"On the other hand, Subway recently announced in March 2007 that it has removed the L-cysteine from its otherwise animal product-free Carb Conscious Wrap. When asked about the source of L-cysteine in several of its products, Domino's Pizza told us that L-cysteine is "microbially derived" in its Hand-Tossed Crust and informed us that the L-cysteine in Domino's Breadsticks, Cheesy Bread, and Cinna Stix is "vegetable-derived."
http://www.vrg.org/nutshell/faqingredients.htm#cystine
