Advances in Food Preservation Lead to New Products, New Markets, and New Sources of Food Production

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Advances in Food Preservation Lead to New Products, New Markets, and New Sources of Food Production

Overview

At the beginning of the nineteenth century people relied on the same methods of preserving fresh food that their ancestors had used thousands of years before: drying, fermentation, salting, and chilling. By the end of the century a series of innovations had revolutionized food preservation, leading to new products, new markets, and new sources of food production.

Background

In order to survive primitive people had to preserve their precarious supply of food for as long as possible. One of the earliest preservation techniques was to dry meat, fish, or fruit in the sun or over a fire. Smoke added flavor to an often monotonous diet and also slowed spoilage. The ancient Egyptians and Romans stored wheat and barley in silos, where hot, dry air kept the grain usable for years. They used fermentation, a process activated by certain bacteria, to make wine and bread. Many cultures fermented dairy products into yogurt and cheese and fermented (or cured) meat into sausage. Salt, which suppresses the growth of harmful bacteria in addition to adding flavor, was another traditional preservative, particularly for fish and meat. Freezing or chilling food in natural refrigerants such as ice and snow also inhibited the growth of bacteria. In warmer climates food was stored in caves or underground pits to slow the rate of spoilage.

Drying preserves food because yeasts, molds, and bacteria cannot grow without sufficient moisture. Several new methods of artificially drying food, or dehydration, were invented in Europe at the end of the eighteenth century. One called for immersing vegetables in hot water before drying them in hot air, a technique later used for drying meat. Small drying rooms originated in central Europe around this time. They were heated by a stove and filled with racks of drying trays. In the early 1800s a French inventor named Masson tried cutting vegetables into thin slices before drying them. His partner, Chollet, invented a mechanical warm air system for drying the vegetables, which were then compressed under high pressure. According to contemporary accounts the dried vegetables retained their flavor, and their condensed size simplified storage and transportation.

An English farmer, Downes Edwards, patented his process for preserving potatoes and other vegetables in 1841. He extruded cooked potatoes through a perforated disk, then dried the resulting "rice" on trays in gentle heat. A. E. Spawn, an American inventor, patented the first mechanized dehydration machine in 1886. Named the "Climax Fruit Evaporator," it consisted of trays of fruit that revolved slowly in an upward current of hot air.

Dehydration is the easiest way to preserve and store milk, one of the most nutritious foods and also one of the fastest to spoil. Milk was dried in the sun as early as the 1200s, when it was carried by Kublai Khan's soldiers as part of their rations. In the 1820s a more practical method was invented by Nicolas Appert (1749-1841). Appert also dehydrated meat and vegetable broth into solid cubes that could be reconstituted with water. Malted milk, a powdered combination of whole milk, ground barley malt, and wheat flour, was invented in Wisconsin in the 1880s. It quickly became popular as a sweet and nutritious drink.

Fermentation, the mechanism that creates yogurt, cheese, and butter, is so simple that it has changed little over the centuries. Scalded milk is exposed to special bacteria that convert lactose into lactic acid, resulting in a solid and less perishable product. Around the middle of the nineteenth century butter and cheese production began to shift away from farms as factory production made it possible to control environmental conditions more tightly and to take advantage of advances in refrigeration and transportation. The dry curing method of sausage-making perfected by the Romans became less common as other methods of preserving meat—especially refrigeration—became available in the second half of the century.

The most important advance in modern food preservation was canning. It was invented by means of trial and error and careful observation by Nicolas Appert, who opened his first factory in 1797. His three-step process is the same one used for home canning today. The food was placed in wide-necked bottles, sealed tightly, then heated in hot water. Appert theorized that heating destroyed or neutralized the "ferments" that make food spoil.

Appert's process, which he described in a pamphlet in 1810, was copied throughout Europe and the United States. Peter Durand obtained an English patent for preserving food in tin containers that same year. Soon after, Bryan Donkin and John Hall opened their own canning factory, and by 1814 they were shipping food to British military bases in tin cans, which had become the preferred food containers. Thomas Kessett received the first U.S. patent for canning and tin containers in 1825. Around that time the first sardine-canning factory was built on the coast of France, and other factories were constructed in Germany and Portugal.

Louis Pasteur's (1822-1895) research on spontaneous generation in the 1860s provided the scientific rationale underlying Appert's process. He found that heat kills microorganisms that cause food and beverages to spoil. He applied his research to the wine, vinegar, and beer industries, making it possible to transport these products without risk of deterioration. In the late 1800s John Tyndall (1820-1895), a British physicist, took Pasteur's heating process one step further. He heated food for 45 to 60 minutes to kill the active bacteria, then chilled it for 24 hours to kill any dormant bacteria spores. Milk pasteurization, introduced in the United States at the end of the nineteenth century, requires that milk be heated either to 145 degrees F (63 degrees C) for 30 minutes or to 161 degrees F (72 degrees C) for 15 seconds. Pasteurization kills disease-causing bacteria as well as those that lead to spoilage.

In 1856 Gail Borden (1801-1874), an American businessman who wanted to eradicate childhood illnesses caused by contaminated milk, patented a process for making condensed milk. Milk was heated in a vacuum pan that prevented outside air from entering, a device invented by the Shakers to condense fruit juice. There was not much demand for condensed milk until the Civil War (1861-65), when it became an important provision for soldiers.

Refrigeration preserves food by slowing the rate of growth of the bacteria. Several kinds of mechanical refrigeration were invented in the nineteen century. John Gorrie (1803-1855), an American physician, built the first ice-making and air-conditioning machine in 1844 but never found adequate financial backing for his invention. Around the same time Alexander Twining (1801-1884) patented an ice-making machine and opened the first factory to manufacture ice by vapor compression. The U.S. mechanical icemaking industry started to flourish in the 1870s, thanks to entrepreneurs such as Daniel Holden (1837-1924) and David Boyle (1837-1891). With both artificial and natural ice readily available, iceboxes became more common in American homes and factories, although they were not accepted in Great Britain and Europe. The first cold-storage warehouse was built in New York in 1865, followed by others near piers and railroad lines in major cities around the world. Refrigerated boxcars and steamships carried meat and produce from farms to cities and from one country to another. Keeping food cold during transport was especially important in the meat-packing industry. Meatpackers such as W. James Harrison (1816-1893), Gustavus Swift (1839-1903), and Philip Armour (1832-1901) found that it was cheaper to send frozen meat from centrally located slaughterhouses than to ship cattle to slaughterhouses near customers.

Impact

Advances in food preservation during the nineteenth century increased the healthfulness and variety of food available year-round. At the same time new food-processing technologies turned the pursuit of a constant supply of food from a small-scale, domestic activity to a large-scale, commercial industry, which led to further changes in people's lives at home and at work.

Among the first consumers of preserved food in the early 1800s were sailors, soldiers, and explorers, who were prone to malnutrition, especially scurvy, during long voyages without fresh food. Dried, compressed vegetables, in addition to their portability, minimized scurvy among soldiers in wartime and among miners in the Alaskan and Australian gold rushes. The invention of canning, refrigeration, and pasteurization prevented the loss of the valuable protein and vitamins in perishable foods and reduced the prevalence of some bacterial diseases. For those who could afford them, preserved foods made it easier to enjoy a nutritious, high-protein diet, regardless of season or location.

Changes in food preservation during the nineteenth century were linked to larger trends associated with the Industrial Revolution. Workers in urban manufacturing centers bought food instead of producing it themselves. Freed from the labor of food production and preservation, they were able to specialize in industrial work and were available for construction projects that required large work forces, such as building ships, trains, roads, and bridges. Thousands of additional jobs were created in the food preservation industry itself. This prosperous and growing urban market, in turn, encouraged farmers to specialize in items such as meat, eggs, dairy products, and fruit, to increase production, and to invest in new technology. Larger markets, product specialization, and the high cost of processing plants and refrigerated transport promoted consolidation in the food industry, as exemplified by the empires of Borden, Swift, and Armour. Faster transportation and improvements in refrigeration and canning meant that farms could be located farther from population centers, even as far away as Australia and Argentina. While cities became more densely populated, new farming areas were settled and cultivated. The result was the end of a predominantly farming economy and the beginning of a predominately manufacturing economy.

LINDSAY EVANS