Food Microbiology Commons^™

Microbiological, Thermal Inactivation, And Sensory Characteristics Of Beef Eye-Of-Round Subprimals And Steaks Processed With High-Pressure Needleless Injection, Laura Kahealani Jefferies

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

High-pressure needleless injection (HPNI) is a process where small-diameter, high-velocity burst of liquid, penetrate foods at pressures ≤ 10,000 psi. The potential of HPNI as an enhancing technique for meat was studied. In study 1, HPNI translocated surface E. coli O157 into the interior of beef eye-of-round subprimals with an incidence of 40 (±7), 25 (±8), and 25 (±8)% for meat that had been surface-inoculated with a four-strain cocktail at 0.5, 1, and 2 log₁₀ CFU/cm², respectively. Run-off water contained 2, 2, and 3 log₁₀ CFU/ml and was used for HPNI of additional subprimals, which resulted …

Quantitative Assessment Of The Shelf-Life Of Ozonated Apple Juice, Sonal Patil, Vasilis Valdramidis, Brijesh Tiwari, Patrick J. 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 …

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 …

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. …

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 …

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 …

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 …

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.

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 …

Identification And Characterization Of Salmonella Serotypes Isolated From Pork And Poultry From Commercial Sources, Yulie Edith Meneses-GonzáLez

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

Salmonella is one of the leading causes of foodborne illness worldwide, and it is estimated that 1.4 million infections occur annually in the U.S. alone. The Premi®Test Salmonella (PTS), is a potential tool for rapid detection and identification of Salmonella serovars. The objective of this project was to evaluate the use of the PTS system as a serotyping tool to identify pork and poultry isolates obtained from vertically integrated operations and to characterize their antibiotic resistance. Two hundred isolates were evaluated. All isolates were serotyped using the traditional Kaufmann-White scheme and the PTS system. Among the isolates 63 different serotypes …

Metabolic Profiling And Fingerprinting For The Detection And Discrimination Of Mechanical Damage In Mushrooms (Agaricus Bisporus) During Storage, Aoife O'Gorman

Doctoral

Horticultural products such as mushrooms are exposed to external agents during their postharvest life, which are going to affect product quality. Loss of whiteness during storage is particularly important in the mushroom industry. Rough handling and distribution of crops, fruiting body senescence, bacterial and viral infection are among the causes of mushroom discolouration. The aim of this work was to study the use of metabolic fingerprinting and metabolic profiling tools for the detection and discrimination of mechanical damage on mushrooms. This research involved: 1. Investigating whether the chemical changes induced by mechanical damage and ageing of mushrooms could be (a) …

Quantification Of Aflatoxin B1 In Ready-To-Use Food Thickeners In South-East Geo-Political Zone In Nigeria, G. I. Okwu, Premila N. Achar, Santosh K. Sharma

Faculty Articles

A total of 150 ready to use food thickeners were randomly collected from various markets in both urban and rural settings. Four of the samples tested Achi (Brachystegia eurycoma), Akpalata (Afzelia africana), Ofor (Detarium microcarpum), and Ukpo (Mucuna flagellipes) were contaminated with fungal flora. The most common and prevalent fungi observed on incubated powdered form of food thickeners on media, were the Aspergillus group namely Aspergillus flavus, Aspergillus parasiticus and Aspergillus niger. Pure isolates of A. flavus and A. parasiticus from various food thickeners from open markets in Nigeria were screened for their potential to produce aflatoxin B-1 (AFB(1)) on …

The Effects Of High Pressure Processing On Peanut Sauce Inoculated With Salmonella, Tara K. Stiles

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

Recent Salmonella outbreaks have prompted the need for new processing options for peanut products. Traditional heating kill-steps have shown to be ineffective in lipid-rich matrices such as peanut products. High pressure processing is one such option for peanut sauce because it has a high water activity, which has proved to be a large contributing factor in microbial lethality due to high pressure processing. Four different formulations of peanut sauce were inoculated with a five strain Salmonella cocktail and high pressure processed. Results indicate that increasing pressure or increasing hold time increases log₁₀ reductions. The Weibull model was fitted to …

Effect Of Hydrothermal Processing On Colour, Antioxidant And Free Radical Scavenging Capacities Of Edible Irish Brown Seaweeds, Gaurav Rajauria, Amit Jaiswal, Nissreen Abu-Ghannam, Shilpi Gupta

Articles

The effect of heat processing on change in colour (ΔE), level of bioactive compounds and overall antioxidant capacity in raw and heat processed Irish brown seaweeds was investigated. Raw seaweeds were heated at 85, 95, 100, 110 and 121 °C for 15 min in an autoclave and the samples were extracted with 60% methanol. Total phenol (TPC), total tannin (TTC), DPPH• scavenging and metal chelating ability (FIC) were significantly higher (p < 0.05) at 85 °C while the value of ΔE, total flavonoid (TFC), total sugar (TSC), lipid peroxidation and H2O2 scavenging capacity were higher at 95 °C, as compared to raw seaweeds, in all the species studied. Results showed that heat treatment affects not only the content of bioactive compounds in seaweeds but also beneficial biological activity associated with these compounds which can suggest new processing for the application of seaweeds extract as nutraceutical.

Probiotic Therapy - Recruiting Old Friends To Fight New Foes, Roy D. Sleator

Department of Biological Sciences Publications

Against a backdrop of increasing antibiotic resistance, and the emergence of new and evolving pathogens, clinicians are increasingly forced to consider alternative therapies - probiotics are one such alternative.

Changes In Microbiological, Physicochemical, Biochemical And Therapeutical Characteristics Of Yoghurt Upon The Addition Of Selected Medicinal Herbs., Afsaneh Najarian

Student Works (2010-2019)

The effects of herbs on the changes in probiotic growth and metabolism in yoghurt during storage were studied. Angelica sinensis, Codonopsis pilosula, Illicium verum, Lycium barbarum, Momorsdica grosvenori and Psidium gujava water-extracts were co-incubated with pasteurized full cream milk containing Lactobacillus acidophilus, Bifidobacterium, Streptococcus thermophilus and L.casei as starter culture. The addition of herbal water extracts stimulated Lactobacillus sp. growth in P. guajava–yoghurt (126.3±26.3 × 106 CFUml-1) only on day 0 and in L. barbarum–yoghurt from 0 to 3 days (109.3±21.5 to 112.7±28.8×106 CFUml-1 respectively) of refrigerated storage. The growth of S. thermophilus were recorded higher than plain yoghurt for …

An Assessment Of The Antioxidant And Antimicrobial Activity Of Six Species Of Edible Irish Seaweeds, Sabrina Cox, Nissreen Abu-Ghannam, Shilpi Gupta

Articles

Six species of edible Irish seaweeds; Laminaria digitata, Laminaria saccharina, Himanthalia elongata, Palmaria palmata, Chondrus crispus and Enteromorpha spirulina were screened for potential bioactivity. Extraction of secondary metabolites was carried out using different solvents to determine antioxidant and antimicrobial properties of the dried extracts. The total phenolic contents of dried methanolic extracts were significantly different (p < 0.05). H. elongata exhibited highest phenolic content at 151.3 mg GAE/g of seaweed extract and also had the highest DPPH scavenging activity (p < 0.05) with a 50% inhibition (EC50) level at 0.125μg/ml of extract. H. elongata also had the highest total tannin and total flavonoid contents (p < 0.05) of 38.34 mg CE/g and 42.5 mg QE/g, respectively. Antimicrobial activity was determined using a microtitre method which allowed detection of bacterial growth inhibition at low levels. All methanolic seaweed extracts inhibited the food spoilage and food pathogenic bacteria tested; Listeria monocytogenes, Salmonella abony, Enterococcus faecalis and Pseudomonas aeruginosa, except C. crispus extracts. It was found that dried methanolic extracts of red and green seaweeds had significantly lower antimicrobial activity than the brown species; H. elongata had the highest antimicrobial activity with up to 100% inhibition. In the studied work, the antimicrobial activity of red and green seaweed extracts significantly increased when ethanol and acetone were used as extraction solvents (p < 0.05). Inhibition of E. faecalis with C. crispus extracts increased from 39.28 to 100% when ethanol and acetone were applied as solvents.

Enterobacterial Repetitive Intergenic Consensus-Pcr (Eric-Pcr) Analysis Among Raw Vegetables Isolates Of Campylobacter Jejuni., Tuan Suraya Tuan Soh

Student Works (2010-2019)

A total of 20 (n=20) raw vegetable isolates of Campylobacter jejuni were examined for the presence of virulence genes and genetic diversity using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) analysis. All C. jejuni isolates were obtained from the laboratory of Food Science and Biotechnology, University Putra Malaysia, Serdang, Selangor. When specific PCR amplification were determined, all raw vegetables isolates of Campylobacter jejuni contained cadF and ceuE genes. Whereas, 12 (12/20) isolates were positive cdtB and 6 (6/20) were positive cdtC. None of the C. jejuni isolates was cdtA positive. Using ERIC-PCR analysis, all 20 isolates of C. jejuni were …