Analysis of food by nuclear and related analytical techniques. Highlights and achievements

Full text: The work on the project started in 2000 with the selection of foods consumed in the Witwatersrand area of South Africa which is recognised to be the economic heartbeat of the country. A dietician was consulted in identifying the most important food groups for human nutritional health, as well as typical examples of foodstuffs belonging to a specific food group. From this information a suite of 14 foodstuffs were chosen. The primary investigation was aimed at natural occurring radioactive materials (NORM) to explore the capability of our laboratories in analysing the nuclides involved through low- and high-energy gamma-ray spectrometry. The main objective being to investigate our capability and capacity to prepare and analyse these foodstuffs and estimate the committed effective dose to consumers. Information gained served to define future strategies for food analysis for NORM. From this survey it appeared that for certain radionuclides radiochemical separations will be required to arrive at the sensitivities needed to perform adequate dose estimations. For some of the foodstuffs positive values for a suite of radionuclides has been obtained, urging further investigation in the total NORM-nuclide content. Future work will focus on INAA and radiochemical separations to determine all relevant nuclides of the uranium, thorium and actinium decay series. Uranium and thorium content of the foodstuffs under survey will be determined by neutron activation analysis and in the same time the capability of INAA for the determination of toxic and essential elements will be surveyed. This report provides information on the work performed so far and the work envisaged for the year 2002. All actions are defined according to our QAQC procedures applicable at our ISO/IEC 17025 accredited laboratories. (author)