'Following our conference there has been a lot of interest in what children eat and about the levels of salt,' said a Soil Association spokeswoman.

She was speaking following the association's circulation of the results of a University of Washington study which analysed pesticide-breakdown products in pre-school aged children. The research found that children eating organic produce had concentrations of the products – metabolites – six times lower than those eating produce grown conventionally.Testing was carried out for five metabolites of organophosphorous pesticides among a small sample of 39 children aged between two and four years.

A US pesticide-use lobby group is recommending that small children's consumption of conventionally grown pears, melons, strawberries, apples, tomatoes and green beans should be 'limited'.

The Soil Association commented: 'This helps the case for healthier food for children whether it's sold through retail outlets or provided for children through school dinners.'