Food that is farmed, processed and distributed in a way that does not damage the environment and, if possible, boosts the local ecosystems. Organic farming avoids the use of man-made pesticides and fertilisers. It also promotes high standards of animal welfare and keeping livestock in as natural a condition as possible.
What qualifies as organic food?
Farms must meet minimum national and European standards if they want to label their produce organic. In Britain, farms can also opt to have their food certified by one of 11 independent bodies. Of these the best known is the Soil Association, which boast the "highest and most comprehensive standards in the world".
Do customers care?
Yes. Last year British shoppers bought £1.6bn worth of organic food - 30% more than in the previous year. It is now so popular that supermarkets are struggling to keep pace with demand.
What's the problem?
Critics claim that bodies like the Soil Association are under pressure from the supermarkets to relax their standards by accrediting industrialised farming techniques, to help increase supplies. They claim the association is "betraying" its values by certifying as organic farming methods that go against its ethos.
Salmon farming. One of the association's trustees has resigned in protest after it said salmon farms could be classed as organic. But there is also concern about compromises in the standards for poultry farming.
What's wrong with salmon farming?
Fish are kept in cages and their waste is not recycled. It also reduces the biodiversity in the farmed area and the water around it by shutting out other water life. Organic purists say the only organic salmon is a wild salmon.
How can farmed salmon be classed as organic?
Their food is natural and the fish are typically given twice as much room to swim around than those that are conventionally farmed. Organic salmon farms are also located in tidal sea water rather than lochs. Not all the waste is recycled but it can be used to encourage the farming of shellfish such as oysters in the same stretch of water.
What's the problem with organic poultry?
The Soil Association says chicken farmers should limit capacity in their sheds to 500 birds, but it still certifies farms with up to 2,000 birds per shed. It also allows mechanisation in brooding and hatching, and chicks can be reared from non-organic broods. Beak trimming, to prevent birds pecking each other, is also permitted. Critics say this practice is only necessary when birds are under stress.
How does the Soil Association respond?
It admits that its standards on salmon farming and poultry involve the most compromise. But it insists it is sticking to principles of sustainable farming and that it continues to raise the quality of food in the public's interest. It claims that organic salmon farms are much better for the environment and are necessary given the depletion of ocean fish stocks. On poultry, it says its standards are getting tougher. For example, it is trying to phase out beak trimming in organic farms.
What do the supermarkets say?
They deny putting pressure on the association and other bodies to lower standards. But they also warn that British supplies of organic food are low. The biggest shortages are of organic milk, beef and apples. Sainsbury's says it can get only 30% of the organic milk it needs from Britain. Tesco has begun importing organic beef from Argentina.
What's wrong with importing organic food?
It flouts one of the key principles of the organic food movement - to "buy local" - by racking up thousands of food miles. Organic foodies say that shipping in organic food from abroad is "illogical" and should be made more expensive to stop supermarkets doing it.