Food regulators say nanomaterials in our food don't appear to pose a health risk -- as far as they can tell.
Food Standards Australia New Zealand (FSANZ) has just released two reports reviewing evidence for the safety of nanotechnologies in food additives and food packaging.
They find that "the weight of evidence does not support claims of significant health risks for food grade materials". Although they concede that there are some areas that may need further research.
So what do we mean by nanotechnologies in food? They're regular ingredients -- like anti-caking agent silica and titanium dioxide (colour 171) -- only smaller.
Nanotechnologies can also be used in food packaging, like nano-silver particles which have antimicrobial properties.
On a regular scale the ingredients are proven to be safe, but there's concern that particles on a nano scale -- 1000 times smaller than even the microscopic scale -- can more easily permeate the body and be toxic.
A study commissioned by Friends of the Earth last year found evidence of nanotechnology in all 14 products it tested, including M&Ms, Coffee-Mate, Kool Mints and Old El Paso Taco Mix.
Prof Simon Brown, professor of physics at the University of Canterbury, says the FSANZ reports appear to be good news at first sight but also reveals some significant issues.
"In particular the lack of concrete evidence about the safety of these materials, and the fact that we don't even know very well how to measure if they are present," says Prof Brown.
"Very little is known about the effects of long-term exposure to low doses of these materials and such studies are notoriously difficult."
He says the situation is not nearly as simple as FSANZ's key finding suggests.
"FSANZ should be congratulated for commissioning these reports, but its response is glib. It will remain the case for many years to come that there are considerable uncertainties about the effects of the use of nanoparticles in consumer products, and New Zealand's regulatory system would do well to acknowledge those uncertainties, rather than simply giving the green light to these products."
FSANZ says its conclusions "may need to be reviewed as the sophistication and application of nanotechnologies to food and food packaging advances".