Файл: Перевод статьи Облучение пищевых продуктов.docx

Sprout inhibition in bulbs and tubers 0.03-0.15 kGy
Delay in fruit ripening 0.25-0.75 kGy
Insect disinfestation including, quarantine treatment and elimination of food borne parasites 0.07-1.00 kGy

Medium Dose Applications (1 kGy to 10 kGy)

Reduction of spoilage microbes to improve shelf-life of meat, poultry and seafoods under refrigeration 1.50-3.00 kGy
Elimination of pathogenic microbes in fresh and frozen meat, poultry and seafoods 3.00-7.00 kGy
Reducing number of microorganisms in spices to improve hygenic quality 10.00 kGy

High Dose Applications (above 10 kGy)

Sterilisation of packaged meat, poultry and their products which are shelf stable without refrigeration. 25.00-70.00 kGy
Sterilisation of Hospital diets 25.00-70.00 kGy
Product improvement as increased juice yield or improved re-hydration

It is important to note that these doses are above those currently permitted for these food items by the FDA and other regulators around the world. The Codex Alimentarius Standard on Irradiated Food does not specify any upper dose limit.[17][18] NASA is authorized to sterilize food for Astronauts at doses of 44 kGy as a notable exception[citation needed].Irradiation treatments are also sometimes classified as radappertization,radicidation and radurization

Technologies

Electron irradiation

Electron irradiation uses electrons accelerated in an electric field to a velocity close to the speed of light. Electrons are particulate radiation and have cross section many times larger than photons, so that they do not penetrate the product beyond a few inches depending on product density. Electron facilities rely on substantial concrete shields to protect workers and the environment from radiation exposure.

Gamma irradiation

Gamma radiation is radiation of photons in the gamma part of the spectrum. The radiation is obtained through the use of

radioisotopes, generally Cobalt-60 or, in theory, Cesium-137. Cesium-137 is recovered during the refinement of spent nuclear fuel. Because this technology - except for military applications - is not commercially available, insufficient quantities of it are available on the global isotope markets for use in large scale, commercial irradiators. Presently, Cesium-137 is used only in small hospital units to treat blood before transfusion to prevent Graft-versus-host disease.Food irradiation using Cobalt-60 is the preferred method by most processors, because the better penetration enables administering treatment to entire industrial pallets or totes, reducing the need for material handling[19]. A pallet or tote is typically exposed for several minutes depending on dose. Radioactive material must be monitored and carefully stored to shield workers and the environment from its gamma rays. During operation this is achieved by substantial concrete shields. With most designs the radioisotope can be lowered into a water-filled source storage pool to allow maintenance personnel to enter the radiation shield. In this mode the water in the pool absorbs the radiation. Other uncommonly used designs feature dry storage by providing movable shields that reduce radiation levels in areas of the irradiation chamber.One variant of gamma irradiators keeps the Cobalt-60 under water at all times and lowers the product to be irradiated under water in hermetic bells. No further shielding is required for such designs.

X-ray irradiation

Similar to gamma radiation, X-rays are photon radiation of a wide energy spectrum and an alternative to isotope based irradiation systems. X-rays are generated by colliding accelerated electrons with a dense material (target) such as Tantalum or Tungsten in a process known as bremsstrahlung-conversion. X-ray irradiators are scalable and have good penetration, with the added benefit of using an electronic source that stops radiating when switched off. They also permit very good dose uniformity. However, these systems generally have low energetic efficiency during the conversion of electron energy to photon radiation requiring much more electrical energy than other systems and longer exposure times than those required by gamma rays or electron beams. Like most other types of facilities, X-ray systems rely on concrete shields to protect the environment and workers from radiation.

Irradiated foods in the market place

Current U.S. market

Many U.S. supermarkets carry irradiated food products today ranging from fresh tropical fruit from Hawaii or Florida,[20] dehydrated spices[21] and ground meat products.[22][23] Certain supermarkets like Whole Foods Market prefer not to carry irradiated products for reasons of consumer perception.[24]Some foods, particularly fruits and vegetables, are naturally restricted from sale on the global market, unless they are irradiated to prolong quality for transportation. Less spoilage at the receiving end means fewer discards, lowering the unit cost. Irradiation has also been used to reduce bacteria counts in seafood that is shipped over long distances. Because irradiation can reduce or even eliminate pest infestations, it has opened the markets for previously prohibited items, such as mangoes from India that otherwise have a risk of carrying certain insects and pathogens with them into the importing country. On Hawaii a dedicated irradiator serves for insect disinfestation before transfer to mainland USA, and a second facility is under construction. Insect pests can have a devastating effect on crop production. They can also transmit diseases that destroy crops and kill livestock and people. Heavy reliance on pesticides raises environmental concerns and problems of pest adaptation and resistance. As a result, many countries are seeking to minimize insecticide use through irradiation techniques.Such benefits are offset by the cost of this rather capital intensive technology. The actual 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.[25] 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 (cobalt-60), 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[26][27]Treatment costs vary as a function of dose and facility usage. Low dose applications such as disinfestation of fruit range between $US 0.01/lbs and $US 0.08/lbs while higher dose applications can cost as much as $US 0.20 / lbs.[27]

Consumer perception

Some older studies suggest that majority of the public questions the safety of irradiated foods, and if given a choice, will not buy foods that have been irradiated.[28] More recent consumer attitude and markets studies worldwide, however, indicate consumers today will tend to accept irradiated food. Major studies in the United States indicate the number of consumers concerned about the safety of irradiated food has decreased in the last 10 years and continues to be less than the number of those concerned about pesticide residues, microbiological contamination, and live insects in their food. Where ever irradiated food has reached the market, it has found a sufficient number of consumers to buy it. A number of marketing tests has proven, that consumers as soon as they are allowed to try the real irradiated food item and are informed about the technology and the purpose of the treatment are willing to buy. The number of people reporting no concerns about irradiated food is among the lowest for food issues, comparable to that of people with no concern about food additives and preservatives.

[29]

The globalized food supply

Opponents of food irradiation sometimes state that large-scale irradiation would increase processing, transportation, and handling times for fruits and vegetables thus contributing to a negative ecological balance compared to locally grown foods.

Labeling and Terminology Issues

Labeling laws differ from country to country. While Codex Alimentarius represents the global standard in particular under the WTO-agreement, member states are free to convert those standards into national regulations. With regard to labelling of irradiated food detailed rules are published at CODEX-STAN - 1 (2005) labelling of prepacked food[30]The provisions are that any 'first generation' product must be labelled '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 will not appear on the label. The RADURA-logo is optional; several countries use a graphical version which differs from the Codex-version.In the US as in many other countries irradiated food must be labeled as "Treated with irradiation" or "Treated by radiation" and require the usage of the Radura symbol at the point of sale. However, the meaning of the label is not consistent. The amount of irradiation used can vary and since there are no published standards, the amount of pathogens affected by irradiation can be variable as well. In addition, there are no regulations regarding the levels of pathogen reduction that must be achieved. Food that is processed as an ingredient by a restaurant or food processor is exempt from the labeling requirement in the US; other countries follow the Codex Alimentarius provision to label irradiated ingredients down to the last molecule (cf. EU).FDA is currently proposing a rule that in some cases would allow certain irradiated foods to be marketed without any labeling at all. Under the new rules, only those irradiated 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, would bear the Radura symbol and the term "irradiated", or a derivative thereof, in conjunction with explicit language describing the change in the food or its conditions of use. In the same rule FDA is proposing to permit a firm to use the terms "electronically pasteurized" or "cold pasteurized" in lieu of "irradiated", provided it notifies the agency that the irradiation process being used meets the criteria specified for use of the term "pasteurized".[31]Food irradiation is sometimes referred to as 'cold pasteurization'[32] or 'electronic pasteurization'[33] because ionizing radiation used to sterilize the food does not heat the food to high temperatures during the process, as in heat-pasteurization (at a typical dose of 10 kGy, food that is physically equivalent to water would warm by about 2.5 °C). The treatment of solid food by ionizing radiation can provide an effect similar to heat pasteurization of liquids, such as milk. However, the use of the term, cold pasteurization, to describe irradiated foods is controversial, because pasteurization and irradiation are fundamentally different processes, although the intended end results can in some cases be similar.

Enforcement of labelling

There are analytical methods available to detect the usage of irradiation on food items in the marketplace.[34][35][36] This is understood as a tool for government authorities to enforce existing labeling standards and to bolster consumer confidence. The European Union is particularly strict in enforcing irradiation labeling 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 in the OJ of the European Communities.[37]