[en] Currently, for food irradiation highly penetration ionizing radiation sources are used. A new approach to irradiation processing of food and agricultural products is related to the limited penetration of low energy electrons (LEEB), which can effectively reduce the number of microorganisms in food products. The advantage of such a solution is that low energy electrons do not penetrate the whole volume of food products thus interacting less with food components. However, to ensure that microorganisms are effectively inactivated in food products it is necessary to determine all parameters which may influence the effectiveness of LEEB microbial decontamination process. Due to the limited penetration of electrons in treated material, it is important to define which food categories can be treated with the low energy electron beam. In the presented study the work focused on the determination of the thickness of the layer which electrons can penetrate in different types of food products depending on the energy of electrons. Since microorganisms may inhabit different thicknesses of food, for the high LEEB process effectiveness it is important to select process paraments that ensure that the whole sub-surface layer inhabited by microorganisms is reachable by the electrons.

[en] The cellulose, which is the main component of the paper additionally with proteins present in book bindings is the environment very prone to attack of the harmful microorganisms. The investigation of the atmospheric air in libraries revealed the presence of broad spectrum of fungi and bacteria. Records show that large volumes of books and archival collections may be affected by bioburden because of improper storage conditions or accidents such as floods. The harmful influence of microorganisms on paper-based historical objects leads to their degradation and real loss for the culture. Moreover, microorganisms present in books or archives may influence the human health negatively. Thus, effective disinfection methods of paper-based objects are still being developed in order to propose effective, fast and low-cost method that can be applied on the mass scale in emergency situations as well as for the preventive treatment. Currently the most common method used for decontamination of library and archival collections is ethylene oxide treatment, which is toxic to humans and the natural environment. The promising alternative for this technique can be ionizing radiation. Electron beam (EB) irradiation can be effectively applied for decontamination of biodeteriorated archives as well as for preventive conservation of large volumes of books in short time [6]. Moreover, due to the high dose rate of EB irradiation, appropriate dose is delivered to the treated objects in several seconds therefore post-oxidation related effects of paper degradation are significantly limited.

[en] New approaches for the radiation processing of food and agricultural products use the limited penetration of electrons of energy below 300 keV. The aim of the project was to examine the effectiveness of low energy electron beam (LEEB) irradiation to eliminate microbial contamination from the surfaces of food products. The energies of electrons used in our experiments allowed the beam to penetrate to a depth no greater than 400 µm in the food products that we studied. For tested samples the LEEB effectively eliminated microbial contamination, and the decrease in number of microorganisms depended on the energy of electron beam, the absorbed dose on the surface and the microbial species naturally inhabiting tested samples. This study involved some collaboration with the Food Research Institute, National Agriculture and Food Research Organization, Ibaraki, Japan. (author)