ASTM E2381-04(2010)
Standard Guide for Dosimetry In Radiation Processing of Fluidized Beds and Fluid Streams

Standard No.

ASTM E2381-04(2010)

Release Date

2004

Published By

American Society for Testing and Materials (ASTM)

Status

Withdraw 2016-01

Latest

ASTM E2381-04(2010)

Scope

Dosimetric Techniques8212;The processes addressed here utilize a variety of techniques for the dynamic presentation of the product to the radiation source. This may involve gravitational flow or simple pneumatic transport about or past the radiation source. In the case of fluidized beds, the product may be presented to the radiation source while supported in a gaseous or liquid stream moving at relatively high velocities. This document provides a guide to the dosimetric techniques suitable for these processes.

Food Products8212;Food products may be treated with ionizing radiation, such as energetic electrons from accelerators or gamma rays from ⁶⁰Co or ¹³⁷Cs sources, or X-rays, for numerous purposes, including control of parasites and pathogenic microorganisms, insect disinfestation, growth and maturation inhibition, and shelf-life extension.

Note 18212;Food irradiation specifications usually include upper and lower limits of absorbed dose: a minimum to ensure the intended beneficial effect and a maximum to avoid product degradation. For a given application, one or both of these values may be prescribed by regulations that have been established on the basis of available scientific data. Therefore, it is necessary to determine the capability of an irradiation facility to process within these absorbed-dose limits prior to the irradiation of the food product. Once this capability is established, it may be necessary to monitor and record the dose range delivered to the product during each production run to verify compliance with the process specifications within a predetermined level of confidence.

Randomized Flow8212;In a stream of randomized flow; i.e. turbulent instead of laminar, variations occur which lead to a dose distribution for the particles entrained in the stream. The “idealized” maximum and minimum doses possible can be calculated based upon knowledge of the applied dose rate, the product dwell time in the irradiation cell and the product or bed thickness. The experimentally determined maximum and minimum doses delivered to each particle, should not be confused with these idealized dose limits.

Treatment range8212;The location of the product (or of the dosimeter) in the fluidized bed or stream will determine its absorbed dose during passage through the radiation field. The experimental dose measurements in the fluidized bed or stream will define the range of product dose. The desired effect imparted to the product by irradiation will then be based upon this range of product dose and not upon maximum or minimum dose.

Note 28212;In situations where a randomized mixing within the fluidized bed occurs with the intention that the particles or fluid elements pass through several radiation zones and accumulate a total dose with different dose rates, maximum and minimum dose values are difficult to determine and must be based on the results for the experimental dosimetry irradiated with the product . In the case of fluids, stirring after processing results only in effective treatment at a mean dose; no max and min dose measurement. For example, lethality curves will be determined as a function of this range of product treatment to the product in the fluidized bed or stream as determined by dosimetric techniques.

1.1 This guide describes several dosimetry systems and methods suitable for the documentation of the irradiation of product transpor......

ASTM E2381-04(2010) Referenced Document

• ASTM E1026 Standard Practice for Using the Fricke Reference Standard Dosimetry System
• ASTM E170 Standard Terminology Relating to Radiation Measurements and Dosimetry
• ASTM E2232 Standard Guide for Selection and Use of Mathematical Methods for Calculating Absorbed Dose in Radiation Processing Applications
• ASTM E666 Standard Practice for Calculating Absorbed Dose From Gamma or X Radiation
• ASTM F1355 Standard Guide for Irradiation of Fresh Fruits as a Phytosanitary Treatment
• ASTM F1885 Standard Guide for Irradiation of Dried Spices, Herbs, and Vegetable Seasonings to Control Pathogens and Other Microorganisms

ASTM E2381-04(2010) history

• 2004 ASTM E2381-04(2010) Standard Guide for Dosimetry In Radiation Processing of Fluidized Beds and Fluid Streams
• 2004 ASTM E2381-04 Standard Guide for Dosimetry In Radiation Processing of Fluidized Beds and Fluid Streams