{"data":{"id":"us/21-cfr-179.39","jurisdiction":"us","citation":"21 CFR 179.39","heading":"Ultraviolet radiation for the processing and treatment of food.","body":"Ultraviolet radiation for the processing and treatment of food may be safely used under the following conditions:\n(a) The radiation sources consist of low pressure mercury lamps emitting 90 percent of the emission at a wavelength of 253.7 nanometers (2,537 Angstroms).\n(b) The ultraviolet radiation is used or intended for use as follows:\nIrradiated food Limitations Use\nFood and food products Without ozone production: high fat-content food irradiated in vacuum or in an inert atmosphere; intensity of radiation, 1 W (of 2,537 A. radiation) per 5 to 10 ft.2 Surface microorganism control.\nPotable water Without ozone production; coefficient of absorption, 0.19 per cm or less; flow rate, 100 gal/h per watt of 2,537 A. radiation; water depth, 1 cm or less; lamp-operating temperature, 36 to 46 °C. Sterilization of water used in food production.\nJuice products Turbulent flow through tubes with a minimum Reynolds number of 2,200. Reduction of human pathogens and other microorganisms.","path":["Title 21—Food and Drugs","CHAPTER I—FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES","SUBCHAPTER B—FOOD FOR HUMAN CONSUMPTION","PART 179—IRRADIATION IN THE PRODUCTION, PROCESSING AND HANDLING OF FOOD","Subpart B—Radiation and Radiation Sources"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-21.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:47Z","sha256":"2081477a54aab2930b4e453a98a9222d4c8c68bbfaa848dd57c2719d2161d106","source_id":"us-cfr","stale":true,"prev":"us/21-cfr-179.30","next":"us/21-cfr-179.41"},"notice":"GroundRules: Original legal text. Not legal advice."}