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Preserving
People have been preserving food for later use for more than 2,000 years. The primary methods in the past and today are salting, canning, drying, smoking, pickling, fermenting, cold storage and freezing.

Early food preservation including simple “banking” pits – holes dug in the ground that were lined with wood, straw and/or leaves to create a barrier between the soil and the food. Caves were also used for secure food storage against the environment.

Canning
Canning refers to sealing food in containers, both commercially and at home. The method of cooking and then preserving foods by sealing them in containers, often in bank pits, is ancient. In the late 18th century, France offered money to anyone who could develop a method of preserving food for soldiers. After years of experimentation, Nicholas Appert successfully preserved food thoroughly cooked in a water bath in sealed glass jars, creating portable, potable food. A year later an Englishman, Peter Durand, received a patent for the same process but with tin containers as well as glass. Although containers had previously been used for food storage, it was the addition of the water bath and the sealed container that was a breakthrough. Arctic explorer William Edward Parry included canned foods in his 1819 expedition supplies. The bodies of John Franklin’s last 1847 Arctic expedition were discovered in the 80s and corpse analysis in the 90s revealed they were suffering from lead poisoning from the lead seals in food cans. Food cans manufactured in the U.S. have not used lead solder since the mid-1990s, but canned food products from other countries could contain lead solder.

Westward expansion of U.S. settlers in the mid-19th century drove the demand for streamlining tin can production, and Civil War soldiers used canned food. Critical factors for canning techniques commercially and at home are sufficient temperature, sterile containers and an effective seal. John Mason patented a glass jar with a screw cap to seal it in 1858. Presently, home canning has decreased, but in a 1996 survey, 56 percent of all U.S. households said they had canned in the past, of which 28 percent had canned within the last two years. Although pressure canners are considered safer in safeguarding a proper seal to prevent illness and death from the growth of bacteria – including botulism bacteria – many home canners still use the conventional water bath.

Drying (A.K.A. Dehydrating)
Drying occurs naturally and easily when food is left in the sun, or on the vine. Some foods like apples and tomatoes are cut into smaller pieces to ensure uniform moisture evaporation and others, like herbs, are left whole and on the stem to dry. Low humidity, heat and air circulation are the keys to prevent mold from growing. Meats and fish can be dried to the point of extreme desiccation, resulting in jerky. Once dried, foods can keep for up to a year in a cool and dry environment. Dried foods are sometimes additionally smoked or salted.

Smoking
Smoking is commonly used in combination with salting. The ancient Mayans preserved chilies, fish and meat by smoking. There are two basic forms of smoking – hot and cold. Hot smoking requires appropriate temperatures to cook the fish or meat, and cold smoking merely imparts flavor but does not cook the food.

Freezing
Although frozen foods are quite stable, the flavor and texture may change. Natural and artificial freezing techniques have been in practice since ancient times. Clarence Birdseye is generally crediting with creating the techniques for the modern commercial market of frozen foods in 1924. Freeze-drying is like combining dehydration and freezing, requiring food to be reconstituted with water. This method is thought to have originated in Peru where the potato has been cultivated for 9 thousand years. The potato harvest is spread on the ground at high altitudes and exposed to extreme cold then pressure is applied to remove all moisture. Freeze-dried coffee was developed in the 1930s and the U.S. space program used freezedried foods because of their light weight and stability.