Date of Award

2023

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Biological and Environmental Sciences

Specialization

Sustainable Agriculture and Food Systems

Department

Fisheries, Animal and Veterinary Science

First Advisor

Becky Sartini

Abstract

The goal of this dissertation research was to determine the best management and egg washing practices for small-scale egg producers and backyard chicken owners to help improve food safety. The main goals were to establish the most effective management and egg washing procedures to reduce total coliform bacteria load on eggshells and increase egg cleanliness. To determine the methods used for experiments in chapters 3-5, a survey was conducted on egg handling, washing and management techniques in backyard poultry and small-scale producers within the Northeastern U.S. The effect of management practices and egg washing methods on the eggshell cuticle was also evaluated. The impact of varying storage techniques, duration, and housing styles on eggshell bacteria levels and the cuticle deposition was also examined in this research.

The first chapter of this dissertation is a literature review on sustainability and its role in egg production, free-range/pastured poultry production, food safety and the eggshell cuticle. The elements encompassed in this review outline the existing knowledge on these topics and their collective contribution to the rationale and context of this dissertation research.

The second chapter is a manuscript being prepared for submission to the Journal of Applied Poultry Research. In this manuscript, surveys were conducted to determine the most common management practices, egg handling and washing methods from backyard poultry owners and small-scale egg producers in the Northeastern United States. Surveys were conducted/distributed by either Qualtrics or in person questionnaire and had combined responses from Rhode Island, Massachusetts, Connecticut, New Jersey, New Hampshire, Michigan, Vermont and Pennsylvania. The aim of this study was to increase the knowledge of popular egg handling, management and washing practices of backyard chicken owners and small-scale egg producers within the Northeastern United States.

The third chapter is a manuscript that was published in the Journal of Applied Poultry Research in January 2023. This manuscript evaluated if the manure level (ML) of the eggs and management practices will affect both the total bacterial levels (measured in relative light units = RLU) and the cuticle deposition (CD) of the eggshell. The management practices tested were nest box type (rollaway and conventional style), nest box location (mounted vs floor level access), nesting substrate (straw, shavings and AstroTurf. Nest Pads), and time/frequency of egg collection. The CD experiments involved nest box type and nest substrate management practices only. I was able to determine that management practices that minimize manure levels on eggs such as time of egg collection can help to maintain lower eggshell bacteria levels to reduce food safety risk. Level of manure contamination on eggshells also correlates with the amount of overall shell bacteria.

The fourth chapter is a manuscript being prepared for submission to the Journal of Poultry Science. Based on responses to the egg washing questions in chapter 2, this manuscript evaluated different egg washing methods and their effect on total eggshell bacteria levels and cuticle deposition. The washing methods used within this study were bucket washing (BW), antibacterial wipe (ABW), dish soap (DS), dry brushing (DB), egg wipe (EW), enzyme soak (ES), water rinsing (WR), water scrubbing (WSC) and water soaking (WS). I was able to determine the most effective washing methods utilized scrubbing (DB and WSC) and/or detergents, soaps or enzymes with water (BW, DS, ABW, EW and ES) showed a significant reduction in shell bacteria levels. Similarly, most of these methods also deteriorated the eggs cuticle coverage, besides DB, ES and ABW.

The fifth chapter is in the manuscript format for the Journal of Applied Poultry Research. Within this manuscript, the degradation of egg quality and cuticle was evaluated for eggs stored at room temperature (RT) (70-78 ℉) or refrigeration (37-40 ℉) over a 6-week time span. RT storage and time negatively affected egg quality parameters like egg grade and weights. The cuticle remained consistent over the 6-week period for both storage methods, but refrigerated eggs had a higher cuticle reading on average. It was concluded that eggs stored in the fridge degraded at a slower rate than those kept at RT over a 6-week period.

Chapter 6 of this dissertation is also written in the manuscript format for the Journal of Applied Poultry Research. The goal of this manuscript was to determine the effect of different housing systems (indoor cage-free and pasture-raised) on the eggshell bacteria load and cuticle deposition. I found that there was no difference in shell bacteria levels between layers housed in a cage-free indoor environment and those with pasture access in a mobile coop. Eggs collected from hens in the pasture-raised system were found to have higher cuticle deposition on average when compared to indoor-housed hens.

In Chapter 7 of this dissertation, the main conclusions that can be drawn from the results of each manuscript are summarized. The main conclusions that can be drawn from all of these manuscripts are that management and washing methods utilized by many backyard chicken owners and small-scale egg producers are comparable and consistent throughout the Northeastern United States. Determining a decrease in shell bacteria and egg quality hinges on crucial factors such as washing and storage techniques, as well as the duration of storage. The washing method utilized will determine which storage method and potential storage time will need to be used to ensure the safety and quality of the egg. Certain management practices and housing systems can help to decrease shell bacteria, improve egg cleanliness and increase cuticle deposition on eggs. To enhance food safety and improve the quality of eggs, a program aimed at educating local backyard chicken owners and egg producers on the findings of this study should be developed.

Download

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.