1400 Independence Avenue, S.W.

Room 2646-S, Ag Stop 0268

Washington, D.C. 20250-0268

1 

March 12, 2021 

MEMORANDUM TO THE NATIONAL ORGANIC STANDARDS BOARD

FROM: Jennifer Tucker, Ph.D. 

 Deputy Administrator

 National Organic Program 

SUBJECT: Request to Review Lithothamnion Classification

The National Organic Program (NOP) requests that the National Organic Standards Board 

(NOSB) provide recommendations related to the eligibility of Lithothamnion to be certified 

organic. The NOP is requesting the NOSB’s recommendation(s) to help address inconsistencies 

between certifiers and to ensure that organic operations, certifiers, and other interested parties 

have an opportunity to provide input. The NOP requests the NOSB address the classification of 

collected Lithothamnion as “agricultural” or “nonagricultural” and if it may be certified as a 

“wild crop” under the USDA organic regulations. 

Lithothamnion is a genus of coralline marine red algae containing calcareous deposits within its 

cell walls. Lithothamnion is also referred to as “calcified seaweed,” “seaweed-derived calcium,” 

“maerl,” and “calcified maerl.” Ground Lithothamnion is used in processed products as a source 

of calcium. A U.S. Food and Drug Administration (FDA) generally recognized as safe (GRAS) 

notice has been published for seaweed-derived calcium for the intended use: “in foods in general 

as a source of dietary calcium for food enrichment and fortification purposes at various levels 

that range up to 4.0 percent.”1

A Lithothamnion product was petitioned to be added to the National List in February 2007 (see 

“Calcium, Seaweed Derived” on the Petitioned Substances USDA webpage).2 In 2008, the 

NOSB recommended that “calcium, seaweed derived” did not need to be considered for addition 

to 205.605(a) “since use of this material is currently allowed through the existing listing of 

Nutrient Minerals on the National List §205.605(b).” 

Since the NOSB recommendation, the NOP has received questions about whether USDA organic 

regulations allow the certification of Lithothamnion. Organic certification allows organic 

handlers to use ingredients in organic products without the content counting as part of the 5 

percent nonorganic ingredient component. The NOP previously informed a certifier that 

Lithothamnion is a nonagricultural product and therefore cannot be certified organic. Since then, 

1

https://www.cfsanappsexternal.fda.gov/scripts/fdcc/?set=GRASNotices&id=28&sort=GRN_No&order=DESC&startrow=1&type=column&search=GRN%20No%2E%C2%A4DECIMAL%C2

%A428

2 The petition and NOSB recommendation can be found under “calcium, seaweed derived” at: https://www.ams.usda.gov/sites/default/files/media/Calcium%20Seaweed%20Petition.pdf
1400 Independence Avenue, S.W.

Room 2646-S, Ag Stop 0268

Washington, D.C. 20250-0268

2

the NOP has learned that two certifiers certify Lithothamnion under the wild crop portion of the 

USDA organic regulations. Additionally, seven operations are certified to handle organic 

Lithothamnion, identified in the Organic Integrity Database as: “Lithothamnium,” 

“Lithothamnion superpositum,” “Lithothamnion sp.,” “Lithothamnion,” and “Lithothamnion

calcareum.”

Certifiers that the NOP consulted provided the following information:

• Certifiers did not clarify how an agricultural determination was made.

• Lithithamnion superpositum algae species have life spans between 50-100 years and 

appear to favor the volcanic sand/gravel deposits along the coastline shelves near to the 

shore of Iceland, most concentrated in the West Fjords. During their life span, the algae 

fronds accumulate seawater minerals, calcifying the fronds. Calcified pieces of the algae 

break off the live plants, and currents move this material to lower shelves further 

offshore.

• Harvesting in Brazil is done by dredging dead calcareous skeleton sediment material of 

Lithothamnion algae (algae shells), that has detached and accumulated in deposit areas by 

tide movements, from deep waters off the continental shelf of Brazil. State Secretariat for 

the Environment and Natural Resources - SEMA of the State of Maranhão in Brazil 

issues licensing for this processing as “biodetritic limestone.” Harvesting in Iceland is 

done by dredging calcified marine algae from (dead) Lithothamnion sp. from mines in the 

sea (100 yards or more offshore, avoiding the live plants) in fjords.

• After harvest, Lithothamnion is washed/heat treated, dried, milled, and packaged.

We are requesting the NOSB’s recommendation(s) to help us address inconsistencies between 

certifiers and to ensure that organic operations, certifiers, and other interested parties have an 

opportunity to provide input.

We thank you in advance for your work on this topic, and we look forward to your 

recommendations.