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Electrons with energies of 300 keV or lower have the potential to decontaminate the surfaces of various types of food products with minimal loss of quality. The aim of the present work was to determine the thickness of the layer inhabited by microorganisms. The food samples tested were black and white pepper irradiated with 200 keV, 230 keV, 300 keV and 9 MeV beams of electron energy. To determine the depth from the surface which can be inhabited by microorganisms two approaches were tested. The methods used were based on the application of different microbiological recovery techniques and the microbial effectiveness of the irradiation process depending on the energy of the electron beam. It was observed that the layer which microorganisms may contaminate differed for the tested samples it was estimated as being below 100 μm thick for white pepper and about 200 μm for black pepper. The penetration ability was significant in experiments performed, and as a result the electron beam at the lowest levels tested (200 and 230 keV) was found to be insufficient to effectively decontaminate the black pepper samples. The beam of energy 300 keV was found to have a similar microbial inactivation effect as the high energy electron beam (9 MeV)., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The effectiveness of the radiation decontamination process was tested for electron beam of energy 200 keV and 300 keV. The energy of electrons was controlled by the measurements of its penetration ability in stack of B3 dosimetric film. In the presented work, the reduction of total aerobic bacteria count was observed, depending on time of irradiation for samples of dried black pepper, onion flakes and bay leaves. The results were compared with the effect observed for the process where high energy electron beam was used. [ABSTRACT FROM AUTHOR]

Electrons with energies of 300 keV or lower have the potential to decontaminate the surfaces of various types of food products with minimal loss of quality. The aim of presented work was to determine the effectiveness of the process when applied to naturally contaminated food samples. Black pepper, white pepper and allspice samples were irradiated using electron beam at energy of 300 keV (low energy e-beam) and 10 MeV (high energy e-beam) to confirm the inactivation of bacteria. Total aerobic bacteria were counted before and after the irradiation and bacterial species were determined by a microbial identification system based on MALDI-TOF mass spectrometry. The range of applied low energy electron beam in food products estimated based on the depth-dose profile of electron beam and density of samples was about 300 μm thick. The log reduction in the total number of aerobic bacteria for spices samples irradiated with the high energy e-beam was comparable with that of the low energy e-beam, if estimated doses delivered on the surface were equivalent. (The log reduction by irradiation with 300 keV e-beam for 5 min corresponded to that by ca. 6 kGy irradiation with 10 MeV e-beam in conditions employed in this study). In non-irradiated spices, the dominant species was Bacillus subtilis. In irradiation of black pepper, the dominated species that survived after the irradiation were Cronobacter sakazaki and Bacillus megaterium, regardless of the energy of the electron beam. The effectiveness of microbial decontamination by both the low and the high energy e-beams was comparable for spices, where microorganisms exist in the surface layer. This study suggests the low energy e-beam as an alternative technology for the currently used highly penetrating ionising irradiation to eliminate microbial contamination of spices. • Electron beams of energy 300 keV and 10 MeV were used to eliminate microbial contamination of spices. • The energy of electron 300 keV ensured irradiation only in the external layer of black pepper, white pepper and allspice. • The bacterial species that survived were the same, regardless of the electron energy. [ABSTRACT FROM AUTHOR]