Looks like Taco del Mar has switched to using biodegradable bioplastic plates from Trellis Earth:
http://www.trellisearth.com/index.php?main_page=index&cPath=
“Trellis Earth™ bioplastic plates provide a viable, non-toxic, disposable alternative to plastic plates. Made from corn polymers, starches and complimentary ingredients, our plates are 100% biodegradable. Our unique blend even allows them to be taken straight from the fridge to the microwave for easy and efficient reheating. “
See my report on my experience with Trellis Earth (and another company’s) “biodegradable” plastic bags: NO decomposition after a year in a food composter!
http://millerparkseattle.blogspot.com/2008/10/biodegradable-