1. Fun Facts About Food Irradiation

2. Why do we preserve food? Protect people from microorganisms, parasites, and other pests Extend shelf-life, improve long-term quality Make desirable alterations to food properties

3. History of Food Preservation Oldest Methods - Drying - Fermenting - Salting - Smoking Newer Methods - Freezing - Canning - Refrigeration - Preservatives - Pesticides Newest Method: Irradiation

4. What is food irradiation? Treatment of foods by subjecting them to ionizing radiation Does not and cannot make foods radioactive

5. Ionizing Radiation Radiation that has the ability to produce ions - electrically charged particles Examples: alpha particle, beta particle, high energy electron, gamma ray, and x- ray

6. Nonionizing Radiation Does not have sufficient energy to create ions - instead tends to excite molecules without removing electrons Examples: visible light, television waves, radio waves, and microwaves

8. Sources of Ionizing Radiation Cosmic Radiation (the sun) Medical procedures Radon and other terrestrial sources Nuclear weapons fallout Power plants Fertilizers Smoke detectors Accelerators

9. Food Irradiator Sources Cobalt-60 and Cesium-137 –Emit gamma rays –Sealed in container - never touches food –Can be recycled Machine generated beta or x-rays –Produces no waste outside of the machine used to produce the radiation

10. Irradiation Processes Sterilization Pasteurization Disinfestation Sprout Inhibition Delay of Ripening Physical Improvements

11. Irradiation Sterilization Very high dose used to kill all organisms Sterilization of > 50% disposable medical instruments Food sterilization - NASA, military, transplant patients

12. Irradiation Pasteurization Reduces remaining number of living organisms Prevent growth of mold Kill bacteria and parasites

13. Irradiation Disinfestation Kills insects and parasites in grains and other stored foods Fewer chemical residues on fruits and vegetables Does not prevent against re-infestation

14. Physical Improvements Inhibit sprouting of potatoes, onions, and garlic Delay of ripening for strawberries, mangoes, bananas, tomatoes, etc. Incidental improvement in fruit texture and meat color

15. How does irradiation do so many different things? High doses damage or kills cells –Kills microorganisms or insects Lower doses alter chemical reactions and interfere with cell division –Delay fruit ripening –Prevent sprouting or parasite reproduction

16. Are irradiated foods safe to eat? Foods cannot become radioactive at energies used in irradiation Below 10 kGy there are no known toxicological, microbiological, or nutritional problems

17. Foods Approved for Irradiation in the United States Fresh fruits and vegetables Herbs and spices Pork Potatoes Poultry

18. Important Terminology Ion: Atom that has been made electrically charged by the removal or one or more electron. Gray: Unit of energy absorbed by a material. 1000 Gy = 1 kGy Radura: Official symbol or logo indicating that food has been irradiated.

19. Sources of Additional Information American Council on Science and Health http://www.acsh.org/food/index.html World Health Organization Safety and Nutritional Adequacy of Irradiated Foods Institute of Food Technologists Radiation Preservation of Foods