Gorgonzola is made in the regions of Piedmont and Lombardy from whole pasteurized cow's milk to which is added the bacteria Lactobacillus bulgaricus and Streptococcus thermophilus along with spores of the mold Penicillium glaucum. Recently Penicillium roqueforti has started to be used to make Gorgonzola, besides its use in Roquefort cheese. After the whey is removed, it is aged at low temperatures. During the aging process, metal rods are inserted into the cheese. This creates air channels which allows the mold spores to germinate and create the characteristic veining. Gorgonzola is typically aged for three to four months. The length of the aging process determines the consistency of the cheese. A firm Gorgonzola is aged longer than creamy Gorgonzola. It is usually sold wrapped in foil.
Gorgonzola may be consumed in many ways. It may be melted into a risotto in the final stage of cooking, for instance. Another fairly traditional dish sees Gorgonzola served alongside polenta. Because of its distinctive flavor, it is occasionally offered as a topping on pizza.
Today by law the zone of production includes only a defined area. What was once the village of Gorgonzola, not far from Milan, is being swallowed up by suburbs. Most Gorgonzola is actually produced in the province of Novara, but the DOC zone also includes such provinces as Bergamo, Brescia, Como, Cremona, Cuneo, Lecco, Lodi, Milan, Pavia, Varese, Verbano-Cusio-Ossola, and Vercelli, as well as a number of comunes in the area of Casale Monferrato (province of Alessandria).