[sirmarksalot]

This sounds like a difficult problem, because compostability and shelf stability are contradictory goals. Pretty much by definition, anything that doesn't break down on a store shelf after a day, is going to pile up in the compost pile. It's not a problem for fresh foods intended to be consumed that day, but if your produce bags were compostable, they would not be very useful.

[sfink]

My produce bags are compostable, and they work fine. For one, they don't need to last very long - you can't keep produce for weeks anyway. For another, they mostly only break down in the environment of a municipal composting system, which gets hot and is quite different from your backyard compost heap.

Grocery stores around where i live in the sf bay area seem to be switching to them. I think they tried earlier, but I'm guessing they were too much more expensive?

Quite a marvel of engineering, from what i can tell.

Your point still stands though - shelf packaging needs to be pretty robust.