Food Preservation

17 Food Preservation We don't give much thought to food in our modern era. It's just there as a part of our lives-bananas from Vietnam, grapes from California, and milk, meat and vegetables from local farms. Our prehistoric ancestors would be jealous. For them, each day presented a challenge: hunt with success or starve. Periods of plentiful food were often followed by long periods of famine. There was no way to preserve food to be eaten later. When it dies, a living organism is invaded by harmful bacteria that cause food to spoil. As it rots, it becomes toxic. This is where food preservation comes in. The goal of food preservation is to destroy these harmful organisms. There are six main ways to do that: drying, pickling, canning, freezing, freeze-drying and irradiation.

Probably by accident, prehistoric humans discovered that some foods, when left out in the sun, did not rot. They had discovered food preservation. Over the centuries, drying techniques have been perfected. Furnaces, large fans, and artificial heat are now used. But the end result is the samedried food that can last a long time. Another ancient method of preserving food is pickling. Food is preserved in a solution of salt, which makes it impossible for bacteria to survive. Meats and vegetables can be preserved in this way. By 1800, a new method came on the market-canning. Food is cooked at high temperatures to kill the bacteria. It is then put in a sterile container such as a can or a glass jar. The top is sealed to prevent air from entering. Canned food can last for 30 or 40 years, and still taste good. Then, with the invention of freezers, large-scale food preservation became a reality. By cooling food to below freezing temperatures, bacteria are killed. The latest method of food preservation is irradiation. Gamma radiation kills the bacteria, but the long-term effects of eating foods to which radiation has been applied are unknown. Food preservation has come a long way, from drying in the hot sun to large-scale preservation in modern factories. However, the goal remains the same: to have long-lasting safe food to feed the people.