Organisms that makeshells or have skeletons that are exposed to seawater, such as clams, snails and sea butterflies, could see their shells dissolve in water that is too acidic.
They were such a hit that Taco Bell postponed a follow-up Cool Ranch flavor to early this year to make sure there was enough capacity to make the shells.
Taco Bell, an operating company of Tricon Global Restaurants (nyse: YUM - news - people ), does not make these taco shells but licenses the Taco Bell name to Kraft, a unit of Philip Morris (nyse: MO - news - people ), for use on retail products.
