WASHINGTON — The U.S. Department of Agriculture’s National Organic Program reported changes to its National List of Allowed and Prohibited Substances in the May 28 Federal Register. Changes related to food processing involved annatto extract color, beta-carotene extract color, silicon dioxide and potassium hydroxide.

The National List identifies synthetic substances that may be used and the non-synthetic (natural) substances that may not be used in organic production.

The National Organic Program has removed the allowance for non-organic annatto extract color from the National List for organic handling. The rule became effective May 29. The National Organics Standards Board determined annatto extract color is commercially available in organic form in sufficient quantities for organic handling.

An amendment to the National List said beta-carotene extract color is derived from carrots or algae. The amendment became effective May 29.

The N.O.P. has permitted silicon dioxide as a defoamer and for other uses when organic rice hulls are not commercially available. The amendment will become effective Nov. 3.

Ribus, Inc., St. Louis, provides organic alternatives to synthetic ingredients that are made from rice hulls.

“The Organic Foods Production Act of 1990 and U.S.D.A. regulations prohibit the use of any substances in organic production and processing that do not comply with this list, and we are thrilled that silicon dioxide is now on the prohibited list in most cases,” said Steve Pierce, president of Ribus.

He added, “At Ribus, it is our intention to be an information center and to assist our customers and all producers during this transition period. We have the technical know-how to assist in just about any application, and we manufacture the patent-pending, sustainable organic rice hull product, Nu-Flow, which effectively (and organically) replaces silicon dioxide in applications that require anti-caking or flow aids.”

Another amendment said potassium hydroxide is prohibited for use in lye peeling of fruits and vegetables except when used for peeling peaches. The amendment became effective May 29.

U.S. sales of organic food and non-food were $31.5 billion in 2011, which compared with $1 billion in 1990, according to the N.O.P.