Cola by citric or other isolated acids. Coca-Cola's recipe is maintained as a corporate trade secret. A variety of different sweeteners may be added to cola, often partly dependent on local agricultural policy. High-fructose corn syrup (HFCS) is predominantly used in the United States and Canada due to the lower cost of government-subsidized corn. In Europe, however, HFCS is subject to production quotas designed to encourage the production of sugar; sugar is thus typically used to sweeten sodas. In addition, stevia or an artificial sweetener may be used; "sugar-free" or "diet" colas typically contain artificial sweeteners only. In the 1940s, Coca-Cola
Afri-Cola again listed as an ingredient on the label. This mixture was also not sufficiently successful and on April 1, 2006, the company finally changed back to the original recipe, with caffeine content of 250 mg/L. Since then, Afri-Cola has slightly regained market share. In the mid-1990s, Real Soda LLC, a U.S. company, started importing Afri-Cola into the United States, largely in the Seattle area. At the time, it was marketed as "highest caffeine content allowed by law" and positioned to compete with such high-caffeine colas as Jolt Cola and Fukola Cola. In the late 1990s, it was widely available at