Life Sciences Commons^™

Understanding And Developing Safer Sanitation Agents And Strategies In Food Production Environments, Pragathi Kamarasu

Doctoral Dissertations

Food is a primary resource for survival of human beings, and it is also one of the primary resources for spread of infectious diseases. When both these factors come together it does not only cause ill effects on our health but also causes a burden on the food and agricultural industry. Through the help of science, us researchers and scientists have always tried to reduce this burden. And I hope like a drop of water in the ocean in some way my research contributes towards this. According to WHO currently in 2023 there are about 1 in 10 people falling …

To The Window, To The Wall: Improving Environmental Monitoring Protocols, Sarah Jones

Graduate Theses and Dissertations

Detecting microorganisms on environmental surfaces via an environmental monitoring (EM) program is part of a preventive food safety culture. Environmental monitoring should 1) verify that food safety plans are reducing cross-contamination risk from surfaces to food, 2) pinpoint microbial niches, and 3) prevent the transmission of pathogens. Environmental monitoring programs utilize EM tools, such as sponges, to sample food contact and non-food contact surfaces. However, EM tool selection is determined by the individual food firm. This dissertation evaluated and characterized factors influencing EM program effectiveness in the food industry. Specifically, this dissertation focuses on the release of microorganisms from EM …

Investigation Of Fermentation Efficiency In Saccharomyces Cerevisiae Through Telomere Integrity And Maltase Expression, Dana Bennett

All Graduate Theses, Dissertations, and Other Capstone Projects

Many microbreweries practice serial fermentation, or serial repitching. Serial repitching is the process by which one yeast culture is reused for multiple batches of beer. Each batch of subsequent beer is called a “pitch.” This technique helps breweries limit production costs. However, fermentation is difficult to predict throughout serial fermentation. This leads to beer quality issues such as fluctuation in alcohol production, buildup of unwanted flavor compounds, and decreased carbon dioxide production, which results in reduced profit. To combat this issue, many breweries will attempt to predict fermentation efficiency through viable cell counting in order to ensure a consistent number …

Microbiota Characterization Of Poultry Processing Systems And Associated Microbiological Sampling Materials Collected At Commercial Processing Facilities, Jennifer A. Wages

Graduate Theses and Dissertations

The poultry industry and associated regulatory bodies use whole bird carcass (WBC) rinsates to evaluate different stages of broiler processing systems for the prevalence of food-borne pathogens, including Salmonella spp. and Campylobacter spp. Within industry and research groups, the same sample collections are enumerated to determine E. coli, Enterobacteriaceae (EB), and Aerobic Plate Count (APC) microorganisms. Analysis of these indicator microorganisms provides numerical data that can be used to demonstrate the effects of specific process control steps where low occurrences of target pathogens hinder the exclusive use of prevalence data. With the utilization of next generation sequencing (NGS), including analysis …

Applications Of Hydrodynamic Cavitation In Dairy Manufacturing: Process Development And Standardization, Jae Young Sim

Electronic Theses and Dissertations

The phenomenon of hydrodynamic cavitation involves the formation, growth, and subsequent collapse of bubbles when a given liquid experienced a reduction of pressure below its vapor pressure. The presence of cavitation limits the performance and the safe operation of many machinery and pumps. However, innovation in the design of the hydrodynamic cavitation devices has offered promising applications in the food and dairy industry. Upon collapse of the cavities, the fluid experiences significant mechanical effects (shear and turbulence) as well as instantaneously elevation of the fluid temperature. All these effects can be put to work for mixing, dispersion, particle size reduction, …

Effect Of Storage Temperature On The Survival Or Growth Of Listeria Monocytogenes On Whole And Fresh-Cut Produce, Juan F. Moreira Calix

LSU Master's Theses

Whole and fresh-cut produce are minimally processed and, therefore susceptible to microbial contamination. This study examined the survival or growth of Listeria monocytogenes on whole, and fresh-cut produce at different storage temperatures. Fresh fruits (cantaloupes, pears, pineapples, papayas, and watermelon) and vegetables (broccoli, cauliflower, lettuce, kale, and green bell peppers) were cut into 25 g pieces and were spot inoculated with 0.5 mL (8 Log CFU/mL) of Listeria monocytogenes. Inoculated fresh-cut samples were stored at 4°C or 13°C for 6 days. To represent the outer surface of the produce, cantaloupes and green bell pepper disks (20 cm2) were cut with …

Comparison Of The Kinetic Parameters Of Escherichia Coli 0157:H7, Listeria Monocytogenes And Salmonella Typhimurium Derived From The Baranyi And Huang Models In A Chemically Defined Minimal Medium, Jose Isidro Fuentes

LSU Master's Theses

Microbial growth can be characterized by parameters such as lag time, growth rate, and maximum population density at any specific point of time. Mathematical models that predict microbial growth of foodborne pathogens are increasingly used in the food industry as a viable alternative to traditional methods of microbial enumeration. The Baranyi model has been widely used as the primary model of choice by many authors because of its performance and accuracy. The most recently developed Huang model has been less implemented and few comparisons between the Baranyi and Huang models have been made when modeling pathogenic growth. For this research, …

Understanding The Molecular Strategies Of Campylobacter Jejuni For Survival In Amoeba And Chicken., Deepti Pranay Samarth

Graduate Theses and Dissertations

Campylobacter jejuni endure to be major cause of gastroenteritis in humans worldwide. C. jejuni is fastidious in laboratory setup but can cause waterborne infection through contaminated water where none of these fastidious conditions are met. This dissertation presents an assortment of studies focused in reviewing three major factors which could present a helping hand to C. jejuni in its environmental survival viz. i) association with free-living amoebae (FLA) ii) horizontal gene transfer (HGT) contributing towards its genetic diversity iii). Viable but non-culturable (VBNC) state.

Acanthamoeba is a FLA linked to environmental survival of many intracellular pathogens, including C. jejuni. In …

Phenotypic, Physiological And Growth Interactions Among Salmonella Serovars, Juliany Rivera Calo

Graduate Theses and Dissertations

This thesis consists of four research parts: a literature review that covers Salmonella spp., one of the more prominent foodborne pathogens that represents a major risk to humans (chapter 1). Understanding the growth of Salmonella serovars and strains is an important basis for more in depth research. In this case we studied a) the aerobic and anaerobic growth responses of multiple strains from six different serovars, b) how the spent media from different serovars, more importantly S. Heidelberg, affect the growth of S. Typhimurium, and c) determined whether or not two different serovars undergo competitive interactions when they were …