When Portugal joined the European Union (at the time of the CEE), certain changes had to be made to the designation of wines produced. The Denomination of Origin, (DO - Denominação de Origem) is attributed to wines that, due to their characteristics, are intimately associated with a specific region: they originate and are produced in that region and possess qualities or characteristics inherent in that geographical location (natural as well as human factors). These wines are subject to a high control at all levels of the winemaking process. The regional wine commissions examine both the viticulture and vinification stages of the winemaking in order to preserve its qualities and unique characteristics.