MEDIA RELEASE from GNS Science
13 NOVEMBER 2012
Science Helps to Foil Trade in Imitation Milk Powder
New Zealand scientists have come up with an ingenious way to help identify fake milk powder being sold as a New Zealand
product in overseas markets.
New Zealand exports about $2 billion worth of milk products to China each year, and a recent rise in imitation, and
sometimes dangerous, dairy products in China has increased the importance of protecting the New Zealand brand.
Scientists at the University of Otago and GNS Science have completed preliminary work showing they can read milk
powder’s geographical identification.
The scientists make use of the fact that New Zealand’s rainfall has a distinctive natural isotope signature that passes
through pasture and into milk products. The two kinds of hydrogen atoms – or isotopes – naturally present in rainfall
capture whether the rain fell in a warm or cold climate.
The ability to measure hydrogen isotopes in rainfall and biological materials, such as milk, has been advancing rapidly
in the past decade.
Troy Baisden, of GNS Science, said progress was made possible by having the ability to look at the hydrogen isotopes in
rainfall from each storm during the growing season when the milk is produced.
“We work with monthly rainfall samples from all over New Zealand. We turn information derived from these samples into a
map of daily rainfall chemistry using climate data from NIWA,” Dr Baisden said.
Otago University PhD student Emad Ehtesham carried out the research on the milk powder.
The technique involves using mass spectrometry in the University’s Chemistry Department to measure the ratio of the two
hydrogen isotopes of bulk milk powder, or individual fatty acid compounds.
Associate Professor Russell Frew, of Otago University, said the technique opened the possibility of verifying the origin
of the milk component of mixtures such as infant formula. Products such as butter and cheese might also be ideal
applications for the technique.
The use of similar technology to verify the origin of whole foods was well established, Dr Frew said.
“The major advance here is that we are able to link the milk data to the rainfall map and hence use this to identify the
origin of the commodity.”
Dr Baisden said the proof-of-concept work was very promising and was being developed further.
“We can also apply this type of science to other important problems, such as where insects and other biological material
breaching New Zealand’s biosecurity have come from.”
The project to collect rainfall samples from all over the country was funded by the Government through Biosecurity New
Zealand. Milk product samples were analysed at the University of Otago and maps made at GNS Science.
ENDS