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Agency Response Letter GRAS Notice No. GRN 000161

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See also Generally Recognized as Safe (GRAS) and about the GRAS Notice Inventory

CFSAN/Office of Food Additive Safety

April 4, 2005

Eliot I. Harrison
Lewis & Harrison
122 C St., NW
Washington, DC 20001

Re: GRAS Notice No. GRN 000161

Dear Mr. Harrison:

The Food and Drug Administration (FDA) is responding to the notice, dated November 15, 2004, that you submitted on behalf of Engelhard Corporation (Engelhard), in accordance with the agency's proposed regulation, proposed 21 CFR 170.36 (62 FR 18938; April 17, 1997; Substances Generally Recognized as Safe (GRAS); the GRAS proposal). FDA received the notice on December 10, 2004, filed it on December 15, 2004, and designated it as GRAS Notice No. GRN 000161.

The subject of the notice is chlorine dioxide generated from either of two controlled and sustained release (CSR) systems. Engelhard's CSR systems are both powder mixtures composed of sodium chlorite and an activator phase that are incorporated into packaging materials. One CSR system generates chlorine dioxide using sodium chlorite in calcined kaolin clay and the other CSR system generates chlorine dioxide in sulfated kaolin clay. The mixtures are stable when dry. When the mixtures are exposed to at least 25 percent ambient humidity, chlorine dioxide is released in a sustained and controlled manner. Engelhard provides the method of manufacture and specifications for the components of both CSR systems. The notice informs FDA of the view of Engelhard that chlorine dioxide generated by Engelhard's CSR systems is GRAS, through scientific procedures, for use in packaging materials for fresh fruits and vegetables for the purpose of extending the shelf life of the produce contained within the package by exerting a continuous antimicrobial effect.

As part of GRAS notice 000161, Engelhard references GRN 000062. The subject of that notice was chlorine dioxide generated from particles (less than 30 micrometers) composed of sodium polyphosphate, magnesium sulfate, sodium silicate and sodium chlorite that are incorporated into low density polyethylene (LDPE) food-packaging films, at levels not exceeding 17.5 micrograms chlorite/in² of finished package film.

In its notice, Engelhard states that it is anticipated that no residual chlorine dioxide or chlorite ion will remain on the treated food since chlorine dioxide is rapidly converted into chlorite upon contact with organic matter and chlorite is quickly degraded into chloride. Engelhard sponsored a study that investigated the interaction of raspberry extract with the chlorite ion. Engelhard interpreted the results of this study as showing that the chlorite ion reacts with raspberries and thus, the concentration of any chlorite ion formed in fruits treated with chlorine dioxide will be substantially reduced. Any remaining chlorite will then be removed during washing of treated fruits and vegetables.

Therefore, Engelhard concludes that dietary exposure to either chlorine dioxide or the chlorite ion generated by Engelhard's CSR systems in food packaging will be negligible. Engelhard also notes that dietary exposure to the other constituents of CSR systems will not occur since they are enclosed in the packaging materials and will not contact the packaged food.

From your description, the use of this ingredient in packaging appears to represent use as a preservative, with the packaging intended as a vehicle for applying the preservative. Section 403(k) of the Federal Food, Drug, and Cosmetic Act provides that a food shall be deemed to be misbranded if it bears or contains any chemical preservative, unless it bears labeling stating that fact. Section 403(i)(2) of the FFD&C Act provides that a food shall be deemed to be misbranded unless its label bears the common or usual name of each ingredient. Section 403(a) of the FFD&C Act provides that a food shall be deemed to be misbranded if its labeling is false or misleading in any particular. Because Engelhard's use of chlorine dioxide appears to constitute use as a preservative, the ingredient statement on labels of food products that contain chlorine dioxide must comply with the labeling regulations that implement sections 403(k) and 403(i)(2) of the FFD&C Act. For example, 21 CFR 101.22(j) requires that the food to which a chemical preservative is added bear a label declaration stating both the common or usual name of the ingredient and a separate description of its function. Further, food that is subjected to any form of preservation, except as provided in 21 CFR 101.95(c), may not be labeled as fresh. If Engelhard has any questions about the appropriate labeling of this food ingredient, Engelhard should contact the staff in the Office of Nutritional Products, Labeling and Dietary Supplements, Division of Food Labeling and Standards. Engelhard can also reach this Division by telephone at (301) 436-2371.

Based on the information provided by Engelhard, as well as other information available to FDA, the agency has no questions at this time regarding Engelhard's conclusion that chlorine dioxide generated by either of their two CSR systems is GRAS under the intended conditions of use. The agency has not, however, made its own determination regarding the GRAS status of the subject use of chlorine dioxide. As always, it is the continuing responsibility of Engelhard to ensure that food ingredients that the firm markets are safe, and are otherwise in compliance with all applicable legal and regulatory requirements.

In accordance with proposed 21 CFR 170.36(f), a copy of the text of this letter, as well as a copy of the information in your notice that conforms to the information in proposed 21 CFR 170.36(c)(1), is available for public review and copying on the homepage of the Office of Food Additive Safety (on the Internet at


Laura M. Tarantino, Ph.D.
Office of Food Additive Safety
Center for Food Safety and Applied Nutrition

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