Many fungi are pathogens of plants that are grown for food, shelter or
clothing. A smaller number are agents of diseases in animals, including man.
Many saprotrophic fungi attack and degrade raw or manufactured materials of
various kinds, such as foodstuffs, timber, textiles and leather. The economic
loss of such destruction, and the cost of prevention treatment, can be
enormous.
On the positive side, many saprotrophic fungi are useful to man. The use
of yeasts in baking and brewing is well known. Minor source of food include
edible mushrooms and truffles. Various fungi are used to give distinctive
flavors to ripening cheeses. Several extremely useful antibiotics are metabolic
products of fungi, e.g. penicillin.