Scientists pour scorn on 'dirty dozen' food warnings

Toxicologists have accused a food safety campaigner of a lack of understanding after she advised people to eat organic celery to avoid pesticides.

Alison White has ranked celery at the top of a list of foods likely to contain pesticide residue, but scientists say that does not mean indulging in the vegetable will cause any harm.

Ms White, who is a researcher and co-convenor of the Safe Food Campaign, said consumers wanted information about whether their food contained pesticide residues.

"You can't usually see them, and you don't often taste them. They're invisible but nevertheless they are there."

In a list called "the dirty dozen", Ms White has tabled the 12 foods most likely to contain pesticide residues in samples gathered by the Food Safety Authority.

The authority sets limits on pesticide levels, but Ms White said that did not take into account the effect on the body the chemicals could have when combined.

However, Canterbury University toxicology professor Ian Shaw said Ms White's table, which she published on the group's website, displayed "naughtiness" in referencing research about cancer risks among people who sprayed vegetables, not those who ate them.

Ms White's comments also showed she did not understand the difference between how dangerous a chemical was, and the actual chance or risk of it causing any harm.

Ms White said Dr Shaw's beliefs were based on outdated research about pesticides. More recent research showed that a "cocktail of pesticides" was harmful, and the timing of ingesting pesticides could be dangerous. For example, a foetus could be harmed if a pregnant woman was exposed to them at the wrong time, she said.

The Food Safety Authority's principal toxicology adviser, John Reeve, dismissed Ms White's suggestion that pesticide residues could be making our food unsafe.

"Alison White and her colleagues have no expertise in toxicology and don't understand the science."

Dr Reeve said pesticide limits were determined by how much of a chemical growers needed for it to work.

That limit was hundreds of times lower than the levels that would have any impact on human health, he said.

A great deal of research had been done into the "cocktail effect" of chemicals too, and Dr Reeve said none had found that a mix of chemicals at the levels found in foods was of concern.

"The only worry people should have about fresh fruit and vegetables is that they are eating enough."

Ms White said many pesticides had not been tested sufficiently for their long-term effects to be known.

By eating organic food, people would not only reduce the amount of those pesticides that accumulated in their body, but also reduce the amount that went into the environment, she said.

- © Fairfax NZ News