Mycoprotein is a form of single-cell protein, also known as fungal protein, is defined in the Oxford English Dictionary as "Protein derived from fungi, especially as produced for human consumption." "Myco" is from the Greek word for "fungus".
The main mycoprotein on sale in Europe and North America is called Quorn, created from Fusarium venenatum.  In the 1960s F. venenatum was identified by the English company Rank Hovis McDougall as a potential protein source for humans F. venenatum was one of over 3,000 species of fungi screened over a three year period for being cheap to reproduce, nutritious and palatable. Concerns for pathogen-potential of the species on plants lead to a twelve-year testing process. After this period F. venenatum was allowed to be sold on the English market and at the time was the most thoroughly tested food product on the European market. F. venenatum is the only source of mycoprotein which can produce a high percentage of protein biomass approved for market.
The fungus is grown in vats using glucose syrup as food. A fermentation vat is filled with the growth medium and then inoculated with the fungal spores. The F. venenatum culture respires aerobically, so for it to grow at an optimum rate, it is supplied with oxygen, and carbon dioxide is drawn from the vat. To make protein, nitrogen (in the form of ammonia) is added and vitamins and minerals are needed to support growth. The vat is kept at a constant temperature, also optimized for growth; the fungus can double its mass every five hours.
When the desired amount of mycoprotein has been created, the growth medium is drawn off from a tap at the bottom of the fermenter. The mycoprotein is separated and purified. It is a pale yellow solid with a faint taste of mushrooms. Different flavors and tastes can be added to the mycoprotein to add variety.
A reproducible mutation occurs after 1,000 to 1,200 hours of cultivation in F. venenatum which greatly reduces the hypha length in the organism, which is considered unfavorable for production. Under normal conditions, this mutant strain will rapidly displace the parent strain. Replacing ammonia with nitrate as the source of nitrogen, or supplementing ammonium cultures with peptone, prevents this mutant strain from overtaking the product but will still develop. Alternatively, the appearance of the mutant can be delayed by varying selection pressures such as nutrient concentrations or pH levels.
Some strains of F. venenatum produce a variety of mycotoxins such as type A tichothecenes. Mycotoxin-producing genes like isotrichodermin, isotricodermol, sambucinol, apo-trichothecen, culmorin, culmorone and enniatin B can be found in cultures of F. venenatum. Specific strands that do not produce mycotoxins under optimal conditions can be selected to reduce the danger to human consumers. Testing at six-hour intervals can be done to monitor mycotoxin presence.
There is continual testing for concerns of allergic reactions, which can range from abdominal pain, nausea and vomiting to severe asthmatic reactions,  especially when crossed with inhaled mold spores.
Mycoprotein is able to provide greater satiety than traditional protein sources like chicken while also being rich in protein and low in caloric content. Replacing two servings of meat protein with mycoprotein can result in a 80 Calorie deficit per day while also extended the period of satiation which is promising for weight management programs. 
- Wiebe, M. G. (March 2002). "Myco-protein from Fusarium venenatum: a well-established product for human consumption". Applied Microbiology and Biotechnology. 58 (4): 421–427. doi:10.1007/s00253-002-0931-x. ISSN 0175-7598. PMID 11954786.
- Yoder, Wendy T.; Christianson, Lynne M. (1998-02-01). "Species-Specific Primers Resolve Members ofFusariumSectionFusarium: Taxonomic Status of the Edible "Quorn" Fungus Reevaluated". Fungal Genetics and Biology. 23 (1): 68–80. doi:10.1006/fgbi.1997.1027.
- Hoff, Michael; Trüeb, Ralph M.; Ballmer-Weber, Barbara K.; Vieths, Stefan; Wuethrich, Brunello (2003-05-01). "Immediate-type hypersensitivity reaction to ingestion of mycoprotein (Quorn) in a patient allergic to molds caused by acidic ribosomal protein P2". Journal of Allergy and Clinical Immunology. 111 (5): 1106–1110. doi:10.1067/mai.2003.1339. ISSN 0091-6749. PMID 12743577.
- Durme, Paul Van; Ceuppens, Jan L.; Cadot, Pascal (2003-08-01). "Allergy to ingested mycoprotein in a patient with mold spore inhalant allergy". Journal of Allergy and Clinical Immunology. 112 (2): 452–454. doi:10.1067/mai.2003.1613. ISSN 0091-6749. PMID 12897757.
- Williamson, Donald A.; Geiselman, Paula J.; Lovejoy, Jennifer; Greenway, Frank; Volaufova, Julia; Martin, Corby K.; Arnett, Cheryl; Ortego, Lauren (January 2006). "Effects of consuming mycoprotein, tofu or chicken upon subsequent eating behaviour, hunger and safety". Appetite. 46 (1): 41–48. doi:10.1016/j.appet.2005.10.007. ISSN 0195-6663. PMID 16364496.
- Wiebe, M.G. (2002). "Myco-protein from Fusarium venenatum: a well-established product for human consumption". Applied Microbiology and Biotechnology. 58 (4): 421–7. doi:10.1007/s00253-002-0931-x. PMID 11954786.