 Although most Stilton cheeses have been made with pasteurised milk for many years, until 1989 the Colston Bassett dairy did make one Stilton with unpasteurised milk.However, following an outbreak of food poisoning incorrectly linked to the dairy and subsequently revealed to be unfounded, they decided to end production of the unpasteurised cheese.In 1996, this decision was permanently enshrined when Stilton was awarded Protected Designation of Origin status by the EU, with one of the criteria being the use of pasteurised cows milk.