Men have preserved their foods from ancient times in order to keep the results
of harvesting for winter months, for resale, for storage, and for transporting
from sea to inland, overseas, or cross-country. To do so, they generally used
nature's methods, which are drying, parching and fermenting. Parching is the
most natural method, but for many thousands of years, others have also been
used. Direct fermentation of liquids, usually by the introduction of yeast, has
not only preserved liquids but also enhanced their quality, the same of course
applying to salting. Smoking has preserved, and sometimes improved both fish and
meat. Hickory wood is generally used for the fires, and natural juices are
contained by a slight coating of wood creosote.
It was not until recently that
the causes of rottenness were understood, these being the reactions of bacteria,
moulds, yeasts and micro-organisms. Some fermentation and moulds are, of course,
necessary in the production of food and drink; moulds, for example, being used
in cheese-making. But the real 'breakthrough' in preservation against the causes
of rottenness came, when it was learnt how to deal with the micro-organisms
present in all foods and drinks, and which react chemically over a period to
produce unpalatable or poisonous food or drink. There are three basic methods.
Firstly, food may be preserved by cooling or freezing, to a very low
temperature when long-term preservation is required. This was originally done by
packing in a mixture of salt and ice; today, cold storage is big business and
refrigeration is a highly-developed science. 'Dehydration' may be bracketed with
this method, as the principle involved is the same, namely to suspend the
operation of bacteria which requires normal temperatures for chemical reaction.
This is why reconstituted eggs cannot against dehydrated, and melted ice-cream
refrozen. the second method of destruction is by heat-processes, which destroy
all the bacteria present in food and drink. This process is used before canning
foods in hermetically-sealed containers, great care being taken not to allow the
foods or drink s to become re-infested after cooling and before canning. the
third method is to preserve by the addition of chemicals, which control or
destroy bacteria. this is merely a follow-up of the old systems of salting,
smoking and candling.
Eventually, the method of 'cold sterilization' is expected to supersede most
of the others; this amounts to exposing the food-stuffs to ionizing radiation.
Today more than mere food-preservation is sought by the consumer, and for
this reason, processes are becoming more and more sophisticated. Quality,
economy and convenience are sought by modern man -- especially modern woman --
convenience is important, the 'ready-cooked' meal is popular, while, in Western,
or 'Westernized' communities, goods do not sell easily if they lack color, a
good appearance, natural flavor, the right texture, and are free from defects.