UV Inactivation of E-coli in Liquid Egg White

Liquid egg white is currently pasteurized using heat; however, this treatment damages the functional properties of the egg. In this study, a nonthermal ultraviolet light (UV) system was developed to pasteurize liquid egg white. The system consisted of low-pressure mercury bulbs surrounded by UV transparent tubing. Egg white was inoculated with Escherichia coli K12 and pumped through the UV system at a flow rate of 330 ml/min. The effects of treatment time (0 to 160 s), temperature (30 to 50 degrees C), and egg white pH (7 to 9) on the inactivation of E. coli were investigated. The population of E. coli in egg white was reduced by 4.3 log after being exposed to UV at 50 degrees C for 160 s. Inactivation was linearly dependent on treatment time and was adequately described using first-order kinetics (r(2) of 0.94). The electrical energy of the process was calculated to be 44 J/ml. Inactivation was directly dependent on temperature and inversely dependent on pH. Nonthermal UV processing has the potential to improve the safety and functional properties of liquid egg white.