Wheels of Gouda cheese
About Milk
Cheese production starts, of course, with milk. What kind of milk is used can vary drastically from region to region and culture to culture. Cow milk is the most common type used for large-scale cheese production, but cheese from many other animals is also produced, including goat and sheep cheese. In modern times, there are several legal qualifications the milk must meet to be processed as cheese. The European market, home to most of the different cheeses in the world, is especially exacting in these requirements. Milk is usually required to be heat-treated or pasteurized before being made into cheese.
Pasteurization
The pasteurization process varies depending on the type of cheese being made. For fresh cheese, or cheese that does not need to ripen and can go immediately to market, the milk must be pasteurized to prevent the growth of dangerous pathogens in the unripened cheese substance. Cheeses that require a ripening process a month or longer do not need to be pasteurized, but they often are, regardless. A balance between too much heat and too little heat must be maintained--too little heat, and bacteria will linger in the cheese, ruining the flavor and making it possibly dangerous. Too much heat, and the flavor of the cheese is again affected, especially in certain delicate cheeses such as Emmenthal, Parmesan and Grana. To destroy dangerous bacteria that may linger after pasteurization, certain chemicals are often added to the milk, such as sodium nitrate, although there is contention as to how safe and proper these chemical additives are.
Bacteria and Cheese Production
Once the milk is ready to be made into cheese, a specific, carefully controlled bacteria culture is added to it and mixed with rennet, a substance rich in active enzymes. These enzymes set to work, and the milk is soon coagulated into a semi-solid known as curd. The curd is diced and then placed in vats where it is heated and stirred. This helps the bacteria grow and feed on the curd, until the syneresis process is complete and the liquid whey has become separated from the now more-solid curd. This curd is then pressed into moulds and--in some cases--allowed to ripen. Sometimes other substances will be added to the curd to give the cheese additional flavors.
The bacteria used in making cheese can be either mesophilic or thermophilic. Mesophilic bacteria grow in average temperatures, but thermophilic cultures prefer plenty of heat to grow. Often, both types of bacteria are used in cheese production so that they complement each other, but it depends on the type of cheese. The primary jobs of the bacteria are to produce lactic acid, break down the milk protein and occasionally to produce carbon dioxide.
Tags: bacteria grow, bacteria used, being made, cheese production, into cheese