Traditional · Fermented foods
Aspergillus Oryzae Ferment
麹 (Kōji)
Also known as: Koji, Rice Koji
At a glance
| Category | Traditional |
|---|---|
| INCI name | Aspergillus / Rice Ferment Extract (for rice-substrate koji preparations) |
| Japanese labeling name | コウジエキス (for cosmetic extract forms) |
| Common Japanese notations | 麹, コウジ, 米麹 |
| Origin | Fermented (Aspergillus oryzae cultured on rice or other substrate) |
| Typical functions | Fermentation starter (food applications), Skin conditioning (cosmetic applications) |
| Regulatory status in Japan | Aspergillus oryzae is Japan's designated national microorganism. Food applications are regulated under the Food Sanitation Act; cosmetic ferment extracts are listed in the JSCI labeling name dictionary. |
Koji — Aspergillus oryzae cultured on steamed rice — is the organism that makes Japanese fermentation possible. It is the starter for sake, soy sauce, miso, mirin, and rice vinegar, and it is culturally central enough that it was designated Japan's national fungus (kokkin) in 2006. In cosmetics, koji and its extracts connect directly to the fermentation heritage that underpins many Japanese beauty ingredients.
Classification
Tags below link to other ingredients sharing the same attribute, so you can pivot from one ingredient to its peers.
Used in (typical product categories)
Finished-product categories that commonly include this ingredient in Japanese-market formulations.
- Sake, soy sauce, miso, mirin production
- Shio-koji, ama-zake
- Cosmetic extracts positioning around fermentation heritage
What it is
Koji is produced by inoculating steamed rice (or soybeans, barley, or other substrates) with Aspergillus oryzae spores and incubating under controlled temperature and humidity for several days. The resulting fermented material is called koji (specifically rice-koji when the substrate is rice).
Cosmetic applications typically use water or hydro-alcoholic extracts of koji preparations. These extracts concentrate the enzymes, amino acids, polysaccharides, and secondary metabolites produced by Aspergillus oryzae during fermentation.
Typical uses in Japanese products
In food production, koji is the essential intermediate for producing nearly every major Japanese fermented seasoning. The food-grade material is handled under separate food-safety regulation from cosmetic applications.
In cosmetics, koji-derived extracts appear in essences, toners, and fermented-beauty product lines. They are often paired with sake-related ingredients (sake lees extract, rice ferment filtrate) to reinforce a unified fermentation story.
Regulatory classification in Japan
Aspergillus oryzae is Generally Recognized as Safe in food applications under Japanese regulation, with a long history of use.
Cosmetic extracts derived from Aspergillus oryzae fermentation are listed in the JSCI labeling name dictionary under category-specific names (e.g., コウジエキス, コメ発酵エキス).
Regulatory classification in other markets
| EU | Aspergillus oryzae-derived ingredients are listed in CosIng under various fermentation-ingredient INCI names. Permitted for cosmetic use. |
|---|---|
| USA | GRAS status for Aspergillus oryzae in food applications. Cosmetic uses are widely accepted. |
| China | Suppliers should verify their specific cosmetic preparation against IECIC listings. |
| Korea | Permitted as a food and cosmetic ingredient under the relevant regulatory frameworks. |
Example products
Example finished products will be added after each product's current full ingredient list has been verified.
All brand names and product names referenced anywhere on this site are the property of their respective owners. Example entries are provided for informational purposes only and do not imply endorsement.
Related ingredients
References
- Brewing Society of Japan — koji and sake fermentation overview
- JSCI labeling name directory — fermentation-derived extract entries
Last updated: 2026-04-22. Ingredient entries are reviewed at least annually against current regulatory listings.