Salad-in-a-bag is a real time-saver for time-stressed families, but does it need to be washed before use?

Not if the bag is labeled "prewashed" or "ready to eat," which indicates that the greens inside have been dipped in a bacteria-killing chlorine solution before packing. If these words aren't clearly marked on the package, there's no guarantee that the salad inside has been treated. In that case, it should be washed under cool, running water before use.

Although the chlorine bath kills most of the bacteria in ready-to-eat and prewashed salads, it rarely gets all of them. So, be sure to store these convenient greens in the refrigerator and observe the "use by" date.

Mixed greens displayed in open containers on grocery store shelves, on the other hand, should always be washed before use, even if the box is labeled "prewashed" or "ready to eat," because they've been left uncovered and exposed to the hands of shoppers.