In order to be labeled “organic,” a product, its producer, and the farmer must
meet the USDA’s organic standards and must be certified by a USDA-approved
food-certifying agency. Organic foods cannot be grown using synthetic
fertilizers, chemicals, or sewage sludge, cannot be genetically modified, and
cannot be irradiated. Organic meat and poultry must be fed only
organically-grown feed (without any animal byproducts) and cannot be treated
with hormones or antibiotics. Furthermore, the animals must have access to the
outdoors, and ruminants must have access to pasture (which doesn’t mean they
actually have to go outdoors and graze on pasture to be considered organic. See
also “USDA Certified Organic”.)

More Info:

Myths about Organic Food

What Does the ‘Certified Organic Labeled’ mean?

Q/A about Organic Food

More Info on National Organic Program