Scientists turn milk frauds sour
A Lower Hutt scientist has helped develop a way to identify New Zealand milk powder, to foil overseas knock-offs.
Troy Baisden at GNS Science Gracefield has worked with Otago University scientists on a method to trace milk powder back to its geographical source.
Milk powder, butter and cheese are New Zealand's largest export commodities, worth about $12 billion to the economy in the 12 months to September this year.
This month, two large dairy export processing companies expressed concern that the quality image of New Zealand milk powder could be damaged by a proliferation of international counterfeit products claiming New Zealand origins.
Preliminary testing shows they can match a naturally occurring chemical signature in milk powder to a data map to see the grazing area that precise signature originated from. The technique is used to trace the origin of whole foods, but hasn't been widely adapted for processed foods.
Dr Baisden says the project proved that comparing the ratio of different types of hydrogen in milk powder to a set of measurements taken in the field could provide a match. Hydrogen goes through a slight chemical change during rainfall, creating different isotopes (different varieties of hydrogen atoms), depending on whether the rain fell in a warm or cold climate.
The unique mixture of natural isotope signatures passes through pasture and into milk products.
"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," Dr Baisden says.