Radionuclides

There are various causes and processes for the contamination of foods with radionuclides. The radionuclides of most concern and the conditions under which they may contaminate food are described in this paper as are the pathways involved in the contamination process. Similarly the importance of certain foods which are the principal contributors to radioactivity in the diet is also emphasized. Assays of different sensitivities are required to detect the presence of different radionuclides in food depending on the purpose of the analysis, thus various methods can be used to achieve a determination. The analyses of gamma-, beta- and alpha-emitting radionuclides are outlined in this report taking into account the most recent developments in techniques based on the counting of atoms rather than the decay rate of the contaminating radionuclide. The evaluation of the uncertainties associated with these types of measurement represents the challenges faced in the field of metrology.