Drying is an ancient technique that removes water from food to prevent microbe growth.
Food can be dried in the sun, oven, or freezer. Dried foods retain many of their nutrients, can be stored at room temperature, and can be used in their dried form or rehydrated.
Meat, poultry, and fish can be preserved through smoking, another ancient preservation method that dries food while adding colour and flavour.
The food is typically soaked in brine before being exposed to smoke and then refrigerated.
Green vegetables and fruit can be preserved by pickling, a 4000-year-old method which involves soaking them in a hot brine of water, salt, sugar, vinegar, and spices. Pickled foods can be kept in sealed containers for several months without spoiling.
Canning is much like preserving fruit, except that vegetables or sauces are placed in jars with only water, then sealed and immersed in a boiling water bath to kill microbes. These foods last approximately one year.
Like drying, salting pulls the liquid out of foods to inhibit microbe growth. Meat and vegetables can be preserved by pressing them between layers of dry salt and sealing them, or brining them in a liquid solution.
Soaking or injecting meat or poultry with an acidic marinade made from vinegar, lemon juice, soy sauce, or wine can extend its shelf life by limiting microbial growth. Food should be stored in the refrigerator while marinating and cooked within five days.
Ripe fruit can be preserved by cooking it with a high concentration of sugar, sealing it in jars, and boiling the jars in water. This method can be used to make preserves, jams, and jellies, which last for about two years unopened.