...from another forum
I've been using a similar product, Evert-Fresh bags for years. They really do work as advertised. You used to be able to find them in the local grocery stores, but other than the web,
http://www.evertfresh.com/ the only place I find them nowadays is West Marine. I've kept romaine lettuce in the fridge for a month and it's still green and crisp with no discoloration.
Like Chris says, stuff needs to be as dry as possible; I don't wash stuff until I'm ready to use it, just put it in the bag from the store. You also need to get as much air out as possible and seal tightly each time.
PS: I was going to compare prices, but the link from the Evert-Fresh site sends me to the Debbie Meyer green bag site. I guess it's a new marketing angle for them.
Anyway, the website is,
http://www.greenbagsdirect.com/
- I'd be interested if anyone has tried them or thinks they might be worthwhile. They're not cheap, but are reusable up to about 10 times and you should use the same bag for the same fruit or vegetable (a bag for romaine, bag for tomatoes, bag for bananas, etc.).