Stilton is an English cheese, made in two types: Blue, and White. Blue stilton has "Penicillium roqueforti" added. This gives it a characteristic smell and taste. White is the same cheese without having the penicillium added. Both have been given the status of a protected designation of origin (PDO) by the European Commission. This means that the cheese must be made to a strict code in one of the three counties of Derbyshire, Leicestershire or Nottinghamshire. 