Food Processing And Preservation
Throughout the history of mankind science has searched into the realms of the unknown. Along with it bringing new discoveries , allowing for our lives to become healthier, more efficient, safer, and at the same time, possibly more dangerous. Among the forces driving scientists into these many experiments, is the desire to preserve the one fuel that keeps our lives going; FOOD.
As early as the beginning of the 19th century, major breakthroughs in food preservation had begun. Soldiers and seamen , fighting in Napoleons army were living off of salt-preserved meats. These poorly cured foods provided minimal nutritional value , and frequent outbreaks of scurvy were developing. It was Napoleon who began the search for a better mechanism of food preservation, and it was he who offered 12,000-franc pieces to the person who devised a safe and dependable food-preservation process.
The winner was a French chemist named Nicolas Appert . He observed that food heated in sealed containers was preserved as long as the container remained unopened or the seal did not leak. This became the turning point in food preservation history . Fifty years following the discovery by Nicolas Appert, another breakthrough had developed. Another Frenchman , named Louis Pasteur , noted the relationship between microorganisms and food spoilage . This breakthrough increased the dependability of the food canning process. As the years passed new techniques assuring food preservation would come and go, opening new doors to further research.
Farmers grow fruits and vegetable s and fatten livestock. The fruits and vegetables are harvested, and the livestock is slaughtered for food. What happens between the time food leaves the farm and the time it is eaten at the table? Like all living things, the plants and animals that become food contain tiny organisms called microorganisms. Living, healthy plants and animals automatically control most of these microorganisms. But when the plants and animals are killed, the organisms yeast, mold, and bacteria begin to multiply, causing the food to lose flavor and change in color and texture. Just as important, food loses the nutrients that are necessary to build and replenish human bodies. All these changes in the food are what people refer to as food spoilage. To keep the food from spoiling, usually in only a few days, it is preserved. Many kinds of agents are potentially destructive to the healthful characteristics of fresh foods. Microorganisms, such as bacteria and fungi, rapidly spoil food. Enzymes which are present in all raw food, promote degradation and chemical changes affecting especially texture and flavor. Atmospheric oxygen may react with food constituents, causing rancidity or color changes. Equally as harmful are infestations by insects and rodents, which account for tremendous losses in food stocks. There is no single method of food preservation that provides protection against all hazards for an unlimited period of time. Canned food stored in Antarctica near the South Pole, for example, remained edible after 50 years of storage, but such long-term preservation cannot be duplicated in the hot climate of the Tropics.
Raw fruits and vegetables and uncooked meat are preserved by cold storage or refrigeration . The cold temperature inside the cold-storage compartment or refrigerator slows down the microorganisms and delays deterioration. But cold storage and refrigeration will preserve raw foods for a few weeks at most. If foods are to be preserved for longer periods, they must undergo special treatments such as freezing or heating. The science of preserving foods for more than a few days is called food processing.
Human beings have always taken some measures to preserve food. Ancient people learned to leave meat and fruits and vegetables in the sun and wind to remove moisture. Since microorganisms need water to grow, drying the food slows the rate at which it spoils. Today food processors provide a diet richer and more varied than ever before by using six major methods. They are canning, drying or dehydration, freezing, freeze-drying , fermentation or pickling , and irradiation.
The process of canning is sometimes called sterilization because the heat treatment of the food eliminates all microorganisms that can spoil the food and those that are harmful to humans, including directly pathogenic bacteria and those that produce lethal toxins. Most commercial canning operations are based on the principle that bacteria destruction increases tenfold for each 10? C increase in temperature. Food exposed to high temperatures for only minutes or seconds retains more of its natural flavor. In the Flash 18 process, a continuous system, the