Food Microbiology Commons^™

Effect Of Reduced Sodium Cheese On The Growth Of Pathogenic Bacteria And Inactivation Of Listeria Innocua Using Supercritical Fluid Extraction With Co2, Suyapa Padilla Antunez

Master's Theses

Listeria monocytogenes continues to challenge the dairy industry in causing post-process contamination of cheeses. To reduce risk of contamination, it is crucial to understand the growth and survival of pathogenic bacteria in cheese products and to develop post-process mitigation strategies. This study evaluated the fate of pathogens in reduced and regular sodium Mozzarella cheese, and the potential of Supercritical Fluid Extraction with CO₂ (SFE) to reduce Listeria innocua on Mozzarella and Queso Fresco. The survival of L. monocytogenes, Salmonella, and E.coli O157:H7 (2-3 log CFU/g) in reduced sodium Mozzarella (1.62%), compared to regular sodium Mozzarella cheese (2.15%) …

Use Of The Mitochondrial Control Region As A Potential Dna Mini-Barcoding Target For The Identification Of Canned Tuna Species, Jacquelyn K. Mitchell, Rosalee S. Hellberg

Food Science Faculty Articles and Research

In this study, a DNA mini-barcoding methodology was developed for the differentiation of species commonly found in canned tuna. Primers were designed to target a 236-base pair (bp) fragment of the mitochondrial control region (CR) and a 179-bp fragment of the first internal transcribed spacer region (ITS1). Phylogenetic analysis revealed the ability to differentiate 13 tuna species on the basis of the CR mini-barcode, except in a few cases of species introgression. Supplementary use of ITS1 allowed for differentiation of introgressed Atlantic bluefin tuna (Thunnus thynnus) and albacore tuna (Thunnus alalunga), while differentiation of introgressed Atlantic …

Effect Of Green Tea On Interaction Of Lipid Oxidation Products With Sarcoplasmic And Myofibrillar Protein Homogenates Extracted From Bovine Top Round Muscle, Nahathai Stapornkul, Tatiana Prytkova, Lilian Were

Food Science Faculty Articles and Research

The interaction between lipid oxidation products and bovine sarcoplasmic (SP) and myofibrillar protein (MP) homogenates in the presence of green tea was investigated. To monitor the effect of green tea on lipid oxidation, aldehydes were measured while effect on protein was monitored via changes in myoglobin, thiols, and tryptophan fluorescence over nine days of refrigerated storage. The presence of SP and MP decreased free aldehydes in the buffers. The SP bound more aldehydes than MP. The tea compounds exhibited more favorable binding energies than aldehydes near histidine 64 close to the heme moiety of myoglobin. Addition of tea lowered tryptophan …

High Throughput Genomic Sequencing Of Bioaerosols In Broiler Chicken Production Facilities, Kate M. O’Brien, Michael S. Chimenti, Morgan Farnell, Tom Tabler, Thomas Bair, Joey Lynn Bray, Matthew W. Nonnenmann

Faculty Publications

Chronic inhalation exposure to agricultural dust promotes the development of chronic respiratory diseases among poultry workers. Poultry dust is composed of dander, chicken feed, litter bedding and microbes. However, the microbial composition and abundance has not been fully elucidated. Genomic DNA was extracted from settled dust and personal inhalable dust collected while performing litter sampling or mortality collection tasks. DNA libraries were sequenced using a paired-end sequencing-by-synthesis approach on an Illumina HiSeq 2500. Sequencing data showed that poultry dust is predominantly composed of bacteria (64–67%) with a small quantity of avian, human and feed DNA (< 2% of total reads). Staphylococcus sp. AL1, Salinicoccus carnicancri and Lactobacillus crispatus were the most abundant bacterial species in personal exposure samples of inhalable dust. Settled dust had a moderate relative abundance of these species as well as Staphylococcus lentus and Lactobacillus salivarius. There was a statistical difference between the microbial composition of aerosolized and settled dust. Unlike settled dust composition, aerosolized dust composition had little variance between samples. These data provide an extensive analysis of the microbial composition and relative abundance in personal inhalable poultry dust and settled poultry dust.

Acoustic Emission Of Lactococcus Lactis Ssp. Lactis C2 Infected With Three Bacteriophages C2, Sk1 And Ml3, Luxi Meng

Theses and Dissertations--Animal and Food Sciences

The objective of this research was to monitor the Acoustic Emission (AE) produced by Lactococcus lactis ssp. lactis C2 infected with three bacteriophages (c2, sk1 and ml3 at 90 min) using an acoustic emission-monitoring device which was designed at University of Kentucky in Lexington KY. The acoustic emission data was collected and then analyzed. These Acoustic Emission (AE) data suggested that bacteriophage ml3, sk1 and c2 can easily be distinguished by the differences in Absolute Energy (ABE), Centroid Frequency (CF) and Peak Frequency (PF) signals. The AE data suggested that bacteriophage sk1 and c2 caused greater stress on the lactis …

Aptameric Sensors: In Vitro Selection Of Dna That Binds Bromocresol Purple, Derek B. Miller

Honors Undergraduate Theses

Aptamers being used as sensors is an emerging field that has capabilities of being tomorrow’s diagnostic tools. As aptameric sensors have become more popular, their visualization systems have been limited. The majority of today’s aptameric sensors require expensive machinery such as a fluorometer in order to visualize results. We propose a system that will cut the need for instrumentation and be detected via the naked eye. With the selection of an aptamer to bind the pH indicating dye bromocresol purple (BCP) this may be achieved. When rendered active, the binding towards BCP will facilitate a color change from yellow to …

Unraveling The Dose-Response Puzzle Of L. Monocytogenes: A Mechanistic Approach, S. M.Ashrafur Rahman, Daniel Munther, Aamir Fazil, Ben Smith, Jianhong Wu

Mathematics and Statistics Faculty Publications

Food-borne disease outbreaks caused by Listeria monocytogenes continue to impose heavy burdens on public health in North America and globally. To explore the threat L. monocytogenes presents to the elderly, pregnant woman and immuno-compromised individuals, many studies have focused on in-host infection mechanisms and risk evaluation in terms of dose-response outcomes. However, the connection of these two foci has received little attention, leaving risk prediction with an insufficient mechanistic basis. Consequently, there is a critical need to quantifiably link in-host infection pathways with the dose-response paradigm. To better understand these relationships, we propose a new mathematical model to describe the …

Effect Of Phytosanitary Irradiation And Methyl Bromide Fumigation On The Physical, Sensory, And Microbiological Quality Of Blueberries And Sweet Cherries, Karen Thang, Kimberly Au, Cyril Rakovski, Anuradha Prakash

Food Science Faculty Articles and Research

Background

The objective of this study was to determine whether irradiation could serve as a suitable phytosanitary treatment alternative to methyl bromide (MB) fumigation for blueberries and sweet cherry and also to determine the effect of phytosanitary irradiation treatment on survival of Salmonella spp. and Listeria monocytogenes on these fruit. ‘Bluecrop’ blueberries (Vaccinium corymbosum) and ‘Sweetheart’ cherries (Prunus avium) were irradiated at 0.4 kGy or fumigated with methyl bromide and evaluated for quality attributes during storage.

Results

Irradiation caused an immediate decrease in firmness of both fruit without further significant change during storage. Fumigated fruit, in …

Prebiotics And Synbiotics: Dietary Strategies For Improving Gut Health, Janina A. Krumbeck, Maria X. Maldonado-Gomez, Amanda E. Ramer-Tait, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Purpose of review — A wide range of dietary carbohydrates, including prebiotic food ingredients, fermentable fibers, and milk oligosaccharides, are able to produce significant changes in the intestinal microbiota. These shifts in the microbial community are often characterized by increased levels of bifidobacteria and lactobacilli. More recent studies have revealed that species of Faecalibacterium, Akkermansia, and other less well studied members may also be enriched. We review the implications of these recent studies on future design of prebiotics and synbiotics to promote gastrointestinal health.

Recent findings — Investigations assessing the clinical outcomes associated with dietary modification of the …

Microbiological Control And Mechanisms Of Action Of High Voltage Atmospheric Cold Plasma, Lu Han

Doctoral

Dielectric barrier discharge-atmospheric cold plasma (DBD-ACP) is a promising non-thermal technology effective against a wide range of microorganisms. These studies were performed using a custom built DBD-ACP system. The inactivation efficacy was found to be governed by a series of critical control parameters, including treatment time, mode of exposure (Direct/Indirect exposure), applied voltage, applied gas content but was also very dependent on the characteristics of treatment targets. In this study, these parameters were investigated using in-package design along with a post-treatment storage procedure to align with industrial processing times as well as mitigation of post-process contamination. A range of food …

Proteomics Study Of Pre-Harvest Sprouting In Wheat, Pramod Khadka

Electronic Theses and Dissertations

Pre-harvest sprouting (PHS) of wheat (Triticum aestivum L.) is a condition characterized by the early germination of spikes during moist environmental conditions. PHS lowers yield, degrades the quality of grain and thus limits the profits of wheat producers groups. During this investigation, proteomics studies of PHS-resistant and PHS-susceptible wheat embryos were conducted at different imbibition time periods via a cutting-edge technology called iTRAQ. Proteomic analysis revealed that 190 differentially expressed proteins might be involved in various cellular functions, such as carbohydrate metabolism, nitrogen metabolism, stress response, redox regulation, ATP synthesis, and protein translation, during this untimely germination of the wheat …

Controlling Microbial Safety Challenges Of Meat Using High Voltage Atmospheric Cold Plasma, Lu Han, Dana Ziuzina, Caitlin Marie Heslin, Daniela Boehm, Apurva Patange, David Millan-Sango, Vasilis Valdramidis, Patrick J. Cullen, Paula Bourke

Articles

Atmospheric cold plasma (ACP) is a non-thermal technology, effective against a wide range of pathogenic microorganisms. Inactivation efficacy results from plasma generated reactive species. These may interact with any organic components in a test matrix including the target microorganism, thus food components may exert a protective effect against the antimicrobial mode of action. The effect of an in-package high voltage ACP process applied in conjunction with common meat processing MAP gas compositions as well as bacteria type and meat model media composition have been investigated to determine the applicability of this technology for decontamination of safety challenges associated with meat …