Date of Graduation

12-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Poultry Science (PhD)

Degree Level

Graduate

Department

Poultry Science

Advisor

Dan J. Donoghue

Committee Member

Michael Slavik

Second Committee Member

Charles Rosenkrans

Third Committee Member

Ann M. Donoghue

Abstract

Poultry is one of the main sources of protein in the United States and in 2014 Americans ate approximately 100 lbs per person. However, consumption of poultry products is strongly associated with foodborne illness from Campylobacter. In the first study, chitosan, caprylic acid and their combination were evaluated as a coating treatment for the reduction of Campylobacter jejuni on poultry products. For the initial screening trials, chitosan of three different molecular weights (15-50 kDa, 190-310 kDa and 400-600 kDa) was evaluated at three concentrations (0.5%, 1.0%, 2.0%) and separately, caprylic acid was tested at 0.5%, 1.0% and 2.0% using chicken skin pieces. From these initial screenings a solution of 2% medium molecular weight (190-310 kDa) chitosan was chosen for continued evaluation, as was 1% and 2% caprylic acid. To determine short term and long term efficacy of the 2% chitosan, 1% caprylic acid, 2% caprylic acid individually and in combination wingettes were inoculated with Campylobacter, coated with a given treatment and sampled at 0, 1, 3, 5 and 7 days. The 2% chitosan and both 1% and 2% caprylic acid continually reduced Campylobacter counts starting at day 3 through day 7. The combination of either 1% or 2% caprylic acid plus 2% medium molecular weight chitosan continuously reduced Campylobacter starting at day 0 through day 5.

In the second study Lactobacillus spp. isolates with in-vitro anti-Campylobacter activity were evaluated for their efficacy as a protective culture when applied to chicken wingettes. An original 13 isolates of Lactobacillus were screened, resulting in the selection of 4 isolates for further evaluation. Wingettes were inoculated with Campylobacter jejuni and treated with either a Lactobacillus broth culture or a BPD control, followed by sampling at days 0, 1, 3, 5 and 7. All isolates were able to reduce Campylobacter counts by day 3, however two isolates produced more consistent reductions. These two isolates were combined with a 2% chitosan solution (190-310 kDa) and applied as a coating treatment for evaluation of increased efficacy. The combination of 2% chitosan plus either Lactobacillus isolate failed to increase the efficacy.

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