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United States Department of Agriculture
Washington, D.C. 20250-3700
Irradiation of Meat and Poultry Products

Ionizing Radiation as an Additive in Unrefrigerated, Refrigerated, and Frozen Poultry Products

U.S. Department of Agriculture
Food Safety and Inspection Service

Volume 1 of 1

PETITIONER: United States Department of Agriculture
Food Safety and Inspection Service
ADDRESS: Washington, DC 20250
DATE: August 19, 1999
ADDITIVE: Ionizing radiation
PURPOSE OF ADDITIVE: For control of foodborne pathogens in fresh [refrigerated or unrefrigerated] or frozen, uncooked poultry products that are: (1) Whole carcasses or disjointed portions [or other parts] of such carcasses that are "ready-to-cook poultry" within the meaning of 9 CFR 381.1(b)(44) [with or without nonfluid seasoning; includes, e.g., ground poultry], or (2) mechanically separated poultry product (a finely comminuted ingredient produced by the mechanical deboning of poultry carcasses or parts of carcasses).

Petitions Control Branch
Food and Drug Administration
Department of Health and Human Services
Washington, DC 20204

Dear Sirs:

The undersigned, the Food Safety and Inspection Service (FSIS), submits this petition, pursuant to Sec. 409(b) of the Federal Food, Drug, and Cosmetic Act, with respect to ionizing radiation as an additive used for control of foodborne pathogens in poultry products. In this petition, FSIS is asking the Food and Drug Administration (FDA) to amend its regulation for poultry irradiation (21 CFR 179.26(6)) and thereby change the maximum dose allowed for poultry products from 3 kGy (300 krad), fresh or frozen, to 4.5 kGy (450 krad) for fresh product [refrigerated or unrefrigerated ("hot-boned")] and 7.0 kGy (700 krad) for frozen product. This change in maximum dose would make the poultry regulation consistent with the regulation for irradiation of meat food products. FSIS is also here petitioning FDA to amend Sec. 179.26(6) to remove the requirement that packaging shall not exclude oxygen. FSIS was a petitioner for the original approval of poultry irradiation, granted in 1990.

The petition, enclosed in triplicate, consists of the following sections, in accordance with 21 CFR 171.1:

(A) the name and all pertinent information concerning the food additive;

(B) a statement of the conditions of the proposed use of such additive, including all directions, recommendations, and suggestions proposed for the use of such additive;

(C) all relevant data bearing on the physical or other technical effect such additive is intended to produce, and the quantity of such additive required to produce such effect;

(D) a description of practicable methods for determining the quantity of such additive in or on food, and any substance formed in or on food, because of its use; and

(E) full reports of investigations made with respect to the safety for use of such additive, including full information as to the methods and controls used in conducting such investigations.

Finally, FSIS requests that this petition receive expedited review, as is described in the FDA guidance dated January 4, 1999. The use of sources of ionizing radiation as an additive in fresh or frozen, uncooked poultry products may significantly decrease the incidence of foodborne illness through its antimicrobial effect against human pathogens, including Salmonella spp. and Campylobacter.



Thomas J. Billy


(A) Identification of Food Additive

Sources of ionizing radiation approved in 21 CFR 179.26(a), namely, cobalt-60 or cesium-137 sources, electron beam accelerators, or x-ray generators, are used to treat fresh [refrigerated or unrefrigerated] or frozen, uncooked poultry products with or without nonfluid seasoning, including, e.g., ground poultry, or mechanically separated poultry product.

(B) Proposed Use

Ionizing radiation can significantly reduce the levels of many microbial pathogens commonly found in uncooked poultry and poultry products, including Salmonella spp. and Campylobacter.

On May 2, 1990, FDA issued a final rule (55 FR 18538) permitting the use of ionizing radiation for the control of foodborne pathogens in poultry. In this petition of July 1999, FSIS is requesting that FDA make its regulation governing poultry irradiation consistent with the regulation for meat irradiation by raising the maximum dose from 3 kGy (300 krad), fresh or frozen, to 4.5 kGy (450 krad) for fresh poultry product and 7.0 kGy (700 krad) for frozen poultry product. FSIS is also here requesting that FDA eliminate the requirement that packaging for irradiated poultry product must not exclude oxygen.

The specific poultry products that are irradiated under 21 CFR 179.26 are:

Ready-to-cook poultry, as defined in 9 CFR 381.1(b)(44): any slaughtered poultry free from protruding pin-feathers, vestigial feathers (hair or down as the case may be) and from which the head, feet, crop, oil gland, trachea, esophagus, entrails, mature reproductive organs, and lungs have been removed, and in the case of certain mature poultry, as defined in Sec. 381.179(a) (1)(vi), (vii) and (2)(iv), the kidneys have been removed in accordance with the requirements of Sec. 381.65(d), and with or without the giblets, and which is suitable for cooking without need of further processing. Ready-to-cook poultry also means any cut-up or disjointed portion of poultry or other parts of poultry such as reproductive organs, head, or feet that are suitable for cooking without need of further processing [including, e.g., ground poultry].

Mechanically separated poultry product, as defined in 9 CFR 381.173(a): any product resulting from the mechanical separation and removal of most of the bone from attached skeletal muscle and other tissue of poultry carcasses and parts of carcasses that has a paste-like form and consistency, that may or may not contain skin with attached fat. Mechanically separated poultry product must meet specific provisions of Sec. 381.173(b): bone solids content shall not exceed 1 percent, and at least 98 percent of bone particles present shall be no greater than 1.5 mm in their greatest dimension and no bone particles shall be greater than 2.0 mm in their greatest dimension. Sec. 381.173(c) requires that mechanically separated poultry product not exceed a calcium content of 0.235 percent when made from mature chickens or from turkeys as defined in Sec. 381.170(a)(1)(vi) and (vii) and (a)(2), respectively, or 0.175 percent when made from other poultry, based on the weight of product that has not been heat treated, as a measure of a bone solids content not exceeding 1 percent.

If this petition is granted, any of the above poultry products could be treated with ionizing radiation to a maximum dose of 4.5 kGy (450 krad) for fresh product and 7.0 kGy (700 krad) for frozen product. Further, if this petition is granted, these poultry products may be packaged in materials that exclude oxygen.

In recent proposed regulations concerning the irradiation of meat food products (64 FR 9089; February 24, 1999), the Agency stated its intention to change the poultry regulations to make them as consistent as possible with the meat regulations and with the Agency's Pathogen Reduction; Hazard Analysis and Critical Control Point (HACCP) Systems Final Rule of July 25, 1996 (61 FR 38806). The Pathogen Reduction/HACCP Final Rule requires every federally-inspected meat and poultry establishment to develop and implement science-based process control systems designed to improve the safety of meat food products and poultry products.

FSIS specifically proposed to eliminate its requirements in 381.19 and 381.149 that establishments irradiate poultry only in accordance with Partial Quality Control programs (PQC's). FSIS proposed to require that, as with meat establishments, poultry establishments irradiating product develop and implement process schedules or HACCP plans that account for the irradiation treatment. PQC's contain all or most of the elements required in a process schedule or HACCP plan, and all poultry establishments eventually will be required to implement HACCP (by January 2000). Consequently, FSIS anticipates that this conversion, if the proposal is finalized, will be relatively simple and pose no significant burden.

FSIS also proposed eliminating the requirement that only packaged poultry may be treated with irradiation. FSIS originally adopted this requirement to ensure that the antimicrobial effects of irradiation would be maintained throughout the processing and distribution of the poultry:

To best ensure a reduction of the microbial load on poultry product, FSIS believes that all irradiated poultry would be packaged, in compliance with 21 CFR 179.25 and 179.26, prior to irradiation and remain in the same package through the distribution in commerce to the point of purchase.

(57 FR 19463; May 6, 1992)

Because FSIS is requiring all poultry establishments to develop and implement HACCP plans, this prescriptive packaging requirement is no longer necessary. Under the HACCP requirements, poultry establishments have both the responsibility and the flexibility to determine the best means for reducing hazards within a specific processing environment. A poultry establishment with irradiation as a CCP within its HACCP plan may choose whatever means is appropriate to preserve the antimicrobial effects of irradiation throughout processing and distribution. One result of this proposed revision will be that, as with irradiated meat food products, irradiated poultry products can be used as ingredients in further processed products.

FSIS has also proposed eliminating the minimum dose requirement for irradiated poultry contained in Sec. 381.147(f)(4). FSIS adopted this requirement in its 1992 final regulation to ensure that the irradiation of poultry, which may occur only after the product is packaged for retail sale, does in fact achieve a specific reduction in pathogens. However, as stated above, FDA and FSIS have concluded that different doses of ionizing radiation can be appropriate, in different circumstances, for achieving different technical effects and, therefore, that to continue to require a minimum dose of irradiation for poultry would limit the flexibility needed for the successful implementation of HACCP. FSIS considers irradiation to be just one of many treatments that could be used within a HACCP system to achieve a compounded reduction in pathogens.

The optional labeling statements currently allowed for irradiated poultry in Sec. 381.135(c) are premised upon an establishment employing the minimum dose. As with meat food products, FSIS has proposed instead to approve qualifiers based upon whether a poultry establishment has in place a HACCP plan or process schedule validated as achieving, through irradiation, the elimination or reduction of pathogens indicated on the label (proposed Sec. 381.135(c)).

FSIS further proposed eliminating two of the labeling requirements in Sec. 381.135(a): the requirement that the radura logo on irradiated poultry labels must be colored green and the requirement that "letters used for the qualifying statement shall be no less than one-third the size of the largest letter in the product name.'' The elimination of these requirements will make FSIS requirements consistent with FDA requirements and provide more flexibility for labeling irradiated meat food products and poultry products, without affecting the information content of such labels.

Because FSIS proposed allowing irradiated poultry products to be used as ingredients in further processed products, FSIS also proposed requiring that the ingredient statement on such products reflect the inclusion of irradiated poultry products (Sec. 381.135(b)). For example, an ingredient statement for a sausage product containing irradiated poultry would be required to include an entry such as "irradiated poultry'' or "poultry, treated by irradiation.'' Consumers and consumer advocacy groups have requested that such information be disclosed in the labeling of multi-ingredient food products. This proposed disclosure requirement is identical to the requirement proposed for irradiated meat food product used as an ingredient.

Further, because FSIS proposed allowing unpackaged poultry product to be irradiated, it also proposed labeling requirements for unpackaged, irradiated poultry product sold at the retail level (proposed Sec. 318.135(b)). The proposed labeling requirements are consistent with those proposed for unpackaged, irradiated meat food products and with FDA labeling requirements for irradiated products sold in bulk (21 CFR 179.26(c)(2)).

To further streamline and clarify the regulations governing the irradiation of poultry, FSIS proposed removing the "Definitions'' section from those regulations (current Sec. 381.149(a)). These definitions serve as general references for the PQC requirements that FSIS is proposing to remove from the regulations. Further, these definitions are already acknowledged and understood by irradiation facilities, as they are paraphrases of recognized industry standards.

Under the proposed requirements, FSIS will allow products composed of both meat food products and poultry products to be irradiated. Such products would have to meet the requirements in proposed Sec. 318.7(c)(4) and in existing Sec. 381.147(f)(4) concerning the types of meat food products and poultry products that may be irradiated. Establishments that irradiate combination product in its entirety will be required to meet the current requirements of the FSIS poultry irradiation regulations, namely the maximum radiation dose requirement in 9 CFR 381.147(f)(4) and the air-permeable packaging requirement in 9 CFR 381.149(c)(7). If this petition is granted, establishments irradiating combination product will be required to meet a single standard for meat food products and poultry products. FSIS anticipates that establishments producing low-fat products such as pepperoni or salami, which are composed of both meat food product and poultry product, will be especially interested in irradiation as an antimicrobial treatment before the addition of other ingredients.

Establishments that irradiate fresh or frozen, uncooked poultry and poultry products are required to meet the same requirements proposed by FSIS for establishments that irradiate fresh or frozen, uncooked meat, meat byproducts, and meat food products:

(C) Effectiveness of the Additive

Extensive available scientific data indicate that ionizing radiation can significantly reduce the levels of many of the pathogenic microorganisms of concern in poultry and poultry products, including Salmonella spp., Clostridium perfringens and botulinum, Staphylococcus aureus, Listeria monocytogenes, and Campylobacter.

(D) Measuring the Quantity of the Additive

Dosimetry is the process of measuring an absorbed dose of radiation. Establishments employ dosimetry systems to ensure that each lot of treated product has received the dose defined within its HACCP plan.

As detailed in 9 CFR 381.149, establishments that irradiate poultry food products must have in place: procedures for determining the absorbed radiation dose value from the dosimeter(s); procedures for calibrating dosimeters and other means of measurement (e.g., time clocks and weight scales); procedures for ensuring specific absorbed dosages of irradiation by product unit and product lot; and procedures for verifying the integrity of the radiation source and the processing procedure. The current and proposed dosimetry requirements are based upon standards promulgated by the American Society for Testing and Materials.

(E) Safety of the Additive

In this petition, FSIS is requesting that FDA allow the irradiation of fresh (refrigerated or unrefrigerated) poultry products to a maximum dose of 4.5 kGy and frozen poultry products to a maximum dose of 7.0 kGy (and that the requirement for air permeable packaging be eliminated). FDA already has approved these doses of ionizing radiation for fresh (refrigerated) and frozen uncooked meat food products. Therefore, in this petition FSIS will address only the specific questions that originally led to the differences between meat and poultry in dosage and packaging requirements.

The FSIS choice of a dosage for poultry in its original petition to FDA (October 24, 1986) was based on specific concerns about Clostridium botulinum, an anaerobic, Gram-positive, spore-forming rod that produces a potent neurotoxin. The spores are heat-resistant and in fact proliferate after being heat-shocked; they can survive in foods that are inadequately processed but which processors - commercial or domestic - erroneously believe have been treated properly. Of the seven identified types of botulina, types A, B, E, and F cause human botulism. Foodborne botulism is a severe food poisoning caused by ingestion of food in which the neurotoxin has already formed during growth of the organism. This intoxication is rare - between 10 and 30 outbreaks annually in the United States - but can readily be fatal if not identified and treated immediately. The vast majority of outbreaks were associated with canned foods that have been inadequately processed, almost always by home canners but very occasionally by commercial processors. Although C. botulinum is exceedingly rare in meat or poultry, its potential severity as a health hazard makes it an unavoidable food safety concern.

The 1986 FSIS petition to FDA to approve poultry irradiation limited absorbed dose to 3 kGy (300 krad) and specified air-permeable packaging - both measures were expressly designed to prevent C. botulinum growth and toxin production. Although the 1986 FSIS petition cited no references on this issue, FDA reviewed two pertinent studies during this period by Firstenberg-Eden, Rowley, and Shattuck (1) and Dezfulion and Bartlett (2) that addressed the matter. The Firstenberg-Eden et al. study of 1982 found that Type E C. botulinum-inoculated chicken skins irradiated at 3 kGy retained enough competing microorganisms that spoilage (from lactobacillus and other nonpathogenic organisms) was evident to the senses before botulinal toxin was produced, thereby allowing for a simple but effective safety mechanism. This study also stated that at 5 kGy toxin production preceded noticeable spoilage. The Dezfulion-Bartlett study of 1987 found that Type A and B C. botulinum-inoculated chicken skins irradiated at 3 kGy and incubated at 30 degrees C (86 degrees F) spoiled noticeably and became toxic at approximately the same time - two days; when incubated at 10 degrees C (50 degrees F), chicken skins spoiled at seven to 12 days and produced no botulinal toxin during that period. These results were thought to be particularly significant in that Types A and B are more radiation-resistant than E and F.

As a result of these studies, FSIS and FDA elected to limit absorbed dose to 3 kGy and, knowing that C. botulinum is an anaerobic organism, chose to require aerobic packaging for irradiated poultry.

It has not been shown, however, that these restrictions are either necessary or effective. Indeed, there are very compelling reasons for removing these restrictions on poultry irradiation and making the regulations consistent with those for meat and meat food products.

First, C. botulinum is very rare in meat and poultry. The landmark Greenberg et al. study of 1966 (3) surveyed raw chicken, beef, and pork from packing plants in the United States and Canada over an entire year and found one sample out of 2358 that was positive for C. botulinum. This sample, a chicken, had a very low count of clostridia and just a single spore of C. botulinum Type C, which has not been identified as a human pathogen. Type E C. botulinum was a concern for some time because it was thought that Type E could contaminate fish meal used as chicken feed, but in recent years fish meal has been almost completely replaced by high-protein soybean and corn meal.

Second, C. botulinum occurs in very low numbers. All studies have used inoculations of huge numbers, orders of magnitude greater than anything that is likely to be found on a meat food product or poultry product.

Third, several studies have shown that the growth of C. botulinum and other pathogens is inhibited by nonpathogenic lactic acid-producing bacteria (such as lactobacillus) that predominate in and on irradiated raw chilled meat, surviving doses up to 5 kGy (4), and flourish in anaerobic environments (5, 6, 7). The lactic acid-producers accomplish this through production of both acid and bacteriocin, as well as by competing successfully with pathogens for nutrients. Another study (8) has indicated that the ability of anaerobic lactic acid-producers to flourish under anaerobic conditions, and thereby successfully inhibit growth of C. botulinum and other pathogens, argues for vacuum packaging rather than the oxygen-permeable packaging required now. The Firstenberg-Eden et al. study cited above (1) tested inoculated samples under two temperatures - 10 degrees C (50 degrees F) and 30 degrees C (86 degrees F). It found that irradiated samples produced no toxin at 10 degrees C, whether incubated aerobically or anaerobically; at 30 degrees C, samples produced toxin whether aerobic or anaerobic. The inference may be drawn that aerobic conditions have less of a beneficial effect than has been thought.

Fourth, it has been shown that C. botulinum does not grow or produce toxin when handled under appropriate temperatures, and particularly at the very low numbers that are likely to occur if at all. The Firstenberg-Eden et al. study cited above (1) indicates that temperature is likely to be the key factor: At 10 degrees C irradiated samples produced no toxin. Numerous other studies have shown similar results.


In light of these complex research findings and its new HACCP requirements described above, FSIS believes that these prescriptive requirements of the poultry regulations are no longer necessary. Years of research studies have not produced a simple picture of C. botulinum in meat food products and poultry products and thus there is no single "magic bullet" that will prevent its growth and toxin production. Under HACCP, poultry establishments have both the responsibility and the flexibility to determine the best means for controlling any hazards that could conceivably result from the irradiation of poultry at the higher doses allowed for meat or in anaerobic packaging.


  1. Firstenberg-Eden, R., D.B. Rowley and G.E. Shattuck. 1982. Factors Affecting Growth and Toxin Production by Clostridium Botulinum Type E on Irradiated (0.3 Mrad) Chicken Skins. J. Food Protection 47: 867-870.

  2. Dezfulion, M. and J.G. Bartlett. 1987. Effects of Irradiation on Growth and Toxicity of Clostridium Botulinum Types A and B Inoculated onto Chicken Skins. Appl. Environ. Microbiol. 53(3): 201-203.

  3. Greenberg, R.A., R.B. Tompkin, B.O. Bladel, R.S. Kittaka, and A. Anellis. 1966. Incidence of mesophilic Clostridium spores in raw pork, beef, and chicken in processing plants in the United States and Canada. Appl. Microbiol. 14(5):789-793.

  4. Hastings, J.W., W.H. Holzapel and J.G. Niemand. 1986. Radiation resistance of lactobacilli isolated from radurized meta relative to growth and environment. Appl. Environ. Microbiol. 52(3):201-203.

  5. Matilla-Sandholm, T. and E. Skytta. 1991. The effect of spoilage flora on the growth of food pathogens in minced meat stored at chilled temperature. Lebensm-Wiss & Technol. 24:116-120.

  6. Lambert, A.D., J.P. Smith and K.L. Dodds. 1991a. Shelf life extension and microbiological safety of fresh meat: A review. Food Microbiology 8:267-297.

  7. Lambert, A.D., J.P. Smith and K.L. Dodds. 1991b. Combined effect of modified atmosphere packaging and low-dose irradiation on toxin production by Clostridium Botulinum in fresh pork. J. Food Protection 54:94-101.

  8. Lambert, A.D., J.P. Smith and K.L. Dodds. 1991c. Effect of Headspace CO2 concentration on toxin production by Clostridium Botulinum in MAP, irradiated fresh pork. J. Food Protection 54:588-592.

Note: Copies of the reference articles are available for viewing in the FSIS Docket Room. The articles will not be made available on this Web site due to copyright restrictions.



For Further Information Contact:
Director, Regulations and Directives Development Staff
Food Safety and Inspection Service, USDA
Phone: (202) 720-5627
Fax: (202) 690-0486
E-mail: daniel.engeljohn@usda.gov