What radioactive material is found in Australian foodstuffs?
Very low levels of Caesium-137 are observed in foodstuffs from time to time and arise from the trace quantities in Australian soils from global fallout up to 1974.
Like all countries in the southern hemisphere, Australia has experienced fallout from atmospheric nuclear weapons tests conducted by several nations. However, the fallout in Australia has generally been much lower compared to northern hemisphere countries. Monitoring since the Chornobyl accident has shown no increase in fallout deposits.
For information on guideline levels for food, refer to pages 50-54 of the FAO/WHO Codex Alimentarius International Food Standards.
How we measure
Radionuclides (normally caesium-137 and caesium-134, sometimes ruthenium-103) are measured by high resolution gamma-ray spectrometry.
Amount required
A minimum volume of 250 mL (1 cup) of material is required.
Composite samples
If requested, multiple samples can be mixed together and analysed as a single composite sample. In this case, the result will apply to the composite sample only and not to the individual samples that were mixed to form it.
Reporting limit
In most cases, the reporting limit for analysing Caesium-137 and Caesium-134 in food samples will be 2 Bq/kg (2 becquerels per kilogram). This value is much lower than any known regulatory limit and is far below the levels of natural radioactivity found in many foodstuffs. If multiple samples are mixed and analysed as a composite sample, the reporting limit will only apply to the composite sample.
Reports
A report will be issued normally within one week, depending on the current workload. Where the result of a measurement exceeds 2 Bq/kg, or does so after uncertainties have been taken into account, the result will be reported together with an estimated uncertainty.
Food certificates
If requested, food certificates for export purposes can be issued. Information required on the certificate must be provided by the client.
