Date of Graduation

2017

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Agricultural and Resource Economics

Committee Chair

Cangliang Shen

Committee Co-Chair

Brett P Kenney

Committee Member

Kristen Matak

Abstract

The aim of this study was to evaluate the microbial quality of broiler carcasses and efficacy of antimicrobials on unstressed or cold-stress adapted cells of Salmonella and Enterococcus on broiler carcasses and wings. Broiler carcasses and wings were processed at a small USDA-inspected slaughter facility, located in West Virginia. The first part of the study included 42 broiler carcasses that had been pre-enriched in Buffered Peptone Water then secondarily-enriched into Rappaport Vassiliadis following incubation. Secondary enrichment broth was then streaked on to Xylose Lysine Tergitol 4 (XLT-4) and HardyCHROM(TM) agar for Salmonella detection; and further confirmation was performed using an API 20E kit and Latex Agglutination test. Various petrifilms such as aerobic plate count (APC), Escherichia coli (ECC), total coliforms (TCC), and yeast/ mold were analyzed. APC, ECC/TCC and Yeast/ Mold counts were 2.61, 1.08, and 2.37 og10 CFU/mL respectively on broiler carcasses. Thirty and forty percent of the carcasses were positive for detection of Salmonella spp. and Escherichia coli (0.48 to 1.70 og10 CFU/mL) respectively. Study II included fresh broiler carcasses and wings; these meat products were inoculated with unstressed and cold-stress adapted (grown in 4 °C for 7 days) Salmonella Typhimurium ATCC 14028, Salmonella Tennessee ATCC 10722, and Enterococcus faecium ATCC8459 (roughly 5.5 to 6.5 og10 CFU/mL). Carcasses and wings were later assigned to undipped (control) or dipped treatments, these treatments consisted of peroxyacetic acid (PAA; 0.1%), lactic acid (LA; 5%), lactic/ citric acid blend (LCA; 2.5%), and sodium hypochlorite (SH; 67-69 ppm). Dip treatments were 30 seconds with carcasses and wings, with wings having a 2 minute drying period following dipping. Immediately following treatments, surviving bacteria were recovered onto selective and non-selective agar to analyze total Salmonella and Enterococcus. Carcasses had antimicrobials reduce cold-stress adapted cells (1.1 to 1.7 and 1.0 to 2.1 og10 CFU/mL) more (P<0.05) than the unstressed cells (0.7 to 1.5 and 0.2 to 1.7 og10 CFU/mL) for Salmonella and Enterococcus. As for wings, cold-stress adapted Salmonella cells were more sensitive (P>0.05) to antimicrobials (reduced by 0.9 to 1.5 og10 CFFU/mL) than the unstressed cells (reduced by 0.5 to 1.2 og10 CFU/mL). However, unstressed and cold-stress adapted Enterococcus behaved similar, (P>0.05), with reductions ranging from 0.9 to 2.0 og 10 CFU/mL. Salmonella and Enterococcus reductions on carcasses and wings increased in the following order: SH?LCAThe aim of this study was to evaluate the microbial quality of broiler carcasses and efficacy of antimicrobials on unstressed or cold-stress adapted cells of Salmonella and Enterococcus on broiler carcasses and wings. Broiler carcasses and wings were processed at a small USDA-inspected slaughter facility, located in West Virginia. The first part of the study included 42 broiler carcasses that had been pre-enriched in Buffered Peptone Water then secondarily-enriched into Rappaport Vassiliadis following incubation. Secondary enrichment broth was then streaked on to Xylose Lysine Tergitol 4 (XLT-4) and HardyCHROM(TM) agar for Salmonella detection; and further confirmation was performed using an API 20E kit and Latex Agglutination test. Various petrifilms such as aerobic plate count (APC), Escherichia coli (ECC), total coliforms (TCC), and yeast/ mold were analyzed. APC, ECC/TCC and Yeast/ Mold counts were 2.61, 1.08, and 2.37 og 10 CFU/mL respectively on broiler carcasses. Thirty and forty percent of the carcasses were positive for detection of Salmonella spp. and Escherichia coli (0.48 to 1.70 og10 CFU/mL) respectively. Study II included fresh broiler carcasses and wings; these meat products were inoculated with unstressed and cold-stress adapted (grown in 4 °C for 7 days) Salmonella Typhimurium ATCC 14028, Salmonella Tennessee ATCC 10722, and Enterococcus faecium ATCC8459 (roughly 5.5 to 6.5 og10 CFU/mL). Carcasses and wings were later assigned to undipped (control) or dipped treatments, these treatments consisted of peroxyacetic acid (PAA; 0.1%), lactic acid (LA; 5%), lactic/ citric acid blend (LCA; 2.5%), and sodium hypochlorite (SH; 67-69 ppm). Dip treatments were 30 seconds with carcasses and wings, with wings having a 2 minute drying period following dipping. Immediately following treatments, surviving bacteria were recovered onto selective and non-selective agar to analyze total Salmonella and Enterococcus. Carcasses had antimicrobials reduce cold-stress adapted cells (1.1 to 1.7 and 1.0 to 2.1 og10 CFU/mL) more (P<0.05) than the unstressed cells (0.7 to 1.5 and 0.2 to 1.7 og10 CFU/mL) for Salmonella and Enterococcus. As for wings, cold-stress adapted Salmonella cells were more sensitive (P>0.05) to antimicrobials (reduced by 0.9 to 1.5 og10 CFFU/mL) than the unstressed cells (reduced by 0.5 to 1.2 og10 CFU/mL). However, unstressed and cold-stress adapted Enterococcus behaved similar, (P>0.05), with reductions ranging from 0.9 to 2.0 og10 CFU/mL. Salmonella and Enterococcus reductions on carcasses and wings increased in the following order: SH≤LCA

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