Lax GM rules may bite back - scientists

21:41, Mar 24 2013

Potentially unsafe genetically modified foods are slipping into our diet because of "systematic neglect" by regulator Food Standards Australia-New Zealand (FSANZ), scientists say.

International researchers - including leading New Zealand geneticist Professor Jack Heinemann of the University of Canterbury - say FSANZ and other regulatory bodies in Australia and Brazil are assuming a new type of GM molecule is safe to eat without requiring proof.

The regulators are then approving products containing the GM material, which in New Zealand includes soybeans that may be present in foods such as margarines, mayonnaises, chocolate and miso.

Heinemann, the director of the university's Centre for Integrated Research in Biosafety (INBI), said there was no evidence such products were unsafe for humans to eat, but neither was there proof they were safe.

New research showed the GM molecule - double-stranded RNA (dsRNA) - could survive cooking and digestion. As a result it could be absorbed into the bodies of people who ate plants containing the molecules, potentially "turning off" human genes.

He said spraying the molecules directly on to crops would contaminate the air and ground within several kilometres. Also, dsRNAs could persist for a long time in the environment.

Advertisement

Potentially they could also be transferred into people inhaling dust from the plants, say by breathing in flour when baking with GM wheat, or through the skin.

"Our current understanding of dsRNA in GM plants is in its infancy and we are still trying to understand how they may work and therefore how they may affect humans, animals and the environment," Heinemann said in a briefing paper.

"We don't want to learn that one or more of these crops or sprays is toxic after millions of people have been exposed to them for years."

Heinemann's peer-reviewed research with Judy Carman of Adelaide's Flinders University and Sarah Agapito-Tenfen of the Federal University of Santa Catarina, Brazil, was published in Environment International on Friday.

FSANZ said it should be able to comment "in the next few weeks". "We need some time to assess the paper," spokeswoman Saffron Urbaniak said.

In the paper, the researchers said FSANZ "regularly dismissed" INBI's recommendations to describe and evaluate the GM molecule in modified foods.

The regulator had argued instead that:

- dsRNA did not transmit to humans through food.

- dsRNA would be unstable in cooking or during digestion.

Techniques that might be used to find dsRNAs were not routinely used in safety studies.

FSANZ had approved at least five GM products with dsRNA molecules for use as human food since 2000, despite "acknowledgment that there was scientific uncertainty" about how the modification worked, the paper said.

Heinemann told The Press the team's findings hardly came as a surprise. "We hope to engage in a constructive way with the regulatory authorities. The point is not to say, ‘we've caught you doing something bad', it's to say, ‘we need some science in the risk assessments'."

For that reason, the researchers had developed a recommended safety testing procedure for all GM plants with the molecules, which was published in their paper, Heinemann said.

Heinemann also said: "It seems amazing that FSANZ needs weeks to read the content of a scientific paper written on a topic on which they are presumably experts."

WHAT IS dsRNA?

GM plants are being designed to make a new RNA (ribonucleic acid) molecule, which is either double-stranded (dsRNA) or has the ability to create one. These dsRNA molecules can silence or activate certain genes in the plant.

Examples include Australian barley and wheat varieties modified to change the type of starch they produce.

Biopesticide plants containing dsRNA silence a gene in the insects that eat them, causing the insect to die.

The Press