Foods that can be safely stored at room temperature, or "on the shelf," are called "shelf stable." These non-perishable products include jerky, country hams, canned and bottled foods, rice, pasta, flour, sugar, spices, oils, and foods processed in aseptic or retort packages and other products that do not require refrigeration until after opening. Not all canned goods are shelf stable. Some canned food, such as some canned ham and seafood, are not safe at room temperature. These will be labeled "Keep Refrigerated."

In order to be shelf stable, perishable food must be treated by heat and/or dried to destroy foodborne microorganisms that can cause illness or spoil food. Food can be packaged in sterile, airtight containers. All foods eventually spoil if not preserved.

Drying is the world's oldest and most common method of food preservation. Drying technology is both simple and readily available to most of the world's culture. Examples of dried foods are jerky, powdered milk, dried beans and peas, potatoes in a box, dried fruits and vegetables, pasta, and rice. Canning technology is just over 200 years old, and freezing became practical only during this century as electricity became increasingly available.

Two types of natural drying occur in open air - solar (sun) drying and "adibatic" (shade) drying.

Adibatic drying occurs without heat.

Solar drying can be as simple as spreading a layer of fruit or vegetables in the sun, and it can also take place in a special container that catches and captures the sun's heat. These types of drying are used mainly for high-acid fruits and vegetables, such as apricots, tomatoes, and grapes (to make raisins). (Perishable, low-acid food such as meat and poultry may not be dried by these methods. See below.)

Drying from an artificial heat source is done by placing food in either a warm oven or a food dehydrator. Follow the appliance's directions carefully to ensure the food is dried safety.

There have been illnesses from Salmonella and E. coli O157:H7 from homemade jerky that raise questions about the safety of traditional drying methods for making beef and venison jerky.

To make jerky safely at home, the USDA Meat and Poultry Hotline recommends that consumers cook all meat to 160 °F and all poultry to 165 °F before they begin the dehydrating process. This cooking step ensures that any bacteria present will be destroyed. Most dehydrator instructions do not include this step, and a dehydrator may not reach high enough temperatures to heat meat and poultry to these safe temperatures.

After heating meat to 160 °F and poultry to 165 °F, maintain a constant dehydrator temperature of 130 to 140 °F during the drying process. This is important because the process must be fast enough to dry food before it becomes unsafe; and it must remove enough water so that microorganisms are unable to multiply.

The danger in dehydrating meat and poultry without cooking it to a safe temperature first is that the dehydrator will not heat meat to 160 °F or poultry to 165 °F — temperatures at which bacteria are destroyed — before the jerky dries. Bacteria that are not destroyed by cooking can survive dehydrating and cause foodborne illness.

In a dehydrator or low-temperature oven, most of the heat is absorbed by evaporating moisture. Thus, the temperature of the meat does not begin to rise until most of the moisture has evaporated. Therefore, when the dried meat temperature finally begins to rise, the bacteria have become more heat resistant and are more likely to survive. If these surviving bacteria are pathogenic (types that cause foodborne diseases), anyone who consumes the jerky can get a foodborne illness.

Yes. Commercially produced jerky is monitored in federally inspected plants by inspectors from the U.S. Department of Agriculture's Food Safety and Inspection Service. Products made into jerky may be cured or uncured, dried, smoked or unsmoked, and air or oven dried.

The process of making jerky at home can vary, so USDA recommends a shorter shelf life for homemade jerky than for jerky made under Federal inspection.

Salt binds or removes water so that it does not enable the growth of microorganisms. It is a food additive that has been used for thousands of years. Until canning was invented, salt was a critical food preservation item. In Colonial America, food preservation required 40 pounds of salt per person per year. Even though we don't need that much salt today, salt is still used to preserve or cure such foods as country hams, bacon, frankfurters, and corned beef.

Dry-cured hams are shelf stable. These uncooked hams are safe when stored at room temperature because they contain so little water that bacteria can't multiply in them.

In dry curing — the process used to make country hams and prosciutto, fresh meat is rubbed with a dry-cure mixture of salt and other ingredients. Dry curing produces a salty product. Since dry curing draws out moisture, it reduces ham weight by at least 18% (usually 20 to 25%). This results in a more concentrated ham flavor. Dry-cured hams may be aged from a few weeks to more than a year. Six months is the traditional process, but may be shortened according to the aging temperature. Country hams may not be injected with curing solutions or placed in curing solutions, but they may be smoked. In 1992, FSIS approved a Trichina-treatment method that permits substituting up to half of the sodium chloride with potassium chloride to lower sodium levels.

Some dry sausages are shelf stable. Dry sausages include: Soppersata (a name of a salami); Salami; air-dried Pepperoni; Cerevelat; Lola, Lolita, and Lyons sausage (mildly seasoned pork with garlic); and Genoa salami (an Italian sausage usually made from pork, but might contain a small amount of beef and be moistened with wine or grape juice and seasoned with garlic). Dry sausages require more production time than other types of sausage and result in a concentrated form of meat. If the product is shelf stable and ready-to-eat, the product is not required to have a safe handling statement, cooking directions, or a "Keep Refrigerated" statement. For more information about sausages, see the document "Sausages and Food Safety" at www.fsis.usda.gov.

Pasteurized, dried egg products can be shelf stable, with or without added ingredients. Most are distributed in bulk quantities and are used by food manufacturers (noodle makers, bakers, etc.) or by institutional food service (hotels, hospitals, nursing homes, etc.).

USDA Dried Egg Mix — a dried blend of whole eggs, nonfat dry milk, soybean oil, and a small amount of salt — is distributed to schools and to needy families. This is a government commodity not usually available commercially. To reconstitute, blend 1/4 cup of the mix with 1/4 cup water to make one "egg." The reconstituted mix requires cooking. Pasteurized, dried egg whites are also available in stores that sell cake baking and decorating supplies. They do not require cooking.

Yes, freeze-dried foods are shelf stable. Freeze-drying is a commercial process that can be used to preserve such food as dried soup mixes, instant coffee, fruits, and vegetables. To freeze dry, frozen food is placed in a special vacuum cabinet. There, ice changes from a solid state directly to a vapor state without first becoming a liquid. This process, whereby water escapes from the food, is called "sublimation." To use freeze-dried foods, they must be rehydrated with water. They retain their original flavor, texture, and nutrients, but must be packaged in moisture-proof, hermetically sealed containers.