Organic: Most of us have a rough idea what organic means: grown without synthetic pesticides, herbicides, or fertilizers, on land that has been clean for at least three years. No sewage sludge as fertilizer, no genetically modified organisms (GMOs: see below). Food must not be irradiated. For animal products, no anti-biotics or synthetic hormones, and the animals must be fed organic feed containing no animal by-products. (A recent amendment to national organic standards allows animals to be fed non-organic feed if it costs less than half of organic feed).