Theses and Dissertations

Issuing Body

Mississippi State University


Bailey, R. Hart

Committee Member

Brooks, John P.

Committee Member

Coble, Keith H.

Committee Member

Hall, Michael E.

Committee Member

Donaldson, Janet R.

Date of Degree


Document Type

Dissertation - Open Access


Veterinary Medical Science

Degree Name

Doctor of Philosophy


College of Veterinary Medicine


Veterinary Medical Science Program


The increase in production farming, also known as concentrated animal feeding operations (CAFOs), garners more investigations on the implications to public health regarding the disposal of the wastes of food production animals. In addition to the vast amount of animal manure produced, human biosolids is another waste residual that must be managed. The research focus was the sustainability of foodborne pathogens in waste products and the variables that manipulate these environments such as moisture, temperature, organic matter and time. The first study was designed to analyze spatial differences in microbial populations in broiler litter by investigating the relationship of intra-house location, age of flock, bedding moisture, and seasonality. Antibiogram profiles of selected isolates were explored to determine if antibiotic resistant bacteria are common in these environments and if multiple class resistance is present. These findings provided insight into new targets that may reduce zoonotic bacteria that are problematic from a food safety prospective as well as nuisance bacteria that threaten broiler health. The second study was designed to establish current decay rates of viral and bacterial pathogens when seeded in various waste residuals and the effects soil type and application method have on those rates. Decay rates were established by standard culture and molecular methods, such as qPCR. A comparison of both derived inactivation rates were analyzed to determine if these methods were significantly different. Both cultural and molecular methods have limitation and advantages, and the argument that both are useful and needed is asserted. The decay rates associated with each method were used to simulate a one-time exposure to a land application site to assess the microbial risk of Salmonella using a Quantitative Microbial Risk Assessment model.



Foodborne pathogens||Waste Management||Salmonella