Pickling is the process of preserving, even extending the lifespan of food by either anaerobic fermentation in brine or immersion in vinegar. The resulting food is called a pickle or "pickled" and can preserve perishable foods for months. Antimicrobial herbs and spices, such as mustard seed, garlic, cinnamon or clove, are often added. Natural fermentation at room temperature by lactic acid bacteria, produces the required acidity. Other pickles are made by placing vegetables in vinegar. Unlike the canning process, pickling (which includes fermentation) does not require that the food be completely sterile before it is sealed. The acidity or salinity of the solution, the temperature of fermentation and the exclusion of oxygen determine which microorganisms dominate and determine the flavour of the end product.
Dehydration is the process of removing water or moisture from a food product. Dehydration is a process by which many types of food can be preserved for indefinite period by extracting the moisture, thereby inhibiting the growth of micro-organisms. Dehydration equipment varies in form with different food products and includes tunnel driers, cabinet driers and vacuum driers depending upon food and capacity to be dehydrated.
Canning is a method of preserving food in which the food contents are processed and sealed in an airtight container. When fruits or vegetables are canned they do not lose any of their nutrients. This is because the decomposition process is halted until the can is opened again. This means that if they are packaged soon after picking then they can contain higher levels of nutrients than fresh fruit and vegetables brought from a grocery store. Canned fruits and vegetables are very convenient because they are available throughout the year regardless of the season. Canning provides a shelf life typically ranging from one to two years, although under specific circumstances it can be much longer without the need for refrigeration.
Ready to eat food are foods that have been cooked and then packed.