At home, wash leafy greens under cold running water before you eat them; rinse even the tightly packed leaves in the interior. One method of washing: immerse loose greens in a large pot of cool water and allow a minute or two for debris to sink to the bottom. (Crinkled greens like spinach may need three rinses.) Then place the greens in a colander and wash them under running water. Discard the outer leaves of lettuce and cabbage heads. Use a salad spinner to dry the greens, or pat them dry with a clean cloth or paper towel.
When buying packaged greens, don’t assume that everything in cellophane or plastic has been washed. The label should say “prewashed,” “triple-washed” or “ready to eat.” The Food and Drug Administration (FDA) says these prewashed greens are safe to eat without further washing because they are processed in facilities more sanitary than the average home kitchen. Should you still rewash? Some experts say that rewashing only ups the risk of contamination, but others recommend it. Prewashed greens are costly—so just buy unwashed greens if you are planning to wash them anyway.
Organic greens are no safer than conventionally grown ones. They must be washed in the same way. The same is true of locally grown produce or even greens from your own garden. Outbreaks from big processors get the most publicity, but that doesn’t mean local is always clean.