By James Melik Business reporter, BBC World Service

Ask the average shopper what they think when they walk into a supermarket and see organic food on display, and the majority respond with two observations: expensive - and chemical free.m

Some supermarket staff were unable to correctly explain what organic means

On the first point they are correct. Organic items can cost between 10% and 100% more than food grown under conventional conditions.

But on the second point people are mistaken, as foods certified as organic can be grown with the use of chemicals - albeit from a list approved by various organisations across Europe and the UK.

The confusion is understandable.

On a recent visit to branches of major supermarkets, members of staff told me that organic food did not use any fertilisers or pesticides at all.

One said the organic label meant food had not been genetically modified.

Only one gave the correct information, saying organic food is grown with "less chemicals".

I'm shocked to find out that any pesticides are used in organic foods Mother-of-two Julie D'Wan

Even a spokesperson for the Soil Association said organic food meant "without pesticides", before amending that to "a minimal amount".

Mixed messages

There is no deliberate ploy to bamboozle consumers, but some feel cheated because they say they should be better informed.

"I'm shocked to find out that any pesticides are used in organic foods," says mother-of-two Julie D'Wan, while browsing in the fruit and vegetables aisle of a major supermarket.

ORGANIC FACTS AND MYTHS Myth: There are no pesticides, insecticides, fertilisers or additives in organic food. Fact: There is a list of approved products which organic farmers can use. Up to 20% of chicken feed and 10% of cow feed can be non-organic Myth: Organic food is produced locally Fact: The UK is Europe's biggest consumer of organic food - but only 5% is grown in the UK. Some of it is transported thousands of miles Myth: It is healthier for you Fact The British Nutrition Foundation says there is no scientific proof of any extra health benefits

"The public believe what the so-called experts tell us, when really they just fool us so they can make their money," she adds.

Mrs D'Wan says she would not feel duped if it said on the packaging, or in store, that certain chemicals were permitted and used.

But looking, for example, at a bag of organic potatoes in one of Britain's largest supermarkets, the labelling just states:

"Farmers work with nature, helping to maximise wildlife on their farms and growing flowers to discourage pests. Our produce meets the standards laid down by law in the EU and by the UK government."

A spokesman for the retailer says: "The vast majority of our organic produce is grown in the UK, and the rest is grown in Europe. All organic food is certified by the Soil Association."

But it is not easy for consumers to find out what those standards are, and what pesticides or additives are allowed.

The Soil Association's Jack Hunter says that detailed standards covering what farmers can and cannot do or use is available on its website.

"They get fairly technical however and may be a little impenetrable to most consumers, so we've also produced a Consumer Guide To Our Standards," he adds.

Although that guide explores the issues of organic farming, it does not actually list the approved products which can be used to grow organic produce.