University of Otago scientists have helped come up with an
ingenious way to help identify whether milk powder being sold
as a New Zealand-made in overseas markets is in fact from
This comes as New Zealand exports about $2 billion of milk
products to China each year, and amid a recent rise in
imitation and sometimes dangerous dairy products in China.
The work by researchers at Otago University and GNS Science
showed information on where milk was produced could be gained
through testing milk powder - which could help identify if a
product suspected of being fake was actually from New
The scientists made use of the fact New Zealand's rain had a
distinctive natural isotope signature that passed through
pasture and into milk products.
Otago University Associate Prof Russell Frew 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 could also be ideal
applications for the technique.
Dr Troy Baisden, of GNS Science, said the process was made
possible by having the ability to look at the hydrogen
isotopes in rain from each storm during the season when milk
"We work with monthly rainfall samples from all over New
"We turn information derived from these samples into a map of
daily rainfall chemistry using climate data from Niwa," Dr
The project to collect rain samples from all over the country
was funded by the Government, the samples analysed at Otago
University and the maps made at GNS Science.
Otago University PhD student Emad Ehtesham carried out
analyses of the milk powder and was able to narrow down the
origin of the products to either the North or South Island.
Otago University analytical forensic science programme
director Associate Prof Jurian Hoogewerff said the technique
could help protect New Zealand's agricultural brand.
"In general, New Zealand is very dependent on food exports,
so there is an urgent need to protect New Zealand Inc from
any major food scandals."