A prominent encyclopedia has suggested that the invention with the greatest impact on worldwide economic life since the railroad is, no, you’d never guess, the refrigerator! Isn’t the refrigerator more of a convenience item? Hardly. Refrigeration technology has completely revolutionized farming and led to the rapid development of a worldwide food trade. It would be difficult indeed to find a person in the world today who has not benefited in some way from the introduction of refrigerated food preservation.
The growth of cities and suburbs in the last century has steadily moved most of us further and further away from our food source, the farm. Without food-preservation techniques, especially refrigeration, it’s doubtful that this urban growth could have moved ahead so rapidly. And since the advent of refrigeration, a nation no longer has to feed itself, the abundant supply of one nation can balance the scarcity in another, allowing many nations to industrialize more quickly. Improved food preservation has also helped increase the world’s food supply by eliminating much waste. Foods that would otherwise perish can remain in storage until needed.
Refrigeration may be a recent advance, but food preservation itself has engaged man’s attention since the beginning of time. Cheese and butter may, in a sense, be regarded as preserved milk; wine, as preserved grapes. For thousands of years, meat and fish have been preserved by salting or drying, or more recently, by curing with sugar or nitrate compounds. Most of these early stratagems were discovered by chance, they worked, but no one knew why. Only when the existence of bacteria and their influence on foodstuffs became known, could man begin to deal adequately with food preservation.
Without bacteria, edibles would last almost indefinitely. All food-preservation techniques, then, are designed to kill or limit the growth of bacterial life. For instance, the process of drying works because bacteria cannot grow in the absence of moisture. Sterilization by heat, cooking, will completely destroy bacterial life, but the effects are temporary. Cooked food will spoil as rapidly as uncooked food if left untreated or uneaten.
Cooling does not kill bacteria, but it does stop their growth. Once scientists learned that most bacteria cannot grow at temperatures below the freezing point of water, and also that long-term freezing or cooling of foods does not influence their nutritional content, they knew what was needed for the perfect food-preservation system, a refrigerator. It remained only to invent one.
It had long been known that low temperatures would, for some then unknown reason, preserve food. People in Arctic lands often stored their meat in snow and ice. But to preserve food, people in warmer climes needed man-made ice.
Ancient Indians made ice the simplest and least dependable way possible, leaving water in special outdoor receptacles overnight. The ancient Romans cooled their wine cellars with snow brought from nearby mountains. They also discovered, as did the Indians, that water could be cooled with the addition of saltpeter. The Romans sometimes chilled liquids by immersing bottles in vessels filled with water and saltpeter, and rotating the bottles rapidly. The records of a Roman doctor, Blasius Villafranca, show that cooling water with saltpeter was still common in the sixteenth century.
Primitive cooling techniques could chill food and drink, but not freeze them; the beneficial effects were temporary. During the 18th century, many scientists developed an interest in mechanical refrigeration, but with neither electricity not the means to manufacture large quantities of ice, the scientist’s road to the new “ice age” was a long and difficult one.
The first “refrigerator” in the United States was invented in 1803 by Thomas Moore of Baltimore, but Moore’s machine was really a “thermos” device, two boxes, one inside the other, with insulating material in between. Food stored with ice in the inner box would remain cool for a time, but not cool enough to inhibit bacterial growth for very long.
The next giant step toward successful refrigeration came in 1834, when Jacob Perkins, an American living in England, developed an ice-making machine functioning on the compression principle. Gases subjected to high pressures will remain in the liquid state at temperatures beyond their normal boiling point. Perkins showed that when these compressed liquids were used as refrigerants, they would absorb a great deal of heat before changing to the gaseous state.
In 1851, an American engineer named John Gorrie took Perkins’ techniques one step further, filing a patent for “an improvement in the process for the artificial production of ice.” Gorrie stunned a dinner crowd by exhibiting blocks of man-made ice the size of bricks. Gorrie’s compression-principle machine failed as a dependable refrigerator for a number of reasons, but his primitive machine formed the basis of much later work.
The 1870’s saw vast improvements in refrigeration techniques. A refrigerator car, really a rolling icebox, had made its earliest appearance in 1851, when several tons of butter made the journey by rail from Ogdensburg, New York to Boston. But the first application of refrigeration technology to marine food transportation came in 1880, when the steamer Strathleven carried a meat cargo from Australia to England. Oddly enough, the meat was meant to be cooled, not frozen, but freezing did take place, and the excellent results led to the subsequent freezing of all meat cargoes.
The domestic refrigerator was not to be used on any scale until this century. In the past, urban Europeans had often hung dairy products out the window to keep them cool for a time. The larder was also used throughout the West for temporary preservation. Earlier in this century, most American homes relied on the icebox for their victuals. The icebox, however, left much to be desired, especially when the iceman did not cometh.
The modern domestic refrigerator is based to a great extent on the work of the Frenchman Edmond Cane. In the 1830’s, Carre perfected the first refrigerating machine to be widely adopted for individual use. Carre’s machines were used in many Paris restaurants for the production of ice and ice cream products. The first household refrigerator patent in the United States was granted in 1899 to one Albert T. Marshall of Brockton, Massachusetts.
Modern refrigerators and freezers use a circulating refrigerant that continually changes from the gaseous to the liquid state. Most machines use dichlordifluoromethane and other refrigerants mercifully known under the trade name of Freon. The liquid refrigerant changes to a gas in the evaporator, then absorbs heat from the food chamber and carries it to the condensing coils, where the refrigerant is cooled by air passing over the coils, and is reconverted into liquid. The cycle is then repeated, spurred on periodically by a small electric motor. Incidentally, your refrigerator is probably your greatest electricity consumer, after your air conditioner.
Wartime restrictions limited the growth of the domestic refrigerator in this country, but after World War II the ‘fridge found its way into almost every American home, and so did frozen foods. The American, Clarence Birdseye, is responsible for the development of methods for freezing foods in small packages for the retail trade. The General Foods Corporation introduced the now familiar Birds Eye commercial pack in 1929. Since then, the use of frozen foods has grown with the refrigerator. As early as 1944, Americans were consuming some three billion pounds of frozen meats, vegetables, fruits, fish, and dairy products each year.
During and after World War II, military and industrial research led to the development of the science of cryogenics, the study of matter at extremely low temperatures. Basically, cryogenics, from the Greek word kryos, “icy cold”, deals with the production of temperatures below that of liquid oxygen (-297 degrees F.). You hardly need such frigid temperatures to keep your eggs fresh, but cryogenic engineering has had an impact on many elements of modern life, from medicine to space travel.
Scientists have been freely discussing the ultimate cryogenic marvel, suspended animation. Living organisms, including man, can theoretically be kept in a deep freeze almost indefinitely, and resume normal life functions upon thawing. Persons with presently incurable diseases could be frozen before death in the hope of reviving them when cures are found. Intergalactic space travelers could be frozen and revived upon reaching their destination thousands of years later. And think of the possibility of a living time capsule, a human being frozen for thousands of years, to be resurrected by some future civilization to see how we lived in the twentieth century!