Humans have long harnessed fungi for food, drink, and medicine. Cultivating mushrooms at home or commercially starts with understanding the fungal lifecycle. Spores germinate into mycelium, which colonizes a substrate such as sawdust, straw, grain, or logs. This colonized material is called spawn and is used to inoculate a larger substrate. Sterilization or pasteurization of the substrate kills competing microbes so the chosen fungus can establish itself; sterilization is more thorough, while pasteurization is a milder treatment suitable for some materials. After a colonization phase called spawn run, environmental triggers such as fresh air exchange, a drop in CO₂, the right temperature, light, and high humidity induce pinning, the formation of tiny primordia that mature into full fruiting bodies over several days.
Many edible mushrooms are now grown commercially. The button mushroom (Agaricus bisporus) is the most consumed worldwide, with cremini and portobello being simply more mature stages of the same species. Oyster mushrooms (Pleurotus), shiitake (Lentinula edodes), lion's mane (Hericium erinaceus), and king oyster are also widely cultivated, and traditional log cultivation, in which plugs of mycelium are inserted into hardwood logs, remains a popular outdoor method. Pre-inoculated mushroom kits make home cultivation accessible to beginners, while more advanced growers use agar plates for isolating clean strains from a colony or culture, or liquid culture in nutrient broth for fast inoculation.
Wild mushrooms bring extraordinary culinary value as well. Their glutamates and nucleotides produce the savory umami flavor that makes them prized in cuisines worldwide, and many species serve as hearty meat substitutes. Most edible wild mushrooms should be cooked before eating, because some raw mushrooms contain mild toxins or are hard to digest. Dehydration preserves mushrooms for long-term storage and sometimes concentrates their flavor; freezing works best after cooking, because raw freezing damages texture. Beyond food, fungi underpin the production of bread, beer, wine, and cheese: Saccharomyces cerevisiae is the baker's and brewer's yeast that ferments sugar into alcohol and CO₂, while Penicillium roqueforti gives blue cheese its characteristic veins, and wild yeasts including Kazachstania and Saccharomyces species drive sourdough fermentations. Fungi have also given us some of modern medicine's most important drugs. Alexander Fleming's 1928 discovery of penicillin from Penicillium revolutionized medicine, and other fungi supply immunosuppressants like cyclosporine and cholesterol-lowering statins. Medicinal mushrooms such as reishi (Ganoderma lucidum), turkey tail (Trametes versicolor), lion's mane, and cordyceps are used traditionally and are under active research for immune, cognitive, and energy benefits, though rare sensitivities such as so-called lion's mane fingerprints have been reported. The flip side of fungal chemistry is the threat of mycotoxins, including the carcinogenic aflatoxins produced by Aspergillus on stored grains and the ergot alkaloids that historically caused mass poisonings known as St. Anthony's Fire.