Minneapolis ? An ultra-secret project begun years ago by two corporate giants broke into the open last week as Coca-Cola and Cargill announced that they have developed a new sweetener from the stevia plant, a South American bush known to locals as honey leaf.

The announcement could upend the world of sweeteners in which aspartame, sucralose and other concoctions are valued for their ability to trick the tongue with sweet tastes that have nothing to do with natural sugar.

Unlike competitors, the new zero-calorie sweetener can claim itself all-natural.

“This has been a closely held secret for a while,” said Zanna McFerson, business director for Cargill Sweetness Solutions, the division that handles the company’s roughly 20 sweeteners.

The new additive would be available in one year at the soonest in countries like Japan, where stevia already is a widely used tabletop sweetener. The sweetener, known for now as rebiana, would appeal to consumers who want a natural alternative, and to companies seeking relief from the pressure that ethanol has put on the price of high fructose corn syrup.

But whether it appears on U.S. food shelves anytime soon is another question.

The stevia plant and its derivatives do not have Food and Drug Administration approval for use as a food additive in the United States, and as recently as 1995 there was an import ban. The FDA has turned down up to three requests since 1989 from food companies to use the plant. The ban was lifted in 1995, but stevia-derived sweeteners have approval only as a dietary supplement in the United States, not a food additive.

A 1985 National Academy of Sciences study raised concerns over stevia and possible liver damage. Some studies also have linked it to infertility in men.

The sweetener has won unfavorable reviews from several major regulatory bodies, including the World Health Organization. A WHO study conducted last year found no evidence that stevia was toxic, but said more study was needed to determine the acceptable daily intake.

Yet stevia sweeteners are approved for food use in 12 countries including China, Japan and Brazil, and it has many supporters in the dietary supplement industry who say it’s the victim of bad science.

The company expects to show through peer-reviewed studies that rebiana should win FDA approval.

A call to the FDA was not immediately returned. The agency published a letter last year stating that “available toxicological information on stevia is inadequate to demonstrate its safety as a food additive or to affirm its status as” safe.

It has shown up on foods imported from Japan, including radishes and seafood, but any food items containing the sweetener are subject to FDA seizure.

The sweetener comes from the leaves of the stevia plant, commonly found in Central and South America.