Date of Graduation

5-2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Poultry Science (PhD)

Degree Level

Graduate

Department

Poultry Science

Advisor

Susan Watkins

Committee Member

Geraldine Huff

Second Committee Member

Wen Zhang

Keywords

Biological sciences; Poultry; Sanitizers; Waterline biofilm

Abstract

Enclosed water system has created a minimal sanitation focus leading to biofilm issues which are a source of flock health challenges. A series of in vitro tests were conducted to evaluate biofilm growth on polyvinylchloride (PVC) surfaces when exposed to treated/untreated water sources (test water) that are typically supplied in commercial barns. PVC test coupons (15.16 cm2) were immersed in test water in beakers to grow biofilm. Test water supplies were characterized for microbial, mineral and pH content. Temperature of test water was set at 90 °F (32.2 ᵒC) on d1 and then dropping 1°F each day over 7-day period (in ᵒC, from d 2-d 6 - 31.6, 31.1, 30.5, 30, 29.4). Water inside beakers was gently agitated that bathed the coupons to mimic flowing water. Experiment 1 was conducted using low microbial content water (< 3 log10 APC cfu/ml); and experiments 2, 3 and 4 utilized higher bacteria content water (> 3 log10 APC cfu/ml) to produce biofilm in test coupons. Experiment 4 also included seeding the avian pathogenic E. coli sero group O2 strain in pathogen free water containing 7 d old biofilm test coupons and determining if it would incorporate into the biofilm community post 48- hour exposure. Sanitizers tested on the coupons included chlorine based product (CBP) (T1) and a hydrogen peroxide based product (HPBP) (T2) dosed to attain residuals in water of 3-5 ppm free chlorine and 25-50 ppm hydrogen peroxide. Control was untreated test water (T3). Results showed that biofilm can quickly (< 7d) develop on PVC surface even in minimally contaminated water (> 2 log10 cfu/cm2 by day 7 in experiment 1); and the use of sanitizers was effective in limiting rapid biofilm formation ( < 2 log10 APC cfu/cm2 in treated test coupons vs. > 4 log10 cfu/cm2 in untreated test coupons in experiment 2) or reducing bacterial load in already established biofilm (3.82 log10 cfu/cm2 by day 7 in experiment 3), yet CBP proved more effective than HPBP tested (3.82 vs 2.14 log10 cfu/cm2 reduction). Experiment 4 demonstrated that treating water inhibited E. coli O2 from being incorporated into established biofilm.

Key Words: PVC, biofilm levels, sanitizers, E. coli sero group O2

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