Effect of ultrasonication assisted UV-C light treatment on inactivation of salmonella typhimurium in egg yolk

Different processing methods such as pasteurization, cooling, freezing, drying and addition of preservatives have been used for the preservation of liquid eggs and their products that contain nutritional ingredients for human body. Food industry has been searching non-thermal processes such as ultraviolet light (UV-C) and ultrasonication (US), and scientific and technological studies are continuing to improve the microbial inactivation efficiency of these novel methods. In this study, US was used to increase the effectiveness of UV-C light application on Salmonella inactivation in egg yolks. UV-C light combined with ultrasonication (US-UVC light) was exposed to liquid egg yolks for up to 90 minutes. The 90-minute application of US-UVC light decreased the S.Typhimurium load by 1.33 logarithmic units, and this decrease was statistically significant (p<0.05). The effect of US-UVC light processing on the L * and ΔE values of egg yolks was found statistically significant (p <0.05), while the effect of US-UVC light treatment on the a * and b * color values of egg yolks was statistically insignificant (p>0.05). All liquid egg samples in this study showed pseudoplastic flow characteristics, and the effect of this treatment on the viscosity of egg yolk samples was insignificant (p>0.05). As a result, compared to the literature findings, the effect of US process during UV-C light treatment on S.Typhimurium inactivation in liquid egg yolks was technologically insignificant and no negative effect of this combined treatment was determined on the viscosity and color values of egg yolks.