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Author = Cullen, Patrick;
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Displaying Results 1 - 25 of 46 on page 1 of 2
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Application of Natural Antimicrobials for Food Preservation
(2009)
Tiwari, Brijesh; Valdramidis, Vasilis; O' Donnell, Colm; Muthukumarappan, Kasivisw...
Application of Natural Antimicrobials for Food Preservation
(2009)
Tiwari, Brijesh; Valdramidis, Vasilis; O' Donnell, Colm; Muthukumarappan, Kasiviswanathan; Cullen, Patrick; Bourke, Paula
Abstract:
In this review, antimicrobials from a range of plant, animal, and microbial sources are reviewed 10 along with their potential applications in food systems. Chemical and biochemical antimicrobial 11 compounds derived from these natural sources and their activity against a range of pathogenic and 12 spoilage microorganisms pertinent to food, together with their effects on food organoleptic proper- 13 ties, are outlined. Factors influencing the antimicrobial activity of such agents are discussed 14 including extraction methods, molecular weight, and agent origin. These issues are considered in 15 conjunction with the latest developments in the quantification of the minimum inhibitory (and 16 noninhibitory) concentration of antimicrobials and/or their components. Natural antimicrobials can 17 be used alone or in combination with other novel preservation technologies to facilitate the 18 replacement of traditional approaches. Research priorities and future trends focusing on the impact ...
https://arrow.dit.ie/schfsehart/134
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Assessing Stress Responses to Atmospheric Cold Plasma Exposure Using Escherichia Coli Knock Out Mutants
(2016)
Han, Lu; Boehm, Daniela; Patil, Sonal; Cullen, Patrick; Bourke, Paula
Assessing Stress Responses to Atmospheric Cold Plasma Exposure Using Escherichia Coli Knock Out Mutants
(2016)
Han, Lu; Boehm, Daniela; Patil, Sonal; Cullen, Patrick; Bourke, Paula
Abstract:
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 determined. ΔrpoS strain showed higher microbial reduction and greater cell permeability than other mutants, while ΔoxyR only showed this effect after 5 min treatment. With increased post-treatment storage time, ΔsoxS and ΔsoxR had increased sensitivity and resistance, respectively. ΔdnaK cell suspensions had much higher ROS than other strains and showed increased sensitivity with 24 h pos...
https://arrow.dit.ie/schfsehart/208
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Assessing the Mechanism of Microbial Inactivation during Ozone Pocessing
(2011)
Patil, Sonal; Valdramidis, Vasilis; Karatzas, Kimon; Cullen, Patrick; Bourke, Paula
Assessing the Mechanism of Microbial Inactivation during Ozone Pocessing
(2011)
Patil, Sonal; Valdramidis, Vasilis; Karatzas, Kimon; Cullen, Patrick; Bourke, Paula
Abstract:
Ozone has numerous applications in food industry because of its advantages over traditional preservation techniques. Damage to cell membranes and cytoplasmic contents was proposed as involved in ozone inactivation but there is no available information concerning oxidative stress effect of ozone on regulated knockout genes and the protection or sensitivity of microbial mutants (lacking these genes) against ozone or ozone generated radicals. The aim of this work was to investigate the mechanism of action of ozone on microbial populations during the treatment of liquid food systems. E. coli BW25113 and its isogenic mutants in soxR, soxS, oxyR, rpoS, dnaK genes were treated with ozone at a previously optimized concentration of 6µg/mL for a period up to 4 min in a 100 mL bubble column. Ozone gas was generated using a corona discharge ozone generator. Oxygen was supplied via air cylinder and the flow rate (0.06 L/min) was controlled using a flow regulator. A significant effect of ozone ex...
https://arrow.dit.ie/schfsehart/131
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Assessing the Microbial Oxidative Stress of Ozone: Significant Role of the Oxidative Stress Proteins in the Survival of E. coli in Ozone Treatment
(2011)
Patil, Sonal; Valdramidis, Vasilis; Katratzas, A.; Cullen, Patrick; Bourke, Paula
Assessing the Microbial Oxidative Stress of Ozone: Significant Role of the Oxidative Stress Proteins in the Survival of E. coli in Ozone Treatment
(2011)
Patil, Sonal; Valdramidis, Vasilis; Katratzas, A.; Cullen, Patrick; Bourke, Paula
Abstract:
Aims: To investigate the effect of the oxidative stress of ozone on microbial inactivation, cell membrane integrity, membrane permeability and morphology changes of Escherichia coli during ozone treatment. Methods and Results: E. coli BW 25113 and its isogenic mutants in soxR, soxS, oxyR, rpoS, dnaK genes were treated with ozone at a concentration of 6 µg mL-1 for a period up to 4 min. A significant effect of ozone exposure on microbial inactivation was observed. After ozonation, minor effects on the cell membrane integrity and permeability were observed. Scanning Electron Microscopy (SEM) analysis showed slightly altered cell surface structure. Conclusions: The results of this study suggest that cell lysis was not the major mechanism of microbial inactivation. The deletion of oxidative stress-related genes resulted in increased susceptibility of E. coli cells to ozone treatment, implying that they play an important role for protection against the radicals produced by ozone. However...
https://arrow.dit.ie/schfsehart/127
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Atmospheric Cold Plasma Dissipation Efficiency of Agrochemicals on Blueberries
(2017)
Sarangapani, Chaitanya; O'Toole, Grainne; Bourke, Paula; Cullen, Patrick
Atmospheric Cold Plasma Dissipation Efficiency of Agrochemicals on Blueberries
(2017)
Sarangapani, Chaitanya; O'Toole, Grainne; Bourke, Paula; Cullen, Patrick
Abstract:
Cold plasma has emerged as a potential bio-decontamination technology for microbial and chemical risks associated with food products such as fruits and vegetables. This study investigated the efficacy of cold plasma treatment for the degradation of pesticides (boscalid and Imidacloprid) on blueberries in tandem with the need to retain critical quality attributes of a fresh high value berry product post treatment. An in-package high voltage dielectric barrier discharge plasma reactor was employed for this study. The degradation efficacy of pesticides after 80 kV and 5 min of cold plasma treatment were found to be 80.18% for boscalid and 75.62% for Imidacloprid. Total phenol and flavonoid contents of blueberries increased significantly for 1 min treated samples for all applied voltages. However, plasma treatment significantly decreased the ascorbic acid at longer plasma doses. There was no significant effect on physical parameters such as color while acceptable changes were observed i...
https://arrow.dit.ie/schfsehart/229
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Atmospheric Cold Plasma Inactivation of Escherichia Coli in Liquid Media Inside a Sealed Package
(2013)
Ziuzina, Dana; Patil, Sonal; Bourke, Paula; Keener, Kevin; Cullen, Patrick
Atmospheric Cold Plasma Inactivation of Escherichia Coli in Liquid Media Inside a Sealed Package
(2013)
Ziuzina, Dana; Patil, Sonal; Bourke, Paula; Keener, Kevin; Cullen, Patrick
Abstract:
Abstract Aims: The main objective of this study was to determine the inactivation efficacy of dielectric barrier discharge atmospheric cold plasma (DBD-ACP) generated inside a sealed package for Escherichia coli ATCC 25922. Methods and Results: A plasma discharge was generated between two circular aluminium electrodes at 40 kV. E. coli suspensions (10^7 CFU/ml) in either maximum recovery diluent (MRD) or phosphate buffered saline (PBS) were treated in a 96-well microtitre plate inside a sealed package. The effects of treatment time, post-treatment storage time, either direct or indirect samples exposure to the plasma discharge and suspension media were studied. Regardless of the media tested, 20 s of direct and 45 s of indirect plasma treatment resulted in complete bacterial inactivation (7 log CFU/ml). At the lower plasma treatment times (10–30 s) investigated, the effects of suspension media and mode of exposure on the inactivation efficacy were evident. The inactivation efficacy ...
https://arrow.dit.ie/schfsehart/121
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Atmospheric Cold Plasma Inactivation of Escherichia Coli, Salmonella Enterica Serovar Typhimurium and Listeria Monocytogenes Inoculated on Fresh Produce
(2014)
Ziuzina, Dana; Patil, Sonal; Cullen, Patrick; Keener, Kevin; Bourke, Paula
Atmospheric Cold Plasma Inactivation of Escherichia Coli, Salmonella Enterica Serovar Typhimurium and Listeria Monocytogenes Inoculated on Fresh Produce
(2014)
Ziuzina, Dana; Patil, Sonal; Cullen, Patrick; Keener, Kevin; Bourke, Paula
Abstract:
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 of Salmonella, E. coli and L. monocytogenes populations on tomato to undetectable levels from initial populations of 3.1, 6.3, and 6.7 log10 CFU/sample, respectively. However, an extended ACP treatment time was necessary to reduce bacterial populations attached on the more complex surface of s...
https://arrow.dit.ie/schfsehart/141
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Atmospheric Cold Plasma Interactions with Modified Atmosphere Packaging Inducer Gases for Safe Food Preservation.
(2016)
Han, Lu; Boehm, Daniela; Milosavljević, Vladimir; Amias, Ester; Cullen, Patrick; Bourke...
Atmospheric Cold Plasma Interactions with Modified Atmosphere Packaging Inducer Gases for Safe Food Preservation.
(2016)
Han, Lu; Boehm, Daniela; Milosavljević, Vladimir; Amias, Ester; Cullen, Patrick; Bourke, Paula
Abstract:
Diverse microbiological challenges and pervasive microbial resistance drive technological development in food processing, where increasing process complexity and consumer demand for less processed goods leads to strong demand for effective decontamination. Atmospheric cold plasma (ACP) has wide potential for decontamination application in the food sector. We investigated the effect of Modified Atmosphere Packaging (MAP) gas mixtures on reactive species generated, their efficacy and mechanism of inactivation against Escherichia coli, Listeria monocytogenes and Staphylococcus aureus. Oxygen levels in the applied working gas had positive interactive effects on ROS generation, in-package inactivation efficacy in conjunction with post-treatment storage time. Listeria populations were undetectable after 15s treatment with high Oxygen MAP mix using 24 h post-treatment storage time. However, RNS generation and effect was dependent on the nitrogen content but also on the presence of oxygen. ...
https://arrow.dit.ie/schfsehart/210
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Bacterial Inactivation by High Voltage Atmospheric Cold Plasma: Influence of Process Parameters and Effects on Cell Leakage and DNA
(2014)
Han, Lu; Patil, Sonal; Keener, Kevin M; Cullen, Patrick; Bourke, Paula
Bacterial Inactivation by High Voltage Atmospheric Cold Plasma: Influence of Process Parameters and Effects on Cell Leakage and DNA
(2014)
Han, Lu; Patil, Sonal; Keener, Kevin M; Cullen, Patrick; Bourke, Paula
Abstract:
Aims: This study investigated a range of atmospheric cold plasma (ACP) process parameters for bacterial inactivation with further investigation of selected parameters on cell membrane integrity and DNA damage. The effects of high voltage levels, mode of exposure, gas mixture and treatment time against Escherichia coli and Listeria monocytogenes were examined. Methods and Results: 108 CFU ml-1 E. coli ATCC 25922, E. coli NCTC 12900 and L. monocytogenes NCTC11994 were ACP treated in 10ml phosphate buffered saline (PBS). Working gas mixtures used were; Air (gas mix 1), 90% N2+10% O2 (gas mix 2) and 65% O2+30% CO2+5% N2 (gas mix 3). Greater reduction of viability was observed for all strains using higher voltage of 70 kVRMS, and with working gas mixtures with higher oxygen content in combination with direct exposure. Indirect ACP exposure for 30 s inactivated below detection level both E. coli strains. L. monocytogenes inactivation within 30 s was irrespective of the mode of exposure. L...
https://arrow.dit.ie/schfsehart/122
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Characterisation of Cold Plasma Treated Beef and Dairy Lipids Using Spectroscopic and Chromatographic Methods
(2017)
Sarangapani, Chaitanya; Dorran, David; Dunne, Julie; Bourke, Paula; Cullen, Patrick
Characterisation of Cold Plasma Treated Beef and Dairy Lipids Using Spectroscopic and Chromatographic Methods
(2017)
Sarangapani, Chaitanya; Dorran, David; Dunne, Julie; Bourke, Paula; Cullen, Patrick
Abstract:
The efficacy of cold plasma for inactivation of food-borne pathogens in foods is established. However, insights on cold plasma-food interactions in terms of quality effects, particularly for oils and fats, are sparse. This study evaluated plasma-induced lipid oxidation of model matrices, namely dairy and meat fats. Product characterisation was performed using FTIR, 1H NMR and chromatographic techniques. The oxidation of lipids by cold plasma followed the Criegee mechanism and typical oxidation products identified included ozonides, aldehydes (hexanal, pentenal, nonanal and nonenal) and carboxylic acids (9-oxononanoic acid, octanoic acid, nonanoic acid), along with hydroperoxides (9- and 13-hydroperoxy-octadecadienoylglycerol species). However, these oxidation products were only identified following extended treatment times of 30 min and were also a function of applied voltage level. Understanding cold plasma interactions with food lipids and the critical parameters governing lipid o...
https://arrow.dit.ie/schfsehart/227
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Cold Plasma Inactivation of Bacterial Biofilms and Reduction of Quorum Sensing Regulated Virulence Factors
(2015)
Ziuzina, Dana; Boehm, Daniela; Patil, Sonal; Cullen, Patrick; Bourke, Paula
Cold Plasma Inactivation of Bacterial Biofilms and Reduction of Quorum Sensing Regulated Virulence Factors
(2015)
Ziuzina, Dana; Boehm, Daniela; Patil, Sonal; Cullen, Patrick; Bourke, Paula
Abstract:
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 colony count and XTT assays, respectively. All samples were treated ‘inpack’ using sealed polypropylene containers with a high voltage dielectric barrier discharge ACP generated at 80 kV for 0, 60, 120 and 300 s and a post treatment storage time of 24 h. According to colony counts, ACP treatment for 60 s reduced populati...
https://arrow.dit.ie/schfsehart/199
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Cold Plasma Inactivation of Internalised Bacteria and Biofilms for Salmonella Enterica Serovar Typhimurium, Listeria Monocytogenes and Escherichia Coli
(2015)
Ziuzina, Dana; Han, Lu; Cullen, Patrick; Bourke, Paula
Cold Plasma Inactivation of Internalised Bacteria and Biofilms for Salmonella Enterica Serovar Typhimurium, Listeria Monocytogenes and Escherichia Coli
(2015)
Ziuzina, Dana; Han, Lu; Cullen, Patrick; Bourke, Paula
Abstract:
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 further incubated for 0, 24 and 48 h at either 4 °C or room temperature (~ 22 °C) in combination with light/dark photoperiod or at 4 °C under dark conditions. Inoculated samples were sealed inside a rigid polypropylene container and indirectly exposed (i.e. placed outside plasma discharge) to a high voltag...
https://arrow.dit.ie/schfsehart/155
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Controlling Microbial Safety Challenges of Meat Using High Voltage Atmospheric Cold Plasma
(2016)
Han, Lu; Ziuzina, Dana; Heslin, Caitlin Marie; Boehm, Daniela; Patange, Apurva; Millan-...
Controlling Microbial Safety Challenges of Meat Using High Voltage Atmospheric Cold Plasma
(2016)
Han, Lu; Ziuzina, Dana; Heslin, Caitlin Marie; Boehm, Daniela; Patange, Apurva; Millan-Sango, David; Valdramidis, Vasilis; Cullen, Patrick; Bourke, Paula
Abstract:
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 products. E. coli, L. monocytogenes and S. aureus in PBS were undetectable after 60 s of treatment at 80 kVRMS in air, while ACP treatment of the contaminated meat model required post treatment refrigeration to retain antimicrobial effect. The nutritive components in the meat model exerted a pro...
https://arrow.dit.ie/schfsehart/209
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Diagnostics of an O2–He RF Atmospheric Plasma Discharge by Spectral Emission
(2014)
Milosavljevic, Vladimir; Donegan, Mick; Cullen, Patrick; Dowling, Denis
Diagnostics of an O2–He RF Atmospheric Plasma Discharge by Spectral Emission
(2014)
Milosavljevic, Vladimir; Donegan, Mick; Cullen, Patrick; Dowling, Denis
Abstract:
In this paper optical emission spectroscopy (OES) is used as a Diagnostic technique for the measurement of atomic and molecular spectral emissions generated using a helium rf industrial atmospheric plasma jet system. The OES of neutral atomic spectral lines and molecular bands are investigated over a range of plasma process parameters.Wavelength resolve optical emission profiles suggest that the emission of helium’s spectral lines shows that the high energy electrons have a larger influence than helium metastables on the overall spectral emission. Furthermore, the experimental data indicates that the use of high helium flow rates, in any confined open air plasma discharge, limits thesignificance of air impurities, e.g., nitrogen, for the creation and sustainability of plasma discharges in helium–oxygen gas chemistry.
https://arrow.dit.ie/schfsehart/132
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Dielectric Barrier Discharge Atmospheric Cold Plasma for Inactivation of Pseudomonas aeruginosa Biofilms
(2014)
Ziuzina, Dana; Patil, Sonal; Cullen, Patrick; Boehm, Daniela; Bourke, Paula
Dielectric Barrier Discharge Atmospheric Cold Plasma for Inactivation of Pseudomonas aeruginosa Biofilms
(2014)
Ziuzina, Dana; Patil, Sonal; Cullen, Patrick; Boehm, Daniela; Bourke, Paula
Abstract:
In recent years, atmospheric cold plasma (ACP) has been widely investigated for potential application as an alternative decontamination technology in biomedical and healthcare sectors. In this study, the antimicrobial efficacy of ACP against Pseudomonas aeruginosa biofilms was investigated. The 48-h biofilms were treated inside sealed polypropylene containers with a high-voltage dielectric barrier discharge (DBD) ACP (80 kVRMS) and subsequently stored for 24 h at room temperature. Treatment for 60 s by either the direct or indirect mode of ACP exposure (inside or outside plasma discharge, respectively) reduced bacterial populations by an average of 5.4 log cycles from an initial 6.6 log10 CFU/mL. Increasing the treatment time from 60 s to 120 s and 300 s reduced biofilms to undetectable levels. According to XTT assay (a metabolic activity assay), an extended treatment time of 300 s was necessary to reduce metabolic activity of cells in biofilms by an average of 70%. Further investig...
https://arrow.dit.ie/schfsehart/150
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Effect of Ultrasonic Processing on Food Enzymes of Industrial Importance
(2010)
Bourke, Paula; Tiwari, Brijesh; O Donnell, Colm; Cullen, Patrick
Effect of Ultrasonic Processing on Food Enzymes of Industrial Importance
(2010)
Bourke, Paula; Tiwari, Brijesh; O Donnell, Colm; Cullen, Patrick
Abstract:
In the last decade power ultrasound has emerged as an alternative processing option to conventional thermal approaches for pasteurisation and sterilisation of food products. While sonication alone is not adequate for inactivation of various spoilage and harmful enzymes present in food, ultrasound in combination with mild heat treatment and/or pressure has shown potential for both enzyme and pathogen inactivation. Numerous studies have investigated ultrasound for inactivating enzymes such as pectinmethylesterase, polyphenoloxidases and peroxidases responsible for deterioration of fruit & vegetable juice and various enzymes pertinent to milk quality. The efficacy of ultrasound for the inactivation of enzymes in food is outlined in this review along with a description of the inactivation mechanism to elucidate the effect of ultrasound on important enzymes in fruit juices and dairy products.
https://arrow.dit.ie/schfsehart/129
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Estimating the Efficacy of Mild Heating Processes taking into Account Microbial Non-linearities: a Case Study on the Thermisation of a Food Simulant
(2011)
Valdramidis, Vasilis; Tiwari, Brijesh; Cullen, Patrick; Kondjoyan, Alain; Van Impe, Jan
Estimating the Efficacy of Mild Heating Processes taking into Account Microbial Non-linearities: a Case Study on the Thermisation of a Food Simulant
(2011)
Valdramidis, Vasilis; Tiwari, Brijesh; Cullen, Patrick; Kondjoyan, Alain; Van Impe, Jan
Abstract:
Traditional and novel approaches for the calculation of the heat treatment efficiency are compared in this work. The Mild Heat value (MH-value), an alternative approach to the commonly used sterilisation, pasteurisation and cook value (F, P, C–value), is calculated to estimate the efficiency of a mild heat process. MH-value is the time needed to achieve a predefined microbial reduction at a reference temperature and a known thermal resistant constant, z, for log-linear or specific types of non log-linear microbial inactivation kinetics. An illustrative example is given in which microbial inactivation data of Listeria innocua CLIP 20-595 are used for estimating the inactivation parameters under isothermal conditions of 58, 60, 63 and 66oC by the use of the log-linear and the Geeraerd et al., (2000) model. Thereafter, dynamic temperature profiles (targeting at 54 and 57 C) representing milk thermisation are exploited for illustrating the application of MH-value. Finally, the equivalen...
https://arrow.dit.ie/schfsehart/26
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Extrinsic Control Parameters for Ozone Inactivation of Escherichia Coli Using a Bubble Column
(2009)
Patil, Sonal; Cullen, Patrick; Cullen, Bridget; Frias, Jesus Maria; Bourke, Paula
Extrinsic Control Parameters for Ozone Inactivation of Escherichia Coli Using a Bubble Column
(2009)
Patil, Sonal; Cullen, Patrick; Cullen, Bridget; Frias, Jesus Maria; Bourke, Paula
Abstract:
Aims: To investigate the effect of extrinsic control parameters for ozone inactivation of E. coli in a bubble column. Methods and Results: Ozone inactivation of Escherichia coli ATCC 25922 in Tryptic Soya Broth was examined. The parameters studied included temperature (ambient, 20, 25 and 30°C), exposure time (up to 30 min), gas flow rate (0·03, 0·06, 0·12, 0·25, 0·5 and 0·75 l min−1) and concentration level (five different levels). The efficacy of ozone treatment was a function of the parameters investigated and optimum control parameters of flow rate (0·12 l min−1), temperature (ambient) and ozone concentration (75 μg ml−1) resulted in a td5 (time required to achieve 5 log reduction) of 20 min. Conclusions: Optimum control parameters of gas flow rate, ozone concentration and temperature are reported for E. coli inactivation within a bubble column. Significance and Impact of the Study: In 2001, the FDA approved use of ozone as a direct additive to food and in 2004, issued guideline...
https://arrow.dit.ie/schfsehart/5
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Ferric Chloride Assisted Plasma Pretreatment of Lignocellulose
(2017)
Ravindran, Rajeev; Sarangapani, Chaitanya; Jaiswal, Swarna; Cullen, Patrick; Jaiswal, Amit
Ferric Chloride Assisted Plasma Pretreatment of Lignocellulose
(2017)
Ravindran, Rajeev; Sarangapani, Chaitanya; Jaiswal, Swarna; Cullen, Patrick; Jaiswal, Amit
Abstract:
In this study, a novel pretreatment for spent coffee waste (SCW) has been proposed which combines two techniques viz. atmospheric air plasma and FeCl3 to create a superior pretreatment that involves Fenton chemistry. The pretreatment was optimised employing Taguchi Design of Experiments, and five parameters were taken into consideration viz. biomass loading, FeCl3 concentration, H2SO4 concentration, plasma discharge voltage and treatment time. The composition analysis of the pretreated SCW revealed substantial amounts of lignin removal, with a maximum for process conditions of 70kV for 2min in an acidic environment containing 1% H2SO4. FTIR, XRD and DSC were performed to characterise the samples. The pretreated SCW after enzymatic hydrolysis yielded 0.496g of reducing sugar/g of SCW. The hydrolysate was subjected to fermentation by S. cerevisiae and led to the production of 18.642g/l of ethanol with a fermentation efficiency of 74%, which was a two-fold increase in yield compared to...
https://arrow.dit.ie/schfsehart/239
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Hyperspectral Imaging for Non-Contact Analysis of Forensic Traces
(2012)
Cullen, Patrick; Edelman, G.; Van Leeuwen, T.; Aalders, M.; Gaston, E.
Hyperspectral Imaging for Non-Contact Analysis of Forensic Traces
(2012)
Cullen, Patrick; Edelman, G.; Van Leeuwen, T.; Aalders, M.; Gaston, E.
Abstract:
Hyperspectral imaging (HSI) integrates conventional imaging and spectroscopy, to obtain both spatial and spectral information from a specimen. This technique enables investigators to analyze the chemical composition of traces and simultaneously visualize their spatial distribution. HSI offers significant potential for the detection, visualization, identification and age estimation of forensic traces. The rapid, non-destructive and non-contact features of HSI mark its suitability as an analytical tool for forensic science. This paper provides an overview of the principles, instrumentation and analytical techniques involved in hyperspectral imaging. We describe recent advances in HSI technology motivating forensic science applications, e.g. the development of portable and fast image acquisition systems. Reported forensic science applications are reviewed. Challenges are addressed, such as the analysis of traces on backgrounds encountered in casework, concluded by a summary of possible...
https://arrow.dit.ie/schfsehart/97
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Hyperspectral Imaging for the Detection of Microbial Spoilage of Mushrooms
(2011)
Gaston, Edurne; Frias, Jesus Maria; Cullen, Patrick; O’Donnell, Colm; Gowen, Aoife
Hyperspectral Imaging for the Detection of Microbial Spoilage of Mushrooms
(2011)
Gaston, Edurne; Frias, Jesus Maria; Cullen, Patrick; O’Donnell, Colm; Gowen, Aoife
Abstract:
Brown blotch, caused by pathogenic Pseudomonas tolaasii, is the most problematic bacterial disease in Agaricus bisporus mushrooms; it reduces their consumer appeal in the market place, thus generating important economical losses worldwide. The mushroom industry is in need of fast and accurate evaluation methodologies to ensure that only high quality produce reaches the market. Hyperspectral imaging (HSI) is a non-destructive technique that combines imaging and spectroscopy to obtain spatial and spectral information from an object. The aim of this study was to investigate the potential of Vis-NIR HSI to identify microbiological damage in mushrooms and to discriminate it from mechanical damage. Hyperspectral images of mushrooms subjected to i) no treatment, ii) microbiological spoilage and iii) mechanical damage were taken during storage and spectra representing each of the classes were selected. Partial least squares- discriminant analysis (PLS-DA) was carried out in two steps: i) di...
https://arrow.dit.ie/schfsehcon/2
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In-Package Atmospheric Pressure Cold Plasma Treatment of Cherry Tomatoes
(2014)
Misra, N.; Keener, Kevin; Bourke, Paula; Mosnier, J; Cullen, Patrick
In-Package Atmospheric Pressure Cold Plasma Treatment of Cherry Tomatoes
(2014)
Misra, N.; Keener, Kevin; Bourke, Paula; Mosnier, J; Cullen, Patrick
Abstract:
Cold plasma is increasingly under research for decontamination of foods, especially fresh fruits and vegetables. The effect of cold plasma on food quality, however, remains under researched. This study investigates the effects of cold plasma generated within a sealed package from a dielectric barrier discharge on the physical quality parameters and respiration rates of cherry tomatoes. Respiration rates and weight loss were monitored continuously, while other parameters are reported at the end of storage period. Differences among weight loss, pH and firmness for control and treated cherry tomatoes were insignificant towards the end of storage life. Changes in respiration rates and colour of tomatoes were recorded as a function of treatment, which were not drastic. The results implicate that cold plasma could be employed as a means for decontamination of cherry tomatoes while retaining product quality.
https://arrow.dit.ie/schfsehart/142
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In-Package Atmospheric Pressure Cold Plasma Treatment of Strawberries
(2014)
Misra, N.; Bourke, Paula; Cullen, Patrick; Patil, Sonal
In-Package Atmospheric Pressure Cold Plasma Treatment of Strawberries
(2014)
Misra, N.; Bourke, Paula; Cullen, Patrick; Patil, Sonal
Abstract:
The ability to generate low temperature plasma at atmospheric pressure offers new opportunities to decontaminate biological materials, including fresh foods. In this study, strawberries were treated with atmospheric cold plasma (ACP), generated with a 60 kV dielectric barrier discharge (DBD) pulsed at 50 Hz, across a 40 mm electrode gap, generated inside a sealed package containing ambient air (42% relative humidity). The current-voltage characteristics revealed that the plasma operated in the filamentary regime. The background microflora (aerobic mesophillic bacteria, yeast and mould) of strawberries treated for 5 min was reduced by 2 log 10 within 24 h of post-ACP treatment. The respiration rate of ACP treated produce, measured by the closed system approach, showed no significant increase. The effect of ACP on strawberry colour and firmness was insignificant.
https://arrow.dit.ie/schfsehart/115
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In-package Nonthermal Plasma Degradation of Pesticides on Fresh Produce
(2014)
Misra, N.; Pankaj, Shashi; Walsh, Tony; O'Regan, Finbarr; Bourke, Paula; Cullen, P...
In-package Nonthermal Plasma Degradation of Pesticides on Fresh Produce
(2014)
Misra, N.; Pankaj, Shashi; Walsh, Tony; O'Regan, Finbarr; Bourke, Paula; Cullen, Patrick
Abstract:
In-package nonthermal plasma (NTP) technology is a novel technology for the decontamination of foods and biological materials. This study presents the first report on the potential of the technology for the degradation of pesticide residues. A cocktail of pesticides, namely Azoxystrobin, Cyprodinil, Fludioxonil and Pyriproxyfen was tested on strawberries. The concentrations of these pesticides were monitored in priori and post- plasma treatment using GC-MS/MS. An applied voltage and time dependent degradation of the pesticides was observed for treatment voltages of 60, 70 and 80 kV and treatment durations ranging from 1 to 5 min, followed by 24 h in-pack storage. The electrical characterisation revealed the operation of the discharge in a stable filamentary regime. The discharge was found to generate reactive oxygen and excited nitrogen species as observed by optical emission spectroscopy.
https://arrow.dit.ie/schfsehart/136
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Inactivation of Escherichia Coli by Ozone Treatment of Apple Juice at Different pH Levels
(2010)
Patil, Sonal; Valdramidis, Vasilis; Cullen, Patrick; Frias, Jesus Maria; Bourke, Paula
Inactivation of Escherichia Coli by Ozone Treatment of Apple Juice at Different pH Levels
(2010)
Patil, Sonal; Valdramidis, Vasilis; Cullen, Patrick; Frias, Jesus Maria; Bourke, Paula
Abstract:
This research investigated the efficacy of gaseous ozone for the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in orange juice. Orange juice inoculated with E. coli (106 CFU mL-1) as a challenge microorganism was treated with ozone at 75-78µg mL-1 for different time periods (0-18 min). The efficacy of ozone for inactivation of both strains of E. coli was evaluated as a function of different juice types: model orange juice, fresh unfiltered juice, juice without pulp, and juice filtered through 500mm or 1mm sieves. Fast inactivation rates for total reduction of E. coli were achieved in model orange juice (60 seconds) and in juice with low pulp content (6 min). However, in unfiltered juice inactivation was achieved after 15-18 min. This indicated that juice organic matter interferes with antibacterial activity of gaseous ozone. The effect of prior acid (pH 5.0) exposure of E. coli strains on the inactivation efficacy of ozone treatment was also investigated. There ...
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