Food Processing


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 vegetables 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.

Canning

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 food is flash-sterilized in a pressurized chamber to
prevent the superheated food from boiling while it is placed in containers.
Further sterilizing is not required.

Freezing

Although prehistoric humans stored meat in ice caves, the food-freezing
industry is more recent in origin than the canning