Moulds are the cause of considerable economic losses, due to spoilage of such food products as flour, bread, canned goods, fruit juices, meat, dairy goods and beer. In particular they cause the destruction of stored fruits and vegetables, lower the quality of fodders, and also cause various diseases of plants, thus lowering yield. Environmental moulds potentially can result in human illness by the production of allergens, proteases, beta-glucans and volatile organic compounds.
Mould (or mold) is usually identified as a furry or spotty growth on the surface of plants, animals and nonliving organic objects. Contamination by mould is a more serious condition that surface colonization. When mould contaminates, the mycelial elements will actually penetrate the substrate. The mycelium is connected to the conidiophore, which is the reproductive structure of the mould. The food source for fungal growth in buildings, for example, may include cellulose, which can be found in ceiling tile, insulation, sheetrock, as well as wood and dirt. The ecological types of molds are: those included in the classes of phylloplane, which are moulds that can grow on leaf surfaces and include Cladosporium and Alternaria. Soil-based moulds are typified by Penicillium and Aspergillus. Typical moulds found in wood decay include the Basidiomycetes. Indoor moulds typically include Alternaria, Cladosporium, and Epicoccum, but these are typically from outdoor sources. Fusarium and other pathogenic fungi are found in many temperate and tropical parts of the world.
All moulds require moisture to grow. The temperature tolerance of moulds is extremely variable.