Food companies, environmentalists, farmers and some lawmakers have eagerly anticipated a National Organic Standard as grocery shoppers seek alternatives to genetically modified crops and hormone-injected livestock. Agriculture Secretary Dan Glickman was to announce the national definition for foods labelled and sold as "organic" at a news conference. The final rule is expected to be similar to a draft proposal which the USDA published in March.

Under the proposal, the USDA banned all biotechnology and irradiation procedures in organic foods. Meat produced from animals that receive antibiotics could not be labelled "organic". The USDA said once the proposal was finalised, consumers would be able to recognize organic products by a USDA shield on them, similar to the "USDA Prime" identification for beef or the grade labels on egg cartons. Mr Glickman called the March 7 proposal the most comprehensive and strictest organic standard in the world.

Although Congress ordered the USDA to develop uniform organic standards more than a decade ago, the department did not swing into action until two years ago when it proposed a set of rules. That triggered hundreds of thousands of letters, faxes and e-mails from consumers who wanted to ensure the USDA rules would not allow foods labelled as "organic" to be genetically modified or fertilized by sewage sludge and recycled by municipal waste plants.

The US organic industry sold more than $6 billion worth of products, from food to clothing, in 1999. The USDA estimates organic sales will increase by another 20 per cent this year. There are currently 12,000 organic farmers in the United States and that number is rising by 12 per cent each year, while other sectors of farming are seeing a decline in producers. But, the industry said it needed standards to maintain the surge in organic sales.