven-dried larvae; EnviroMeal = nutritious, premium feed ingredient produced from defatted black soldier fly larvae.

Table 2
Comparison between the plant, animal, and insect-based protein

Table 3
Potential health benefits of using insects as feed for animals

Table 4
Legal status and regulations of insect protein as food and feed in the European Union

Table 5
Environmental parameters of insect protein production compared with plant and animal-based protein production concluded Journal of Insects as Food and Feed 0 (2023) 1-27 Downloaded from Brill.com 12/29/2023 12:58:50PM via Open Access.This is an open access article distributed under the terms of the CC BY 4.0 license.https://creativecommons.org/licenses/by/4.0/

Table 6
Life cycle assessment (LCA) of some insects and other protein sources for food and feed production systems Kim et al. (2020)ed.A study byKim et al. (2020)estimated that the water uses for producing 1 kg of black soldier fly larvae (BSFL) is around 5.5 L/kg.Given the high demand for water in many regions of East Africa, this could have significant implications for local water resources.