Meju is a product made traditionally from soybeans that are soaked, cooked, mashed, formed into blocks and dried. The blocks are then fermented — traditionally by natural microflora, increasingly with defined starter cultures — to produce soy sauces and bean pastes (doenjang) as the liquid and solid fractions. Proteolysis and microbial metabolism during the long fermentation develop the deep umami flavour and dark colour. The process must be controlled for salt concentration, temperature and hygiene to favour desirable Bacillus and Aspergillus species while suppressing pathogens and mycotoxin-producing moulds; the finished pastes and sauces are high-salt, shelf-stable products.