The Bellingham Food Co-op is now using biodegradable plastic for its deli containers. The nice server at the Swan Cafe told me they were compostable, but he wasn't sure how fast. So I've been trying it out in my backyard bins these last few months. I've put some in whole, some cut into strips, and with or without first pouring boiling water over them. As yet, nada. The vegies, leaves, and shredded paper are decomposing in their leisurely cold-weather fashion. The plastic looks good as new.
A bit of research tells me that breaking the containers down into CO2, water, and non-toxic organics takes about 6 months in a high-temperature commercial composting facility and closer to a year in a home bin. The actual manufacturer's website, below, says 45 days, but I think that's a marketing fantasy.
These containers are a joint brainchild of Dow and Cargill, and are made from cornstarch--that's three strikes against them in some circles. The technology can also be used to make plastic out of sugarcane, potato, tapioca, cellulose, or soy protein.
My conclusion is that I'll try to remember to bring my own containers to the Swan, and when I forget, I'll be adding my bioplastics to the food-waste tote I share with my nice neighbors. But I am curious if others have hit on a home composting solution.