Ultraviolet-C inactivation of Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa, and Salmonella enterica in liquid egg white

Abstract

The study determined and compared the ultraviolet-C (UV-C) resistance of selected foodborne microorganisms including Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa and Salmonella enterica in turbulent flowing liquid egg white. Results showed that all test organisms exhibited first-order inactivation kinetics, characterized by logarithmic-linear inactivation behavior (R2 = 0.91–0.98). The decimal reduction times (D) of the organisms ranged from 26.44 to 37.22 min; with corresponding UV-C energy dose (DUV-C) of 170.71–240.33 mJ/cm2. P. aeruginosa had the highest resistance while E. coli O157:H7 had the least. The differences between the D and DUV-C values of the test organisms were however not statistically significant. The inactivation rate of P. aeruginosa was used to establish UV-C processes capable of reducing the reference organism by 99.9 (3D) and 99.999% (5D). Quality evaluations of UV-C processed liquid egg whites showed that both process schedules resulted in significant alterations in color and sensory quality attributes. Increasing the number of UV-C lamp, or combining UV-C treatment with mild heating to achieve the target reference organism reduction without the unacceptable change in quality was recommended for future studies. The results reported in this work may serve as baseline information for further improving the UV-C processing technique for liquid egg whites and similar commodities.