Always wash pre-washed salad mixes again, and other tips for cleaning greens

Question: Packaged lettuce mixtures cut down on prep time, but they taste vaguely musty, moldy and not really fresh, even though they look fresh and there's no spoilage in the package. Rinsing the lettuce in cold water helped, but the lettuce still doesn't taste totally fresh.

I've purchased a few of the packaged salads and they've never been quite right.

Our favorite food scientist, Shirley O. Corriher, recommends that you buy fresh unpackaged greens. Fill the sink with ice water, then toss in the greens, discarding any that look wilted. Let them sit about 20 minutes. 

Spin the greens dry in a salad spinner, roll them up in paper towels and let them sit for a little while -- I might even refrigerate them overnight.

Remove the greens from the paper towels and put them in heavy, freezer-type plastic bags, along with a sheet of paper toweling that acts as a wick to absorb any excess moisture. Press out all the air and seal the bag. Corriher says if you eliminate all the moisture and oxygen, the greens will easily keep for 2 weeks in the refrigerator.

I would say this to everyone: Those "pre-washed" salad mixes are not clean enough. Always wash them again before using.