Food Preservation
Food preservation
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, molds, yeasts and micro-organisms. Some fermentation and molds are, of course, necessary in the production of food and drink; molds, 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
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, molds, yeasts and micro-organisms. Some fermentation and molds are, of course, necessary in the production of food and drink; molds, 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