PULSED UV LIGHT INACTIVATION OF ESCHERICHIA COLI AND SALMONELLA IN LIQUID EGG WHITE AND ITS EFFECTS ON QUALITY
Open Access
- Author:
- Ouyang, Beining
- Graduate Program:
- Agricultural and Biological Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 27, 2019
- Committee Members:
- Ali Demirci, Thesis Advisor/Co-Advisor
Paul H. Patterson, Committee Member
Virendra Puri, Committee Member - Keywords:
- decontamination
liquid egg white
pulsed UV light
response surface modeling
Escherichia coli
Salmonella Enteritidis
flow-through system - Abstract:
- Eggs and egg products are one of the most common foods all around the world. Heat pasteurization is currently being used to decontaminate liquid egg white to ensure food safety. However, alternative methods are desired to improve decontamination as well as maintain the quality of liquid egg white. Pulsed ultraviolet (UV) light is a promising technology that can be applied for decontamination of foods. It has gained interest in recent years because of its effectiveness over very short treatment times. In this study, pulsed UV light treatment was evaluated and optimized for inactivation of Escherichia coli K12 NSR and Salmonella Enteritidis NSR in liquid egg white under static and flow-through processing systems. In the static pulsed UV light system, processing parameters including treatment time, volume of liquid egg white, and sample distance to the pulse UV light strobe have been optimized for the log reduction of microorganisms using response surface methodology. And in the flow-through system, the effect of various flow rates, number of the passes, distances were investigated for optimum conditions. The maximum log reductions obtained after 40 s pulsed UV light static treatment at 5 cm were 1.28 log CFU/mL for E. coli K12 NSR and 1.98 log CFU/mL for S. Enteritidis NSR in 5 mL fresh liquid egg white. For the flow-through pulsed UV light treatment, the maximum reduction obtained was 1.57 log CFU/mL at the optimum conditions of 5 cm distance and 3 passes with a flow rate of 40 mL/min. In addition, the temperature of egg white and energy dose were measured during the two processing conditions. Finally, the effects of pulsed UV light treatments on egg quality parameters including pH, color, lipid oxidation, foaming ability, and foam stability were evaluated. Overall, this study showed that pulsed UV light can inactivate E. coli K12 and S. Enteritidis in liquid egg white with little or no change in egg quality.