Cheese processing: Roquefort, Gorgonzola and Blue Cheese

The main different among these cheeses is that Roquefort is made from sheep’s milk while Gorgonzola and blue cheese are made from cow’s milk.

Roquefort cheese is a delicacy that has heretofore been manufactured only in parts of Europe where it was asserted the proper conditions for ripening existed. Also, to be labeled, Roquefort cheese must be made in France.

Blue cheese may be made from raw, heated or pasteurized whole milk or from skim milk and cream mixtures, but butterfat content should be about 3.5%.

Raw milk or milk that has been heated at temperatures lower than those used for pasteurization is preferred, since lipase action is required for ripening of this type of cheese and heating pasteurization temperature inactivates lipase. Lipase is an enzyme that splits fats into glycerin and fatty acids. It is to impart characteristics flavors, accelerate cheese ripening.

If skim milk and cream used as the main ingredients, and the cream is too yellow in color, it may bleached by treating with benzoyl peroxide. If the whole milk is used, the temperature is adjusted to 85 F (29.4 C) and the milk is homogenized.

After homogenization, the temperature of the product is raised to 90 F (32.2 C), a lactic acid starter culture is added and the product is held at 90 F (32.2 C) for a period of 1 hr.

During homogenization, the composition of the milk is changed and this in turn will affect the cheesemaking process. The best milk to use for cheesemaking is raw milk; however, it’s available only from a farm.

The enzyme rennet is the added to coagulate the mixture, which is allowed to stand for another 45-60 mins. The rennet is used to bring about coagulation while the milk is still sweet. Rennet contains enzymes that act on the milk protein casein, separating the milk into curds and whey.

The curd then is cut into half in. (1-3 cm) cubes, after which it is stirred for 15 min while being held at the incubation temperature.

The whey is then drained and the curd is mixed with about 1% salt, and then placed in racks lined with cheesecloth and allowed to drain. After draining, the curd in sterilized hoods, and as the hoops are filled, and the curd is mixed with bread crimson which a culture of mold Penicillium roqueforti has been inoculated and allowed to grow.

Penicillium roqueforti gives Roquefort its distinctive piquancy by breaking some fats down into fatty acids.

The hoop containing the curd are held at 65 – 68 F (18.3 – 20 C) for part of the day, after which the product is placed in the room at 50-55 F (10-12.8 C) where salt is applied to the surface of the cheese daily until the salt content reaches 4-4.5%.

The cheeses are then removed to a ripening room where they are held for 2-3 months at 50-55 F (10-12.8 C) and a relative humidity of 5%. In general, the longer a chesses is ripened, the less likely it is that pathogens will survive in the cheese and cause foodborne illness.

The latter procedure permits air to enter to the products so that the mold, which requires oxygen, will grow.

Chemical environment within a chesses becomes more hostile to mold growth, and the range of microorganisms that survive and proliferate becomes increasingly limited as: pH decreases, the salt content increases and the available moisture decreases.

After curing, the surfaces of the cheeses are scrapped, and the cheeses are then cut into small wedges and wrapped in the plastics cups.
Cheese processing: Roquefort, Gorgonzola and Blue Cheese

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