21 June 2009
The invention: It was long known that low temperatures helped to protect food against spoiling; the invention that made frozen food practical was a method of freezing items quickly. Clarence Birdseye’s quick-freezing technique made possible a revolution in food preparation, storage, and distribution. The people behind the invention: Clarence Birdseye (1886-1956), a scientist and inventor Donald K. Tressler (1894-1981), a researcher at Cornell University Amanda Theodosia Jones (1835-1914), a food-preservation pioneer Feeding the Family In 1917, Clarence Birdseye developed a means of quick-freezing meat, fish, vegetables, and fruit without substantially changing their original taste. His system of freezing was called by Fortune magazine “one of the most exciting and revolutionary ideas in the history of food.” Birdseye went on to refine and perfect his method and to promote the frozen foods industry until it became a commercial success nationwide. It was during a trip to Labrador, where he worked as a fur trader, that Birdseye was inspired by this idea. Birdseye’s new wife and five-week-old baby had accompanied him there. In order to keep his family well fed, he placed barrels of fresh cabbages in salt water and then exposed the vegetables to freezing winds. Successful at preserving vegetables, he went on to freeze a winter’s supply of ducks, caribou, and rabbit meat. In the following years, Birdseye experimented with many freezing techniques. His equipment was crude: an electric fan, ice, and salt water. His earliest experiments were on fish and rabbits, which he froze and packed in old candy boxes. By 1924, he had borrowed money against his life insurance and was lucky enough to find three partners willing to invest in his new General Seafoods Company (later renamed General Foods), located in Gloucester, Massachusetts. Although it was Birdseye’s genius that put the principles of quick-freezing to work, he did not actually invent quick-freezing. The scientific principles involved had been known for some time. As early as 1842, a patent for freezing fish had been issued in England. Nevertheless, the commercial exploitation of the freezing process could not have happened until the end of the 1800’s, when mechanical refrigeration was invented. Even then, Birdseye had to overcome major obstacles. Finding a Niche By the 1920’s, there still were few mechanical refrigerators in American homes. It would take years before adequate facilities for food freezing and retail distribution would be established across the United States. By the late 1930’s, frozen foods had, indeed, found its role in commerce but still could not compete with canned or fresh foods. Birdseye had to work tirelessly to promote the industry, writing and delivering numerous lectures and articles to advance its popularity. His efforts were helped by scientific research conducted at Cornell University by Donald K. Tressler and by C. R. Fellers of what was then Massachusetts State College. Also, during World War II (1939-1945), more Americans began to accept the idea: Rationing, combined with a shortage of canned foods, contributed to the demand for frozen foods. The armed forces made large purchases of these items as well. General Foods was the first to use a system of extremely rapid freezing of perishable foods in packages. Under the Birdseye system, fresh foods, such as berries or lobster, were packaged snugly in convenient square containers. Then, the packages were pressed between refrigerated metal plates under pressure at 50 degrees below zero. Two types of freezing machines were used. The “double belt” freezer consisted of two metal belts that moved through a 15-meter freezing tunnel, while a special salt solution was sprayed on the surfaces of the belts. This double-belt freezer was used only in permanent installations and was soon replaced by the “multiplate” freezer, which was portable and required only 11.5 square meters of floor space compared to the double belt’s 152 square meters.The multiplate freezer also made it possible to apply the technique of quick-freezing to seasonal crops. People were able to transport these freezers easily from one harvesting field to another, where they were used to freeze crops such as peas fresh off the vine. The handy multiplate freezer consisted of an insulated cabinet equipped with refrigerated metal plates. Stacked one above the other, these plates were capable of being opened and closed to receive food products and to compress them with evenly distributed pressure. Each aluminum plate had internal passages through which ammonia flowed and expanded at a temperature of -3.8 degrees Celsius, thus causing the foods to freeze. A major benefit of the new frozen foods was that their taste and vitamin content were not lost. Ordinarily, when food is frozen slowly, ice crystals form, which slowly rupture food cells, thus altering the taste of the food. With quick-freezing, however, the food looks, tastes, and smells like fresh food. Quick-freezing also cuts down on bacteria. Impact During the months between one food harvest and the next, humankind requires trillions of pounds of food to survive. In many parts of the world, an adequate supply of food is available; elsewhere, much food goes to waste and many go hungry. Methods of food preservation such as those developed by Birdseye have done much to help those who cannot obtain proper fresh foods. Preserving perishable foods also means that they will be available in greater quantity and variety all year-round. In all parts of the world, both tropical and arctic delicacies can be eaten in any season of the year. With the rise in popularity of frozen “fast” foods, nutritionists began to study their effect on the human body. Research has shown that fresh is the most beneficial. In an industrial nation with many people, the distribution of fresh commodities is, however, difficult. It may be many decades before scientists know the long-term effects on generations raised primarily on frozen foods.