Pasteurization and Irradiation

See also Food Preservation Hazardous-Waste Disposal Immunology and Vaccination Parasitology Pasteurization and Irradiation Pathology Sanitary Engineering. 

See also i ricultural Science Food Science Nutrition and Dietetics Pasteurization and Irradiation. 

See also i ricultural Science Animal Breeding and Husbandry Cell and Tissue Engineering Egg Production Fisheries Science Food Preservation Genetically Modified Food Production Genetically Modified Organisms Nutrition and Dietetics Pasteurization and Irradiation Plant Breeding and Propagation. 

See also Cardiology Food Preservation Food Science Gastroenterology Genetically Modified Food Production Geriatrics and Gerontology Pasteurization and Irradiation Pediatric Medicine and Surgery. 

See also Agricultural Science Genetic Engineering Genomics Immunology and Vaccination Pasteurization and Irradiation Pharmacology Virology. 

Pasteurization and irradiation require a balance between minimizing undesirable organisms and retaining desirable characteristics of the food. 

Fellows, P. J. Food Processing Technology Principles and Practice. 3d ed. Boca Raton, Fla. CRC Press, 2009. A comprehensive treatment of the technology that includes separate chapters on pasteurization and irradiation. 

Irradiation. Although no irradiation systems for pasteurization have been approved by the U.S. Food and Dmg Administration, milk can be pasteurized or sterilized by P tays produced by an electron accelerator or y-rays produced by cobalt-60. Bacteria and enzymes in milk are more resistant to irradiation than higher life forms. For pasteurization, 5000—7500 Gy (500,000—750,000 tad) are requited, and for inactivating enzymes at least 20,000 Gy (2,000,000 rad). Much lower radiation, about 70 Gy (7000 tad), causes an off-flavor. A combination of heat treatment and irradiation may prove to be the most acceptable approach. 

Rich sources of the coenzyme forms of the vitamin are liver, kidney, and heart. Many vegetables are also good sources, but cereals are rather low in flavin content. However, current practices of fortification and enrichment of cereal products have made these significant contributors to the daily requirement. Milk, from cows ° and humans, is a good source of the vitamin, but considerable loss can occur from exposure to light during pasteurization and bottling or as a result of irradiation to increase the vitamin D content. 

To put into perspective the chemistry associated with radiation pasteurization and sterilization, the basic chemical processes occurring in the constituents of irradiated meat and poultry are considered. Major constituents include the aqueous phase, the muscle and pigment proteins, the lipid (or fat) phase, and the carbohydrates. Minor constituents include salts, vitamins, and nucleic acids. The implications for assessing the wholesomeness of irradiated products, for gaining additional regulatory approvals, and for optimizing product quality and functionality are also considered. 

The concentration of a stable product in an irradiated food can be expressed using the G-value for either the product or its precursor radical and the absorbed dose. For example, the concentration of a product or products formed from the reaction of either es or OH with a solute in the fluid aqueous phase of a food irradiated to 4.5 kGy would be 1.2 mmol/L. In contrast to other pasteurization and sterilization treatments, irradiation produces a small and generally predictable amount of chemical change. 

This occurred after sanitation in dairies had already reached a high level. In the future, other foods can be made much safer by new pasteurizing technologies, such as in-shell pasteurization of eggs, and irradiation of ground beef Just as with milk, these new technologies. should be implemented in addition to good sanitation, not as a replacement for it. 

For irradiation, the ionizing radiation used are gamma rays, generated from the decay of radioisotopes cobalt 60 or cesium 137, X rays, and electrons, the latter two generated by machines for such purposes. The operators of equipment involving ionizing radiation need to be protected from its effects. The ability subsequently to pasteurize or irradiate food should not compensate for best practices to minimize contamination of food before treatment. Moreover, treated food also needs to be protected from subsequent contamination. 

In the United States, millions become ill and as many as 5,000 die annually from food-borne infections, most of which could have been prevented by pasteurization or irradiation. The problem is more acute in the developing world. 

Food irradiation. Technology for controlling food spoilage and eliminating pathogens through exposure to ionizing radiation, usually y-rays. The result is similar to conventional pasteurization and is often called cold pasteurization or irradiation pasteurization . 

Torres, Z. Arias, F. In Irradiation to Control Vibrio Infection from Consumption of Raw Seafood and Fresh Produce, International Atomic Energy Agency Vienna, 2001, 31 pp. Anon. Irradiation (Cold Pasteurization) of Molluscan Shellfish. National Fisheries Institute News Release 99-41. June 25, 1999 (available online at www.nfi.org/hdlines). 

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