Disinfecting Effects

Getting rid of parasites and microbes …

Editorial review 2026

The radiobiological action of radiation causes damage to DNA molecules, which carry genetic information. If the applied dose is appropriate and reaches all cells, it leads to the destruction of the organism. This property is used for the disinfestation and disinfection of contaminated materials.

The targeted cells are those of small animal or plant organisms, or even microorganisms. The aim is to rid objects intended for sterilization of tiny insects, parasites, fungi, molds, or on an even smaller scale, bacteria and other microbes (in the case of food products, the goal is rather preservation and conservation).

It is gamma rays that are most commonly used because they penetrate deeply throughout the entire mass of the material being treated and affect all the cells of the parasite to be destroyed. High doses, and therefore powerful sources, are required, generally cobalt-60 or cesium-137 sources emitting high-energy and highly penetrating gamma rays.

Irradiation using powerful sources is also employed for the sterilization of medical devices and pharmaceutical products. The irradiation of blood products is carried out to eliminate certain cells likely to cause a fatal disease in patients requiring transfusions. After this treatment, these products can be administered to patients.

These irradiations, like those used for food products, leave no radioactive residues. It should be noted that these processes are used less often than in the past. This technique is still used for spices imported from abroad.

Wearers of contact lenses will be pleased to learn that the saline solutions used to clean and store these lenses are sterilized by irradiation. Some readers may also be interested to know that most cosmetics undergo gamma irradiation before being marketed. Oils and ointments tend to attract impurities that would not be desirable during application. Cosmetic products are therefore exposed to radiation that guarantees the absence of living parasites at the time of use.

Radiation is also suitable for the curative treatment of heritage objects, such as the disinfestation and disinfection of furniture, statues or even mummies. It is not used for paper disinfection because of the cellulose degradation caused by the irradiation dose that would need to be applied.

Disinfestation consists in sterilizing or destroying wood-boring insects that attack ancient wood. Sterilization and disinfection aimed at destroying fungi, molds and other parasites require higher doses. While 500 grays (Gy) are sufficient, for example, to sterilize wood-boring insects, 2000 Gy are required to stop the growth of certain fungi, and 10,000 Gy or more are needed for full sterilization.