The new Consumer Reports magazine just had a section on this. They tested various foods in different conditions both in the Green Bags and regular Ziplok bags.
They concluded that in nearly every case, the food kept in the Ziplok bags developed less mold or no mold compared to the Green Bags. Only bananas seemed to last better in the Green Bags than Ziplok
Cook’s Illustrated, published by the folks at America’s Test Kitchen, say that they don’t work very well. And when the zeolite has absorbed all the ethylene it can they are no different from any other plastic bag.
As always, YMMV.
Thanks, all. I think I’ll pass for now… at least until the price comes down.
I’m waffling like the answers in this thread… they sound too good to be true. It’s very hard to keep good produce in the house with only two of us so I was hoping that this “ancient Japanese secret” could save us some cash from the trash.
I’ve got a coworker who swears by them. I prefer to only buy amounts of produce I can eat before they spoil.
You can buy other forms of Zeolite, typically sold for removing odors from enclosed household spaces. We debated as to whether they would be as effective in a cripser drawer, since you’re treating a larger space than that inside a bag, and you have less zeolite surface area available versus the thin coating inside the bags.
Your fruit makes acetylene? Better not light a match! 
it’s ethylene
ethyne, ethene, ethylene, acetylene. BAH! It’s all hydrocarbon to me.
I usually wait until I see a TV product in Walgreens before I get them. The green bags have been there for quite some time but I still haven’t tried them. From this thread I think I’ll wait a bit longer - we have four kids in the house and three more that come to visit on weekends so keeping fruit fresh is not as big of a problem as just keeping the fruit around long enough to eat is.
Oh yeah? Well *my * fruit makes phosgene!