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Full-Text Articles in Life Sciences

Thermal Inactivation Kinetics Of Salmonella In Milk Powder As Impacted By Water Activity And Powder Type, Erika Litta Kadas Dec 2022

Thermal Inactivation Kinetics Of Salmonella In Milk Powder As Impacted By Water Activity And Powder Type, Erika Litta Kadas

Graduate Theses and Dissertations

Historically, low-water activity (aw) foods (aw <0.65) were considered to be microbiologically safe for consumption. However, these foods have been implicated in outbreaks of pathogens such as Salmonella enterica, at a frequency that surely challenges this assumption of safety. Although usually implicated in outbreaks involving poultry and egg products, Salmonella spp. have frequently been the culprit in several outbreaks and recalls associated with low-water activity foods (LWAF) due to contamination resulting from the environment, animals, or even the employees during pre-or post-processing. One such LWAF that has been associated with Salmonella spp. outbreaks is milk powder. Milk powders are used in a variety of products ranging from infant formula to confectionary goods. With their widespread use, improving their safety is imperative. A key step in improving their safety is to thoroughly investigate preventive controls related to milk powder processing. The Food Safety Modernization Act (FSMA) established the Preventive Controls for Human Foods Rule, which mandates that processors design and establish a food safety plan outlining any potential hazards and the steps they will take to ensure those hazards do not compromise the safety of the product. Presently, the dairy industry does not have an established kill-step for milk powders post-spray drying. Spray drying may reduce some microbial populations, however, desiccation(e.g., spray drying) is not considered a kill-step. The work outlined in this thesis aims to assist our dairy industry partners in establishing their own thermal process for milk powders post-spray drying. Moisture sorption isotherms of two milk powders (nonfat dry milk: NFDM and a milk protein concentrate with 85% protein content: MPC-85) were determined and showcased that the temperatures at which the isotherms were determined (23, 40, or 60°C) significantly affected both the adsorption and desorption isotherms (p<0.0001) for each powder. Secondly, the thermal inactivation kinetics of Salmonella spp. in both powders were evaluated at two different water activities (0.20 and 0.30) and three temperatures (75, 80, and 85°C) to determine the effect of water activity on the thermal resistance of a cocktail of Salmonella spp. The D-values of Salmonella were heavily influenced by the thermal treatment temperature (p< 0.0001), but not the water activity (p >0.05). The overall findings contained within this thesis provide valuable information about the thermal inactivation kinetics of Salmonella spp. to our partners in the dairy industry so that they may implement an appropriate thermal process for their milk powders.


Applying A Material Science Approach To Improve Rice Processing Performance, Michelle Oppong Siaw Dec 2022

Applying A Material Science Approach To Improve Rice Processing Performance, Michelle Oppong Siaw

Graduate Theses and Dissertations

Rice is typically consumed as whole kernel, which makes the economic value of whole kernels twice that of brokens. Macro-structural defects such as fissures and chalkiness have been recognized to weaken kernel mechanical strength, and thereby increase breakage during milling. However, high percentages of brokens are sometimes recorded even though these defects are controlled prior to milling. It was hypothesized that rice milling characteristics are influenced by endosperm porosity from the structural arrangement of chemical components and by bran thickness and composition. Thus, this study aimed to modify chemical components by applying treatments to alter rice porosity and its associated …


Investigating Quality Attributes And Wine Production Methods Of Arkansas-Grown Grapes, Amanda Fleming Dec 2022

Investigating Quality Attributes And Wine Production Methods Of Arkansas-Grown Grapes, Amanda Fleming

Graduate Theses and Dissertations

Grapevines (Vitis species) are grown worldwide to produce table grapes, juice grapes, dried grapes, and wine with the United States as one of the world’s largest wine and grape producers. Though not a large contributor to the U.S. grape and wine industry, Arkansas’ industry plays an important role in the state’s agritourism and economy. Most grapes grown in Arkansas’ warm climate include native species, such as muscadines (V. rotundifolia) and hybrids (crosses of Vitis species). Two important hybrid red wine grapes grown in Arkansas are Chambourcin, grown commercially for its positive viticulture and enological quality, and Enchantment, a newer cultivar …


Application Of Microwave-Assisted Technology For Single-Pass Drying Of Rough Rice, Rebecca Mawusi Bruce Aug 2022

Application Of Microwave-Assisted Technology For Single-Pass Drying Of Rough Rice, Rebecca Mawusi Bruce

Graduate Theses and Dissertations

The 915 MHz industrial microwave is a novel technology that has the potential to achieve one-pass drying of rice within a short drying duration and reduce rice drying losses. However, processing recommendations for the commercialization of this technology for rice drying is lacking. The goal of this research is to provide processing conditions that are useful for the commercialization of the 915 MHz industrial microwave technology for rice drying. This was achieved by studying the impact of microwave specific energy and processing conditions such as harvest moisture content, milling duration, and aging on the physicochemical properties of a 915 MHz …


To The Window, To The Wall: Improving Environmental Monitoring Protocols, Sarah Jones May 2022

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 …


Arkansas Fresh-Market Blackberries: Identifying Unique Attributes And Harvest Practices That Impact Marketability, Andrea Lea Myers May 2022

Arkansas Fresh-Market Blackberries: Identifying Unique Attributes And Harvest Practices That Impact Marketability, Andrea Lea Myers

Graduate Theses and Dissertations

Fresh-market blackberries (Rubus subgenus Rubus) are sold worldwide and have attributes that appeal to consumers. The delicate-nature of the fruit requires hand harvesting, and minimal handling of the fruit postharvest. Objectives of this research on Arkansas fresh-market blackberries was to 1) identify the unique attributes 2) determine the best handling practices to increase postharvest quality, and 3) evaluate the potential of soft robotic gripper for harvesting. For the first objective, blackberry genotypes were harvested from the University of Arkansas System (UA System) Division of Agriculture Fruit Research Station in Clarksville, AR. Nineteen genotypes were harvested in 2020, eight genotypes were …


A Mixed Methods Approach To Context Specific Curriculum Design For Very Small And Small Strawberry Growers In The Southeastern United States, Thomas A. Yeargin May 2022

A Mixed Methods Approach To Context Specific Curriculum Design For Very Small And Small Strawberry Growers In The Southeastern United States, Thomas A. Yeargin

Graduate Theses and Dissertations

Outbreaks of foodborne illness due to fresh produce are a continued threat to both the publichealth and the economy in the United States. Though there are many factors which influence the perpetuation of foodborne pathogens, the inability of the food industry to curtail this issue indicates systemic failure of interventions aimed at improving food safety practices. In this dissertation, we detail the efforts made over the past few decades to provide training to food producers and food handlers as well as recommendations that have been made for improvement based on these studies. By borrowing from more advanced fields of study …