Bacteria That Feed Your Family

TINY bacteria, too small to be seen by the unaided eye, produce a nourishing food for you and your family. It is a tasty food that can be enjoyed just as it is, or it can be used to enhance many other foods. This delicious food is cheese.

There are many varieties. But, of course, the ones you see in a market are not all of them. All together, there are approximately four hundred different kinds. When you look at the variety of cheeses where you shop, do you ever wonder how they are made and what makes one differ from another?

Cheese is usually made from cow’s milk, but the milk of any animal can be used. In India there are cheeses made from buffalo’s milk, and in the Middle East camel’s milk is used to make a cheese called Krutt. Laplanders make one from reindeer milk, and in Nepal yak milk is used. The milk of goats and sheep is also used in a number of countries.

But when you look at a glass of milk and a piece of cheese you do not see much resemblance, do you? Yet the one comes from the other. Bacteria make possible the remarkable transformation of milk to cheese.

Preparing the Milk

If you were going to make cheese, how would you go about it? First, remember that milk is ideally suited to the growth of microorganisms, so it can easily become contaminated. For that reason the containers as well as the utensils used in making cheese must be sterilized. If the wrong type of bacteria gets into the milk, your cheese-making efforts may not succeed.

To give a freer field to the bacteria used for making cheese, heat the milk so as to destroy a portion of the microorganisms already in it. Then put in the bacteria needed to transform the milk to cheese. It is a type of bacteria that produces lactic acid by fermentation of the milk.

The bacteria can be obtained, either in liquid form or in a powder, from companies that specialize in producing high-quality cultures. When the powder is put into a small amount of sterilized milk, the bacteria are reactivated. Regard this milk as your starter culture or mother culture. Carefully protect it from contamination by other microorganisms.

It takes about twelve to eighteen hours for a mother culture to become ready for preparing a bulk starter of milk. Then when the bulk starter is ready, mix it into the vat of milk that is to be made into cheese. This bulk starter should amount to about 4 percent of the entire vat.

Once the bulk starter has been mixed through the milk, a fermentation process begins. This establishes an acid condition in the milk as a result of bacterial action. To aid the activity of the bacteria, warm the milk to 85 degrees Fahrenheit for the first hour or so.

Ripening Cheese

From the presses the cheese goes to a storage room for the ripening process. This also involves bacterial action that causes a breakdown of fat, protein and carbohydrates. Enzymes produced by the bacteria bring about these chemical actions, and they continue throughout the ripening period.

For the ripening process to go well the temperature and humidity of the storage room must be carefully controlled. The temperature may range from 40 to 60 degrees Fahrenheit, depending upon the type of cheese, flavor, texture and appearance desired.

The time that a cheese stays in this temperature-controlled room varies according to the type of cheese. It may be from two to forty-eight months. During that time the bacteria and the enzymes they produce bring about chemical changes in the cheese, causing it to become softer, more pliable and to have a more aromatic flavor.