Date of Defense

4-19-2024

Date of Graduation

4-2024

Department

Biological Sciences

First Advisor

Silvia Rossbach

Second Advisor

Carol Beaver

Abstract

This research aims to investigate and analyze the presence of bacterial contamination of various types of eggs, including duck, chicken, and goose eggs. This study, conducted under the supervision of Dr. Silvia Rossbach and microbiology laboratory instructor Carol Beaver (MS), began with the isolation of different types of bacteria from eggs. Techniques such as Polymerase Chain Reaction (PCR), gel electrophoresis and DNA sequencing were used to identify the taxon of each bacterial isolate found on or in the eggs. By gaining insights into the types of bacteria thriving in different egg varieties, this research aimed to enhance our understanding of conditions conducive to bacterial growth within eggs. Bacterial contamination of eggs poses significant health risks and economic challenges due to foodborne illnesses and potential reputation damage to egg industries. Eggs can become contaminated during manufacturing, handling, and preservation stages, with sources including both vertical transmission from the hen’s digestive system and horizontal transmission through unsanitary farm conditions and human handling. The study found that bacterial contamination levels varied among egg types, with 108 isolated bacteria identified across duck, goose, and chicken eggs. Refrigerated store-bought chicken eggs had lower contamination levels compared to unrefrigerated farm-raised chicken eggs, primarily involving Kocuria, suggesting contamination through human contact post-cleaning. The outer shell of the eggs exhibited the highest bacterial contamination, while the interiors were mostly bacteria-free. Notably, goose eggs showed the highest contamination levels. PCR and Sanger sequencing identified predominant bacterial genera, including Staphylococcus, Kocuria, and Psychrobacter. While no pathogenic bacteria were found, opportunistic pathogens were present, which could pose risks to individuals with compromised health. This study highlights the importance of proper handling and thorough cooking to mitigate contamination risks. Overall, environmental and manufacturing conditions seem to influence bacterial contamination levels in eggs.

Access Setting

Honors Thesis-Restricted

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