There are dozens of conflicting studies but a 2009 British review of evidence over 50 years found no nutritional or health difference between organic and ordinary food. Organic growers criticised the study for rejecting more recent comparisons which did show a difference and ignoring the possible long-term effects of pesticides on human health.
Is it better for the environment?
Organic growers say conventional methods are ruining our soil and rivers. Organics Aotearoa New Zealand executive (OANZ) chairman Derek Broadmore says the country is only now waking up to the impact of "dirty dairying" practices, which have polluted waterways with cattle effluent and fertiliser run-off, killing fish and plant life.
"It's taken us 25 years to realise the effect it's having on rivers, it might take another 25 years to find out its effect on soils."
However some scientists have challenged organic farming's low-energy, non-polluting credentials.
Is organic food becoming morepopular?
Yes, but off a very low base. Last year an Otago University report commissioned by OANZ found total organic product sales had more than tripled in four years from $140 million in 2005 to $485 million in 2009, including $315 million sold here. However the best estimate for organic food as a proportion of total food sales is about 2 per cent.
The two big supermarket chains say they don't collect these statistics because organics are now spread across so many product ranges but Foodstuffs, which runs the Pak'n Save and New World chains, put the figure at 1 per cent in 2008. OANZ executive chairman Derek Broadmore says you could probably double that as specialist organic shops sell about the same amount as supermarkets.
Why is it so expensive?
Fresh and packaged organic foods can cost over twice as much as conventional products. A Weekend Herald supermarket food shop found organic carrots cost $6.99 a kg at New World, Mt Roskill, compared with $2.99 for the regular variety. Organic pasta was $3.27 for a 500g packet, triple the price of the home brand.
Mr Broadmore says organic food costs more because growers have higher labour costs and lower production rates per hectare. He says another likely reason for low sales in New Zealand is that shoppers believe conventionally produced local food is healthy, although he regards that "clean, green" image as a myth.
