Food Irradiation The present & the future of food processing

1. Food IrradiationThe present & the future of food processing The Law and the Science of Food Irradiation

2. Food Safety • New Paradigm for Y2K • Emerging Pathogens • Foodborne Illness Outbreaks • Food Safety Regulation

3. Food Irradiation • Exposure of foods to ionizing radiation in form of gamma radiation, X-rays and electron beams to destroy pathogenic microorganisms • In use for over 50 years in European Union • US consumers perceptions of effects of radiation prevented widespread acceptance of food irradiation • Limited use allowed since 1963 on specific food products for specific purposes.

4. Ionizing Radiation • Causes disruption of internal metabolism of cells by destruction of chemical bonds • DNA cleavage results in loss of cells ability to reproduce • “Free radicals” formed upon contact with water containing foods • Free radicals react with cellular DNA causing radiation damage • DNA considered “radiation sensitive” portion of cells

5. Ionizing Radiation • Exists in form of waves • Shorter wavelength = greater energy • Light, radio, microwave, television = long wavelength, low energy cannot alter structure of an atom • Shorter wavelengths have enough energy to “knock off” an electron to form a “free radical” but not high enough to “split” an atom and cause target to become “radioactive” • Interaction between free radicals and DNA responsible for “killing effect” of IR

6. X- Rays • Produced during high energy collisions of gamma rays and heavy elements (i.e. Tungsten) • Little practical application because of low conversion efficiency of gamma to X-rays

7. Electron Beams • Produced by linear accelerators • Coherent, directional beam of high energy electrons • Low dose • Portable (no reactor required) • Not inherently radioactive • Requires less shielding than gamma radiation • Flip of the switch technology • Lack penetration depth of gamma • Advantage is shorter exposure time

8. Gamma Radiation • Most widely used type of ionizing radiation • All penetrating, emitted in all directions continuously • Produced at MURR by exposure of natural Cobalt-59 to neutrons in a reactor where reaction between the two species produces Cobalt-60 • Cobalt-60 specifically manufactured, for radiotherapy, medical device sterilization and food irradiation, not a waste product of nuclear reactors

9. What is Food Irradiation • Food irradiation is a process in which food products are exposed to a controlled amount of radiant energy to increase the safety of the food and to extend shelf life of the food • Like pasteurization of milk and pressure cooking of canned foods, treating food with ionizing radiation can kill bacteria and parasites that would otherwise cause foodborne disease.

10. Irradiation….also known as: • Ionizing radiation • Surface pasteurization • Electronic pasteurization • E-beam sterilization/pasteurization

11. Ionizing radiation • When radiation strikes other material, it transfers energy. • This can cause heating, as with microwave cooking, or if there is enough energy, it can knock electrons out of the material bombarded, breaking the molecular structure-thus leaving ions (free radicals) hence the name ionizing radiation.

12. Electromagnetic Spectrum High Frequency Short Wavelengths Low Frequency Long Wavelengths

13. Sources of Ionizing irradiation • Gamma sources of irradiation • X-ray machines • Electron accelerators

14. Gamma () rays • Energy comes from decay of radioactive isotopes • Cobalt-60 (half life of 5.3 years) • Produced by neutron bombardment • Cesium-137 (half life of 30 years) • By-product of spent nuclear fuel

15. Gamma () rays • Isotope is contained and stored in pool of water and raised when produce is to be exposed to-rays • facility is concrete chamber with 6-12’ thick walls • completely penetrates product and packaging (pallets)

16. Electron-beam • electricity is power source-switch on and off • uses stream of high-energy electrons accelerated at near the speed of light • electrons are showered on the product • facilities are shielded with concrete or steel walls • penetrates approximately 2-3” of product and packaging • ideal for thin ground beef patties

17. How ionizing radiation works • Electrons disrupt the DNA chain either destroying or preventing reproduction of the organism

20. Factors affecting irradiation effectiveness against microorganisms in foods • Growth phase of microorganism • Type of food (lean vs fat) • Moisture content (water level) • Temperature of food (frozen vs heated) • Presence of oxygen (aerobic vs anaerobic)

21. Irradiation Dosage • Dose - amount of energy transferred • rad - old unit • gray (Gy) - new unit • 1 kGy = 100,000 rad • 1 chest X-ray = .01 rad • natural background = 0.1 rad/year

22. Approximate doses of radiation needed to kill various organisms

23. Typical irradiation D-values of pathogens D-value is equivalent to radiation dose required to reduce a bacterial population 90%

24. Typical irradiation D-values of pathogens D-value is equivalent to radiation dose required to reduce a bacterial population 90%

25. Destruction of microorganisms IrradiationkGy dose 1 D value Contains 10 microorganisms 1 microorganism survives Irradiation kGy dose 2 D value Contains 10 microorganisms 1 microorganism survives/ 10 steaks

26. Pasteurization • To reduce microorganisms but not to sterilize the product • Purpose is to destroy pathogenic microorganisms to make food safe • This is normally 5 to 7 D values

27. Effect of irradiation on shelf life of fresh meats • Spoilage organisms, especially pseudomonads, are susceptible to low dose irradiation • Spoilage of low dose irradiated meats may be due to yeast, LAB, or Moraxella spp. (increased lag time)

28. Shelf life extension of fresh meat

29. How does irradiation food processing operation work? • Food is packed in containers and moved by conveyer belt into a shielded room. • Food is exposed briefly to a radiant-energy source. (The amount of energy depends on the food.) • Food is left virtually unchanged, but the number of harmful bacteria, parasites and fungi is reduced and may be eliminated.

30. Gamma () ray processing facility

31. Gamma () ray processing facility

32. Electron-beam Dosimeter

33. Levels of Food Irradiation • Radurization (low) < 1 kGy • vegetable sprouting, fruit ripening, insect sterilization • Radicidation (medium) 1-10 kGy • kills most pathogens and many food spoilage organisms, kills insects and parasites • Rappertization (high) > 10kGy • can sterilize by killing all bacteria and viruses

34. Technology Comparison

35. Meat Irradiation • December 23, 1999 Federal Register • Effective date – February 22, 2000 • Ionizing radiation approved for use • Cobalt-60, Cesium-137, X-ray machines, Electron accelerators • Dosage • 4.5 kGy if refrigerated • 7.0 kGy if frozen

36. Safety and efficacy of food irradiation • The following statements are in the Federal Register (12/23/1999) • The safety and efficacy of food irradiation, as demonstrated by numerous experiments and studies, is widely accepted by Federal regulatory agencies and national and international food and public health organizations • FDA examined numerous studies on the chemical effects of radiation, the impact of radiation on nutrient content of foods, potential toxicity concerns and effects on microorganisms in or on irradiated products. FDA concluded that irradiation is safe in reducing disease-causing microbes in or on meat food products and it does not compromise the nutritional quality of treated products. • The World Health Organization, Food and Agriculture Organization, American Medical Association and American Dietetic Association endorse food irradiation

37. Exposure of foods to ionizing radiation in form of gamma radiation, X-rays and electron beams to destroy pathogenic microorganisms • In use for over 50 years in European Union • US consumers perceptions of effects of radiation prevented widespread acceptance of food irradiation • Limited use allowed since 1963 on specific food products for specific purposes. Food Irradiation “The Law”

38. History of Irradiation First documented use of ionizing radiation was to “bring about an improvement in the condition of foodstuffs” and in “their general keeping quality”. British patent issued to J. Appleby and A.J. Miller, analytical chemists British patent No. 1609 (January 26, 1905)

39. History of Irradiation • US Army investigates use of irradiation to improve safety and quality of troop diets in 1930 • MIT hamburger sterilization study in 1943 • Approved by Soviet Union to increase potato consumption in 1958

40. History of Irradiation • Approved for potatoes by Canada in 1960 • 1963 First FDA approval for insect control in wheat flour • 1964 - dehydrated vegetable seasoning • 1986 - fruit and vegetable ripening • 1990 - fresh and frozen poultry to control salmonella and other pathogens

41. Food Additives The term “food additive” means any substance the intended use of which results or may reasonably be expected to result , directly or indirectly, in its becoming a component of or otherwise affecting the characteristicsof any food...(and including any source of radiation intended for such use), if such substance is not generally recognized.....to be safe under the conditions of its intended use;”

42. Food Additive Amendment • Enacted in 1958 to control use of chemicals in food products • First legislation to address irradiation directly • Defined all sources of ionizing radiation as food additives (blanket prohibition)

43. Classification of Irradiation as a Food Additive

44. Legal Basis: • Deposition of radiolytic byproducts considered “components” of food product. • Radiolytic byproduct “affect the characteristics” of the food

45. Scientific Basis: • Ionizing radiation produces byproducts (radiolytic byproduct) which interact with and thereby become a component of foods • The interaction of ionizing radiation with foods affects the characteristics of foods

46. Factual Basis: • Perceived need to inform consumer of all “material facts” about the foods they consume • Little understanding of the nature and effects of ionizing radiation in biological systems • Inability to identify irradiated products • Public reaction “Irradiation = Radioactive”

47. Impact of Classification • Requirement for pre-market approval • Costly and protracted review process • Limited utilization of effective food safety tool • Labeling requirement (Radura) • Limited opportunity for consumer education and acceptance of irradiated products

48. Statutory Exemptions to Classification • Prior Sanctioned substances • Approved substances (FAP) • Substances generally recognized as safe (GRAS)

49. Generally Recognized as Safe • General recognition of safety among experts qualified by scientific training and experience to evaluate its safety • No FDA approval required • Can petition FDA for affirmation • Congressional recognition of “safety” criteria

50. GRAS Criteria • General recognition of safety through scientific procedures based on published literature • GRAS status must be based on same quality and quantity of scientific evidence as would be required for “food additive” petition (FAP) What do you need for GRAS status?