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Few Packaging Materials Are Cleared for Use in Holding Food for Irradiation – But That's Not the Whole Story

July 1, 2001

Irradiation has emerged in recent years as an effective and safe way to kill harmful bacteria, including E. coli, salmonella, and listeria, among others, in food and food packaging materials. However, increased use of irradiation (including gamma, x-ray, and, more commonly now, electron beam) to enhance the safety of pre-packaged food is severely limited by the small number of packaging materials and additives cleared for this use in the U.S. Food and Drug Administration regulations.

Specifically, 21 C.F.R. § 179.45 ("Packaging materials for use during the irradiation of pre- packaged foods") lists a limited number of materials cleared for this use. However, it is possible to establish a suitable FDA status for use of materials not listed in Section 179.45 to hold food for irradiation.

In our view, packaging materials that have FDA compliance for contact with the type of food and at the temperatures involved in a particular application may be used to hold such food for irradiation (even in the absence of a listing in Section 179.45) if testing demonstrates no new or increased potential migrants to food above levels considered to be "generally recognized as safe" (GRAS).

Another focus article this month describes our discussions with FDA over the type of testing needed to support a food-contact notification for materials to hold food for irradiation. The same type of testing would be called for as the basis for a self-determination of compliance. This article explores the background for our position that materials not listed in Section 179.45 may be used to package food for irradiation.

I. Background

A substance that meets the Federal Food, Drug, and Cosmetic Act's (the act's) "food additive" definition will be considered "unsafe" unless it is used in accordance with an applicable food additive regulation, an effective food contact notification (FCN),1 or is exempt from such regulation. A "food additive" is defined in Section 201(s) of the act as:

. . . any substance the intended use of which results or may reasonably be expected to result, directly or indirectly, in its becoming a component of food or otherwise affecting the characteristics of any food (including any substance intended for use in producing, manufacturing, packing, processing, preparing, treating, packaging, transporting, or holding food; and including any source of radiation intended for any such use), if such substance is not generally recognized, among experts qualified by scientific training and experience to evaluate its safety, as having been adequately shown through scientific procedures (or, in the case of a substance used in food prior to January 1, 1958, through either scientific procedures or experience based on common use in food) to be safe under the conditions of its intended use. (Emphasis added.)

Under Section 201(s) of the act, sources of radiation are considered food additives even though they are treatment methods for food and are not intended to add anything to the food. Nonetheless, as with all food additives, radiation is not permitted to be used with food unless it is the subject of a food additive regulation, is generally recognized as safe, or is otherwise exempt from regulation. FDA also traditionally has taken the position that packaging materials that will be subject to radiation incidental to the irradiation of pre-packaged food also must be cleared for this use. Thus, under Section 179.45 of the food additive regulations, FDA lists specific packaging materials that may be used with pre-packaged irradiated food.

The agency's primary concerns are to ensure that the material does not undergo a major change when subjected to irradiation and, more importantly, to ensure that the irradiation does not produce low-molecular-weight (volatile) species or radiolytic products in the material that might migrate to food.

II. FDA and USDA Regulations for Irradiating Food

FDA regulates the irradiation of food products under Part 179 of the food additive regulations. In particular, Section 179.26 ("Ionizing radiation for the treatment of food") of the regulations specifies the treatment of foods by way of ionizing radiation. This regulation indicates the sources of radiation that may be used, the types of food that may be irradiated, the purpose for which such food products may be irradiated, and limitations on the dosage of the irradiation that is permitted. The types of food that FDA permits to be irradiated include pork, poultry, red meat products, fresh food (for certain purposes), and spices. Petitions are pending to allow irradiation of additional types of food, including a number of ready-to-eat foods.

The regulation of meat and poultry products in the United States is carried out largely by the U.S. Department of Agriculture by way of its Food Safety and Inspection Service. Under a Dec. 23, 1999, final rule, USDA permits the use of radiation to treat uncooked meat and poultry products.2 This USDA rule is intended to mirror FDA's clearance.

III. FDA Regulation of Irradiation of Pre-Packaged Food

Section 179.25 ("General provisions for food irradiation") of FDA's food additive regulations defines "good manufacturing practice" for purposes of food irradiation. One of its requirements is that "[p]ackaging materials subjected to irradiation incidental to the radiation treatment and processing of pre-packaged foods shall comply with § 179.45." 21 C.F.R. § 179.25(c).

Section 179.45, in turn, lists the materials that may safely be used with each of the three sources of radiation (gamma, electron beam, or X-radiation), subject to the requirement that no induced radioactivity is detectable in the packaging material itself. Previously, the only material cleared in the regulation for electron beam radiation was ethylene-vinyl acetate copolymers; however, FDA's Feb. 16, 2001, final rule expanded the conditions of safe use of X-radiation and electron beam energy sources for all packaging materials currently listed for use with gamma radiation under Section 179.45. 3

While Section 179.45, when read in conjunction with Section 179.25, appears to limit packaging materials for holding food to be irradiated to those that are listed in 21 C.F.R. § 179.45, the official FDA explanation for these regulations invites a more liberal interpretation. Specifically, FDA's April 18, 1986, final rule for the production, processing, and handling of irradiated foods acknowledged that a company can assure the appropriateness of some irradiated packaging through testing (51 Fed. Reg. 13,376 (1986)). The preamble to the 1986 rule states:

[A]ll packaging materials or components of packaging materials that may reasonably be expected to migrate to food must comply with appropriate regulations authorizing their use. Components of packaging materials that have been irradiated may migrate to food to a different degree than components of an unirradiated material. (51 Fed. Reg. at 13,394.)

FDA then notes that there are two aspects to the issue: (1) a packaging material that is irradiated prior to being used with food may degrade or undergo cross-linking or some other change that is significantly different from the non-irradiated material, and (2) packaging material irradiated while in contact with food may produce low-molecular-weight materials that might migrate to food.

In addressing the first issue, FDA states that the irradiated packaging material may be tested to determine whether it is suitable for use in contact with food and complies with appropriate regulations. If so, "no additional regulations are required" (51 Fed. Reg. at 13,395). With respect to packaging material irradiated while in direct food contact, FDA expressed concern that low-molecular-weight materials might be produced that could migrate into food:

[V]olatile materials migrating to pre-packaged foods during irradiation would not have been considered in evaluating whether the packaging material was safe for its intended use, unless the packaging material had been specifically authorized under Section 179.45. Id.

In other words, each food contact material subjected to radiation must be examined to determine whether the radiation affects its otherwise suitable FDA status. In response to several comments complaining that the agency did not discuss packaging materials in its proposed rule, and that this omission might create confusion with respect to 21 C.F.R. § 179.45, FDA added Section 179.25, clarifying "the intended requirement that packaging material containing food during irradiation must comply with Section 179.45" (Id. at 13,395).

There appears to be no basis for the agency to permit a company to test its packaging to assess compliance with existing regulations, where the package is empty, and not permit the same for packaging that holds food when irradiated. Since testing can be conducted that addresses FDA's legitimate concerns about the creation of volatiles (and other potential migrants), in our view the same "self-testing/self-determination of compliance" paradigm should apply to "pre-packaged" foods as to packaging alone.

As discussed below, agency actions regarding packaging of food for irradiation support this position.

A. NASA Rulemaking

In the preamble to its 1995 final rule to allow the irradiation of frozen, packaged meats for use in the National Aeronautics and Space Administration space flight program, FDA concluded that the packaging materials need not comply with Section 179.45, "provided that their use is otherwise permitted by applicable regulation[s]."

In discussing its evaluation, FDA concluded that the "total amount of radiolytic products that could be formed in the packaging materials during irradiation processing, and then migrate to the food and subsequently be consumed by individuals in the spaceflight programs, is too small to be of any toxicological significance."

FDA's determination for astronauts was made easy by the very low dietary consumption of irradiated foods that could be expected. However, even if use is more widespread, in cases where testing conducted on a material demonstrates that irradiation of the material, when filled with food, produces no significant amount of radiolytic products that might become components of the packaged food, a similar conclusion should be available; that is, the amount of radiolytic products, if any, that could be consumed is too small to be of toxicological significance and additional FDA clearance of packaging materials should not be required.

B. Amoco Threshold of Regulation Letter

In a letter to Amoco Corporation, the agency provided an additional strong indication that an explicit listing under Section 179.45 is not required if there is no reason for concern.

In this letter, the agency granted Amoco's request for an exemption under the Threshold of Regulation policy, thus permitting Amoco to market its uncolored polystyrene foam trays, containing certain additional components and adjuvants, for use with pre-packaged irradiated foods. (While polystyrene "film" is listed under 21 C.F.R. § 179.45, polystyrene "foam" is not).

In support of its request, Amoco provided data to the agency that compared the irradiated versus non-irradiated tray, demonstrating that migration to food as a result of irradiation resulted in a dietary concentration below the 0.5 part per billion Threshold of Regulation.

C. Testing to Determine Exposure to Radiolysis Products from Packaging Materials Irradiated in Contact with Food

In most, if not all, cases, testing will be needed to determine whether irradiation of pre-packaged food will create new or increased radiolytic products in the packaging and the extent to which such products may migrate to food. It is only with this type of data that a company typically will be able to make a legitimate self-determination of compliance for a material that is not listed in Section 179.45. Elsewhere in this Monthly Focus section, we report on our ongoing discussions with FDA on the appropriate testing approaches for this purpose.

IV. Conclusion

Given FDA's publicly stated views on pre-packaged foods that are subsequently irradiated, we take the position that any material that is the subject of an applicable food additive regulation or otherwise has an acceptable regulatory status for use in contact with food under the intended conditions of use, other than irradiation (e.g., time, temperature, and type of food contact), may be employed to hold food for irradiation, provided that irradiation does not create additional migrants above a level that can be considered GRAS.

In essence, to the extent that FDA has found the underlying packaging material to be safe, if the irradiated material has not undergone any significant change with respect to the potential for migration of packaging components to the food, such irradiated packaging material may be considered acceptable for such use.

FOOTNOTES

1 The Food and Drug Administration Modernization Act of 1997 amended the Federal Food, Drug, and Cosmetic Act to provide for the submission of notifications for food contact substances in lieu of food additive petitions. Under this program, a manufacturer or supplier of a food contact material may submit a notification to FDA regarding the identity and use of the new food contact substance, along with information supporting the conclusion that the substance is safe for the intended use. If FDA does not object in writing to the notification within 120 days of its receipt, the submitter may market the product. Unlike food additive regulations, the notifications may be relied upon only by the submitter and its customers.

2 Prior to this final rule, USDA permitted the use of irradiation on poultry; however, the Dec. 23, 1999, rule expands and modifies that clearance to make it more consistent with the regulations governing the FDA irradiation of meat products. See 64 Fed. Reg. 72,149, 72,151.

3 See 66 Fed. Reg. 10574. The final rule was promulgated in response to a petition filed by the National Center for Food Safety and Technology (NCFST), Illinois Institute of Technology.