California has implemented a law requiring folic acid in corn tortillas, a staple in many Latino households, which could reshape grocery shelves nationwide and prevent birth defects that disproportionately affect Hispanic babies. The law took effect on Jan. 1, but its impact is only becoming clearer as manufacturers standardize products and other states consider similar moves. Folic acid, a B vitamin, prevents serious birth defects of the brain and spine early in pregnancy and can significantly reduce these. However, corn masa flour, a popular ingredient in tortillas and other staples, was left out of the mandate. The change is causing a divide within the tortilla industry, with large manufacturers able to scale fortification nationwide, while smaller, artisanal makers are often exempt. Critics argue that fortification could interfere with consumer choice and food traditions.