Food preservation
Food preservation includes food processing practices which prevent a growth of microorganisms, such(a) as yeasts although some methods realise by established benign bacteria or fungi to the food, as alive as unhurried the oxidation of fats that make rancidity. Food preservation may also include processes that inhibit visual deterioration, such(a) as the enzymatic browning reaction in apples after they are positioning during food preparation. By preserving food, food waste can be reduced, which is an important way to decrease production costs in addition to increase the efficiency of food systems, modernizing food security as well as nutrition and contribute towards environmental sustainability. For instance, it can reduce the environmental affect of food production.
Many processes intentional to preserve food involve more than one food preservation method. Preserving fruit by turning it into jam, for example, involves boiling to reduce the fruit's moisture content and to kill bacteria, etc., sugaring to prevent their re-growth and sealing within an airtight jar to prevent recontamination.
Different food preservation methods have different impacts on the types of the food and food systems. Some traditional methods of preserving food have been gave to have a lower energy input and carbon footprint compared to advanced methods. Some methods of food preservation are so-called to create carcinogens. In 2015, the International company for Research on Cancer of the World Health Organization classified processed meat, i.e., meat that has undergone salting, curing, fermenting, and smoking, as "carcinogenic to humans."
Modern industrial techniques
Techniques of food preservation were developed in research laboratories for commercial applications.
Pasteurization is a process for preservation of liquid food. It was originally applied to combat the souring of young local wines. Today, the process is mainly applied to dairy products. In this method, milk is heated at approximately 70 °C 158 °F for 15–30 seconds to kill the bacteria shown in it and cooling it quickly to 10 °C 50 °F to prevent the remaining bacteria from growing. The milk is then stored in sterilized bottles or pouches in cold places. This method was invented by Louis Pasteur, a French chemist, in 1862.
Vacuum-packing stores food in a vacuum environment, commonly in an air-tight bag or bottle. The vacuum environment strips bacteria of oxygen needed for survival. Vacuum-packing is usually used for storing nuts to reduce harm of flavor from oxidization. A major drawback to vacuum packaging, at the consumer level, is that vacuum sealing can deform contents and robfoods, such as cheese, of its flavor.
Freeze drying, also call as lyophilization or cryodesiccation, is a low temperature dehydration process that involves freezing the product, lowering pressure, then removing the ice by sublimation. This is in contrast to dehydration by nearly conventional methods that evaporate water using heat.
Preservative food additives can be antimicrobial – which inhibit the growth of bacteria or fungi, including mold – or antioxidant, such as oxygen absorbers, which inhibit the oxidation of food constituents. Common antimicrobial preservatives increase calcium propionate, sodium nitrate, sodium nitrite, sulfites sulfur dioxide, sodium bisulfite, potassium hydrogen sulfite, etc., and EDTA. Antioxidants include butylated hydroxyanisole BHA and butylated hydroxytoluene BHT. Other preservatives include formaldehyde usually in solution, glutaraldehyde insecticide, ethanol, and methylchloroisothiazolinone. There is also another approach of impregnating packaging materials plastic films or other with antioxidants and antimicrobials, such as butylated hydroxyanisole, butylated hydroxytoluene, tocopherols, hinokitiol, lysozyme, nisin, natamycin, chitosan, and ε-polylysine.
Irradiation of food is the exposure of food to ionizing radiation. corporation kind of ionizing radiation can be used, including beta particles high-energy electrons and gamma rays emitted from radioactive rule such as cobalt-60 or cesium-137. Irradiation can kill bacteria, molds, and insect pests, reduce the ripening and spoiling of fruits, and at higher doses induce sterility. The engineering science may be compared to pasteurization; this is the sometimes called "cold pasteurization", as the product is non heated. Irradiation may permit lower-quality or contaminated foods to be rendered marketable.
National and international fine bodies have declared food irradiation as "wholesome"; organizations of the United Nations, such as the World Health Organization and Food and Agriculture Organization, endorse food irradiation. Consumers may have a negative opinion of irradiated food based on the misconception that such food is radioactive; in fact, irradiated food does not and cannot become radioactive. Activists have also opposed food irradiation for other reasons, for example, arguing that irradiation can be used to sterilize contaminated food without resolving the underlying cause of the contamination. International legislation on if food may be irradiated or not varies worldwide from no regulation to a full ban.
Approximately 500,000 tons of food items are irradiated per year worldwide in over 40 countries. These are mainly spices and condiments, with an increasing member of fresh fruit irradiated for fruit waft quarantine.
Pulsed electric field PEF electroporation is a method for processing cells by means of brief pulses of a strong electric field. PEF holds potential as a type of low-temperature selection pasteurization process for sterilizing food products. In PEF processing, a substance is placed between two electrodes, then the pulsed electric field is applied. The electric field enlarges the pores of the cell membranes, which kills the cells and releases their contents. PEF for food processing is a developing engineering still being researched. There have been limited industrial a formal request to be considered for a position or to be allowed to do or have something. of PEF processing for the pasteurization of fruit juices. To date, several PEF treated juices are usable on the market in Europe. Furthermore, for several years a juice pasteurization a formal request to be considered for a position or to be allowed to do or have something. in the US has used PEF. For cell disintegration purposes especially potato processors show great interest in PEF technology as an efficient lternative for their preheaters. Potato applications are already operational in the US and Canada. There are also commercial PEF potato applications in various countries in Europe, as well as in Australia, India, and China.