Citric acid is mainly produced by fermentation processes of molasses from beet or cane as the raw material, using Aspergillus niger as the preferred mould. After fermentation, citric acid is separated from broth by precipitation using lime or calcium carbonate and filtration. Calcium citrate is washed and then solubilised with sufluric acid to form crud citric acid, whereas calcium precipitates as CaSO4 (gypsum) and is filtered off. Finally, crud citric acid is decoloured and demineralised to meet food quality standards.