The controversial debate surrounding supposed added health benefits attributed to organic food looks set to continue this week as the results of a comprehensive review of international studies were released in New Zealand.
According to a report by AZ Central.com, researchers in New Zealand found no convincing evidence to back claims that organically grown foods were healthier or tastier than those grown using chemicals.
In addition, Diane Bourn, a food science lecturer at Otago university, said the bulk of around 100 reviewed studies - mainly from Europe, but with some from the United States and Australia - were poorly done.
The nutritional value of food was influenced by the time of harvest, freshness, storage, and weather, but many studies claiming organic food had more vitamins and minerals did not take proper account of these factors, she said.
"To date, I feel there's no evidence that organic food is nutritionally superior,'' she said.
"When you look at those studies in detail, they're actually pretty awful...they're not really strong enough to be able to say that convincingly.''
The organic food sector has grown massively in recent years, accelerated by food scares, especially in Europe and Japan. The sector was recently valued by a new London-based organic produce exchange at $30 billion (€18billion) plus a year, with organic produce usually commanding a premium in shops.
Otago University was commissioned by state-owned science agency Crop & Food Research to carry out the study. While there was a lot of anecdotal evidence about organic food tasting better than conventionally grown food, the studies reviewed could not conclusively back-up those claims, Bourn said.
However she added there were clear environmental benefits from growing organically and reduced pesticide residues in organics supported claims of improved food safety.
New Zealand food exports total $6 billion a year, the bulk of its total exports. Only a small fraction of the food exports are promoted as organic.