Food Microbiology Commons^™

The Antimicrobial Activity Of Cold Pressed Terpeneless Valencia Orange Oil At Cold Temperatures, Sean Jeffrey Pendleton

Graduate Theses and Dissertations

This research was undertaken to identify an antimicrobial for use during chilling in beef processing, including periods of temperature abuse, as well as to evaluate membrane filtration as means to remove essential oils from bacteria to prevent further antibacterial action. Cold pressed terpeneless Valencia orange oil was examined in combination with various temperatures (37°C, 10°C, and 4°C) to determine its antimicrobial activity against various strains of bacteria. The strains were tested using a ninety-six well microtiter plate method, with or without membrane filtration. The compound 2, 3, 5-triphenyl tetrazolium chloride was used as a growth indicator. Serial, two fold dilutions …

Optimisation Of Accelerated Solvent Extraction Of Antioxidant Compounds From Rosemary (Rosmarinus Officinalis L.), Marjoram (Origanum Majorana L.) And Oregano (Origanum Vulgare L.) Using Response Surface Methodology, M. Hossain, Catherine Barry-Ryan, Ana Belen Martin-Diana, N. Brunton

Articles

The present study optimised the accelerated solvent extraction (ASE) conditions (Dionex ASE® 200, USA) to maximise the antioxidant capacity of the extracts from three spices of Lamiaceae family; rosemary, oregano and marjoram. Optimised conditions with regard to extraction temperature (66–129 °C) and solvent concentration (32–88% methanol) were identified using response surface methodology (RSM). For all three spices results showed that 129 °C was the optimum temperature in order to obtain extracts with high antioxidant activity. Optimal methanol concentrations with respect to the antioxidant activity of rosemary and marjoram extracts were 56% and 57% respectively. Oregano showed a different response to …

Analysis Of Rice Blast Resistance Genes In The National Small Grains Collection (Nsgc), Moytri Roychowdhury

Graduate Theses and Dissertations

Identification of blast resistance genes in rice germplasm is one of the most important activities of rice breeding programs in worldwide. The objective of this research was to characterize two major blast resistance genes, Pi-z and Pi-b, in selected rice germplasm. A simple sequence repeat DNA marker, AP5659-1 linked to the Pi-z gene, and a Pib dominant marker derived from the Pi-b gene were first used to screen a rice core collection consisting of 1700 accessions estimated to represent 70% of the genetic diversity of rice in the US National Small Grains Collection. There were 131 rice germplasm accessions with …

Knowledge Of Young African American Adults About Heart Disease: A Cross-Sectional Survey, Donna Winham, Kathleen M. Jones

Donna Winham

Background: African Americans have higher rates of cardiovascular disease (CVD) mortality than other ethnic groups. Young adults are prime targets for intervention strategies to prevent and reduce disease risk. The study purpose was to determine the level of knowledge of lifestyle risk factors for CVD among young African American adults in Phoenix. The results will be used to guide the development of CVD outreach programs targeted to this population. The Health Belief Model was used as a conceptual framework. Methods: A convenience sample of 172 African American men and women aged 18-26 years completed a questionnaire adapted from the American …

Quantitative Assessment Of The Shelf-Life Of Ozonated Apple Juice, Sonal Patil, Vasilis Valdramidis, Brijesh Tiwari, Patrick Cullen, Paula Bourke

Articles

Sterile apple juice inoculated with S. cerevisiae ATCC 9763 (10³ CFU/mL) was processed in a bubble column with gaseous ozone of flow rate of 0.12 L/min and concentration of 33-40 µg/mL for 8 min. The growth kinetics of S. cerevisiae as an indicator of juice spoilage was monitored at 4, 8, 12 and 16 ºC for up to 30 days. The kinetics were quantitatively described by the primary model of Baranyi and Robert’s and the maximum specific growth rate was further modeled as a function of temperature by the Ratkowsky type model. The developed model was successfully validated for …

Transfer Of Listeria Monocytogenes From Stainless Steel And High Density Polethylyene To Cold Smoked Salmon And Listeria Monocytogenes Biofilm Cohesive Energy Investigation, Fujia Zhang

Masters Theses 1911 - February 2014

Listeria monocytogenes is a major concern for the food industry. It is one of the major agents causing listeriosis. The objective of the first part of this study is to evaluate the effect of hydration level on attached listeria monocytogenes on stainless steel/High density polyethylene transferred to food products. Attached cells were prepared on stainless steel/High density polyethylene. Transfer experiments were conducted from inoculated surface material slides to cold smoked salmon fillets. This experiment was repeated 6 times. The results were analyzed with an analysis of variance by SAS. The differences between the different RH% and surface conditions were not …

A Multidisciplinary Approach To Food Safety Evaluation: Hummus Spoilage And Microbial Analysis Of Kitchen Surfaces In Residential Child Care Institutions (Rcci) In Massachusetts, U.S.A., Elsina E. Hagan

Masters Theses 1911 - February 2014

Food borne illnesses continues to be a public health challenge in the United States (U.S.); an estimated 9.4 million incident cases occurred in 2011. In view of this challenge we conducted two food safety studies; 1) related to product formulation (hummus spoilage challenge study) and 2) evaluating the microbial safety of domestic kitchen surfaces in Residential Child Care Institutions (RCCI pilot study).

Hummus is of Mediterranean origin but is currently eaten globally. This challenge study evaluates a variety of industrial hummus formulations (four in total, differing in pH and/or addition of a preservative (natamycin). Two batches were setup: batch 1; …

Evaluation Of Natural Antimicrobial Phenolic Compounds Against Foodborne Pathogens, Hayriye Cetin-Karaca

University of Kentucky Master's Theses

Raw and processed foods are vulnerable to contamination during their production, distribution and sale. Thus, a wide variety of chemical preservatives are used in the food industry to prevent the growth of food spoilage and pathogenic bacteria. However, health and economic concerns have led to an intensive search for natural alternatives, such as plant extracts, that can safely be used as substitutes for synthetic antimicrobials and preservatives to partially or completely inhibit the growth of bacteria.

This study evaluated the antimicrobial effects of natural phenolic compounds extracted from vegetables, fruits, herbs and spices. The main objective was to determine the …

Capsular Serotyping Of Pasteurella Multocida From Various Animal Hosts - A Comparison Of Phenotypic And Genotypic Methods, Thong Kwai Lin

Thong Kwai Lin

One hundred and fourteen strains of Pasteurella multocida were isolated from different domestic animals species (cattle, buffalo, sheep, goat, pig, rabbit, dog, cat), avian species (chicken, duck, turkey) and wild animals (deer, tiger, orang utan, marmoset). The serogroups of P multocida were determined by both conventional capsular serotyping and a multiplex PCR assay targeting specific capsular genes. Based on the conventional serotyping method, the 114 strains of P multocida were subtyped into 55 species-specific (untypeable strains) P. multocida, 15 serogroup A, 23 serogroup B and 21 serogroup D. Based on the multiplex PCR assay on the specific capsular genes associated …

Sucrose Monolaurate Improves The Efficacy Of Sodium Hypochlorite Against Escherichia Coli O157:H7 On Spinach, Dan Xiao, Ran Ye, P. Michael Davidson, Douglas G. Hayes, David A. Golden, Qixin Zhong

David A Golden

It is well-recognized that chlorine has limited efficacy when applied to inactivate pathogens on fresh produce. One of the many factors limiting efficacy is the high interfacial tension of chlorine-based sanitizers that limits the access of chlorine to the microorganisms. In this work, we investigated the efficacy of sodium hypochlorite (200 ppm, pH 6.0) at 4 and 20 °C against Escherichia coli O157:H7 inoculated on baby spinach leaves as affected by the surfactant sucrose monolaurate (SML) at below (100 ppm), above (250 ppm), and well above (10,000 ppm) the critical micelle concentration (CMC) of ~ 200 ppm at 20 °C. …

Effect Of Processing Conditions On Phytochemical Constituents Of Edible Irish Seaweed Himanthalia Elongata., Sabrina Cox, Nissreen Abu-Ghannam, Shilpi Gupta

Articles

Seaweed iswell recognized as an excellent source of phytochemicals. This study was a preliminary screening to investigate the effects of various food processing methods on the phytochemicals of Himanthalia elongata. Hydrothermal processing was carried out until an edible texture was achieved. The total phenolic content (TPC) of fresh H. elongata was 175.27 mg gallic acid equivalent (GAE)/100 g fresh weight (FW) while boiling significantly reduced the TPC to 25.4 mg GAE/100 g FW
(P < 0.05).A drying pretreatment before boiling reduced the cooking time therefore leading to less leaching of antioxidants upon boiling. In terms of extract, drying of H. elongata followed by boiling had the most significant effect on the phytochemicals as TPC increased by 174%. Boiled extracts had the most effective 2, 2-diphenyl- 1-picrylhydrazyl scavenging activity (EC50 of 12.5 mg/mL). As a comparison, seaweed subjected to the same treatments was studied in terms of antimicrobial activity.Overall, extracts fromfresh H. elongata achieved the highest inhibition.

Storage Effects Of Gel Encapsulation On Stability Of Chokeberry Monomeric Anthocyanins, Procyanidins, Color Density, And Percent Polymeric Color, Mary Kordsmeier, Luke Howard

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Chokeberries (Aronia melanocarpa) are an antioxidant-rich plant product due to their high content of polyphenols, especially anthocyanins and procyanidins. These polyphenols have been shown to provide protection against coronary heart disease, stroke, and lung cancer, as well as against oxidative stress, the main cause behind chronic diseases promoted by free radicals. The objective of this study was to determine the storage effects of gelatin encapsulation on monomeric anthocyanins, procyanidins, color density, and percent polymeric color of three gummy candies of different strengths formulated with a base of 25.4% chokeberry concentrate, 47.6% sucrose, 1.3% Splenda, and 0.025% potassium sorbate. The gum …

Properties Of Gluten-Free Pasta Prepared From Rice And Different Starches, Alexandria W. Mertz, Ya-Jane Wang

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Rice is one of the few cereal products that does not contain gluten. However, the absence of gluten poses problems in the structure of and cooking quality of rice pasta. The objective of this project was to investigate the addition of starch on the physicochemical properties and cooking quality of rice-based pasta. Rice-based pasta was prepared from parboiled long-grain rice flour with the addition of 25% cooked starch from different sources. The color and pasting properties of the ground pasta flour were measured by a chroma meter and a Rapid Visco Analyser, respectively. The pasta was cooked to the optimum …

Application Of Principal Component And Hierarchical Cluster Analysis To Classify Different Spices Based On In Vitro Antioxidant Activity And Individual Polyphenolic Antioxidant Compounds, M. Hossain, A. Patras, Catherine Barry-Ryan, Ana Belen Martin-Diana, N. Brunton

Articles

This study investigated the variations in antioxidant profiles between spices using pattern recognition tools; classification was achieved based on the results of global antioxidant activity assays (2,2-diphenyl-1-picrylhydrazyl [DPPH], oxygen radical absorbance capacity [ORAC], ferric reducing antioxidant power [FRAP], microsomal lipid peroxidation [MLP] and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) [ABTS]), levels of different polyphenolic compounds (gallic acid [GA], carnosol [CAR], carnosic acid [CRA], caffeic acid [CA], rosmarinic acid [RA], luteolin-7-O-glucoside [LOG], apigenin-7-O-glucoside [APOG] and total phenols [TP]) of spices namely rosemary, oregano, marjoram, sage, basil, thyme, fennel, celery, cumin and parsley, commonly consumed in Ireland were analyzed. Rosemary showed the highest antioxidant activity measured …

The Effect Of Untreated And Enzyme-Treated Commercial Dairy Powders On The Growth And Adhesion Of Streptococcus Mutans, Rachel Halpin, D.B. Brady, E.D. O’Riordan, M. O’Sullivan

Articles

Dental caries is a common bacterial infection, but the progression of this disease can be delayed by preventing initial attachment of cariogenic bacteria such as Streptococcus mutans to tooth surfaces. This study firstly compares the effect of untreated (UT) and enzyme-treated (ET) dairy powders on the adherence of S. mutans to hydroxylapatite (HA), an analogue of tooth enamel. A fluorescence-based method was used to quantify adherence of S. mutans to HA both in the presence (S-HA) and absence (PBS-HA) of saliva. Secondly, binding of proteins present in the test materials to HA was quantified using bicinchonic acid assays and SDS-PAGE. …

Determination Of The Effect Of Dairy Powders On Adherence Of Streptococcus Sobrinus And Streptococcus Salivarius To Hydroxylapatite And Growth Of These Bacteria, Rachel Halpin, D.B. Brady, E.D. O’Riordan, M. O’Sullivan

Articles

Dental caries is a highly prevalent disease caused by colonisation of tooth surfaces by cariogenic bacteria, such as Streptococcus sobrinus and Streptococcus salivarius. Reducing initial adherence of such bacteria to teeth may delay onset of caries. Many foods, such as milk, can inhibit microbial adherence. In this investigation, the effect of untreated (UT) and enzyme-treated (ET) dairy powders on adherence of S. sobrinus and S. salivarius to hydroxylapatite (HA), an analogue of tooth enamel, was examined. Untreated (UT) acid whey protein concentrate (AWPC) 80 inhibited streptococcal adherence to phosphate-buffered saline-coated HA (PBS-HA) and saliva-coated HA (S-HA) by >80% at …

Growth Inhibition Of Common Food Spoilage And Pathogenic Microorganisms In The Presence Of Brown Seaweed Extracts, Shilpi Gupta, Sabrina Cox, Gaurav Rajauria, Amit Jaiswal, Nissreen Abu-Ghannam

Articles

The possibility of using extracts from brown seaweed, Himanthalia elongata, as a natural antimicrobial agent for food preservation is presented. The effect of different concentrations of seaweed extract on the growth kinetics of four common food spoilage (Pseudomonas aeruginosa and Enterococcus faecalis) and food pathogenic micro-organisms (Listeria monocytogenes and Salmonella abony) was examined. Seaweed extract at a concentration of 6% inhibited the growth of all four of the studied organisms. Lower concentrations of seaweed extract prolonged the lag phase and reduced both the exponential growth rate and final population densities of the culture. Suitability of three kinetic models, Baranyi-Roberts, Modified …

The Bifidogenicity Of The Prebiotic Galactooligosaccharides, Lauren M. G. Davis

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

The goal of this research was to determine the effect of different doses of galactooligosaccharide (GOS) on the fecal microbiota of healthy adults, with a focus on bifidobacteria. The study was designed as a single-blinded study, with eighteen subjects consuming GOS-containing chocolate chews at four increasing dosage levels; 0, 2.5, 5.0, and 10.0 g. Subjects consumed each dose for 3 weeks, with a two-week baseline period preceding the study and a two-week washout period at the end. Cultural methods were used for bifidobacteria, Bacteroides, enterobacteria, enterococci, lactobacilli, and total anaerobes; culture-independent methods included denaturing gradient gel electrophoresis (DGGE) and …

Antimicrobial Activity Of Casein Hydrolysates Against Listeria Monocytogenes And Escherichia Coli O157:H7, Jessica M Christman

Masters Theses

Listeriosis has the highest fatality and hospitalization rate among foodborne illnesses. Listeria monocytogenes causes listeriosis and is a difficult bacterium for ready-to-eat food processors to eliminate because of its ability to grow in the absence of oxygen and under refrigeration. Recently, milk and its proteins have gained recognition as the largest source of biologically active peptides, and, it stands reason that several antimicrobial peptides (AMP) can be released from casein as it is the most abundant milk protein. AMPs are commonly obtained by cutting the whole protein into peptide fragments using enzymes or by acidification. The objective of this study …

Novel Approaches For The Efficient Sampling And Detection Of Listeria Monocytogenes And Brochothrix Thermosphacta On Food Contact Surfaces, Jessica Anne Clemons

Masters Theses

The primary step in the microbiological assessment of highly dynamic and complex food processing conditions is environmental sampling. The objectives of this study were to: (1) compare the efficacy of four sampling devices including Microbial-Vac system (MV), cellulose sponge (SP), polyester swab (SW) and composite tissue (CT), for the recovery of Listeria monocytogenes and Brochothrix thermosphacta on five surfaces and (2) to determine if there was a significant difference between the recovery of low (10 CFU/900cm²) and high (100 CFU/900cm²) L. monocytogenes inoculum levels using the sampling devices in a simulated food processing environment. Surfaces used …