The FDA's Definition of a Natural Flavor
To understand the nuances of stevia labeling, one must first consider the FDA's official definition of a "natural flavor." The FDA defines a natural flavor or flavoring as a substance extracted, distilled, or similarly derived from natural sources, including plant material. Its "significant function in food is flavoring rather than nutritional". This distinction between an ingredient's primary function—whether it's sweetening or flavoring—is the cornerstone of stevia's regulatory status.
Stevia's Regulatory Status: Sweetener vs. Flavor Modifier
Stevia's legal status is a tale of two products: the whole leaf and the highly purified extract. Since 2008, the FDA has granted "no objection" letters for the Generally Recognized as Safe (GRAS) status of highly purified steviol glycosides (with at least 95% purity) for use as a general-purpose sweetener. Conversely, whole stevia leaves or crude extracts have not been approved for use as food additives due to insufficient toxicological data.
Stevia as a High-Intensity Sweetener
When purified steviol glycosides like Rebaudioside A (Reb A) are used to add significant sweetness to a product, they must be labeled as a sweetener. The intensity of sweetness, often 200–400 times sweeter than sugar, places them in a category where their primary function is clearly sweetening. Labeling regulations in many countries mandate that the ingredient be identified as a sweetener based on steviol glycosides.
Stevia as a Flavor with Modifying Properties (FMP)
This is where the gray area for "natural flavor" labeling emerges. Certain stevia derivatives, such as enzymatically modified steviol glycosides, can be used at sub-sweetening levels (below the threshold of detectable sweetness) to modify other flavors. Their function is not to add sweetness but to reduce bitterness or enhance other notes in the product's flavor profile. In these specific applications, guided by standards from the Flavor and Extract Manufacturers Association (FEMA), these stevia-based ingredients can potentially be listed as a natural flavor or natural flavoring. This is only possible if they meet the strict criteria for having a demonstrable flavor-modifying effect without imparting a sweet taste.
The Extraction and Processing of Stevia
The journey of stevia from a plant to a refined ingredient is extensive, which is a key factor in its regulatory status. The process typically involves:
- Harvesting and Drying: Stevia leaves are harvested and dried to preserve the sweet compounds, known as steviol glycosides.
- Water Extraction: The dried leaves are steeped in hot water, similar to brewing tea, to dissolve the steviol glycosides.
- Purification: The watery extract undergoes multiple purification stages. This includes filtering to remove leaf particles, treating with activated carbon to remove organic matter and color, and ion exchange to remove minerals.
- Concentration: The glycosides are concentrated into a resin.
- Crystallization: The extract is recrystallized multiple times to separate different types of steviol glycosides and increase the purity of desirable compounds like Reb A.
- Drying: The final highly purified steviol glycoside crystals are dried.
This multi-stage refining process differentiates the final ingredient from the raw plant material. Crude stevia extracts, which are less than 95% pure, do not have GRAS status and are subject to import alerts.
Comparison Table: Stevia as Sweetener vs. Flavor Modifier
| Feature | Stevia as a Sweetener | Stevia as a Flavor Modifier |
|---|---|---|
| Ingredient Purity | Must be at least 95% pure steviol glycosides for GRAS status. | Typically enzymatically modified steviol glycosides. |
| Primary Function | To provide intense, low-calorie sweetness. | To mask bitterness or enhance other flavors at sub-sweetening levels. |
| Dosage | Used in amounts necessary to achieve desired sweetness. | Used at levels below the sweetness detection threshold. |
| Labeling | Must be labeled as a sweetener based on steviol glycosides. | Can potentially be labeled as a "natural flavor". |
| Regulatory Pathway | Requires GRAS status for intended use as a sweetener. | Requires adherence to FMP guidelines and use limits. |
Conclusion
While public perception might simplify stevia into a single, straightforward ingredient, its regulatory reality is far more complex. The FDA and other global authorities recognize a critical difference between high-purity steviol glycoside extracts and crude stevia leaves. High-purity extracts, used primarily for sweetening, must be labeled as sweeteners. However, certain modified steviol glycosides used at very low, sub-sweetening levels to improve a product's flavor profile can qualify as a "natural flavor." The key determining factor is the ingredient's function in the final food product, not simply its plant-derived origin. Manufacturers must navigate these precise regulatory guidelines to ensure accurate and legal labeling.
Navigating Stevia Labeling: Key Factors to Consider
- Ingredient Purity: Only highly purified steviol glycosides (≥95%) have GRAS status for use as a sweetener in the US, while crude extracts are not permitted.
- Functionality is Key: An ingredient's primary function—whether sweetening or modulating flavor—determines its proper labeling.
- Sub-Sweetening Levels: Stevia derivatives can be labeled as a natural flavor only when used below the sweetness threshold to modify other flavor attributes.
- Regulatory Body Guidelines: Groups like FEMA provide guidance for how stevia can be used as a flavor with modifying properties, which is respected by regulators.
- Label Transparency: To avoid consumer confusion, clear ingredient labeling that specifies the type of stevia extract is often required.
- Global Variation: Labeling regulations can differ significantly by country, so international manufacturers must comply with multiple standards.
