21 CFR § 579.22 - Ionizing radiation for treatment of animal diets.

---
identifier: "/us/cfr/t21/s579.22"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 579.22 - Ionizing radiation for treatment of animal diets."
title_number: 21
title_name: "Food and Drugs"
section_number: "579.22"
section_name: "Ionizing radiation for treatment of animal diets."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "E"
subchapter_name: "ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS"
part_number: "579"
part_name: "IRRADIATION IN THE PRODUCTION, PROCESSING, AND HANDLING OF ANIMAL FEED AND PET FOOD"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "21 U.S.C. 321, 342, 343, 348, 371."
cfr_part: "579"
---


# 579.22 Ionizing radiation for treatment of animal diets.

Ionizing radiation for treatment of complete diets for animals may be safely used under the following conditions:

(a) *Energy sources.* Ionizing radiation is limited to:

(1) Gamma rays for sealed units of the radionuclides cobalt-60 or cesium-137.

(2) Electrons generated from machine sources at energy levels not to exceed 10 million electron volts.

(b) *Uses.* (1) The ionizing radiation is used or intended for use in single treatment as follows:

| Food for irradiation | Limitations | Use |
| --- | --- | --- |
| Bagged complete diets, packaged feeds, feed ingredients, bulk feeds, animal treats and chews | Absorbed dose: Not to exceed 50 kiloGrays. Feeds and feed ingredients treated by irradiation should be formulated to account for nutritional loss | Microbial disinfection, control or elimination |

(2) If an irradiated feed ingredient is less than 5 percent of the final product, the final product can be irradiated without being considered to be re-irradiated.

[51 FR 5993, Feb. 19, 1986; 51 FR 8315, Mar. 11, 1986, as amended at 58 FR 18148, Apr. 8, 1993; 66 FR 18540, Apr. 10, 2001]