Decontamination of Shell-Eggs with Pulsed UV-Light

Currently, most methods used by the food industry to decontaminate shell-eggs involve washing the egg surface with various chemical solutions. In this study, the effectiveness of pulsed UV-light was evaluated for the decontamination of shell-eggs. Samples inoculated with Salmonella Enteritidis on top surface on the equator were treated with pulsed UV-light for 1, 3, 5, 10, 15, 20, and 30 seconds at 9.5 and 14.5 cm from the UV-strobe in a chamber. An input voltage of 3,800 V was used to generate a 1.27 J/cm2/pulse of radiant energy at 1.5 cm below the lamp surface, producing a polychromatic radiation in the wavelength range of 100 to 1100 nm, with 54% of the energy being in the UV-light region. Log reductions in microbial population were determined after treatments. A maximum log10 reduction of 5.3 (CFU/cm2) was obtained after 20-s treatment at 9.5 cm without any visual damage to the egg. The temperature and total energy absorbed at each treatment condition was determined using a K-type thermocouple and a radiometer, respectively. Temperature and energy increased with higher treatment time and shorter distance from the UV-lamp. A maximum temperature increase of 10.5 ±1.6°C and a maximum energy of 35.3±0.1 J/cm2 were observed after 30-s treatment at 9.5 cm. This study demonstrated that pulsed UV-light has potential to decontaminate shell-egg surfaces.