Food IrradiationThe present & the future of food processing

The Law and the Science of Food Irradiation

Food Safety

•New Paradigm for Y2K

• Emerging Pathogens

• Foodborne Illness Outbreaks

• Food Safety Regulation

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.

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

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

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

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

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

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.

Irradiation….also known as:

• Ionizing radiation Ionizing radiation • Surface pasteurization Surface pasteurization • Electronic pasteurization Electronic pasteurization • E-beam sterilization/pasteurizationE-beam sterilization/pasteurization

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.

Electromagnetic SpectrumElectromagnetic Spectrum

Low Frequency

Long Wavelengths

High Frequency

Short Wavelengths

Sources of Ionizing irradiationSources of Ionizing irradiation

• Gamma sources of irradiationGamma sources of irradiation• X-ray machinesX-ray machines• Electron accelerators Electron accelerators

Gamma (Gamma () rays) rays

• Energy comes from decay of radioactive Energy comes from decay of radioactive isotopes isotopes – Cobalt-60 (half life of 5.3 years)Cobalt-60 (half life of 5.3 years)

• Produced by neutron bombardment Produced by neutron bombardment

– Cesium-137 (half life of 30 years)Cesium-137 (half life of 30 years)• By-product of spent nuclear fuelBy-product of spent nuclear fuel

Gamma (Gamma () rays) rays

• Isotope is contained and stored in pool of Isotope is contained and stored in pool of water and raised when produce is to be water and raised when produce is to be exposed toexposed to -rays-rays

• facility is concrete chamber with 6-12’ facility is concrete chamber with 6-12’ thick walls thick walls

• completely penetrates product and completely penetrates product and packaging (pallets)packaging (pallets)

Electron-beamElectron-beam

• electricity is power source-switch on and off electricity is power source-switch on and off • uses stream of high-energy electrons uses stream of high-energy electrons

accelerated at near the speed of light accelerated at near the speed of light • electrons are showered on the product electrons are showered on the product • facilities are shielded with concrete or steel facilities are shielded with concrete or steel

walls walls • penetrates approximately 2-3” of product penetrates approximately 2-3” of product

and packaging and packaging • ideal for thin ground beef patties ideal for thin ground beef patties

How ionizing radiation works

• Electrons disrupt the DNA chain either destroying or preventing reproduction of the organism

Factors affecting irradiation Factors affecting irradiation effectiveness against effectiveness against

microorganisms in foodsmicroorganisms in foods

• Growth phase of microorganism Growth phase of microorganism • Type of food (lean vs fat) Type of food (lean vs fat) • Moisture content (water level) Moisture content (water level) • Temperature of food (frozen vs heated) Temperature of food (frozen vs heated) • Presence of oxygen (aerobic vs anaerobic)Presence of oxygen (aerobic vs anaerobic)

Irradiation DosageIrradiation Dosage

• Dose - amount of energy transferredDose - amount of energy transferred– rad - old unit rad - old unit – gray (Gy) - new unit gray (Gy) - new unit – 1 kGy = 100,000 rad1 kGy = 100,000 rad

• 1 chest X-ray = .01 rad 1 chest X-ray = .01 rad • natural background = 0.1 rad/yearnatural background = 0.1 rad/year

Approximate doses of radiation Approximate doses of radiation needed to kill various organismsneeded to kill various organisms

Organisms Dose (kGy)

Higher animals 0.005 to 0.1

Insects 0.01 to 1

Non-spore forming bacteria

0.5 to 10

Bacterial spores 10 to 50

Viruses 10 to 200

Typical irradiation D-values of pathogens

kGy

Organism Fresh (refrigerated) Frozen

Camplobacter jejuni 0.08 – 0.20 0.21 – 0.32

E. Coli O157:H7 0.24 – 0.27 0.31 – 0.44

Staphlococcus aureus 0.26 – 0.60 0.30 – 0.45

Salmonella spp. 0.30 – 0.80 0.40 – 1.30

Listeria monocytogenes 0.27 – 1.00 0.52 – 1.30

D-value is equivalent to radiation dose required to reduce a bacterial population 90%

Typical irradiation D-values of pathogens

kGy

Organism Fresh (refrigerated)

Clostridium botulinum spores

1.00 – 3.60

Toxoplasma 0.40 – 0.70

Trichinella spiralis 0.30 – 0.60

D-value is equivalent to radiation dose required to reduce a bacterial population

90%

Destruction of microorganisms

IrradiationkGy dose 1 D value

Contains 10 microorganisms

1 microorganism survives

Irradiation kGy dose 2 D valueContains 10

microorganisms

1 microorganism survives/ 10 steaks

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

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)

Shelf life extension of fresh meat

Meat product

DosekGry

Untreated shelf life(days)

Irradiatedshelf life(days)

Beef cuts 2 14-21 70

Ground beef 1.5 8-10 26-28

Pork loins 3 41 90

Ground pork 1 8 12

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.

Gamma (Gamma () ray ) ray processing facilityprocessing facility

Gamma (Gamma () ray ) ray processing facilityprocessing facility

Electron-beamElectron-beam

DosimeterDosimeter

Levels of Food IrradiationLevels of Food Irradiation

• Radurization (low) < 1 kGy Radurization (low) < 1 kGy – vegetable sprouting, fruit ripening, insect vegetable sprouting, fruit ripening, insect

sterilization sterilization

• Radicidation (medium) 1-10 kGy Radicidation (medium) 1-10 kGy – kills most pathogens and many food spoilage kills most pathogens and many food spoilage

organisms, kills insects and parasitesorganisms, kills insects and parasites–

• Rappertization (high) > 10kGy Rappertization (high) > 10kGy – can sterilize by killing all bacteria and virusescan sterilize by killing all bacteria and viruses

Technology ComparisonTechnology ComparisonElectron BeamElectron Beam Cobalt-60Cobalt-60

TechnologyTechnology

Focused beam of electrons (10 MeV energy)

Photons created from decay of radioactive material

AdvantagesAdvantages Safe ON/OFFCost efficientIn-Line capabilityCompact systemsHigh dose rate = reduced oxidation

Increased ability to penetrate dense materialProcess pallet load

DisadvantagDisadvantagee

Reduced ability to penetrate dense material (3 ½ in. of highly dense product – approx. 8 meat patties high)

Cannot be turned OFF – always emitting gamma radiationRequires source disposal and replenishmentLow dose rate = increased oxidationConsumer perception

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

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

Food Irradiation

“The Law”

• 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.

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)

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

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

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 characteristics of 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;”

21 U.S.C. Section 321 (s)

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)

Classification of Irradiation as a Food

Additive

Legal Basis:

• Deposition of radiolytic byproducts considered “components” of food product.

• Radiolytic byproduct “affect the characteristics” of the food

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

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”

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

Statutory Exemptions to Classification

•Prior Sanctioned substances

• Approved substances (FAP)

• Substances generally recognized as safe (GRAS)

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

GRAS Criteria

What do you need for GRAS status?

•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)

GRAS Criteria

•Substantial history of consumption by significant number of consumers in the US (”common use”)

• GRAS status based on “common use” requires lesser quantity of scientific evidence than FAP

• GRAS affirmation should consider manufacturing process

GRAS Examples

•U.S. v. Articles of food.....Buffalo jerky 456 F. Supp 207 Nebraska, 1978. Affirmed by the 8th circuit in 1979. Buffalo patties adulterated because ingredient (nitrite) not GRAS.

• Caffeine, GRAS since 1960

• Simplesse, GRAS in 1990

• Menhaden fish oil, GRAS in1989

• Chymosin from recombinant DNA, GRAS in 1990.

Self Determination of GRAS Status

•No requirement for Food Additive Petition

• Places burden on FDA to prove additive unsafe

• Avoids costly and protracted FDA approval process

• Can market product immediately

• Can seek FDA affirmation of GRAS status by petition

Self Determination Criteria:

• Safety Determination by proponent

• Common use over a period of time (the “nothing happened” test)

• Lesser degree of scientific evidence if based upon “common use”

Irradiation as GRAS

•Common useage for over 50 years in US and European Union (nothing happened!)

• FDA approval is government admission of the safety of irradiation

• Irradiation does not fit definition of a food additive

Irradiation as GRAS

•Original classification erroneous

•Radiolytic byproducts products by irradiation are the same as those produced by traditional processing methods whose status as GRAS or as a food additive has never been asserted or challenged. (Heat treatment, freezing)

• Advances in analytical capabilities have determined nature, quantity and effects of radiolytic byproducts in biological systems

Some Examples

Nutra-Sweet

•Aspartyl-phenylalanine-methyl ester

• Heavily criticized because of delayed submission of negative data

• Agency insiders retained by industry

• Caused FDA to adopt “strict scrutiny” of all data submission in support of FAPs

Olestra•Originally submitted for approval as a DRUG for cholesterol reduction in 1974.

• Withdrew drug application in 1988

• Filed as “fat replacer” in 1988

• Not approved until 1996

• 200,000 pages of data submitted

High Fructose Corn Syrup

•Developed at time as Olestra

• Marketed as GRAS in mid-60's

• “Self Determination” of GRAS status

• Marketed and sold continuously for over 30 years without resort to FDA approval process

Benecol

•New Approach

• Cholesterol absorption inhibitor

• FDA alleged Benecol margarine “plant stanol ester” is un-approved food additive

• Manufacturer alleges Benecol is Dietary Supplement in food form

• Sold in Finland since 1995

• FDA can seize or sue (refer to Dept of Justice)

• Why not assert “GRAS” status?

Approval of Irradiation

•Recent outbreaks of foodborne illness

• FDA Modernization Act of 1997

• President’s Food Safety Initiatives

(Food Safety From Farm to Table)

• NASA Petitions

• Isomedix Petition

Approval of Irradiation

Isomedix petition filed 1994 seeking approval to use ionizing radiation for treatment of beef products.

December 1997 FDA approved use of ionizing radiation for the treatment of refrigerated or frozen uncooked meat, meat byproducts and certain meat food products to control foodborne pathogens and extend shelf life.

Labeling of Irradiated Foods

FDA has required labeling of irradiated food products since 1966

Radura logo required since 1986

Irradiated ingredients excluded

Only “First Generation” foods must be labeled

Reduces acceptability of irradiated food products because of consumer association with radioactivity and lack of consumer education regarding safety and efficacy of irradiation

Labeling Considerations

Effect of Irradiation Declaration on acceptance of irradiated foods and food safety generally

Does labeling at the retail level ensure the safety of the food product

Inconsistent application of labeling requirement (potatoes, wheat flour)

Consumer Acceptance

Affected by Irradiation label declaration

Tested by consumer surveys, limited market testing and retail sales

Affected by perception that irradiation equals radioactive

72% of consumers have heard of irradiation but 30% of those think irradiated foods are radioactive (1996 survey)

Survey found that education increases acceptanc

Food Irradiation“The Science”