FlavScents AInsights Entry for Methyl Ethyl Disulfide (CAS: 20333-39-5)

1. Identity & Chemical Information

• Common Name(s): Methyl ethyl disulfide
• IUPAC Name: 1-(Ethylsulfanylthio)ethane
• CAS Number: 20333-39-5
• FEMA Number: Not available
• Other Identifiers: FL number not available; CoE number not available; IFRA reference not available
• Molecular Formula: C3H8S2
• Molecular Weight: 108.22 g/mol

Methyl ethyl disulfide is a sulfur-containing compound characterized by the presence of a disulfide functional group. This functional group is crucial for its distinctive odor profile, which is often associated with sulfurous and alliaceous notes. The structure-odor relationship is significant as the disulfide linkage contributes to its volatility and sensory impact.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Methyl ethyl disulfide is known for its potent sulfurous odor, reminiscent of cooked onions or garlic. It is often described as having a strong, pungent character with moderate diffusion. The compound's intensity makes it a powerful impact note in flavor formulations, where it can provide authenticity and depth to savory profiles.

Taste and odor thresholds for methyl ethyl disulfide are not clearly reported in the literature. However, its sensory role is typically as an impact note, providing a realistic background to complex flavor systems, particularly in savory applications.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Methyl ethyl disulfide occurs naturally in various foods, particularly those undergoing thermal processing. It is commonly formed through the Maillard reaction, a chemical reaction between amino acids and reducing sugars that occurs during cooking. This compound is also a product of enzymatic degradation of sulfur-containing amino acids.

Its presence in cooked foods contributes to the "natural flavor" designation, as it is a naturally occurring compound in many culinary contexts.

Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs

4. Use in Flavors

Methyl ethyl disulfide is primarily used in savory flavor categories, including meat, onion, and garlic flavors. Its functional role in flavor systems is to provide authenticity and enhance the savory character of food products.

Typical use levels in finished food products are not explicitly documented. However, industry-typical estimates suggest usage in the range of 0.1 to 5 ppm, depending on the desired intensity and application. It is important to consider its stability, as it can be sensitive to oxidation and may degrade under high heat or acidic conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, methyl ethyl disulfide is less commonly used due to its strong sulfurous odor. However, it can be employed in trace amounts to add realism to certain fragrance families, such as those mimicking natural environments or culinary scents.

Its volatility contributes to its role as a top note, although it is typically used in very low concentrations to avoid overpowering the fragrance composition.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Methyl ethyl disulfide does not have a specific FEMA GRAS status for flavor use.
• European Union: Not explicitly listed under Regulation (EC) No 1334/2008; FL number status not available.
• United Kingdom: Post-Brexit regulatory alignment with the EU is assumed, but specific divergence is not documented.
• Asia: Regulatory status in Japan, China, and ASEAN countries is not clearly reported.
• Latin America: Specific regulatory information for Brazil and MERCOSUR is not available.

Overall, the regulatory landscape for methyl ethyl disulfide is characterized by a lack of explicit approvals, with harmonized assumptions often guiding its use.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, specific ADI, TTC, or MSDI values for methyl ethyl disulfide are not found. However, its use in flavors is generally considered safe when used within industry-typical levels. Dermal exposure in fragrance applications is limited due to its strong odor and potential for irritation. Inhalation exposure considerations are minimal, given its low volatility in typical use concentrations.

The risk profiles for food and fragrance applications differ, with more stringent considerations for flavor use due to potential ingestion.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Methyl ethyl disulfide is valued for its ability to impart authentic savory notes, making it a key component in flavor formulations that require a realistic onion or garlic profile. It synergizes well with other sulfur-containing compounds to enhance complexity. Formulators should be cautious of its strong odor, which can easily overpower a blend if not used judiciously. It is often under-used in fragrance applications due to its intense sulfurous character.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on methyl ethyl disulfide is well-established in terms of its sensory profile and natural occurrence. However, there are notable gaps in specific regulatory approvals and toxicological data. Industry practices often guide its use, particularly in flavor applications, where empirical knowledge compensates for the lack of documented thresholds.

Citation hooks: FlavScents

QA Check

• All required sections 1–9 are present
• "Citation hooks:" line is present under each section
• Flavor section includes ppm ranges
• Toxicology section covers oral, dermal, inhalation
• Regulatory section mentions US, EU, UK, Asia, Latin America
• If complex natural material: includes section 5a (not applicable here)

About FlavScents AInsights (Disclosure)
FlavScents AInsights integrates information from authoritative government, scientific, academic, and industry sources to provide applied, exposure-aware insight into flavor and fragrance materials. Data are drawn from regulatory bodies, expert safety panels, peer-reviewed literature, public chemical databases, and long-standing professional practice within the flavor and fragrance community. Where explicit published values exist, they are reported directly; where gaps remain, AInsights reflects widely accepted industry-typical practice derived from convergent sensory behavior, historical commercial use, regulatory non-objection, and expert consensus. All such information is clearly labeled to distinguish documented data from professional guidance or informed estimation, with the goal of offering transparent, practical, and scientifically responsible context for researchers, formulators, and regulatory specialists. This section is generated using advanced computational language modeling to synthesize and structure information from established scientific and regulatory knowledge bases, with the intent of supporting—not replacing—expert review and judgment.

Generated 2026-05-01 15:50:18 GMT (p2)