SUPPLEMENTARY INFORMATION:

Section 203(c) of the Agricultural Marketing Act of 1946 (7 U.S.C. 1621-1627), as amended, directs and authorizes the Secretary of Agriculture “[t]o develop and improve standards of quality, condition, quantity, grade, and packaging, and recommend and demonstrate such standards in order to encourage uniformity and consistency in commercial practices.”

AMS is committed to carrying out this authority in a manner that facilitates the marketing of agricultural commodities and makes copies of official standards upon request. The U.S. Standards for Grades of Fruits and Vegetables which no longer appear in the Code of Federal Regulations (CFR) are maintained by AMS at www.ams.usda.gov/​grades-standards. AMS is revising the U.S. Standards for Grades of Mushrooms (the Standards) using the procedures that appear in part 36 of title 7 of the CFR (7 CFR part 36).

Background

On April 2, 2020, the American Mushroom Institute (AMI), a trade association representing growers, retailers, and shippers from the United States, petitioned AMS to revise the Standards. From 2020 to 2024, AMS worked closely with AMI to provide guidance and discuss the proposal, including relevant revisions. In its petition, AMI stated that USDA standards for mushrooms do not conform to current industry practices, and no standards for “Portabella” mushroom varieties exist. AMI also requested new definitions to cover defects that are not currently defined in the Standards. AMS reviewed and incorporated recommendations from AMI's petition and subsequent feedback into this revision, which reflects a collaborative effort between AMS and industry. The updates to the Standards, identified below, affect definitions, grades, size, and defects of mushrooms. On April 10, 2026, AMS published in the Federal Register (91 FR 18390; Docket No. AMS-SC-25-0056) a Notice and request for comments (Notice) on proposed revisions to the Standards. AMS also made publicly available AMI's petition for proposed changes to the Standards and a discussion draft of the Standards implementing such proposed changes.

Through this action, AMS is implementing the following revisions to the Standards to align with modern production, handling and harvesting practices, and to provide guidance for the effective utilization of this commodity:

• Add a new “General” section (51.3385) to describe the types of mushrooms covered by the Standards: theAgaricus bisporus species of cultivated white button, brown button (commonly called crimini or cremini (alternative spelling), baby, and baby bella), and portabella (including portobello (alternative spelling), ports, and giant crimini) mushrooms.
• Redesignate existing sections 51.3385 through 51.3398 as sections 51.3386 through 51.3399.
• Add a new grade section (51.3388) “U.S. No. 1 Portabella” and its associated tolerances in section 51.3389(a)(3).
• Remove tolerance and size specifications from the criteria for each grade and create new separate sections (51.3389 and 51.3391, respectively) for those specifications.
• Revise the definition of “Open veils” (now section 51.3392(f)) to allow for a small degree of exposed gills before open veils are considered damage (materially detracting) in mushrooms other than portabella mushrooms, while also recognizing that open veils are a characteristic of and are not considered damage in portabella type mushrooms.
• Add a separate tolerance for open veils “at shipping point” for U.S. No. 1 grade button mushrooms (section 51.3389(a)(1)(i)).
• Revise the defect tolerances for “at shipping point” and “en route or at destination” for both U.S. No. 1 and U.S. No. 2 grades (section 51.3389 (a)(1)-(2)).
• Reorganize and update the definition section to reflect current industry practices and terminology, and revise “Damage” to now include the following specific defects that are considered as damage: “Bruising,” “Cuts or mechanical defects,” “Discoloration,” “Extraneous material,” “Feathering,” “Open veils,” and “Spots” (now sections 51.3392(a)-(g)). The existing defect at current 51.3395(b) (“Dirt when any amount is embedded in the cap or stem”) is now included under “Extraneous Material” at new 51.3392(d).
• Revise “Application of Tolerances” section (now 51.3390(a)-(c)) to establish different package tolerance limits based on the size of the packaging. The “Application of Tolerances” section of the Standards identifies the maximum limit of defects and off-size mushrooms that are allowed in an individual package of mushrooms.
• Add language to the newly designated grades provisions for “U.S. No. 1” (section 51.3386), “U.S. No. 1 Portabella” (section 51.3388) and definition of “Similar varietal ( printed page 54846) characteristics” (section 51.3398) to permit mixed specialty packs of white and brown mushrooms. When lots are not intentionally packed as mixed/specialty packs, a dissimilar colored mushroom is considered a defect. This revision recognizes mixed color specialty packs and better reflects current marketing trends.

Comments

AMS provided a 60-day comment period for interested parties to submit comments on the proposed grade standards. In response to its request, AMS received and considered 9 comments. All comments were posted on www.regulations.gov. All 9 commentors expressed their support for the proposed revisions to the U.S. Standards for Grades of Mushrooms.

AMS is moving forward with the revisions to the U.S. Standards for Grades of Mushrooms as proposed by the American Mushroom Institute, as these updates will provide the clarity and consistency industry seeks by better aligning with modern mushroom production practices and current marketing trends.

Authority:7 U.S.C. 1621-1627.

91 FR 54845