These hydrocolloids appear on the National List of exempted and prohibited substances, established by the National Organic Program (NOP) under the Organic Foods Production Act of 1990.
Agar and carrageenan are among 11 exempted synthetic substances added in 2003 that are not automatically given organic status because they are not made from farmed plants.
However, they use no pesticides and contain no additives and so considered deserving of an organic certification.
All exempted substances have to be reviewed every five years, and the two hydrocolloids are due to have their organic status discontinued from November 3, 2008.
They are prepared from red seaweed.
Agar is a gelatinous substance used as a natural vegetarian gelatin replacement in icings, glazes, processed cheeses, jelly and sweets.
Carrageenan is a polysaccharide used in desserts, ice cream, sauces, beer, pates, processed meat and soy milk.
If their organic status is removed, products using the hydrocolloids could no longer claim they are organic.
However, Dennis Seisun, president of IMR International, which carries out market studies on food hydrocolloids, said: "Agar and carrageenan are derived and processed in a way no less organic than many other approved organic ingredients.
We therefore see no justification in removing these two specific hydrocolloids from the approved list."
Because the expiration of these products could cause disruption of well-established and accepted organic production, handling, and processing systems, the NOP is initiating the "sunset review" and renewal process now, in order to provide ample opportunity for public comment.
IMR International has supported a petition to ask the NOSB to maintain their organic status.
It specifically calls for comment from the end-users of hydrocolloids, believing them to carry the most weight with the NOP as it reviews this policy.
Such petitions have worked in the past.
For example, last month the NOSB, voted unanimously to recommend gellan gum for addition to the NOP list after a petition submitted by CP Kelco, which produces gellan gum under its Kelcogel brand.
Tartaric acid, a crystalline organic acid occurring naturally in plants such as grapes, bananas and tamarinds and used to give foods a sour taste, will no longer be allowed after November 3.
The same applies to animal enzymes, calcium sulfate, glucono delta lactone and cellulose, all currently allowed for use in organic handling, Meanwhile, calcium chloride, currently prohibited from use in organic crop production, will be allowed for use after this date.
The NOSB will review the exemptions and prohibitions of the substances designated to sunset, including the public comments received.
The NOSB will then make a recommendation to the Secretary about the continuation of specific exemptions and prohibitions, leading to a proposed rule, which will again provide additional opportunity for public comment.