while higher-dose applications can cost as much as us$0.20/lbs. electron beam treatment of electron beams is created as a result of high energy electrons in an accelerator that generates electrons accelerated to 99% the speed of light. this system uses electrical energy and can be powered on and off. the high power correlates with a higher throughput and lower unit cost, but electron beams have low dose uniformity and a penetration depth of centimeters. therefore, electron beam treatment works for products that have low thickness. irradiated guava: spring valley fruits, mexico x-ray x-rays are produced by bombardment of dense target material with high-energy accelerated electrons(this process is known as bremsstrahlung-conversion), giving rise to a continuous energy spectrum. heavy metals, such as tantalum and tungsten, are used because of their high atomic numbers and high melting temperatures. tantalum is usually preferred versus tungsten for industrial, large-area, high-power targets because it is more workable than tungsten and has a higher threshold energy for induced reactions. like electron beams, x-rays do not require the use of radioactive materials and can be turned off when not in use. x-rays have high penetration depths and high dose uniformity but they are a very expensive source of irradiation as only 8% of the incident energy is converted into x-rays. uv-c uv-c does not penetrate as deeply as other methods. as such, its direct antimicrobial effect is limited to the surface only. its dna damage effect produces cyclobutane-type pyrimidine dimers. besides the direct effects, uv-c also induces resistance even against pathogens not yet inoculated. some of this induced resistance is understood, being the result of temporary inactivation of self-degradation enzymes like polygalacturonase and increased expression of enzymes associated with cell wall repair. cost irradiation is a capital-intensive technology requiring a substantial initial investment, ranging from $1 million to $5 million. in the case of large research or contract irradiation facilities, major capital costs include a radiation source, hardware (irradiator, totes and conveyors, control systems, and other auxiliary equipment), land (1 to 1.5 acres), radiation shield, and warehouse. operating costs include salaries (for fixed and variable labor), utilities, maintenance, taxes/insurance, cobalt-60 replenishment, general utilities, and miscellaneous operating costs. perishable food items, like fruits, vegetables and meats would still require to be handled in the cold chain, so all other supply chain costs remain the same. food manufacturers have not embraced food irradiation because the market does not support the increased price of irradiated foods, and because of potential consumer backlash due to irradiated foods. the cost of food irradiation is influenced by dose requirements, the food's tolerance of radiation, handling conditions, i.e., packaging and stacking requirements, construction costs, financing arrangements, and other variables particular to the situation. state of the industry irradiation has been approved by many countries. for example, in the u.s. and canada, food irradiation has existed for decades. food irradiation is used commercially and volumes are in general increasing at a slow rate, even in the european union where all member countries allow the irradiation of dried herbs spices and vegetable seasonings, but only a few allow other foods to be sold as irradiated. although there are some consumers who choose not to purchase irradiated food, a sufficient market has existed for retailers to have continuously stocked irradiated products for years. when labeled irradiated food is offered for retail sale, consumers buy it and re-purchase it, indicating a market for irradiated foods, although there is a continuing need for consumer education. food scientists have concluded that any fresh or frozen food undergoing irradiation at specified doses is safe to consume, with some 60 countries using irradiation to maintain quality in their food supply. radurization risks the following risks can be mentioned in regards to radurization: it is impossible guarantee the complete removal of germs even at high doses. while irradiation removes germs which mark food spoilage, it also may cause damage or loss of vitamins and proteins. additionally it may cause production of potentially cancerogenic reactive radicals. standards and regulations the codex alimentarius represents the global standard for irradiation of food, in particular under the wto-agreement. regardless of treatment source, all processing facilities must adhere to safety standards set by the international atomic energy agency (iaea), codex code of practice for the radiation processing of food, nuclear regulatory commission (nrc), and the international organization for standardization (iso). more specifically, iso 14470 and iso 9001 provide in-depth information regarding safety in irradiation facilities. all commercial irradiation facilities contain safety systems which are designed to prevent exposure of personnel to radiation. the radiation source is constantly shielded by water, concrete, or metal. irradiation facilities are designed with overlapping layers of protection, interlocks, and safeguards to prevent accidental radiation exposure. meltdowns are unlikely to occur due to low heat production from sources used. labeling the radura symbol, as required by u.s. food and drug administration regulations to show a food has been treated with ionizing radiation. the provisions of the codex alimentarius are that any "first generation" product must be labeled "irradiated" as any product derived directly from an irradiated raw material; for ingredients the provision is that even the last molecule of an irradiated ingredient must be listed with the ingredients even in cases where the unirradiated ingredient does not appear on the label. the radura-logo is optional; several countries use a graphical version that differs from the codex-version. the suggested rules for labeling is published at codex-stan – 1 (2005), and includes the usage of the radura symbol for all products that contain irradiated foods. the radura symbol is not a designator of quality. the amount of pathogens remaining is based upon dose and the original content and the dose applied can vary on a product by product basis. the european union follows the codex's provision to label irradiated ingredients down to the last molecule of irradiated food. the european union does not provide for the use of the radura logo and relies exclusively on labeling by the appropriate phrases in the respective languages of the member states. the european union enforces its irradiation labeling laws by requiring its member countries to perform tests on a cross section of food items in the market-place and to report to the european commission. the results are published annually on eur-lex. the us defines irradiated foods as foods in which the irradiation causes a material change in the food, or a material change in the consequences that may result from the use of the food. therefore, food that is processed as an ingredient by a restaurant or food processor is exempt from the labeling requirement in the us. all irradiated foods must include a prominent radura symbol followed in addition to the statement "treated with irradiation" or "treated by irradiation. bulk foods must be individually labeled with the symbol and statement or, alternatively, the radura and statement should be located next to the sale container. packaging under section 409 of the federal food, drug, and cosmetic act, irradiation of prepackaged foods requires premarket approval for not only the irradiation source for a specific food but also for the food packaging material. approved packaging materials include various plastic films, yet does not cover a variety of polymers and adhesive based materials that have been found to meet specific standards. the lack of packaging material approval limits manufacturers production and expansion of irradiated prepackaged foods. approved materials by fda for irradiation according to 21 cfr 179.45: material paper (kraft) paper (glassine) paperboard cellophane (coated) polyolefin film polyestyrene film nylon-6 vegetable parchment nylon 11 irradiation (kgy) .05 10 10 10 10 10 10 60 60 food safety in 2003, the codex alimentarius removed any upper dose limit for food irradiation as well as clearances for specific foods, declaring that all are safe to irradiate. countries such as pakistan and brazil have adopted the codex without any reservation or restriction. standards that describe calibration and operation for radiation dosimetry, as well as procedures to relate the measured dose to the effects achieved and to report and document such results, are maintained by the american society for testing and materials (astm international) and are also available as iso/astm standards. all of the rules involved in processing food are applied to all foods before they are irradiated. united states the u.s. food and drug administration (fda) is the agency responsible for regulation of radiation sources in the united states. irradiation, as defined by the fda is a "food additive" as opposed to a food process and therefore falls under the food additive regulations. each food approved for irradiation has specific guidelines in terms of minimum and maximum dosage as determined safe by the fda. packaging materials containing the food processed by irradiation must also undergo approval. the united states department of agriculture (usda) amends these rules for use with meat, poultry, and fresh fruit. the united states department of agriculture (usda) has approved the use of low-level irradiation as an alternative treatment to pesticides for fruits and vegetables that are considered hosts to a number of insect pests, including fruit flies and seed weevils. under bilateral agreements that allows less-developed countries to earn income through food exports agreements are made to allow them to irradiate fruits and vegetables at low doses to kill insects, so that the food can avoid quarantine. the u.s. food and drug administration and the u.s. department of agriculture have approved irradiation of the following foods and purposes: packaged refrigerated or frozen red meat — to control pathogens (e. coli o157:h7 and salmonella) and to extend shelf life packaged poultry — control pathogens (salmonella and camplylobacter) fresh fruits, vegetables, and grains — to control insects and inhibit growth, ripening and sprouting pork — to control trichinosis herbs, spices and vegetable seasonings — to control insects and microorganisms dry or dehydrated enzyme preparations — to control insects and microorganisms white potatoes — to inhibit sprout development wheat and wheat flour — to control insects loose or bagged fresh iceberg lettuce and spinach crustaceans (lobster, shrimp, and crab) shellfish (oysters, clams, mussels, and scallops) european union european law stipulates that all member countries must allow the sale of irradiated dried aromatic herbs, spices and vegetable seasonings. however, these directives allow member states to maintain previous clearances food categories the ec's scientific committee on food (scf) had previously approved (the approval body is now the european food safety authority). presently, belgium, czech republic, france, italy, netherlands, and poland allow the sale of many different types of irradiated foods. before individual items in an approved class can be added to the approved list, studies into the toxicology of each of such food and for each of the proposed dose ranges are requested. it also states that irradiation shall not be used "as a substitute for hygiene or health practices or good manufacturing or agricultural practice". these directives only control food irradiation for food retail and their conditions and controls are not applicable to the irradiation of food for patients requiring sterile diets. in 2021 the most common food items irradiated were frog legs at 65.1%, poultry 20.6% and dried aromatic herbs, spices and vegetables seasoning. due to the european single market, any food, even if irradiated, must be allowed to be marketed in any other member state even if a general ban of food irradiation prevails, under the condition that the food has been irradiated legally in the state of origin. furthermore, imports into the ec are possible from third countries if the irradiation facility had been inspected and approved by the ec and the treatment is legal within the ec or some member state. australia in australia, following cat deaths after irradiated cat food consumption and producer's voluntary recall, cat food irradiation was banned. nuclear safety and security interlocks and safeguards are mandated to minimize this risk. there have been radiation-related accidents, deaths, and injury at such facilities, many of them caused by operators overriding the safety related interlocks. in a radiation processing facility, radiation specific concerns are supervised by special authorities, while "ordinary" occupational safety regulations are handled much like other businesses. the safety of irradiation facilities is regulated by the united nations international atomic energy agency and monitored by the different national nuclear regulatory commissions. the regulators enforce a safety culture that mandates that all incidents that occur are documented