Date of Graduation

12-2020

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor/Mentor

Billy Hargis

Committee Member

Guillermo Tellez-Isaias

Second Committee Member

Walter Bottje

Keywords

Ceca, Food safety, Lungs, Oral-fecal infection, Processing, Pulmonary tissue, Reading, Salmonella, Turkeys

Abstract

This study aimed to evaluate the fate and dissemination of Salmonella Reading (SR) in market-age turkeys using an oral gavage challenge model. One hundred twenty-eight-week-old commercial turkey hens were moved from commercial production to research facilities. Upon arrival, a combination of enrofloxacin, 10 mg/kg, and florfenicol, 20 mg/kg, were orally administered sequentially before comingled placement on fresh pine shavings. Turkeys were challenged with 108 cfu SR by oral gavage on days 4 and 7 post-placement. Subsets were subjected to simulated commercial processing on days 14 (n=40), 21 (n=40) and 28 (n=32) post-placement (corresponding to 10, 11, and 12 weeks of age). After scald and feather picking, samples of stifle joint, skin, trachea, crop, lung, liver, and spleen (L.S.), and ceca were aseptically sampled, enriched in tetrathionate broth, and streaked on XLT-4 agar for recovery and serotyping of SR colonies. SR could not be recovered from stifle joint 14 days P.I. Skin samples showed the highest incidence of SR recovery (80 %) 14 PI, followed by crop (75 %); LS (67.5 %); lungs (60 %); and ceca (57.5 %). The organ with the lowest percentage of SR recovery was the trachea with 40 % of positive samples (P < 0.01). At 21 days P.I., ceca samples showed the highest rate of positive samples followed by the crop, suggesting a fecal-oral infection that allows the colonization and systemic organ invasion of SR that persisted at 28 days P.I. While cecal samples were consistently positive for SR at all time points, recovery of SR from skin and trachea declined rapidly. While interventions to reduce foodborne pathogens such as Salmonella should target all parts of the supply chain, including slaughter and processing facilities, and upstream farm sources, public health agencies, and industry must take steps to provide more consumer education about food safety. The present work suggests that pulmonary tissue may be an unexpected source of turkey carcass and ground turkey contamination with this serovar at processing. If confirmed, new intervention steps to reduce cross contamination from lung tissue during evisceration may be needed.

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