The objective of the study was to assess the microbiological condition of eggshell surface of eggs suitable for eating, which were treated (for the purpose of their hygienization) using an UV-C 254 nm ultraviolet radiation, as well as to determine the effect of this process on some selected quality factors of the egg content. The eggs were exposed to the UV-C 254 nm ultraviolet radiation in an egg radiator type UV 254 (CompArt). A microbiological analysis of the quality of eggshell surface included the determination of the following: – total number of micro-organisms on the eggshell surface; – the count of bacteria belonging to the coli group; – the occurrence of Salmonella enteritidis. The determination procedure was performed directly after the eggshell irradiation and after 2 and 4 weeks storage thereof, and compared with the control sample of eggs (which were not irradiated). Various radiation doses were applied; those doses were expressed using a radiation time duration of 30, 60, and 90 sec. In the experiment, there were used eggs showing different dirt on their eggshells, i.e.: dirty, visually clean, and washed eggshells. Next, the following was determined: white and yolk indices, Haugh units, foaming, foam stability; also, the pH was measured. It was found that the exposure of eggs to the UV-C 254 nm radiation for a period of 30, 60, and 90 sec caused no statistically significant reduction in the count of microbes on the eggshell surface of eggs suitable for eating. However, it was found that when the eggs were treated with this radiation during 30 and 90 sec, the total count of microbes tended to fall. Furthermore, it was proved that it was possible to effectively reduce the count of E. coli, when the eggs were, at the same time, washed and irradiated using the UV-C 254 nm radiation. The statistical analysis of the experimental data using a Tukey’s test did not show any significant impact of the UV-C 254 nm radiation on any of the quality factors of the egg content. The changes that were stated in the egg features studied were correlated exclusively with the aging process of eggs progressing during their storage. The results obtained prove that the UV-C 254 nm radiation can be a safe eggshell higienization method of the eggs suitable for eating. The experiment presented in this paper encourages further studies on the efficacy of the UV-C 254 nm.
UV-C irradiation, higienization, eggshell, microbiological analysis, egg quality