Food Microbiology Commons^™

Heat, Acid And Osmotic Stress Tolerance Of Leuconostoc Mesenteroides As Influenced By Prior Exposure To Various Mild Stress Conditions, Ingrid C. Osorio Rodriguez

LSU Master's Theses

The importance of Leuconostoc mesenteroides is recognized for its contribution to taste in cultured dairy products. It has been cited for its potential role as a probiotic. Consumer demand exists for new dairy products with health benefits. In the manufacture of probiotic-products survival of Leuconostoc mesenteroides would depend on its ability to tolerate challenging processing and storage conditions. Improved viability by prior exposure to mild stresses can increase stress tolerance toward a more severe stress. Furthermore, it can result in cross-protection due to connection of several proteins in response to stresses. Objective was to evaluate the effect of prior …

Interaction Of Cocoa Powder With Intestinal Microbiota, Martha M. Escoto Sabillon

LSU Master's Theses

Cocoa is the fully fermented and dried seed of the cacao tree (Theobroma cacao L.) which has prebiotic properties, due to their high concentration of polyphenols. Therefore, the ingestion of cocoa could cause changes in the proportions of the intestinal microbiota that can influence the intestinal immune response. The objective of this study was to determine the effect of alkalization process of the cocoa bean in the diversity of the gut microbiota. The samples were “lavado” unprocessed cocoa powder, “natural” unprocessed cocoa powder, “D-11-S” as alkalized cocoa powder, “D-11-B” heavily alkalized cocoa powder, and raw cocoa “shells” and a control …

Validation Of Extrusion Processing For The Safety Of Low-Moisture Foods, Tushar Verma

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

Salmonella in low-moisture foods is an emerging challenge due to numerous food product recalls and foodborne illness outbreaks. The new Food Safety Modernization Act requires the food processors to validate their process controls that indeed kills the desired number of bacteria. This research had two major objectives: 1) Develop a response surface model for Salmonella inactivation during the extrusion of low-moisture food 2) Evaluate the use of Enterococcus faecium NRRL B-2354 as an adequate surrogate for Salmonella during the extrusion of low-moisture food. Oat flour was selected as a low-moisture food model. For inoculation, cocktail of five different strains of …

Phylogenetic Diversity Of The Bacterial Communities In Craft Beer, Lindsey Rodhouse

Graduate Theses and Dissertations

The craft beer industry is increasing in popularity in the United States. The craft brewing process typically does not use a pasteurization step, therefore the boiling process is the primary critical control step. Any microorganisms introduced after boiling, or those that are not killed during boiling, are likely to participate in fermentation and persist in the final product. Previous culture-based studies have isolated bacteria and yeast from craft beers at specific time points, but little research has been done on the process as a whole. The objectives of this research are to (1) track bacteria development throughout the brewing process …

The Recovery Of Protein From Egg Yolk Protein Extraction Granule Byproduct, Irene Jennifer Kaufman

Master's Theses

In addition to proving an excellent source of nutrients, eggs are used in the food, cosmetic, and biotechnology industries for their rheological and bioactive properties. Much of the potential for the added value is in individual components of the egg, rather than the whole egg. At low speed centrifugation, yolk separates into two distinct fractions—granules and plasma. It is becoming increasingly popular in the industry to remove the plasma fraction of the egg yolk to use for its livetins, particularly immunoglobulin Y, leaving behind a granule by-product (“yellow cake”). Previous research has shown potential added-value from the granule fraction, especially …

Effect Of Red Cabbage Extract On Minced Nile Perch Fish Patties Vacuum Packaged In High And Low Oxygen Barrier Films, Ayse Demirbas, Yavuz Yagiz, Ziynet Boz, Bruce A. Welt, Eric Mclamore, Maurice Marshall, William Pelletier, Amarat Simonne

Journal of Applied Packaging Research

Oxidation of polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish causes loss of product quality. Oxidative rancidity causes loss of nutritional value and undesirable color changes. Therefore, powerful antioxidant extracts may provide a relatively low cost and natural means to reduce oxidation, resulting in longer, higher quality and higher value shelf life of foods.

In this study, we measured synergistic effects of red cabbage antioxidant and vacuum packaging on lipid oxidation in fresh tilapia patties using thiobarbituric acid reactive substances (TBARS) assay, peroxide value (PV), pH and color analysis.

Concentrated red cabbage extract was obtained …

Seaweed Carotenoid Fucoxanthin As Functional Food., Nissreen Abu-Ghannam, Emer Shannon

Books/Book Chapters/ Proceedings

Fucoxanthin is a bioactive compound found in one of the most prolific and sustainable organisms on the planet, alga. Its efficacy and potential in terms of health applications have been widely reported in clinical studies. Technical modifications, such as encapsulation, and sensory trials must be undertaken before fucoxanthin can be successfully utilised as a functional food ingredient. Factors to consider include solubility in the food matrix, organoleptic effects, stability, preservation against oxidation, consumer acceptability, bioavailability, and toxicity risk. Possible solutions may include the development of more efficient and greener extraction technologies, which require shorter extraction times and less solvent, and …

Growing Yeast For Livestock, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Over 500,000 tons of organic materials such as food scraps are disposed of each year in Wisconsin. A large percentage of this material could be composted or turned into useful products. The purpose of this article is to educate farmers and organizations on how to turn food waste into a high value food source for livestock. Yeast can be grown at any time of the year without the large inputs of agricultural chemicals and machinery that is common with other feed production methods. A yeast growing facility can be scalable to any size the producer wants such as a small …

Effects Of Fermentation By Yeast And Amylolytic Lactic Acid Bacteria On Grain Sorghum Protein Content And Digestibility, Christina Day

Graduate Theses and Dissertations

Grain sorghum is an underutilized crop despite many advantages to its cultivation. A drought-tolerant plant with many pest-resistant cultivars, its applications are limited by problems with nutrient availability, particularly protein digestibility. Digestibility of grain sorghum protein is reduced by antinutritional compounds in the grain like tannins and phytates, and by moist-heat cooking. Some of these concerns can be mitigated by how the grain is processed. Fermentation is one processing method that can improve digestibility. Fermentation can also concentrate protein in a substrate. In this experiment, grain sorghum was subjected to different treatments and used as a substrate for yeast fermentation. …

Antimicrobial Inhibitory Activities Of Phenolic Extracts From Four Selected Soybean Hulls In Culture And Chicken Skin Model Systems, And Preliminary Ace-Inhibitory Activity, Rajaa Abdulkair Abutheraa

Graduate Theses and Dissertations

Soybean components provide health benefits to humans. Soybean hulls, a major by-product of the soybean processing industry consist of complex carbohydrates, proteins, lipids and polyphenols such as anthocyanidins, proanthocyanidins and isoflavones. The polyphenolic compounds in the hulls give them various colors such as black, brown, green, yellow or even a mottled appearance. Studies have reported different soybean varieties with varying total phenolic compounds in their seed hulls, which have antioxidant property. Phenolic extracts can be used as substitutes for synthetic antimicrobials and preservatives to assist in preventing the growth of pathogens such as Salmonella Typhimurium, E coli 0157:H7, and Campylobacter …

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 …

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 …

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 …

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), …

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 …

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 …

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 …

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 …

Listeria Monocytogenes'. A Genomic Perspective On Its Pathogenesis, Persistence And Bacteriophages., Aidan Casey

Theses

The objective of this study was to investigate the genetic characteristics of Listeria monocytogenes that contribute to the threat it poses to the food processing industry. Transcriptomic analysis of a persistent L. monocytogenes isolate following exposure to an industrial detergent identified key upregulations in biological processes involved m peptidoglycan biosynthesis, chemotaxis and motility. Two bacteriophages against serotype 4b and 4e isolates of L. monocytogenes were isolated and sequenced. Comparative genomic and functional analysis identified the receptor binding proteins in each phage, whi]e transmission electron microscopy demonstrated a conserved baseplate architecture which also exists in other Gram­positive phages. Comparative genomics of …

The Elimination Of Listeria Monocytogenes Biofilms From Stainless Steel Deli Meat Slicer Components By The Use Of Hurdle Technologies, Alexandria Wynne Mertz

Graduate Theses and Dissertations

Listeria monocytogenes growth is of the greatest concern amongst ready-to-eat foods. The United States Department of Agriculture's Food Safety and Inspection Services determined that deli luncheon meats pose the greatest risk of contamination from L. monocytogenes Industrial meat slicers have many removable parts that are connected with sealers and gaskets, which can become worn over time. These spaces cannot be cleaned adequately, therefore are susceptible to bacterial growth. Planktonic cells form biofilms in order to protect the cell from adverse conditions, like during routine cleaning and sanitation. Once a biofilm is formed, the bacteria are much more difficult to eradicate …

Understanding The Factors Affecting Microbiological Quality Of Wheat Milled Products: From Wheat Fields To Milling Operations, Luis E. Sabillón Galeas

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

Although regarded as a low-risk commodity, wheat flour-based mixes have been implicated in several food safety incidents. The present thesis is a compilation of five scientific manuscripts on the effect of weather variation, milling steps and implementation of pre-milling interventions on the microbiological quality and safety of wheat and milled products. The first manuscript is a review of the microbiological quality and safety of wheat-based products. Despite the low water activity, wheat flour may harbor dormant but viable microorganisms, which could lead to safety concerns when flour is used to produce refrigerated dough products. The second manuscript illustrates the effect …

Traceability Implementation In Organic Farming: Case Study, Chamomile Tea Production, Shaima Abdelfattah Ibrahim

Theses and Dissertations

Implementing a traceability plan in an herbal production plant is a complex task. In this study an attempt to integrate food safety, quality and traceability through the different stages of the organic German Chamomile (Matricaria recutita) production chain was made. First, all the current relevant international laws, regulations and standards regarding traceability, safety and quality, with emphasis on how and why they are necessary for any food production chain, were set forward. Second, physico-chemical and microbiological analyses were run throughout the different processing stages of production, for four different Chamomile batches produced over the same season using the same farming …

Tracking Heat-Resistant, Sporeforming Bacteria In The Milk Chain: A Farm To Table Approach, Maricarmen Estrada Anzueto

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

Sporeforming bacteria (such as Bacillus and Paenibacillus spp.) can survive pasteurization conditions (Collins, 1981) and grow in pasteurized fluid milk during refrigerated storage (Huck et al., 2008; Ivy et al., 2012), causing fluid milk spoilage and limiting the further extension of fluid milk’s shelf life (Fromm and Boor, 2004; Durak et al., 2006). Moreover, Bacillus and related genera have been found in raw milk, pasteurized milk and environmental samples from dairy farms, indicating that these organisms are ubiquitous in nature and can enter the milk chain from different sources (Huck et al., 2007b; Huck et al., 2008; Ranieri and Boor, …

Atmospheric Cold Plasma Inactivation Of Escherichia Coli, Salmonella Enterica Serovar Typhimurium And Listeria Monocytogenes Inoculated On Fresh Produce, Dana Ziuzina, Sonal Patil, Patrick J. Cullen, Kevin Keener, Paula Bourke

Articles

Atmospheric cold plasma (ACP) represents a potential alternative to traditional methods for non-thermal decontamination of foods. In this study, the antimicrobial efficacy of a novel dielectric barrier discharge ACP device against Escherichia coli, Salmonella enterica Typhimurium and Listeria monocytogenes inoculated on cherry tomatoes and strawberries, was examined. Bacteria were spot inoculated on the produce surface, air dried and sealed inside a rigid polypropylene container. Samples were indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (70kVRMS) air ACP and subsequently stored at room temperature for 24 h. ACP treatment for 10, 60 and 120 s resulted in reduction …

Kinetic Studies For The Preparation Of Probiotic Cabbage Juice: Impact On Phytochemicals And Bioactivity, Amit Jaiswal, Nissreen Abu-Ghannam

Articles

A kinetic study for the production of probiotic cabbage juice was carried out under controlled pH and dissolved oxygen using several strains of Lactic acid bacteria (LAB). Furthermore, effect of probiotic fermentation on polyphenolic content and antioxidant capacity was investigated. Results showed significant growth in Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus rhamnosus corresponding to 9.19, 9.47 and 10.6 log CFU/ml after 24 h of fermentation, which is satisfying criteria for a food product to be characterized as probiotic. Lactic acid (LA) was the major end product of the fermented cabbage juice attaining the concentrations of 6.97, 9.69 and 12.2 g/l …

Excretion Of Phenolic Compounds After Consumption Of Fresh Versus Aged Chokeberry Juice In Rats, Sarah Elizabeth Graves

Graduate Theses and Dissertations

Flavonoids, such as anthocyanins, may be responsible for the health benefits of chokeberries, as they are present in large quantities in chokeberries and are potent antioxidant and anti-inflammatory agents. Despite these health properties, previous investigations on the bioavailability of flavonoids illustrate that little of the ingested amount reaches the bloodstream. This study investigated two factors that may help to explain these inconsistencies. First, storage of berry fruits and berry fruit products leads to extensive polymerization of their anthocyanins with procyanidins. Additionally, after consumption flavonoids may undergo metabolism into phenolic acids and subsequent conjugation to an extent that may explain their …

Enhancement Of The Phytochemical And Fibre Content Of Beef-Patties With Himanthalia Elongata Seaweed, Sabrina Cox, Nissreen Abu-Ghannam

Articles

The effect of adding Himanthalia elongata seaweed (10 - 40% w/w) as a source of antioxidants and dietary fibre on physical, chemical, microbial and sensory traits of cooked beef patties was studied throughout chilled storage. Patties with seaweed showed reduced cooking losses and were nearly 50% more tender as compared to patties without seaweed. Microbiological counts and lipid oxidation were significantly lower in patties containing seaweed (P < 0.05), by day 30 of storage there was no bacterial growth in samples with ≥ 20% seaweed and lipid oxidation levels were low (0.61 mg malondialdehyde/kg of sample). Seaweed incorporation significantly increased the dietary fibre (1.64 g per 100 g fw in 40% seaweed-patties), total phenolic content (up to 28.11 mg GAE/100 g fw) and DPPH radical scavenging activity (up to 52.32%) of patties compared to the control. Sensory analysis indicated that the seaweed-patties were accepted by consumers in terms of aroma, appearance, texture and taste. Patties containing 40% seaweed were rated highest in terms of overall acceptability, most likely due to improvement in texture and mouthfeel. Addition of seaweed in the formulation of beef patties leads to the enhancement of the nutritional and technological quality together with an acceptable sensory quality.

Food Defense Among Meat Processing And Food Service Establishments In Kentucky, Morgan Webb-Yeates

Masters Theses & Specialist Projects

Agroterrorism is the deliberate introduction of a plant or animal disease with the
goal of causing fear, economic instability, illness, or death. After the 2002 terrorist
attacks on the World Trade Center, the security of the food supply is of increasing
concern to the United States. A major incidence of agroterrorism or food tampering would have far reaching impacts on the economy and public health. The first objective of this project was to determine knowledge and concern of agroterrorism in meat processing facilities in Kentucky, and to determine knowledge and concern of food tampering and food defense in food service …