Not sure, but I know at home my husband gets them all the time. Most Mexican restaurants have these for their Mexican patrons, if you ask for them, they will sell them to you. They actually have two menus, an authentic Mexican menu and a Tex-Mex menu. If you're a "gringo" they automatially bring you the Tex-Mex menu, unless you request the other.
My husband learned about them from a coworker who is from Mexico.
Equal opportunity cruiser since 1998-4 Carnival, 4 RCI, 3 HAL, 3 Princess, 5 Celebrity, 3 NCL, 1 Disney
I have now achieved-
ONE HUNDRED DAYS ON A CRUISE SHIP!!!!!!!!!!
146 days total