a freeze-dried Penicillium roqueforti culture. Although Penicillium roqueforti can be found naturally, cheese producers nowadays use commercially manufactured Penicillium roqueforti. First, Penicillium roqueforti is washed from a pure culture agar plants which is later frozen. Through the freeze drying process, water from the frozen state is evaporated without the transition through the liquid state (sublimation). This retains the value of the culture and is activated upon the addition of water. Salt, sugar or both are added to autoclaved, homogenized milk via a sterile solution. This mixture is then inoculated with Penicillium roqueforti. This solution is first incubated for three to four days at . More salt and/or sugar is added and then aerobic incubation is continued for an additional one to two days. Alternatively, sterilized, homogenized milk and reconstituted non-fat solids or whey solids are mixed with sterile salt to create a fermentation medium. A spore-rich Penicillium roqueforti culture is then added. Next, modified milk fat is added which consists of milk fat with calf pre-gastric esterase. This solution is prepared in advance by an enzyme hydrolysis of a milk fat emulsion. The addition of modified milk fat stimulates a progressive release of free fatty acids via lipase action which is essential for rapid flavor development in blue cheese. This inoculum produced by either methods is later added to the cheese curds. Production and fermentation First, raw milk (either from cattle, goats or sheep) is mixed and pasteurized at for 15 seconds. Then, acidification occurs: a starter culture, such as Streptococcus lactis, is added in order to change lactose to lactic acid, thus changing the acidity of the milk and turning it from liquid to solid. The next step is coagulation, where rennet, a mixture of rennin and other material found in the stomach lining of a calf is added to solidify the milk further. Following this, thick curds are cut typically with a knife to encourage the release of liquid or whey. The smaller the curds are cut, the thicker and harder the resulting cheese will become. After the curds have been ladled into containers in order to be drained and formed into a full wheel of cheese, the Penicillium roqueforti inoculum is sprinkled on top of the curds along with Brevibacterium linens. Then, the curds granules are knit in molds to form cheese loaves with a relatively open texture. Next, whey drainage continues for 10–48 hours in which