The Coca-Cola Co. (NYSE: KO) is expected to launch a drink this week with an ingredient that has not yet received Food & Drug Administration approval, according to The Wall Street Journal. The new drink is a non-carbonated juice containing a natural, calorie-free sweetener made from the herb stevia.

Coke plans to market three juice drink flavors in its Odwalla line using this natural, noncaloric sweetener. PepsiCo Inc. (NYSE: PEP) also has several drinks ready to go in the U.S. market using stevia. There's only one little problem, though. The FDA has approved stevia only as a dietary supplement, but labeled it an "unsafe food additive" in 1991 because some studies suggested adverse health effects from stevia-based products. Companies working with Coke and Pepsi to make the sweetener have submitted new data to refute that but have yet to receive approval.

Thing is, it seems an approval isn't actually required under the FDA's voluntary program for new ingredients. Already Cargill Inc., which makes Coke's stevia-based sweetener, is marketing and selling a table-top version, called Truvia. So while Pepsi is holding its new drinks while waiting for the FDA's blessing, Coke may not wait and could unveil the drinks in the U.S. before the approval.