site.btaScientist: Irradiated Food Is Completely Safe, Can Be Used in Daily Life, Even in Space

Scientists believe that irradiated food is completely safe and recommend its use both in everyday life and in space, Assoc Prof Adelina Miteva told BTA. She works at the Space Research and Technology Institute with the Bulgarian Academy of Sciences.

Miteva explained that food for astronauts must meet even stricter requirements than those for people on Earth. "Products used in space must have a longer shelf life, retain their energy value, be safe and easy to transport. Longer shelf life is a key requirement," Miteva said.

Food irradiation is the process of exposing food to ionizing radiation, for example gamma rays, X-rays or electron beams. Irradiation improves food safety and extends shelf life by effectively destroying the organisms responsible for spoilage, she said. The process prevents sprouting or ripening and is also a means of controlling insects and invasive pests. The term "food irradiation" can apply to any process in which food is exposed to either electromagnetic radiation or irradiation with high-energy particles.

Why food irradiation matters

Food irradiation is a readily applicable technology, and the procedure is performed on packaged food. In this way, it is preserved from recontamination. The treated food does not need to be refrigerated.

"In view of the advances in space research and the increasingly realistic prospects of interplanetary trips, ensuring the astronauts' health and diet during long missions has become a critical challenge. Food irradiation is an innovative solution which addresses this problem - it extends the shelf life of products while protecting them from microbial and other contamination," Miteva said, citing her report to the Nineteenth International Scientific Conference Space, Ecology, Safety - SES 2023 held in Sofia in October. 

"Developing food for space missions is a complex process. These products need to be extremely durable, high in energy density, incredibly nutritious and easily portable. Although modern technology has increased the shelf life of some foods to between three and five years, this still falls short of some stringent requirements," Miteva said in her presentation at the conference.

At present, food irradiation is permitted in some 70 countries and about 600,000 tonnes of food are irradiated every year worldwide. Regulations on food irradiation vary widely from country to country. In Austria, Germany and many other EU countries, only dried herbs and spices can be subjected to this technology and at a certain dose, while in Brazil all foods can be irradiated at any dose, said Miteva.

She added that Bulgaria is lagging behind the leaders in food irradiation - the US and China. A device for food irradiation was first registered in Bulgaria in 2008 - a gamma sterilizer made in Canada. Products are processed in aluminium containers. They are moved by a conveyor system into the irradiation chamber.

To date, the only foods which can be irradiated in Bulgaria are dried herbs, dried spices and dried vegetable seasonings. Although certain items are allowed in the EU, they also require authorization by the national authority of the Member State. One of the places in Bulgaria where food can be irradiated is the National Centre for Radiobiology and Radiation Protection.

"We cannot tell if a product has been irradiated or not, as it does not change its smell or colour. The UN requires all products that are irradiated to be marked as such when sold wholesale or retail," the scientist said.

"The Radura is the international symbol indicating that a food product has been irradiated. It is optional. The proposed labelling rules describe the use of the Radura symbol for all products which contain an irradiated ingredient," Miteva added.

"In the US, all irradiated foods must include a visible Radura symbol followed by the designation 'treated with irradiation' or 'treated by irradiation'. The EU does not require the use of the Radura and relies on labelling with certain phrases in the languages of the Member States," the scientist said.

Challenges and plans

Energy requirements and equipment considerations may be among the challenges and barriers to applying food irradiation in space. Research on advances in food irradiation techniques for space applications is forthcoming, including the development of compact and efficient irradiation systems, Assoc Prof Adelina Miteva said.

She stressed the importance of strengthening collaboration between space agencies, food scientists and engineers to ensure improved food irradiation for the successful conduct of future space research.