【国外标准】 Standard Practice for Dosimetry in Gamma Irradiation Facilities for Food Processing (Withdrawn 2013)

4.1 Food products may be treated with ionizing radiation, such as gamma-rays from 60Co or 137Cs sources, for numerous purposes, including control of parasites and pathogenic microorganisms, insect disinfestation, growth and maturation inhibition, and shelf-life extension. Food irradiation specifications almost always include a minimum or maximum limit of absorbed dose, sometimes both: a minimum limit is set to ensure that the intended beneficial effect is achieved and a maximum limit is set for the purpose of avoiding product or packaging degradation. For a given application, one or both of these values may be prescribed by government regulations that have been established on the basis of scientific data. Therefore, prior to the irradiation of the food product, it is necessary to determine the capability of an irradiation facility to deliver the absorbed dose within any prescribed limits. Also, it is necessary to monitor and document the absorbed dose during each production run to verify compliance with the process specifications at a predetermined level of confidence.NOTE 3 - The Codex Alimentarius Commission has developed an international General Standard and a Code of Practice that address the application of ionizing radiation to the treatment of foods and that strongly emphasize the role of dosimetry for ensuring that irradiation will be properly performed (1).4.2 Some food products are processed in the chilled or frozen state. Therefore, dosimeters used for routine processing should be selected for their functionality under those conditions. Moreover, the temperature of a dosimeter during irradiation should be sufficiently stable to allow correction for temperature effects on the dosimeter response. To avoid the influence of temperature gradients on dosimeter response and the subsequent need to correct for these effects, methods that isolate the dosimeter from temperature gradients may be employed.NOTE 4 - For more detailed discussions of radiation processing of various foods, see ASTM Guides F 1355, F 1356, F 1736, and F 1885 and Refs (1-11).4.3 To ensure that products are irradiated within a specified absorbed-dose range, routine process control requires routine product dosimetry, documented product handling procedures (before, during, and after irradiation), consistent orientation of the products during irradiation, monitoring of critical process parameters, and documentation of all relevant activities and functions.1.1 This practice outlines the installation qualification program for an irradiator and the dosimetric procedures to be followed during operational qualification, performance qualification, and routine processing in facilities that process food with ionizing radiation from radionuclide gamma sources to ensure that product has been treated within a predetermined range of absorbed dose. Other procedures related to operational qualification, performance qualification, and routine processing that may influence absorbed dose in the product are also discussed. Information about effective or regulatory dose limits for food products is not within the scope of this practice (see ASTM Guides F 1355, F 1356, F 1736, and F 1885).Note 1—Dosimetry is only one component of a total quality assurance program for adherence to good manufacturing practices used in the production of safe and wholesome food.Note 2—ISO/ASTM Practice 51431 describes dosimetric procedures for electron beam and X-ray (bremsstrahlung) irradiation facilities for food processing.1.2 For guidance in the selection and calibration of dosimetry systems, and interpretation of measured absorbed dose in the product, see ISO/ASTM Guide 51261 and ASTM Practice E 666. For the use of specific dosimetry systems, see ASTM Practices E 1026 and E 2304, and ISO/ASTM Practices 51205, 51275, 51276, 51310, 51401, 51538, 51540, 51607, 51650, and 51956. For discussion of radiation dosimetry for gamma-rays and X-rays also see ICRU Report 14.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.