Food preservationFrom Wikipedia, the free encyclopediaFood preservation usually involves preventing the growth of bacteria, fungi (such as yeasts), or other micro-organisms (although some methods work by introducing benign bacteria or fungi to the food), as well as retarding the oxidation of fats that cause rancidity. Food preservation may also include processes that inhibit visual deterioration, such as the enzymatic browning reaction in apples after they are cut during food preparation.Many processes designed to preserve food will involve a number of food preservation methods. Preserving fruit by turning it into jam, for example, involves boiling (to reduce the fruits moisture content and to kill bacteria, etc.), sugaring (to prevent their re-growth) and sealing within an airtight jar (to prevent recontamination). Some traditional methods of preserving food have been shown to have a lower energy input and carbon footprint, when compared to modern methods.[1]Maintaining or creating nutritional value, texture and flavor is an important aspect of food preservation, although, historically, some methods drastically altered the character of the food being preserved. In many cases these changes have come to be seen as desirable qualities cheese, yogurt and pickled onions being common examples.Contents [hide] 1 Traditional techniques1.1 Drying1.2 Cooling1.3 Freezing1.4 Heating1.5 Salt1.6 Sugar1.7 Smoking1.8 Pickling1.9 Lye1.10 Canning1.11 Jellying1.12 Jugging1.13 Burial2 Curing2.1 Fermentation3 Industrial/modern techniques3.1 Pasteurization3.2 Vacuum packing3.3 Artificial food additives3.4 Irradiation3.5 Pulsed electric field electroporation3.6 Modified atmosphere3.7 Nonthermal plasma3.8 High-pressure food preservation3.9 Biopreservation3.10 Hurdle technology4 See also5 Notes6 References7 External linksTraditional techniques[edit]New techniques of food preservation became available to the home chef from the dawn of agriculture until the Industrial Revolution.Drying[edit]Main article: Drying (food)Drying is one of the oldest techniques used to hamper the decomposition of food products. As early as 12,000 B.C., Middle Eastern and Oriental cultures were drying foods using the power of the sun. Vegetables and fruit are naturally dried by the sun and wind, but in the Middle Ages, "still houses" were built in areas that did not have enough sunlight to dry things. A fire would be built inside the building to provide the heat to dry the various fruits, vegetables, and herbs.[2]Cooling[edit]Main article: RefrigerationCooling preserves foods by slowing down the growth and reproduction of micro-organisms and the action of enzymes that cause food to rot. The introduction of commercial and domestic refrigerators drastically improved the diets of many in the Western world by allowing foods such as fresh fruit, salads, and dairy products to be stored safely for longer periods, particularly during warm weather.Freezing[edit]Pictorial guide inside a freezer doorMain article: Frozen foodFreezing is also one of the most commonly used processes, both commercially and domestically, for preserving a very wide range of foods, including prepared foods that would not have required freezing in their unprepared state. For example, potato waffles are stored in the freezer, but potatoes themselves require only a cool dark place to ensure many months' storage. Cold stores provide large-volume, long-term storage for strategic food stocks held in case of national emergency in many countries.Heating[edit]Heating to temperatures which are sufficient to kill microorganisms is a method used with perpetual stews. Milk is also boiled before storing