Date of Graduation

5-2014

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor

Daniel Donoghue

Committee Member

Annie Donoghue

Second Committee Member

Michael Slavik

Keywords

Broilers, Campylobacter Jejuni, Chitosan, Food Safety, Post-harvest, Pre-harvest

Abstract

Worldwide, Campylobacter is one of the leading causes of foodborne bacterial gastroenteritis causing an estimated 1.3 million infections in the United States alone. Consumption and/or cross-contamination of raw or undercooked poultry products have been linked as the most common source of Campylobacter infection, making the poultry industry a target for Campylobacter reduction strategies. Campylobacter is prevalent in most poultry flocks in the United States, with as many as 90% of flocks Campylobacter-positive at the time of slaughter. It is estimated that a reduction of Campylobacter in poultry would greatly reduce the risk of campylobacteriosis in humans. Unfortunately, there are a lack of effective intervention options to reduce Campylobacter in poultry. One potential strategy is the use of the natural product, chitosan, a deacetylated byproduct of crustacean shells, has been shown to reduce E. coli and Salmonella. The purpose of this study was to determine the ability of chitosan to reduce enteric Campylobacter colonization in pre-harvest chickens and on post-harvest chicken skin samples. In each of three trials, 100 birds were divided into 10 treatments (n=10) and were fed either 0% (controls), 0.25%, 0.5% or 1% (wt./wt.) of a low, medium or high molecular weight chitosan (300 birds total). Birds were fed treated feed for the duration of the study and were orally challenged with a four-strain mixture of wild type C. jejuni on day 6. On day 15, the ceca were excised and enumerated for Campylobacter. In all three trials, the 0.5% dose of the medium molecular weight chitosan reduced cecal Campylobacter counts. Because this medium molecular weight chitosan was shown to be the most effective, it was evaluated for post-harvest efficacy against Campylobacter on chicken skin. When a 0.5, 1 or 2% concentration was tested in three separate trials, Campylobacter counts were not reduced when compared to controls. These results support the use of chitosan in pre-harvest chickens but not for the reduction of Campylobacter as a post-harvest rinse on skin for the concentrations and strategy used in this study.

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