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Milk powder: foiling the fakers

05 Mar, 2013

Scientists have developed a way of identifying a milk powder’s country of origin to combat imitation dairy products being passed off as New Zealand-made.

New Zealand milk powder is so sought after in some countries that some unscrupulous business people have been passing off imitation, and sometimes dangerous, dairy products as New Zealand-made in overseas markets.

Fake milk powders and black market products

Fake milk powders are a particular issue in China, where New Zealand exports about $2 billion worth of genuine milk products each year. The problem has seen New Zealand supermarket shelves stripped bare of infant formulas and milk powders as foreigners come here to buy up the products in bulk to ship back to their countries. Often these black market products sell at exorbitant prices to consumers not trusting what is in their own shops.

Rainfall has distinctive isotope signature

New Zealand scientists from the University of Otago and GNS Science have come up with a way to help identify a milk powder’s country of origin to help foil the fakers. It would seem that all rain is not the same. According to a press release from GNS Science, New Zealand’s rainfall has a distinctive natural isotope signature that passes through pasture and into milk products. The different hydrogen isotopes in rainfall can also tell scientists whether the rain fell in a warm or cold climate.

Maps of daily rainfall chemistry

Scientists have been looking at hydrogen isotopes in rainfall and biological materials, such as milk, for the past decade. Dr Troy Baisden of GNS Science said progress was made possible by 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,” says Dr Baisden.

New Zealand milk powder is marked with a production date. This means that, if suspicious milk powder packaged as New Zealand milk powder is found in China, the scientists can track it and see if it matches any of the rainfalls that happened in New Zealand when that milk powder should have been produced.
 
Otago University PhD student Emad Ehtesham carried out the research on the milk powder.

Linking the milk data to the rainfall map

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 identified using the technique.
“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.”  

Biosecurity applications

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.”

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