Organic agriculture advocates say the discovery of pesticides in imported Australian vegetables support calls by mainstream growers for country of origin labels on this side of the Tasman.
The insecticide dimethoate found in Australian capsicum labelled as "Product of New Zealand" in an Auckland supermarket, was a clear breach not only of voluntary origin labelling at the Woolworths supermarket but of the Fair Trading Act, the association said in the September issue of its Organic NZ magazine.
It alleged that a "NZ Hothouse 3Pack Capsicum" appeared to have been "topped up" with Australian produce dipped in dimethoate.
Dimethoate, a systemic organophosphate insecticide, is used as an insecticidal dip to kill the Queensland fruit fly in produce imported from Australia to New Zealand. It is difficult to rinse off.
The New Zealand name was dominant on the Hothouse packaging with a tiny "Produce of Australia" label, said Soil and Health spokesman Steffan Browning, of Blenheim.
The pesticide showed up during a sampling survey the association carried out to check on the incidence of another chemical, endosulfan.
Mr Browning said some local packhouses might also be re-packaging Australian tomatoes.
Four out of six samples from loose New Zealand tomatoes showed no pesticide residues at all, and none contained dimethoate, but the pesticide was found in Australian tomatoes, capsicum and zucchini from Countdown Blenheim.
The level in zucchini was more than twice the allowed maximum residue level, and the zucchini and capsicums were labelled only as imported, and did not mention Australia as their country of origin.
Unlabelled capsicum from a PaknSave supermarket in Moorhouse Ave, Christchurch, also contained dimethoate.
New Zealand tomato growers do not use dimethoate or the related chemical omethoate.
Only 25 percent of the 24 produce samples taken showed no detectable residue in multi-residue testing.
Findings of dimethoate in "NZ Product" showed serious breaches of the voluntary country of origin labelling the supermarket owners, Foodstuffs and Progressive Enterprises, said they used. And it was a "giveaway" to have dimethoate residues on the NZ Hothouse capsicums labelled as being of New Zealand origin.
"Voluntary labelling is not working, either not at all or is poorly utilised, and certainly not enforceable," said Mr Browning.
Soil and Health had submitted the pesticide residue information to the Parliamentary select committee on health, which is considering a Green Party-initiated petition calling for mandatory country of origin labels.
A mainstream grower lobby, Horticulture NZ, has also called for mandatory labelling, but not on the grounds that it is necessary for food safety reasons.