Food Microbiology Commons^™

Antimicrobial Effects Of Microwave-Induced Plasma Torch (Minimip) Treatment On Candida Albicans Biofilms, Oliver Handorf, Uta Schnabel, André Bösel, Thomas Weihe, Sander Bekeschus, Alexander C. Graf, Jörg Ehlbeck

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The susceptibility of Candida albicans biofilms to a non-thermal plasma treatment has been investigated in terms of growth, survival and cell viability by a series of in vitro experiments. For different time periods , the C. albicans strain SC5314 was treated with a microwave-induced plasma torch (MiniMIP). The MiniMIP treatment had a strong effect (reduction factor (RF) = 2.97 after 50 s treatment) at a distance of 3 cm between the nozzle and the superior regions of the biofilms. In addition, a viability reduction of 77% after a 20 s plasma treatment and a metabolism reduction of 90% after a …

Efficacy Of Cold Plasma Functionalised Water For Improving Microbiological Safety Of Fresh Produce And Wash Water Recycling, Apurva Patange, Peng Lu, Daniela Boehm, Patrick J. Cullen, Paula Bourke

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Atmospheric cold plasma (ACP) is an effective method for microbiological decontamination. This study evaluated an alternative water-based decontamination approach for inactivation of bacterial population from fresh produce and in the wash water generated from fresh produce washing. The study characterised ACP inactivation of attached Listeria innocua and Pseudomonas fluorescens inoculated on lettuce in comparison to chlorine treatment. P. fluorescens was sensitive to ACP treatment and was reduced below detection limit within 3 min of treatment. L. innocua population was reduced by ∼2.4 Log10 CFU/g after 5 min of treatment; showing similar inactivation efficacy to chlorine treatment. The microbial load in …

High Voltage Atmospheric Cold Air Plasma Control Of Bacterial Biofilms On Fresh Produce, Apurva Patange, D. Boehm, Dana Ziuzina, Patrick J. Cullen, Brendan Gilmore, Paula Bourke

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Atmospheric cold plasma (ACP) offers great potential for decontamination of food borne pathogens. This study examined the antimicrobial efficacy of ACP against a range of pathogens of concern to fresh produce comparing planktonic cultures, monoculture biofilms (Escherichia coli, Salmonella enterica, Listeria monocytogenes, Pseudomonas fluorescens) and mixed culture biofilms (Listeria monocytogenes and Pseudomonas fluorescens). Biotic and abiotic surfaces commonly occurring in the fresh food industry were investigated. Microorganisms showed varying susceptibility to ACP treatment depending on target and process factors. Bacterial biofilm populations treated with high voltage (80 kV) ACP were reduced significantly (p <  0.05) in both mono- and mixed species biofilms after 60 s of treatment and yielded non-detectable levels after extending treatment time to 120 s. However, an extended time was required to reduce the challenge mixed culture biofilm of L. monocytogenes and P. fluorescens inoculated on lettuce, which was dependent on biofilm formation conditions and substrate. Contained treatment for 120 s reduced L. monocytogenes and P. fluorescens inoculated as mixed cultures on lettuce (p <  0.05) by 2.2 and 4.2 Log10 CFU/ml respectively. When biofilms were grown at 4 °C on lettuce, there was an increased resistance to ACP treatment by comparison with biofilm grown at temperature abuse conditions of 15 °C. Similarly, L. monocytogenes and P. fluorescens exposed to cold stress (4 °C) for 1 h demonstrated increased tolerance to ACP treatment compared to non-stressed cells. These finding demonstrates that bacterial form, mono versus mixed challenges as well as environmental stress conditions play an important role in ACP inactivation efficacy.

Effect Of Cold Plasma On The Techno-Functional Properties Of Animal Protein Food Ingredients, Juan M. Pérez-Andrés, Carlos Álvarez, Patrick J. Cullen, Brijesh K. Tiwari

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Proteins, as food ingredients, are employed in the food industry, not only for their high nutritional value, but also because of their techno-functional properties. Modifications of their native structure due to the action of external factors such as pH, temperature or processing by emerging technologies, can lead to changes in their functionality; and consequently, their applicability. The present study investigates the effects of cold atmospheric air plasma on the techno-functional properties of two common food ingredients (haemoglobin and gelatine from pork), and a novel source of functional proteins extracted from a meat co-product (bovine lung protein). Significant effects were found …

Lignocellulosic Biorefineries In Europe: Current State And Prospects, Amit Jaiswal, Shady Hassan, Gwilym A. Williams

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In 2012, the European Bioeconomy strategy was launched, defining the bioeconomy as "the 33 production of renewable biological resources and the conversion of these resources and waste 34 streams into value added products". This strategy and its action plans increased the turnover 35 of the total bioeconomy in the EU from 2.09 trillion Euro in 2008 to 2.29 trillion in 2015 .

Knowledge Of Food Safety And Food Handling Practices Amongst Food Handlers In The Republic Of Ireland, Nora A. Moreb, Anushree Priyadarshini, Amit Jaiswal

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Food safety concerns have existed for a long time, as millions of people across the globe suffer from food borne disease every year. Contamination of food owing to limited knowledge of food safety practices primarily increases the risk of food borne illnesses. In the present study, quantitative research was carried out to gauge the level of food safety knowledge amongst people living in Ireland. A total of 1069 participants from all over the Republic of Ireland contributed to the survey (of which 821 were included in this research). Results showed that the residents of Ireland overall had an average levelonknowledge …

Achieving Reactive Species Specificity Within Plasma Activated Water Through Selective Generation Using Air Spark And Glow Discharges, Peng Lu, Daniela Boehm, Paula Bourke, Patrick J. Cullen

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Plasma activated liquids (PAL) attract increasing interest with demonstrated biological effects. Plasma exposure in air produces stable aqueous reactive species which can serve as chemical diagnostics of PAL systems. Here, we tailor aqueous reactive species inside plasma activated water (PAW) through treating water with AC air spark and glow discharges in contact with water. Chemical probing demonstrated species specificity between two types of PAW. Spark discharge PAW contains 2 2 H O and 3 NO , while 2 NO and 3 NO are generated in glow discharge PAW. Species formation in different PAWs have been discussed in terms of discharge …

Controlling Brochothrix Thermosphacta As A Spoilage Risk Using In Package Atmospheric Cold Plasma, Apurva Patange, Daniela Boehm, Carmen Bueno-Ferrer, Patrick J. Cullen, Paula Bourke

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Brochothrix thermosphacta is a predominant spoilage microorganism in meat and its control in processing environments is important to maintain meat product quality. Atmospheric cold plasma is of interest for control of pathogenic and spoilage microorganisms in foods. This study ascertained the potential of dielectric barrier discharge atmospheric cold plasma (DBD-ACP) for control of B. thermosphacta in response to key parameters such as treatment time, voltage level, interactions with media composition and post treatment storage conditions. Challenge populations were evaluated as suspensions in PBS, as biofilms in meat model medium and surface attached on raw lamb chops under MAP.

ACP treatment …

Assessing Stress Responses To Atmospheric Cold Plasma Exposure Using Escherichia Coli Knock Out Mutants, Lu Han, Daniela Boehm, Sonal Patil, Patrick J. Cullen, Paula Bourke

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Aim: This study investigated the effect of Atmospheric cold plasma (ACP) exposure induced stress on microbial inactivation patterns and the regulation of genes involved in the microbial stress response in conjunction with key processing parameters of exposure time and post treatment storage time.

Methods and Results: Cell suspensions of Escherichia coli BW 25113 and its isogenic knock-out mutants in rpoS, soxR, soxS, oxyR and dnaK genes were treated with high voltage ACP in a sealed package for 1, 3 and 5 min followed by 0, 1 and 24 h post-treatment storage. ROS densities and colony formation were …

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

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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 …

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

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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

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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 …

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

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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

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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 …

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

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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.

Isolation And Partial Characterization Of Bioactive Fucoxanthin From Himanthalia Elongata Brown Seaweed: A Tlc-Based Approach, Gaurav Rajauria, Nissreen Abu-Ghannam

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Seaweeds are important sources of carotenoids, and numerous studies have shown the beneficial effects of these pigments on human health. In the present study, Himanthalia elongata brown seaweed was extracted with a mixture of low polarity solvents, and the crude extract was separated using analytical thin-layer chromatography (TLC).The separated compounds were tested for their potential antioxidant capacity and antimicrobial activity against Listeria monocytogenes bacteria using TLC bioautography approach. For bio-autography, the coloured band on TLC chromatogram was visualized after spraying with DPPH and triphenyltetrazolium chloride reagents which screen antioxidant and antimicrobial compounds, respectively, and only one active compound was screened …

Optimization Of Fermentation Conditions For The Utilization Of Brewing Waste To Develop A Nutraceutical Rich Liquid Product, Shilpi Gupta, Amit Jaiswal, Nissreen Abu-Ghannam

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Utilization of brewers’ spent grain (BSG), for the development of a fermented liquid product rich in value-added phenolic compounds was investigated. Changes in and liberation of phenolic compounds and antioxidant activity during fermentation of BSG was studied. The effect of various particle size (PS), solid liquid (SL) ratio, fermentation time and rotation speed was optimized using response surface methodology (RSM) for the purpose of improving bacterial growth and the enhancement in the release of polyphenolic compounds. Contour maps generated using the response surface equation showed that the experimental variables significantly affected the response. A production of 10.4 log cfu/ml, 2.95 …

The Effect Of Non-Thermal Processing Technologies On Microbial Inactivation: An Investigation Into Sub-Lethal Injury Of Escherichia Coli And Pseudomonas Fluorescens, Rachel Halpin, L. Duffy, O. Cregenzán-Alberti,, J.G Lyng, F. Noci

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In recent years, there has been an increased interest in food processing technologies that could lessen the thermal impact on food products. In the present study, thermosonication (TS) and pulsed electric fields (PEF), applied individually or in combination (TS/PEF), were investigated to determine their effects on inactivation and sub-lethal injury of Pseudomonas fluorescens and Escherichia coli. TS was applied at a low (L) and high (H) wave amplitude (18.6 μm and 27.9 μm, respectively), while PEF was applied at a low and high electrical field strength (29 kV cm⁻¹ and 32 kV cm⁻¹, respectively). In addition, …

Optimization Of Lactic Acid Fermentation Of York Cabbage For The Development Of Potential Probiotic Products, Amit Jaiswal, Shilpi Gupta, Nissreen Abu-Ghannam

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In the present study, York cabbage was used as the sole substrate for the lactic acid (LA) fermentation with Lactobacillus plantarum. York cabbage was blanched at 95°C for 12min to inactivate surface microflora prior to fermentation. To achieve an optimal fermentation condition which would result in higher release of phytochemicals and antioxidant (AO) capacity in the broth, Box-Behnken design integrating a desirability approach was used. A second-order polynomial equation was developed indicating the effect of solute/liquid ratio, agitation rate and fermentation time on desired parameters. The optimized factors were used for fermenting York cabbage to obtain maximum bacterial growth, …

Antimicrobial, Antioxidant And Free Radical-Scavenging Capacity Of Brown Seaweed Himanthalia Elongata From Western Coast Of Ireland, Gaurav Rajauria, Amit Jaiswal, Nissreen Abu-Ghannam, Shilpi Gupta

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Water,methanol and mixtures (20–80%) thereof have been used for the extraction of phenolic compounds from Irish brown seaweed Himanthalia elongata for studying its antimicrobial and antioxidant properties.The 60%methanolic extract exhibited significantly (P < 0.05) the highest value of yield (6.8 6 0.24%), total phenol (286.0 6 4.61 mg gallic acid equivalents/g), flavonoid (109.8 6 2.68 mg quercetin equivalents/g) and condensed tannin content (35.6 6 1.03 mgcatechin equivalents/ g). Antimicrobial activity of 60% methanolic extract tested from disc diffusion and broth dilution methods was effective against various food spoilage and pathogenic bacteria studied.The same extract exhibited statistically highest reducing power and antioxidant capacity againstDPPHradical,metal ions, lipid peroxides and hydrogen peroxide radicals. The UV-visible spectroscopy showed absorption maxima at 205 and 260 nm and the presence of hydroxyl group (3,431 cm-1) and an aromatic ring (around 1,465, 1,505 and 1,624 cm-1) in Fourier Transform Infrared spectroscopy, suggested the presence of phenolic compounds in the extract.

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

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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 …

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

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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 …

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

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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.

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

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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. …

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

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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 …

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

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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

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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 …

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

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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.

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

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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.

Quality And Safety Assessment During The Ozonation Of Cloudy Apple Juice, Sonal Patil, B. Torres, Brijesh Tiwari, Hilda Wingaard, Paula Bourke, Patrick J. Cullen, C. O'Donnell, Vasilis Valdramidis

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Traditionally, ozone processing within the food industry has focused on solid foods by either gaseous treatment or washing with ozonated water. However, with the FDA’s approval of ozone as a direct additive to food, the potential for liquid applications has emerged. This study investigates the effect of ozone processing on microbial inactivation (E. coli ATCC 25922 and NCTC 12900), and quality parameters (colour, phenolic content) of apple juice. Apple juice samples were ozonated at room temperature (20±1.5^oC) with an ozone concentration of 0.048 mg O₃ min^-1 ml^-1 and treatment time of 0 to 10 …