Image of a young child, a little girl, facing the camera resting on her elbows with a line of milk around her mouth suggesting that she has just drunk a glass of milk. She has blue eyes and is wearing a red dress and multicoloured beads.

Strontium as a chemical tracer

Strontium has been used as a chemical tracer in milks to discriminate between products produced in different dairy regions.

  • 1 August 2006 | Updated 14 October 2011

The application of strontium (Sr) as a chemical tracer allows researchers to distinguish between samples from differing localities based upon their isotopic signatures.

The ability to discriminate between animal products grown in different areas is a powerful tool, not only for anthropology and archaeology, but increasingly it is useful for forensic science and for monitoring the provenance of foods such as milk and dairy products.

Because strontium can substitute for calcium, it concentrates in bones, teeth and milk, making these particularly suited to Sr isotopic analysis. The use of composite isotopic data sets (N, O and C isotopic ratios in addition to Sr) appears to be a powerful tool for discriminating between milk produced in different dairy regions. 

The ability to discriminate between animal products grown in different areas is a powerful tool, not only for anthropology and archaeology but increasingly forensic science and for monitoring the provenance of foods.

What we are doing

In collaboration with Food Sciences Australia, CSIRO has recently investigated the Sr composition of milks from a number of different dairy regions in Australia and New Zealand in order to determine from where they were derived. 

Soils inherit Sr and consequently the Sr isotopic signature of the parent rock or sediment in which they develop.

Low levels of Sr are incorporated into plants from the soil and as there is no isotopic fractionation of Sr during this process, plants and ultimately the animals on which feed on them inherit the same Sr isotopic ratio as the soil, making it therefore possible to differentiate between different locations.

Read more about CSIRO’s work in Food or view Timeframes of basin evolution research overview.