Food irradiation – what it is

Food is irradiated for the same reason that milk is pasteurized – to make it safe.

When food is irradiated it passes through an enclosed chamber where it is exposed to ionizing energy.

This penetrates the food and destroys harmful organisms without cooking or otherwise altering its physical or chemical properties.

For this reason, irradiation is currently the best available technology suitable for treating raw and partially raw food.

It leaves no residue, does not change the taste, colour, or smell of the food, nor does it make food radioactive.

Irradiation forfood safety

An uncooked,

fermented pork

sausage called

“Nham” is

irradiated to

render it safe for

consumers at the

Thai Irradiation

Centre near

Bangkok.

Food irradiation:● greatly reduces or eliminates the number of diseasecausing bacteria

and other harmful organisms;

● helps to keep meat, poultry and seafood fresh; also helps to maintain certain food and vegetables for longer periods and reduce food spoilage;

● can replace potentially harmful chemical fumigants when used to eliminate insects from dried grain, legumes, spices, dried fruit etc.;

● has the potential to be used for meeting quarantine requirements for international trade in fresh fruits and vegetables;

● is a useful treatment as a critical control point in a Hazard Analysis and Critical Control Point (HACCP) based food production process.

Country Food ProductsIsrael Potatoes, onions, poultry, 36 spices, fresh fruits and

vegetables

Philippines Potatoes, onions, mushrooms

Czechoslovakia Potatoes, onions, garlic

South Africa Potatoes, onions, garlic, chicken, papaya, mangoes, strawberries, dried bananas, avocados, beans

Spain Potatoes, onions

Thailand Potatoes, onions, garlic, dates, wheat, rice, fish, chicken

U.S.S.R. Potatoes, grain, fresh and dried fruits and vegetables, dry food concentrates, poultry, onions, prepared meat products

U.K. Hospital meals

U.S.A. Wheat and wheat flour, potatoes, spices, pork, fresh fruits and vegetables

Country Food Products

Argentina Potatoes, strawberries, onions, garlic

Belgium Potatoes, strawberries, onions, garlic, shallots, paprika, pepper, gum arabic, 78 spices

Bulgaria Potatoes, onions, garlic, grain, dry food concentrates, dried fruits, fresh fruits

Canada Potatoes, onions, wheat flour, poultry, cod and haddock fillets, spices and certain dried vegetables

Finland Spices, herbs, hospital meals

Chile Potatoes, papaya, wheat, chicken, onions, rice, fish products, spices

France Potatoes, onions, garlic, shallots, spices, dried fruits and vegetables

Germany Hospital meals

Applications

• On the basis of the dose of radiation the application is generally divided into three main categories as detailed under:

Low Dose Applications (up to 1 kGy)

• Sprout inhibition in bulbs and tubers 0.03-0.15 kGy • Delay in fruit ripening 0.25-0.75 kGy • Insect disinfestation including, quarantine treatment and

elimination of food borne parasites 0.07-1.00 kGy

Medium Dose Applications (1 kGy to 10 kGy)• Reduction of spoilage microbes to improve shelf-life of

meat, poultry and seafoods under refrigeration 1.50-3.00 kGy

• Elimination of pathogenic microbes in fresh and frozen meat, poultry and seafoods 3.00-7.00 kGy

• Reducing number of microorganisms in spices to improve hygenic quality 10.00 kGy

High Dose Applications (above 10 kGy)• Sterilisation of packaged meat, poultry and their products

which are shelf stable without refrigeration. 25.00-70.00 kGy

• Sterilisation of Hospital diets 25.00-70.00 kGy • Product improvement as increased juice yield or

improved re-hydration

DOSE OF İRRADİATİON

According to Frazier and Westhoff (1988), the bactericidal efficacy of a given dose of irradiation depends on the following:

• The kind and species of the organism.

• The numbers of organisms (or spores) originally present. The more organisms there are, the less effective a given dose will be.

• The composition of the food. Some constituents [e.g., proteins, catalase, and reducing substances (nitrites, sulfites, and sulfhydryl compounds)] may be protective. Compounds that combine with the SH groups would be sensitizing.

• The presence or absence of oxygen. The effect of free oxygen varies with the organism, ranging from no effect to sensitization of the organism. Undesirable "side reactions" are likely to be intensified in the presence of oxygen and to be less frequent in a vacuum.

• The physical state of the food during irradiation. Both moisture content and temperature affect different organisms in different ways.

• The condition of the organisms. Age, temperature of growth and sporulation, and state (vegetative or spore) may affect the sensitivity of the organisms.

Approximate Killing Doses of Ionizing Radiations in

Kilorays (kGy) Organism Approximate lethal

dose (kGy)Insects 0.22 to 0.93   

Viruses 10 to 40

Yeasts (fermentative) 4 to 9 

Yeasts (film) 3.7 to 18

Molds (with spores) 1.3 to 11

Bacteria (cells of pathogens):     

Mycobacterium tuberculosis   Staphylococcus aureus   Cornybacterium diphtheriae   Salmonella spp.

1.4

1.4 to 7.0

4.2

3.7 to 4.8

advantages of the irradiation technique • Foods can be treated after packaging. • Irradiation processing permits the conservation of

foods in the fresh state. • Perishable foods can be kept longer without

noticeable quality loss. • The cost of irradiation and the low energy

requirements compare favorably with conventional food processing methods. Irradiation treatment up to the prescribed dose leave no residue; changes in nutritional value (i.e., loss of some vitamins) are comparable with those produced by other processes and during storage.

• Foods processed under prescribed conditions for irradiation do not in any way become radioactive, a fact that many people do not understand.

disadvantages of the irradiation technique

Question:  Is irradiated food safe to eat?Answer: No.

• Irradiated food has caused a myriad of serious health problems in laboratory animals that ate irradiated foods, including premature death, fatal internal bleeding, a rare form of cancer, stillbirths and other reproductive problems, mutations and other genetic damage, organ malfunctions, stunted growth and vitamin deficiencies.

• Irradiation can lead to the formation of chemical known and suspected to cause carcer and birth defects, including benzene, toluene and methyl ethyl ketone.

• Irradiation kills beneficial microorganisms, such as the yeasts and molds that can help keep botulism at bay, as well as the microorganisms that create the aromas that tell us when food has gone bad.

• Irradiation can corrupt the flavor, texture and other physical properties of some foods, leading to meat that smells like a wet dog, onions that turn brown, and eggs that are runny.

Question: Are irradiation facilities safe?Answer: Not always.

• Irradiation plant workers are exposed to dangerous radiation hazards. Several have died or been exposed to near-fatal doses of radiation at facilities throughout the world.

• Certain irradiation plants emit smog-forming, ground-level ozone into the environment.

Question:  Can the research into food irradiation be trusted?

Answer: Not all of it.• Very little toxicological testing has been done on irradiated food during the past

20 years. New, updated tests should be performed with the benefit of improved scientific methods.

Question:  Is food irradiation good for the economy?Answer: No. 

• It has a expensive technology.

• Food irradiation adds unnecessarily to the cost of food when less expensive alternatives are available.

Question:  Are consumers receiving credible information about irradiation?Answer: No.

• Food irradiation companies have been increasingly successful in persuading the media to compare  irradiation to “pasteurization,” which is an entirely different process by which microorganisms are killed by quickly heating and cooling food.

• The radiation used to irradiate food is ionizing, meaning that it drastically changes the chemical composition of food. Microwave radiation is non-ionizing, meaning that the chemical structure of food is largely left intact.

Question:  Should vegetarians care about irradiation?Answer: Yes.

• Irradiation does nothing to prevent E. coli and other harmful bacteria from winding up in drinking water supplies.

• Currently, imported fruits and vegetables are not allowed to be irradiated

• Food processing companies aren’t irradiating just meat. Fruit and vegetables are being irradiated, too—all of which suffer nutrient destruction as bad as or worse than in meat. Spices such as garlic powder and paprika are being irradiated as well, and can be added to processed foods without being labeled.

Future

• After decades of research, development, public debate and consumer acceptance trials in many countries, irradiation has emerged as a safe and viable technology for ensuring the safety and quality of food and for combating food-borne diseases.

• Indeed it is currently the best available technology suitable for treating raw and partially raw food products and those countries which adopt it will benefit greatly in both domestic and international markets.