Food storage



Food storage is both a traditional domestic skill and is important industrially. Food is stored by almost every human society and by many animals. Storing of food has several main purposes:


 * preparation for periods of scarcity or famine
 * taking advantage of short term surplus of food as at harvest time
 * enabling a better balanced diet throughout the year
 * preparing for special events and celebrations
 * planning for catastrophe or emergency
 * protection against predators or others

Grain
Grain is stored in rigid sealed containers to prevent ingress of moisture or attack by vermin. For domestic quantities metal cans are used (in the USA the smallest practical grain storage uses closed-top #10 metal cans).

Storage in grain sacks is not effective. Mold and pests destroy a 25kg cloth sack of grain in a year &mdash; even if stored off the ground in a dry area. On the ground or damp concrete, the time is as little as three days, and the grain might have to be dried before it can be milled. Food stored under unsuitable conditions should not be purchased or used because of risk of spoilage. To test whether grain is still good, sprout some. If it sprouts, it is still good, but if not, it should not be eaten. It may take up to a week for grains to sprout. When in doubt, throw it out.

Meat
Unpreserved meat has only a relatively short life in storage. Pork should be eaten within one day but beef and venison improve with up to 5 days storage in a cold room. Dry aging techniques are sometimes used to tenderize specialty gourmet meats by hanging them in carefully controlled environments for up to 21 days. Semi-dried meats like salamis and country style hams are processed first with salt, smoke, sugar, or acid, or other "cures" then hung in cool dry storage for extended periods, sometimes exceeding a year.

Fish and shellfish
It is unsafe to store fish or shellfish without preservation. Fresh shellfish and whitefish should be eaten within a few hours of harvesting..

Use of stored food
Guidance for surviving emergency conditions in many parts of the world recommends acquiring a limited range of grains (usually corn, wheat and beans supplemented with oil, dried milk, and vitamins) and then preparing them in simple ways for long-term survival. This may not be wholly practical because of appetite exhaustion. An unvarying diet of staples prepared in the same way causes most people to eat less. Garden-grown fruits and vegetables, freeze-dried, canned, and fresh-baked foods are essential supplements to such a program.

A special virtue of home stored foods is their low cost. Costs of dry bulk foods (before preparation) are often less than 1/4 of convenience and fresh foods purchased at supermarkets.

Commercial food storage
Grain and beans are stored in tall grain elevators, almost always at a rail head near the point of production. The grain is shipped to a final user in hopper cars. In the former Soviet Union, where harvest was poorly controlled, grain was often irradiated at the point of production to suppress mold and insects. In the U.S., threshing and drying is performed in the field, and transport is nearly sterile and in large containers that effectively suppress pest access, so irradiation is not required. At any given time, the U.S. usually has about two weeks of stored grains.

Fresh fruits and vegetables are either packed in plastic cups in cardboard boxes for fresh premium markets, or placed in large plastic tubs for sauce and soup processors. Fruits and vegetables are usually refrigerated at the earliest possible moment, and even so have a shelf life of two weeks or less.

There is a thriving but small market in bulk vegetables and convenience foods for campers.

In the USA meat animals are usually transported live, slaughtered at a major distribution point, hung and transported for two days to a week in refrigerated rail cars, and then butchered and sold locally. Before refrigerated rail cars, meat had to be transported live, and this placed its cost so high that only farmers and the wealthy could afford it every day. In Europe much meat is transported live and slaughtered close to the point of sale. In much of Africa and Asia most meat is for local populations is reared, slaughtered and eaten locally which is believed to be much less stressful for the animals involved and requires very little meat storage capacity. In Australia and New Zealand where a large proportion of meat production is for export meat is stored in very large freezer plants before being shipped overseas in freezer ships.