The problem of preserving food collected during times of plenty for use when the source of supply fails has been practiced by man from even the remotest ages. Among primitive races, food preservation was essential to avoid famine. In modern civilized countries, the preservation of food is an important factor in maintaining a balance between demand and supply for perishable foods. There is a special need of preservation in order to transport food to the large cities.
Chemical processes of animal and vegetable tissue actively continue in these foods even after the more obvious evidences of life have gone. Fruits ripen, grains mature, starches become sugars, flavors develop, and meat becomes tender. These changes are desirable and nutritively beneficial.
There are numerous artificial methods employed to restrain the activity of these processes in foods. The most important is by refrigeration or cooling. Some other methods are by drying, dehydrating-, smoking, pickling, curing, preserving, and cooking.
Refrigeration is the method of food preservation which causes a minimum of alteration of the desirable food properties. The natural freshness and flavors are retained without abstracting moisture, and there is a minimum change in the physical, chemical, or nutritive qualities of the food.
<Callout type="important" title="Historical Significance">Refrigeration was first used by the Egyptians, Greeks, and Romans who cooled their wines and water in crude vessels which extracted some of the heat from the liquids through evaporation.</Callout> The first methods of preserving food by cooling were very crude—a hole in the ground or a stream of water served this purpose.
In the early part of the nineteenth century, the ice box came into use. Natural ice was placed in the ice compartment. The melting of the ice produced a circulation of cold air which cooled the foods. This was a great improvement over previous methods of storing perishable foods.
Ice of the winter months was stored for this use in specially constructed buildings located near the pond or lake supplying it.
The supply of natural ice was very uncertain. Transportation was difficult and ice was only available to limited localities.
<Callout type="risk" title="Supply Risks">The supply of natural ice was very uncertain, making food preservation unreliable.</Callout> The next important step in household refrigeration was the use of manufactured ice. Active work in the development of machines for producing ice in a commercial way was carried on from 1830-1870. The success of these machines permitted their use even in the warmest climates. In addition, there were difficulties in transporting natural ice any great distance from its source.
In addition to the increased use of manufactured ice, some improvement in the construction of household refrigerators was made. Better insulation was used, more sanitary linings and better air circulating systems designed. The temperature in the food compartments could be maintained from 20° to 30° lower than the room temperature.
During the last twenty years, the household refrigerating machine has been under active development. It is only within the last five years, however, that machines have been manufactured in quantities and proven a commercial success.
Mechanical household refrigeration is having an important influence on refrigerator cabinet construction. It is necessary to have better constructed and insulated refrigerators to operate satisfactorily with the lower food compartment temperatures produced by the mechanical unit.
The cost of operation of the household machine is about the same as the cost of ice. When the interest of the investment and depreciation are considered they will usually cost more than ice. The increased sale of machines indicate that the advantages compensate for this difference in cost.
Key Takeaways
- Refrigeration has been used since ancient times to preserve food and prevent spoilage.
- The development of manufactured ice improved the reliability and availability of refrigeration in households.
- Mechanical refrigerators have become more common due to their efficiency and convenience.
Practical Tips
- Use modern refrigerators for long-term storage of perishable foods, especially during seasonal shortages.
- Understand the historical context of refrigeration to appreciate its evolution and current benefits.
Warnings & Risks
- Natural ice supply can be unreliable due to weather conditions and transportation difficulties.
- Early mechanical refrigerators may not have been as efficient or reliable as modern models.
Modern Application
While this chapter focuses on historical methods of food preservation through refrigeration, the principles remain relevant today. Understanding how early refrigeration techniques evolved helps us appreciate the advancements in technology that ensure our food stays fresh longer and more reliably.
Frequently Asked Questions
Q: What were some early methods of preserving food by cooling?
Early methods included using a hole in the ground or a stream of water to cool foods. Later, ice boxes became common, utilizing natural ice placed in compartments to circulate cold air and preserve perishable items.
Q: How did the development of manufactured ice impact household refrigeration?
The use of manufactured ice allowed for more reliable and consistent cooling in households. It could be produced commercially year-round, overcoming limitations of natural ice supply and transportation difficulties.
Q: What are some advantages of modern mechanical refrigerators over early methods?
Modern mechanical refrigerators offer better insulation, lower food compartment temperatures, and more consistent cooling compared to earlier methods like ice boxes. They also provide greater reliability and efficiency in preserving perishable foods.