Insect farming

Silkworms, the caterpillars of the domestic silkmoth, are kept to produce silk, an elastic fiber made when they are in the process of creating a cocoon. Silk is commonly regarded as a major cash crop and is used in the crafting of many textiles.

The mealworm (Tenebrio molitor L.) is the larvae form of a species of darkling beetles (Coleoptera). The optimum incubation temperature is 25 ̊C - 27 ̊C and its embryonic development lasts 4 – 6 days. It has a long larvae period of about half a year with the optimum temperature and low moisture terminates. The protein content of Tenebrio Molitor larvae, adult, exuvium and excreta are 46.44, 63.34, 32.87, and 18.51% respectively.[1]

Buffaloworms, also called lesser mealworms, is the common name of Alphitobius diaperinus. Its larvae superficially resemble small wireworms or true mealworms (Tenebrio spp.). They are approximately 7 to 11 mm in length at last instar. Freshly-emerged larvae are a milky color. The pale color tinge returns to that of the first/second instar larva when preparing to molt, while a yellowish-brown appearance after molting. In addition, it was reported that it has the highest level of iron bioavailability.[2]

Commodities harvested from honeybees include beeswax, bee bread, bee pollen, propolis, royal jelly, brood, and honey. All of the aforementioned are mostly used in food, however, being wax, beeswax has many other uses, such as being used in candles, and propolis may be used as a wood finish. In recent years, wild populations of honeybees have declined significantly.

Lac insects secrete a resinous substance called lac. Lac is used in many applications, from its use in food to being used as a colorant or as a wood finish. The majority of lac farming takes place in India and Thailand, with over 2 million residential employees.

Made into a red dye known as carmine, cochineal are incorporated into many products, including cosmetics, food, paint, and fabric. About 100,000 insects are needed to make a single kilogram of dye. The shade of red the dye yields depends on how the insect is processed. France is the world’s largest importer of carmine.

Cricket Shelter Modular Edible Insect Farm, designed by Terreform ONE

Among the hundreds of different types of crickets, the house cricket (Acheta domesticus) is the most common type used for human consumption.[3] The cricket is one of the most nutritious edible insects, and in many parts of the world, crickets are consumed dry-roasted, baked, deep-fried, and boiled. Cricket consumption may take the form of cricket flour, a powder of dried and ground crickets, which is easily integrated in to many food recipes. Crickets are commonly farmed for non-human animal food, as they provide much nutrition to the many species of reptiles, fish, birds and other mammals that consume them. Crickets are normally killed by deep freezing, where they feel no pain and are sedated before neurological death.

Waxworms are the larvae of wax moths. These caterpillars are used widely across the world for food, fish bait, animal testing and plastic degradation. Low in protein but high in fat content, they are a valuable source of fat for many insectivorous organisms. Waxworms are popular in many parts of the world, due to their ability to live in low temperatures and their simplicity in production.[4]

Cockroaches are farmed by the million in China, and became an area of growth in the early 2000s.

Purported benefits of entomophagy include:

• Significantly less amounts of resource and space use, less amounts of waste produced, and emissions of very trace amounts of greenhouse gases.[10]
• They include many vitamins and essential minerals, contain dietary fiber (which is not present in meat),[11] and are a complete protein.[10] The protein count of 100 g of cricket is nearly equivalent to the amount in 100 g of lean ground beef.[10]
• As opposed to meat, lower costs are required to care for and produce insects.[3]
• Faster growth and reproduction rates. Crickets mature rather quickly and are typically full-grown within 3 weeks to a month,[3] and an individual female can lay from 1,200 to 1,500 eggs in three to four weeks. Cattle, however, become adults at 2 years, and the breeding ratio is four breeding animals for each market animal produced.[12]
• Unlike meat, insects rarely transmit diseases such as H1N1, mad cow disease, or salmonella.[10]

Cattle use 12 times the amount of feed that crickets do to produce an equal amount of protein.[3] Crickets also only use a quarter of the feed of sheep and one half the amount of feed given to swine and chicken to produce an equivalent amount of protein.[3] Crickets require only two pounds of feed to produce one pound of the finished product.[3] Much of this efficiency is a result of crickets being ectothermic, as in they get their heat from the environment instead of having to expend energy to create their own body heat as typical mammals do.

Insects are nutrient efficient compared to other meat sources. The insect protein content is comparable to most meat products. Likewise, the fatty acid composition of edible insects is comparable to fish lipids, with high levels of polyunsaturated fatty acids(PUFAs). In addition, all parts on edible insect are efficiently used however, some parts on conventional livestock are not directly available for human consumption [5] The nutritional contents of insects vary with species as well as within species depending on their metamorphic stage, their habitat and their diet. For instance, the lipid composition of insects is largely dependent on their diet and metamorphic stage. Insect is abundant in other nutrients, Locusts for example contain between 8 and 20 milligrams of iron for every 100 grams of raw locust. Beef on the other hand contains roughly 6 milligrams of iron in the same amount of meat. Crickets as well are very efficient compared to their nutrients. For every 100 grams of substance crickets contain 12.9 grams of protein, 121 calories, and 5.5 grams of fat. Beef contains more protein containing 23.5 grams in 100 grams of substance, but also has roughly 3 times the calories, and four times the amount of fat as crickets do in 100 grams. So, per 100 grams of substance, crickets contain only half the nutrients of beef, except for iron. High levels of iron are implicated in bowel cancer[13] and heart disease.[14] When considering the protein transition, cold-blood insects are enabling to convert food more efficiently: crickets only need 2.1 kg feed for 1 kg ‘meat’ while poultry and cows need about more than 2 times and 12 times of the feed[15]

The raising of livestock is responsible for 18% of all greenhouse gases emitted.[3] Alternative sources of protein, such as insects, replace protein sourced from livestock and help decrease the number of greenhouse gases emitted from food production. Insect raising has negligible emissions compared to livestock since no farmed insect species besides termites release methane,[3] and none create ammonia.

Livestock raising accounts for 70% of agricultural land use.[16] This results in a land-cover change which destroys local ecosystems and displaces people and wildlife. Insect farming is minimally space intensive compared to other conventional livestock,[16] and can even take place in populated urban centers.

Insects at different life stages can be collected by sieving followed by water cleaning when it is necessary to remove biomass or excretion. Before processing, the insects are sieved and stored alive at 4 ℃ for about one day without any feed.[18]

An inactivation step is needed to inactive any enzymes and microbes on the insects. The enzymatic browning reaction (mainly phenolase or phenol oxidase[19]) can cause the brown or black color on the insect, which leads to discoloration and the off-flavor.

Sufficient heat treatment is required to kill enterobacteriaceae so that the product can meet the safety requirement. D-value and Z-value can be used to estimate the effectiveness of heat treatments. The temperature and duration of the heating will cause insect proteins' denaturation and changes the functional properties of proteins.

To prevent spoilage, the products are dried to lower the moisture content and prolong the shelf life. Longer drying time results from a low evaporation rate due to the chitin layer, which can prevent the insect from dehydration during their lifetime. So the product in granules form give the advantages of further drying. In general, insects have a moisture level in the range of 55-65%. A drying process decreasing the moisture content to a level of less than 10% is good for preservation.

Besides the moisture level, oxidation of lipids can cause high levels of unsaturated fatty acids in products. Hence the processing steps influencing the final fat stability in products are necessary to be considered during drying.