Food Microbiology Commons^™

Comparative Study Of The D-Values Of Salmonella Spp. And Enterococcus Faecium In Wheat Flour, Didier Dodier

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Low-moisture foods contaminated with Salmonella spp. have been implicated in several foodborne illness outbreaks in the United States. The food industry has to incorporate preventive control in their process and validate thermal processes to assure food safety. The thermal destruction of Enterococcus faecium ATTC 8459 and Salmonella spp. was determined at 3 water activity levels (0.11, 0.18 and 0.33) at 80ºC, 85ºC and 90ºC. Aerobic plates counts petrifilms were used as non-selective medium for both bacteria, Enterobacteriaceae petrifilms were used as selective medium for Salmonella spp., and peptone water modified with sodium azide as a selective medium for Enterococcus faecium …

Inactivation Of Escherichia Coli O157:H7 And Shiga Toxin Producing E. Coli (Stec) Throughout Beef Summer Sausage Production And The Use Of High Pressure Processing As An Alternative Intervention To Thermal Processing, Eric L. Oliver

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Escherichia coli O157:H7 and six additional serogroups of Shiga Toxin-producing E. coli (STEC-7) have been implicated in foodborne illness outbreaks related to fermented sausage products and are considered adulterants by the USDA-FSIS. The objective of this study was to evaluate high pressure processing (HPP) as an alternative to thermal treatment to reduce STEC-7 meeting the USDA-FSIS performance standards (5.0-log reduction). A rifampicin-resistant, non-pathogenic E. coli (surrogate) cocktail, was used in manufacturing testing. Sausages were fermented at ~42.2°C, slowly increased to 54.4°C internal temperature, cold showered, and chilled for 6 hours. Sampling occurred post-fermentation (PF; pH 5.0), internal temperature 48.9°C (I-48.9°C), …

Efficacy Of Galactooliosaccharide (Gos) And/Or Rhamnose-Based Synbiotics In Enhancing Ecological Performance Of Lactobacillus Reuteri In The Human Gut And Characterization Of Its Gos Metabolic System, Monchaya Rattanaprasert

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Probiotic L. reuteri has potential to produce antimicrobial compounds and secrete immunosuppressive factors. These metabolic attributes could benefit the human host by providing colonization resistance (competitive and metabolic exclusion) against enteropathogens and mitigating inflammation. As metabolically active cells are fundamental to such probiotic properties, synbiotic approaches that supply L. reuteri with a source(s) of carbon, energy, and/or external electron acceptor for cell growth in the gut environment could therefore prompt the probiotic to engage in beneficial activities. In this study, the efficacy of GOS and/or rhamnose-based synbiotic approaches in promoting colonization persistence and metabolic activity of L. reuteri was evaluated. …

Influence Of Lactobacillus Rhamnosus Isolated From “Amabere Amaruranu” Cultured Milk On Adipogenesis, Justin E. Kotala

Electronic Theses and Dissertations

This study was performed to test the in vitro effects of a Lactobacillus rhamnosus isolate from “amabere amaruranu”, a traditional Kenyan cultured milk, on 3T3-L1 and Caco-2 cell lines. Cultures of fully mature 3T3-L1 adipocytes were treated with bacterial isolate cell extract (CE), filtered spent broth (FSB) from overnight bacterial culture, or with a PBS control. Expression levels of PPAR³1 and 2, C/EBP±, and ATGL proteins in 3T3-L1 cells were upregulated by FSB treatment. CE treatment did not affect protein expression levels. Expression of MTTP and SREBP-1c proteins in Caco-2 cells showed no change with either treatment. Optical density measurements …

Microbial Safety, Shelf Life Stability, Quality Preservation, And Consumer Acceptance Of Vacuum-Infused, Irradiated Chicken Breast Meat Treated With Natural Plant Extracts And Organic Acids, Kenneth Franklin Over

Graduate Theses and Dissertations

Contamination of poultry products with food borne pathogens is a consistently recurring problem in the United States and the world. Recalls associated with chicken contamination are responsible for considerable economic losses to the poultry industry. Many decontamination steps are currently in place to reduce the likelihood of contaminated products reaching the consumer, but despite these safeguards, contamination events are still uncomfortably frequent. Irradiation is a safe and effective means of ensuring the safety of both ready-to-cook and ready-to-eat poultry but is not utilized in the United States. This is due, in part, to certain irradiation dose-dependent quality characteristic defects associated …

A Tail Of Two Phages: Genomic And Functional Analysis Of Listeria Monocytogenes Phages Vb_Lmos_188 And Vb_Lmos_293 Reveal The Receptor-Binding Proteins Involved In Host Specificity, Aidan Casey, Kieran Jordan, Horst Neve, Aidan Coffey, Olivia Mcauliffe

Department of Biological Sciences Publications

The physical characteristics of bacteriophages establish them as viable candidates for downstream development of pathogen detection assays and biocontrol measures. To utilize phages for such purposes, a detailed knowledge of their host interaction mechanisms is a prerequisite. There is currently a wealth of knowledge available concerning Gram-negative phage-host interaction, but little by comparison for Gram-positive phages and Listeria phages in particular. In this research, the lytic spectrum of two recently isolated Listeria monocytogenes phages (vB_LmoS_188 and vB_LmoS_293) was determined, and the genomic basis for their observed serotype 4b/4e host-specificity was investigated using comparative genomics. The late tail genes of these …

Serving The Worldwide Community, Melodie Roschman

Lake Union Herald

No abstract provided.

Cold Plasma Inactivation Of Internalised Bacteria And Biofilms For Salmonella Enterica Serovar Typhimurium, Listeria Monocytogenes And Escherichia Coli, Dana Ziuzina, Lu Han, Patrick J. Cullen, Paula Bourke

Articles

Microbial biofilms and bacteria internalised in produce tissue may reduce the effectiveness of decontamination methods. In this study, the inactivation efficacy of in-package atmospheric cold plasma (ACP) afterglow was investigated against Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli in the forms of planktonic cultures, biofilms formed on lettuce and associated bacteria internalised in lettuce tissue. Prepared lettuce broth (3%) was inoculated with bacteria resulting in a final concentration of ~ 7.0 log₁₀ CFU/ml. For biofilm formation and internalisation, lettuce pieces (5 × 5 cm) were dip-inoculated in bacterial suspension of ~ 7.0 log₁₀ CFU/ml for 2 h and …

Cold Plasma Inactivation Of Bacterial Biofilms And Reduction Of Quorum Sensing Regulated Virulence Factors, Dana Ziuzina, Daniela Boehm, Sonal Patil, Patrick J. Cullen, Paula Bourke

Articles

The main objectives of this work were to investigate the effect of atmospheric cold plasma (ACP) against a range of microbial biofilms commonly implicated in foodborne and health- care associated human infections and against P. aeruginosa quorum sensing (QS)-regu- lated virulence factors, such as pyocyanin, elastase (Las B) and biofilm formation capacity post-ACP treatment. The effect of processing factors, namely treatment time and mode of plasma exposure on antimicrobial activity of ACP were also examined. Antibiofilm activity was assessed for E. coli, L. monocytogenes and S. aureus in terms of reduction of cultur- ability and retention of metabolic activity using …

Determining Antimicrobial Activity In Hydrolysates Obtained From Buttermilk Substrates By Trypsin And Pepsin, Deborah Kim, Karen Ramun, Stephanie Carpintero, Suyapa Padillo, Antonio-Jose Trujillo, Rafael Jimenez-Flores

STAR Program Research Presentations

Milk proteins within their structure and sequence, contain peptides that exhibit antithrombotic, immunomodulatory, antimicrobial, antihypertensive, and other bioactivities. These peptides are released as the enzymes cleave milk proteins at certain locations of the amino acid chains. In this research, four different substrates were hydrolyzed with the gastrointestinal enzymes, pepsin and trypsin. The substrates were buttermilk (BM) and whey buttermilk (WBM), which are waste products of butter and cheese production, and supercritical CO₂ fluid (SFE) treated buttermilk (S-BM) and whey buttermilk (S-WBM). SFE acts as a solvent which removes triglycerides from the substrates and changes the overall composition of samples. …

Shiga Toxin-Producing Escherichia Coli (Stec) Detection Strategies With Formalin-Fixed Stec Cells, Christopher Adam Baker

Graduate Theses and Dissertations

Certain pathogenic Escherichia coli known as Shiga toxin (Stx)-producing Escherichia coli (STEC) are commensals in cattle, and typically cause bloody diarrhea in humans once the Stx toxin is secreted in invaded intestinal epithelial cells. Infections with STEC cells can lead to hemolytic uremic syndrome, which is commonly associated with kidney failure. Several STEC serogroups have been declared adulterants in raw, non-intact ground meat, and future regulations could potentially lead to a higher number of STEC serogroup detection strategies for these pathogenic microorganisms. Microbiological research laboratories may benefit from formalin-fixed STEC cells for periodic (daily, weekly, monthly, among others) instrument validation/calibration …

Prokaryotic Diversity In The Rhizosphere Of Organic, Intensive, And Transitional Coffee Farms In Brazil, Adam Caldwell, Livia Silva, Cynthia Da Silva, Cleber Ouverney

Faculty Publications, Biological Sciences

Despite a continuous rise in consumption of coffee over the past 60 years and recent studies showing positive benefits linked to human health, intensive coffee farming practices have been associated with environmental damage, risks to human health, and reductions in biodiversity. In contrast, organic farming has become an increasingly popular alternative, with both environmental and health benefits. This study aimed to characterize and determine the differences in the prokaryotic soil microbiology of three Brazilian coffee farms: one practicing intensive farming, one practicing organic farming, and one undergoing a transition from intensive to organic practices. Soil samples were collected from 20 …

Dietary Microrna Database (Dmd): An Archive Database And Analytic Tool For Food-Borne Micrornas, Kevin Chiang, Jiang Shu, Janos Zempleni, Juan Cui

School of Computing: Faculty Publications

With the advent of high throughput technology, a huge amount of microRNA information has been added to the growing body of knowledge for non-coding RNAs. Here we present the Dietary MicroRNA Databases (DMD), the first repository for archiving and analyzing the published and novel microRNAs discovered in dietary resources. Currently there are fifteen types of dietary species, such as apple, grape, cow milk, and cow fat, included in the database originating from 9 plant and 5 animal species. Annotation for each entry, a mature microRNA indexed as DM0000*, covers information of the mature sequences, genome locations, hairpin structures of parental …

Screening Of Biocontrol Organisms For The Management Of Phytopathogenic Fungi And Foodborne Pathogens On Produce, Antoinette Boyee De Senna

Master's Theses

The multibillion dollar agricultural industry is an important part of the United States economy, and the management of factors that affect crop and human health is imperative to maintaining this economic sector. The fungi Botrytis cinerea, Fusarium pallidoroseum, and Fusarium moniliforme are the causative agents of several plant diseases and can cause significant crop loss both before and after harvest in commodities such as strawberries, lettuce, citrus, and grains. Fungicides are employed to control these phytopathogens, but the use of these chemicals has led to an increase in fungicide resistance and may negatively affect the environment and human …

The Effects Of Phytochemical Tannin-Containing Diets On Animal Performance And Internal Parasite Control In Meat Goats, Chassity Wright

College of Agriculture, Environment and Nutrition Sciences Graduate Theses and Dissertations

ABSTRACT

The Effects of Phytochemical Tannin-Containing Diets on Animal Performance and Internal Parasite Control in Meat Goats

By

Chassity Wright

Haemonchus contortus (H. contortus) resistance has been reported against almost all chemical anthelmintics available for its control. H. contortus has a remarkable ability to develop resistance and threatens the viability of the goat industry in many regions of the world. Consequently, there is an urgent need to understand the genetic mechanisms underlying anthelmintic resistance and to discover new alternative methods of chemical and non-chemical control. With chemical anthemintics failing, this has led to the evaluation of plants as a natural …

Antimicrobial Susceptibility Of Listeria Monocytogenes To Bacteriophage Listex™ P100 In Alfalfa Sprouts (Medicago Sativa), Tushar Sawant

Food Science (MS) Theses

The seed germination process during sprout production provides suitable environmental conditions for the growth of pathogenic bacteria, such as Listeria monocytogenes. A potential way to control this bacterial growth is through the use of bacteriophages, which are naturally occurring viruses that specifically attack bacterial targets and have been shown to be effective antimicrobials in some foods. Therefore, the objective of this study was to evaluate the antimicrobial susceptibility of L. monocytogenes to bacteriophage on alfalfa sprouts during seed germination and subsequent refrigerated storage at 4 °C. Alfalfa sprout seeds were dip-inoculated with 5.5 x 105 CFU/ml L. monocytogenes serogroups 1 …

The Effects Of Electrostatic Spraying With Organic Acids In The Disintegration Of Biofilms Formed By E.Coli O157:H7 And Salmonella Typhimurium On Spinach And Cantaloupe, Ahmad Almasoud

Graduate Theses and Dissertations

Outbreaks from the consumption of fresh produce are a concern in the United States. The consumptions of fresh produce have increased recently which expose a large segment of society to such outbreaks. Spinach and cantaloupe are minimally heated or processed before consumption which makes them a possible source of foodborne illness. The objective of this research was to investigate the effect of organic acids alone and in combination to reduce attached Salmonella Typhimurium (S.T) and Escherichia coli O157:H7 (E.coli) on spinach and cantaloupe, and to disintegrate biofilm formed by these pathogens by electrostatically spraying with two organic acids. To quantify …

Direct Fermentation Of Sweet Potato Starch Into Lactic Acid By Lactobacillus Amylovorus: The Prospect Of An Adaptation Process, Winifred Akoetey

Graduate Theses and Dissertations

Several studies have verified that lactic acid bacteria are capable of directly producing lactic acid from starch. One of these bacteria, L. amylovorus, has been studied using corn, potato, and cassava starches. However, the use of sweet potato starch, a widely available starch, has not been considered. Furthermore, there exists the possibility that the efficiency of lactic acid production can benefit from the systematic exposure of bacteria to increasing concentrations of a particular starch. In this work, fermentation studies were conducted to understand the adaptation of L. amylovorus to rising concentrations of sweet potato starch. L. amylovorus was cultured in …

Characterization And Investigation Of Fungi Inhabiting The Gastrointestinal Tract Of Healthy And Diseased Humans, Mallory J. Suhr

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Gastrointestinal microbiome studies have failed to include fungi in total community analyses. As a result, their diversity and function in the gut is poorly understood. Recent work has begun to uncover the role intestinal fungi play in diet, immune system development, interactions with other microorganisms in the gut, and pathogenesis of diseases. Advances in sequencing technologies allow for the ability to profile the fungal gut microbiome (“mycobiome”) in healthy and diseased states. This thesis explores the mycobiome in 1) healthy humans with a vegetarian diet and 2) pediatric small bowel transplant recipients that develop fungal bloodstream infections.

The gut mycobiome …

The Influence Of The Bovine Fecal Microbiota On The Shedding Of Shiga Toxin-Producing Escherichia Coli (Stec) By Beef Cattle, Nirosh D. Aluthge

Department of Food Science and Technology: Dissertations, Theses, and Student Research

During the past three decades, Shiga toxin-producing E.coli (STEC) have emerged as an important food safety concern. Although initially E. coli O157 was the main focus, recent outbreaks and resulting investigations have shown that certain non-O157 STEC are as much a threat to food safety as their O157 counterparts. To the beef industry, STEC have been of particular concern due to the frequent association of beef and beef products as vehicles of STEC infection. As a result, along with E. coli O157, six non-O157 STEC serogroups (known as the ‘big six’) are now regulated as adulterants in certain raw beef …

Viability Of Lactobacillus Acidophilus Dds 1-10 Encapsulated With An Alginate-Starch Matrix, Liya Mo

Department of Food Science and Technology: Dissertations, Theses, and Student Research

L. acidophilus DDS1-10 was encapsulated using an alginate, potato starch and type 4 resistant starch (RS4) matrix. The wall material was optimized by varying levels of alginate (1.6 to 4.4%), while maintaining potato starch and RS4 ratio fixed at 2, and the total solid content at 5%. Particles were prepared using an emulsion and an extrusion method. Particles obtained from the emulsion method were smaller with a non-uniform distribution in size while those obtained by the extrusion method were bigger and uniform in size. The emulsion method did not seem to offer protection to the probiotic cells against pH, bile …

Application Of Essential Oil Compounds And Bacteriophage To Control Staphylococcus Aureus, Anisha Ghosh

Graduate Theses and Dissertations

Staphylococcus aureus is one of the most important pathogens, causing various diseases in humans and animals. In addition, S. aureus is a common foodborne pathogen. As methicillin- resistant S. aureus (MRSA) becomes increasingly prevalent, controlling this pathogen in animals and humans with standard antibiotic treatment has become challenging. Combinations of different antimicrobial agents represent one of the most promising approaches for combating multidrug - resistant bacteria both for treatment of clinical disease as well as in food. Two such antimicrobials with potential application in the food industry include essential oils (EO) and host-specific bacteriophage (phage). The objectives of this study …

Phenotypic And Functional Genomics Analyses Of Salmonella For Food Safety Applications, Turki Dawoud

Graduate Theses and Dissertations

Non-typhoidal Salmonella species have been major foodborne zoonotic pathogens causing serious problems in public health and food industry for several decades. Numerous Salmonella species have frequently been associated with different food commodities mainly poultry meat, eggs, and their products. This dissertation begins with a literature reviews discussing many aspects of Salmonella generally; and subsequently focused on two serotypes, Salmonella Enteritidis and S. Typhimurium as they are at the top of all other serovars responsible for most illness cases and outbreaks. In addition, some Salmonella strains have exhibited their ability to tolerate and survive many food processing treatments. We can divide …

Functional Screening Of The Cronobacter Sakazakii Baa-894 Genome Reveals A Role For Prop (Esa_02131) In Carnitine Uptake, Audrey Feeney, Roy D. Sleator

Department of Biological Sciences Publications

Cronobacter sakazakii is a neonatal pathogen responsible for up to 80% of fatalities in infected infants. Low birth weight infants and neonates infected with C. sakazakii suffer necrotizing enterocolitis, bacteraemia and meningitis. The mode of transmission most often associated with infection is powdered infant formula (PIF) which, with an aw of ∼0.2, is too low to allow most microorganisms to persist. Survival of C. sakazakii in environments subject to extreme hyperosmotic stress has previously been attributed to the uptake of compatible solutes including proline and betaine. Herein, we report the construction and screening of a C. sakazakii genome bank and …

Micrornas Are Absorbed In Biologically Meaningful Amounts From Nutritionally Relevant Doses Of Cow’S Milk And Chicken Eggs And Affect Gene Expression In Peripheral Blood Mononuclear Cells, Cell Cultures, And Mouse Livers, Scott Baier

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

Throughout the twenty-first century, evidence has been continually increasing to show the importance of epigenetic regulation in health. While the term “epigenetics” can be applied to many different processes, the focus of this dissertation will be on microRNAs and chromatin structure. Ultimately, both of these forms of epigenetic regulation can be used to fine tune gene expression based on environmental cues. The first three chapters of the dissertation focus on microRNA bioavailability, stability, and function from two commonly consumed food products: cow’s milk and chicken eggs. This important work has been the first of its kind to demonstrate the bioavailability …

Influence And Characterization Of Microbial Contaminants Associated With The Fda Bam Method Used To Detect Listeria Monocytogenes From Romaine Lettuce, Christopher E. Bach

Open Access Theses

Over the past few decades in the US, fresh produce commodities have become increasingly prevalent vehicles for the attribution of foodborne illness. Recent outbreaks of the bacterial foodborne pathogen Listeria monocytogenes linked to fresh produce highlight this immediate issue facing food safety. The most widely used method to screen L. monocytogenes from food matrices in the US is the Bacteriological Analytical Manual (BAM) developed by the Food and Drug Administration (FDA). Detection of this pathogen from all foods is primarily accomplished by using four FDA approved Listeria selective media: Oxford (OXA), modified Oxford (MOX), Lithium chloride-phenylethanol-moxalactam fortified with esculin and …

Diversity Of Yeast And Mold Species From A Variety Of Cheese Types, Nabaraj Banjara, Mallory J. Suhr, Heather E. Hallen-Adams

Department of Food Science and Technology: Faculty Publications

To generate a comprehensive profile of viable fungi (yeasts and molds) on cheese as it is purchased by consumers, 44 types of cheese were obtained from a local grocery store from 1 to 4 times each (depending on availability) and sampled. Pure cultures were obtained and identified by DNA sequence of the ITS region, as well as growth characteristics and colony morphology. The yeast Debaryomyces hansenii was the most abundant fungus, present in 79 % of all cheeses and 63 % of all samples. Penicillium roqueforti was the most common mold, isolated from a variety of cheeses in addition to …

Concomitant Uptake Of Antimicrobials And Salmonella In Soil And Into Lettuce Following Wastewater Irrigation, J. Brett Sallach, Yuping Zhang, Laurie Hodges, Daniel D. Snow, Xu Li, Shannon L. Bartelt-Hunt

Department of Civil and Environmental Engineering: Faculty Publications

The use of wastewater for irrigation may introduce antimicrobials and human pathogens into the food supply through vegetative uptake. The objective of this study was to investigate the uptake of three antimicrobials and Salmonella in two lettuce cultivars. After repeated subirrigation with synthetic wastewater, lettuce leaves and soil were collected at three sequential harvests. The internalization frequency of Salmonella in lettuce was low. A soil horizon-influenced Salmonella concentration gradient was determined with concentrations in bottom soil 2 log CFU/g higher than in top soil. Lincomycin and sulfamethoxazole were recovered from lettuce leaves at concentrations as high as 822 ng/g and …

Microbial Safety And Quality Of Fresh Herbs From Los Angeles, Orange County, And Seattle Farmers’ Markets, Donna J. Levy, Nicola K. Beck, Alexandra L. Kossick, Taylor Patti, J. Scott Meschke, Melissa Calicchia, Rosalee S. Hellberg

Food Science Faculty Articles and Research

BACKGROUND: Farmers' markets have been growing in popularity in the United States, but the microbial quality and safety of the food sold at these markets is currently unknown. The purpose of this study was to assess the microbial safety and quality of fresh basil, parsley and cilantro sold at farmers' markets in the Los Angeles, Orange County and greater Seattle areas.

RESULTS: A total of 133 samples (52 basil, 41 cilantro and 40 parsley) were collected from 13 different farmers' markets and tested for Salmonella and generic Escherichia coli. One sample (parsley) was confirmed positive for Salmonella and 24.1% of …

Antimicrobial Efficacy Of Natural Bioactive Compounds And High Pressure Processing Against Potential Pathogens In Infant Foods, Hayriye Cetin-Karaca

Theses and Dissertations--Animal and Food Sciences

This study investigated the antimicrobial efficacy of bioactive plant compounds along with high pressure processing (HPP) against pathogens Bacillus cereus and Cronobacter sakazakii in infant formula and infant rice cereal. The influence of these applications on antimicrobial activity, shelf-life and sensory attributes of infant foods were examined.

Trans-cinnamaldehyde (TC), (-)-Epigallocatechin gallate (EGCG) and [10]-Gingerol (GI) were incorporated (0.05%) in infant rice cereal reconstituted with infant formula. The cereal was inoculated with either B. cereus (ATCC 14579) or B. cereus spores (10⁷-10⁸ log CFU g^-1). All the samples were stored at 7, 23 or 37°C for …