Castello cheeses remarkable popularity both in Denmark and abroad.” Castello was acquired by Arla Foods, who expanded Castello into cheese markets in North America. Castello blue cheeses were developed in the 1960s. The curds are dipped into salt water, drained, and put into molds. The cheese is punctured with tiny holes and then brought into the ripening room, where it stays for about 15 days. It is then washed, cut, packed, and put in a "cooling room" for about a week at a temperature close to freezing. The washed rind hosts various molds that add to the cheese's mildly spicy flavor. It
Blue cheese of blue veins. The distinctive flavor and aroma of blue cheese arises from methyl ketones (including 2-pentanone, 2-heptanone, and 2-nonanone) which are a metabolic product of "Penicillium roqueforti". These compounds are not formed in other types of cheese fermented by bacterial acidification alone. In the European Union, many blue cheeses, such as Cabrales, Danablu, Gorgonzola, Roquefort and Blue Stilton, carry a protected designation of origin, meaning they can bear the name only if they have been made in a particular region. Similarly, individual countries have protections of their own such as France's Appellation d'Origine Contrôlée and Italy's Denominazione di Origine