FDA Approves UV-Treated Yeast as a Vitamin D2 Source

On September 25, 2026, the U.S. Food and Drug Administration (FDA) issued a final order authorizing UV-treated, heat-inactivated baker's yeast as a direct food additive to fortify foods with vitamin D2. The decision establishes 21 CFR 172.383, giving food manufacturers another way to add vitamin D in specific food categories, at the same vitamin D2 levels already allowed for vitamin D2 mushroom powder. The order took effect on publication, and objections and hearing requests are due by October 26, 2026.

Key takeaways

• Effective September 25, 2026, the FDA added 21 CFR 172.383, approving UV-treated, heat-inactivated baker's yeast as a source of vitamin D2 in specific food categories.
• The permitted uses and maximum levels are the same, on a vitamin D2 basis, as those for vitamin D2 mushroom powder, covering foods such as breakfast cereals, plant milks, grain products and fruit smoothies.
• The FDA estimated 90th-percentile vitamin D intake from all food sources at 3,170 IU per person per day for ages 1 and older, and said intake is below the Institute of Medicine (IOM) upper limits (ULs) for all population groups with a UL.
• An older additive, vitamin D2 bakers yeast (21 CFR 172.381), is approved as a source of vitamin D2 and as a leavening agent in yeast-leavened baked goods; the new one is heat-inactivated and approved as a source of vitamin D2 in many more categories.
• Public objections and hearing requests remain open through October 26, 2026.

What happened

On September 25, 2026, the FDA published a final order in the Federal Register (91 FR 60796, Docket No. FDA-2021-F-1157, FR Doc. 2026-19656) approving a food additive petition filed by Lallemand Inc., based in Montreal, Canada. The petition (FAP 1A4829) was originally announced for public filing on December 29, 2021 (86 FR 74018), so the petition took nearly five years from filing notice to approval.

The resulting regulation establishes 21 CFR 172.383, which amends the federal food additive regulations to permit the safe use of vitamin D2 inactive baker's yeast. This substance is derived from baker's yeast (Saccharomyces cerevisiae) that undergoes ultraviolet (UV) light exposure to convert naturally occurring endogenous ergosterol into ergocalciferol (vitamin D2). Following irradiation, the yeast is thermally inactivated through heat processing.

Although the regulation took effect on the day of publication, September 25, 2026, the FDA set a window allowing anyone to submit formal objections or request a public hearing. These submissions must be delivered by October 26, 2026. Whether any objections have been filed has not been disclosed by the agency.

What changed

Before this order, the yeast-based vitamin D2 option was vitamin D2 bakers yeast under 21 CFR 172.381, which FDA describes as approved "for use as a source of vitamin D2 and as a leavening agent" in yeast-leavened baked goods, baking mixes and yeast-leavened baked snack foods. The new 21 CFR 172.383 covers yeast that is inactivated with heat after UV treatment, and it is approved as a source of vitamin D2 across a much wider list of foods. The order does not describe any leavening role for it.

The order sets purity specifications for the ingredient. The inactive yeast must satisfy maximum chemical limits for heavy metals: lead at no more than 0.5 mg/kg, arsenic at no more than 0.3 mg/kg, cadmium at no more than 0.5 mg/kg, and mercury at no more than 0.1 mg/kg. It must also test negative for microbiological pathogens, including Salmonella, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa.

The maximum use levels match, on a vitamin D2 basis, the limits established under 21 CFR 172.382 for UV-treated mushroom powder (Agaricus bisporus homogenate). Under 21 CFR 172.383 Table 1, the allowable maximums include:

• Breakfast cereals: 350 IU per 100 g
• Plant-based milk alternatives: 84 IU per 100 g
• Plant-based yogurt alternatives: 89 IU per 100 g
• Extruded vegetable snacks: 80 IU per 28 g
• Fruit smoothies: 100 IU per 240 mL
• Calcium-fortified 100% fruit juices (containing at least 330 mg calcium per 240 mL) and juice drinks (containing at least 100 mg calcium per 240 mL), excluding infant products: 100 IU per 240 mL
• Grain products and pastas: 90 IU per 100 g
• Meal replacement beverages: 500 IU per 240 mL
• Plant protein products: 80 IU per 85 g
• Soups: 100 IU per 245 mL
• Soy spreads: 330 IU per 100 g
• Soy cheese alternatives: 270 IU per 100 g
• Soy beverages: 89 IU per 100 g
• Vegetable juices: 100 IU per 240 mL
• Yeast-leavened baked goods, baking mixes, and baked snacks: 400 IU per 100 g

Who is affected

The order matters most to manufacturers. Makers of plant-based dairy alternatives, breakfast cereals, pastas and baked goods now have another approved vitamin D2 ingredient they may use instead of other approved vitamin D sources, within the same limits.

The order does not make fortification mandatory, and it does not require any brand to use the ingredient.

The calcium-fortified juice and juice-drink category excludes products intended for infants. FDA's intake assessment compared estimated vitamin D intake with the IOM upper limits for each age group, including infants and young children.

What it means for shoppers

Shoppers should not expect product formulations to transform overnight. The FDA order authorizes the use of the ingredient, but whether companies or individual brands plan to reformulate or introduce products using vitamin D2 inactive baker's yeast has not been disclosed. Products containing this specific additive are not confirmed to be on retail shelves at this time.

When reading packaging, note that the FDA requires the Nutrition Facts label to list the actual amount and %DV of vitamin D (the Daily Value is 20 mcg), but the panel does not say which form of vitamin D was added. Vitamin D on the nutrition panel may originate from standard vitamin D3 (cholecalciferol), vitamin D2 (ergocalciferol), UV-treated mushroom powder, or UV-treated baker's yeast.

The final order is silent on naming conventions for ingredient statements under 21 CFR 101.4. The text does not specify whether brands must state "vitamin D2 inactive baker's yeast," "UV-treated yeast," or another designated descriptor. For how vitamins are usually named on ingredient lists, see Niacinamide, Cyanocobalamin: Vitamin Names on Labels Decoded. For the difference between a food additive approval like this one and the GRAS route, see FDA Proposes Ending Self-Affirmed GRAS: What Changes for You.

The background

Ergosterol is a sterol found naturally in yeast. When the yeast is exposed to ultraviolet light, some of its ergosterol is converted into ergocalciferol, or vitamin D2. The FDA concluded that using UV light this way does not pose a safety concern, since "the UV light treatment has been shown not to produce any new components of toxicological concern."

Because the petition mirrored the dietary application categories previously cleared for mushroom powder under 21 CFR 172.382, the FDA described the new uses as "substitutional on a vitamin D2 basis" for the mushroom powder uses and concluded they "are not expected to increase the overall dietary exposure to vitamin D."

FDA relied on its cumulative intake estimates for vitamin D. The agency estimated the 90th-percentile cumulative vitamin D intake for the U.S. population aged 1 year and older from all food sources at 3,170 IU per person per day. FDA said estimated intake at the 90th percentile is below the IOM Tolerable Upper Intake Levels (ULs) for every population group with an established UL. The IOM UL stands at 4,000 IU daily for individuals aged 9 and older, 1,000 IU daily for infants 0 to 6 months, 1,500 IU daily for infants 6 to 12 months, 2,500 IU daily for children aged 1 to 3, and 3,000 IU daily for children aged 4 to 8.

This approval came through a food additive petition under Section 409 of the Federal Food, Drug, and Cosmetic Act, which ends in a published regulation, not through a Generally Recognized as Safe (GRAS) notice. The new section's text does not set a UV dose limit.

What to watch next

The next date is October 26, 2026, the deadline for objections and hearing requests. FDA has not said whether any have been filed.

Over coming quarters, supply chain watchers will track how ingredient suppliers commercialize the material and whether mainstream packaged brands incorporate it into plant milks, ready-to-eat cereals, and fortified bakery items. The Federal Register order does not compare vitamin D2 with vitamin D3.

FDA's safety finding is based on population intake estimates, not on individual health needs. To see how these novel components show up on packaged goods, shoppers can scan nutrition and ingredient labels directly using the Aurascan app.