Date of Award

Summer 2014

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Food Science

First Advisor

Kevin M. Keener

Committee Member 1

Fernanda San Martin

Committee Member 2

Ahmed Hassanein

Committee Member 3

Manpreet Singh

Abstract

The global market for eggs is projected to reach 1.154 trillion by the year 2015. The number one risk to consumers from chicken eggs is contamination with Salmonella Enteritidis (SE). FDA estimates each year 142,000 illnesses in the U.S. are caused by SE contamination in chicken eggs. The first objective of this research study was to evaluate a novel High Voltage Atmospheric Cold Plasma (HVACP) technology in reducing externally inoculated SE on refrigerated chicken eggs. Raw, chicken eggs attached with SE population (10 7 CFU/ml), were placed in plastic containers filled with either dry Air (22%O2 , 78%N2 ) or Modified Atmospheric (MA) gas (65%O2 , 30%CO2 , 5%N2 ), and treated directly or indirectly with HVACP for 5, 10, and 15 min. The experiment was conducted in triplicate with each replicate requiring 48 eggs for treatment. Results showed direct HVACP treatment in MA for 15 min achieved maximum SE inactivation of 5.531 log CFU/egg. SE reductions on egg surfaces depended on treatment times, gas type, and mode of exposure of eggs to the plasma.

A second objective of this research study was to examine the effect of HVACP treatment on egg quality during refrigerated storage. The most effective bactericidal conditions of direct treatment for 15 min in MA gas were selected for examination. The experiment was conducted in triplicate with each replicate requiring 56 eggs. A comparison of quality measurements between treated and untreated eggs at storage times of 1, 7, 14, 21, 28, 35, and 42 days were conducted. Quality measurements included Haugh Unit (HU), pH of albumen and yolk, yolk color, vitelline membrane strength, shell strength, and egg weight. Results found no significant quality differences between HVACP treated and untreated eggs at any storage times. In addition, treated and untreated eggs maintained Grade AA quality for six weeks when stored in a MA gas. Previous studies found eggs stored in air begin to lose Grade AA quality after two weeks of refrigerated storage.

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