Radiation Processing

What is radiation processing?

Radiation processing is a controlled application of energy of short wave length radiations of the electromagnetic spectrum known as ionizing radiations and includes gamma rays, accelerated electrons and X-rays to have desired effect on the product.

What are the uses of radiation processing?

Some of the major objectives of radiation processing are:

  • Sterilization of medical and packaging products
  • Phytosanitation to overcome quarantine barriers in fruits and vegetables
  • Insect disinfestations of food products
  • Inhibition of sprouting in tubers, bulbs and rhizomes
  • Delay in ripening of fruits
  • Enhancement in shelf life by destruction of spoilage microbes in foods
  • Elimination of pathogens and parasites in foods
  • Cross-linking of rubbers and polymers
  • Colour enhancement of gemstones
Does the radiation processing make food radioactive?

No. The radiation processing involves passing of food through a radiation field allowing the food to absorb desired radiation energy. The food itself never comes in contact with the radioactive material. Gamma rays, X-rays and electrons prescribed for food irradiation do not induce any radioactivity in foods.

What is the difference between radiation processed and radioactive food ?

Radiation processed foods are those that have been exposed to radiation as prescribed above to bring about the desired effect in food. Radioactive foods, on the other hand, are those that become contaminated with radionuclides. This type of contamination never occurs during radiation processing of food.

What chemical changes are produced in foods and are they harmful?

Radiation processing produces very little chemical changes in food. None of the changes known to occur have been found to be harmful. The radiolytic products and free radicals produced are identical to those present in foods subjected to treatment such as cooking, canning etc. Highly sensitive scientific tests carried out during the past 30 years have failed to detect any new chemical product in radiation-processed foods.

Do the free radicals or radiolytic products affect the safety of food ?

No. There is no evidence to suggest that free radicals or radiolytic products which are produced during radiation processing affect the safety of radiation processed food. This has even been confirmed by much long term multigenerational studies in which laboratory animals were fed radiation processed products exposed up to a dose of 45 kGy.

Does it adversely affect the nutritional value of food?

No. In comparison to other food processing and preservation methods, the nutritional value is least affected by radiation. Extensive scientific studies have shown that radiation processing has very little effect on the main nutrients such as proteins, carbohydrates, fats and minerals. Vitamins show varied sensitivity to food processing methods including radiation processing. For example, vitamin C and B1 (thiamine) are equally sensitive to radiation as well as to heat processing. Vitamin A, E, C, K and B1 in foods are relatively sensitive to radiation, while riboflavin, niacin, and vitamin D are much more stable. The change induced by irradiation on nutrients depends on a number of factors such as the dose of radiation, type of food, and packaging conditions. Very little change in vitamin content is observed in food exposed to doses upto 1 kGy. The Joint Expert Committee of the Food and Agriculture Organization (FAO), World Health Organization (WHO), and International Atomic Energy Agency (IAEA), in 1980 concluded that radiation processing does not induce special nutritional problems in food.

Why to radiation process Spices?

Most spices get heavily contaminated with microbes, including pathogenic bacteria during processing while drying in open. Since radiation processing does not involve increase in temperature and humidity, it extends shelf life of spices in packed form retaining colour, aroma and other sensory properties and at the same time eliminates bacteria and microbes without leaving any chemical residues.

What is the recommended dose for Spices and allied products?

The recommended dose for decontamination of spices by gamma radiation treatment is 8-10 kGy. This dose is sufficient to reduce the microbial burden without having any undesirable effect on food quality of spices provided codes of good manufacturing practices (GMP) established by national and international standards is followed and the initial microbial burden is not too high.

Can it be used to destroy microbial toxins and pathogenic viruses in food ?

No. As in many other food processing procedures only food of good hygienic quality should be radiation processed. It is important that foods intended for processing are of good quality and handled and prepared according to codes of good manufacturing practices (GMP) established by national and international standards.

Can it make spoiled food good or clean up dirty food?

No. Like any other food treatment, radiation processing cannot reverse the spoilage process and make food good. A food that looks smells and tastes bad cannot be saved by any treatment including radiation processing.

Can an accident release radioactivity in the environment?

No. It is impossible for a 'melt down' to occur in an accident at a gamma irradiation facility. A radiation facility cannot explode due to Cobalt-60, it is a non-fissile radioisotope. The question of contamination of the environment can not not take place or endanger people living nearby. Also environmental contamination due to leakage of radioactivity can not occur because the radioisotope is doubly encapsulated in stainless steel tubes.

Do irradiators pose radioactive waste disposal problem?

No. Cobalt-60, which is used as the source of radiation energy, decays over many years to non-radioactive Nickel. When the radioactivity falls to a low level, the source pencils are returned to the supplier, who has the option of safely storing them or process further for eventual disposal.

Are there any tests to detect if food has been irradiated?

Yes. There are specific tests developed for certain class of foods. However, no single method has yet been developed that reliably detects irradiation of all types of foods or radiation dose levels applied. Thermoluminescence measurement and electron spin resonance pectroscopy can be used for detecting irradiated spices and meat containing bone tissue.

Will radiation processing increase the cost of food?

Any processing will add to the cost of food. In most cases, however, food prices may not necessarily rise just because a product has been treated. Many variables affect food costs, and one of them is cost of processing. But processing also brings benefits to consumers in terms of availability, storage life, distribution, and improved hygiene of food. Radiation processing can have a stabilizing effect on market price of commodities by reducing storage losses resulting in increased availability of produce.

How much does a typical radiation facility costs?

This will depend on many parameters including type of food, throughput etc. Estimated cost of a typical food radiation processing facility a few years ago were in the range of Rs. 10 to Rs. 15 crores excluding land cost.

Where can food be Irradiated?

Food can be irradiated in a food irradiation plant, which is authorized by the Atomic Energy Regulatory Board and licensed by the competent authority. The license to carry out food irradiation operation is given only after ascertaining the safety of the installation, its suitability to ensure proper process control, and availability of licensed operators and qualified staff. A facility could be put up as a private, public or joint sector company.

How can radiation processed food be identified in the market?

Irradiated food cannot be recognized by sight, smell, taste or touch. Codex Alimentarius Commission has endorsed a green irradiation logo. As per the PFA (Fifth Amendment) Rules, 1994, all packages of irradiated foods to be marketed in India will be labelled with this logo, along with the words 'Processed by Irradiation method' and the date of irradiation, licence number of the facility and the purpose of irradiation. Consumers will have a free choice to buy radiation processed or non-radiation processed commodity.