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Salmonella Enteritidis (SE) has been the most common Salmonella serotype associated with foodborne infections in the last several years. Dietary applications of yeast-based preparations in feed have shown to reduce Salmonella colonization in chickens augmenting SE control strategies. This study was conducted to evaluate the effects of a mannan-rich yeast cell wall-derived preparation (Actigen ®) administered in feed at a rate of 400 g/ton on SE colonization in the cecum and internal organs of commercial layer chickens. Sixteen week-old layer pullets were orally challenged with a selected nalidixic acid resistant SE strain at a dose of 1.7×10^9 colony forming units (CFU) per bird. SE colonization was assessed by evaluating isolation rates from ovary and pooled liver/spleen samples as well as enumeration of SE in cecal pouches one week post-challenge. Recovery rates of SE from the ovaries of directly challenged birds receiving Actigen ® were significantly lower (P <0.02) than those in directly challenged birds fed an unsupplemented control diet. Recovery rates of SE from pooled liver/spleen samples were not significantly different between Actigen ®-treated pullets and controls (P = 0.22). Using direct plate count methods, cecal SE concentrations were 1 log 10 lower (P <0.001) in challenged pullets in the Actigen ®-supplemented group than in the challenged controls. The SE concentration distributions in the ceca were similar in groups testing positive and groups testing negative for SE in the ovaries and liver/spleens tissues. As a result, SE concentrations in the ceca could not be directly related to the occurrence or prevalence of SE in these tissues. In conclusion, Actigen ® supplementation appears to decrease the prevalence of SE in ovarian tissue and concentrations of SE in cecal contents and may be useful as a tool for reducing the risk of eggshell contamination and transovarian transmission of SE in eggs.

The effects of citrus fiber on the color,texture, lipid oxidation, and sensory characteristics of fully-cookeddeli-style turkey breast during storage (3˚C) were studied. Four treatmentswere evaluated: control (CON), 0.25% citrus fiber (0.25CF), 0.50 % citrus fiber(0.50CF) and 0.105% sodium tripolyphosphate (PHO). The study was independentlyreplicated three times. Proximate analysis and pH were measured once, and color(Hunter L, a, b), lipid oxidation (TBARS), texture (TPA hardness, resilience, cohesiveness,springiness and chewiness) and sensory parameters (turkey aroma, texture, moistness,turkey flavor, off-flavor and color) were measured at regular intervalsthroughout an 84-d storage period. Aside from TPA resiliency and sensorymoistness lower in PHO, all experimental treatments resulted in product with equivalentquality attributes to the control. At the levels tested in this specific application(high moisture, low fat), the citrus fiber evaluated did not affect theproduct’s quality attributes in a measurable way.

This thesis is in memory of my grandparents, Gerald & Bernadette Coyle and Robert & Arla Powell. Your love and passion for school and encouragement growing up impacted me more than I was ever able to thank you for. Thank you for instilling in me such confidence, the importance of taking chances, and teaching me I can achieve anything. You continue to shine as my inspirations. I would not be where I am today without you.

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