Ursula Gonzales-barron - Academia.edu (original) (raw)
Papers by Ursula Gonzales-barron
Zenodo (CERN European Organization for Nuclear Research), Nov 20, 2006
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13th World Congress of Food Science & Technology, 2006
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Journal of Food Engineering, Feb 1, 2008
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Food Microbiology, Jun 1, 2011
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Microbial Risk Analysis, Dec 1, 2016
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Food Control, Aug 1, 2011
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Food Control, May 1, 2012
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Zenodo (CERN European Organization for Nuclear Research), Sep 27, 2005
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International Journal of Food Microbiology, 2010
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As part of a second-order model quantifying the risk of salmonellosis from consumption of fresh p... more As part of a second-order model quantifying the risk of salmonellosis from consumption of fresh pork sausage in Ireland, a separate sub-model was conducted to estimate the initial concentration of Salmonella Typhimurium in fresh pork sausage at retail using most probable number (MPN) results. This approach provided a more informed second-order distribution of CFU/g that would have been possible by the ordinary practice of fitting a distribution to the MPN/g.
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European Food Research and Technology, Feb 14, 2007
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Computers and Electronics in Agriculture, Dec 1, 2008
... To this aim, a longitudinal study was devised to observe the evolution of matching scores (ms... more ... To this aim, a longitudinal study was devised to observe the evolution of matching scores (ms) of lamb retinal images (n = 38) acquired from 1 to 22 weeks after birth. ... 2. Materials and methods. 2.1. Longitudinal study of lamb's retinal images. ...
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Journal of Food Engineering, May 1, 2006
... Image segmentation is the first step of image analysis which aims at either a description of ... more ... Image segmentation is the first step of image analysis which aims at either a description of an image or a classification. Hundreds of segmentation techniques are present in the literature and almost all are ad hoc in nature (Fu & Mui, 1981). ...
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The objective of this article was to compare four Poisson-gamma regression models to assess the e... more The objective of this article was to compare four Poisson-gamma regression models to assess the effect of chilling on the concentration of coliforms from beef carcasses. A total of 600 carcasses were sampled before and after chilling at eight large Irish abattoirs, and the total coliforms were determined. With a coded variable (pre-chill/post-chill) as treatment, and extracting the variability of batches nested in abattoirs, random-effects models confirmed that chilling had a decreasing effect on the overall recovery of coliforms. Furthermore, the expected coliforms concentrations on pre-chill and post-chill carcasses were estimated on a CFU/cm2 scale, as well as their between-batch variability. This study introduced an alternative conceptual framework that can find interesting applications in stochastic risk assessment and in the design of more efficient sampling plans.info:eu-repo/semantics/publishedVersio
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Foods
Listeria monocytogenes is a pathogen of considerable public health importance with a high case fa... more Listeria monocytogenes is a pathogen of considerable public health importance with a high case fatality. L. monocytogenes can grow at refrigeration temperatures and is of particular concern for ready-to-eat foods that require refrigeration. There is substantial interest in conducting and modeling shelf-life studies on L. monocytogenes, especially relating to storage temperature. Growth model parameters are generally estimated from constant-temperature growth experiments. Traditionally, first-order and second-order modeling (or primary and secondary) of growth data has been done sequentially. However, omnibus modeling, using a mixed-effects nonlinear regression approach, can model a full dataset covering all experimental conditions in one step. This study compared omnibus modeling to conventional sequential first-order/second-order modeling of growth data for five strains of L. monocytogenes. The omnibus model coupled a Huang primary model for growth with secondary models for growth ...
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Earlier research has shown that the survivability of Enterobacteriaceae (ENT) and L. monocytogene... more Earlier research has shown that the survivability of Enterobacteriaceae (ENT) and L. monocytogenes (LM) in a Portuguese fermented sausage (linguiça) decreases during the ripening stage, and that such inhibition arises from the adverse conditions caused by the competition with autochthonous lactic acid bacteria (LAB) and the progressively lower water activity and pH. The objective of this work was to mathematically characterise the competition or interactions between LAB, LM and ENT that takes place in fermenting linguiça during ripening.info:eu-repo/semantics/publishedVersio
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Whitepaper of The BioTrack Project: "Development of a protocol for biometric-based animal tr... more Whitepaper of The BioTrack Project: "Development of a protocol for biometric-based animal tracking and tracing". Biosystems Engineering, University College Dublin, Ireland.
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In modelling risk management strategies (i.e., with in-lot batch testing, statistical process con... more In modelling risk management strategies (i.e., with in-lot batch testing, statistical process control), two basic assumptions have been normally made: that the true concentration of microorganisms are log-normally distributed within a batch, and that the variance of the samples is the same for a little or highly contaminated lot. These assumptions were evaluated by characterisin g the between-batch and within-batch variability in microbial counts within a heterogeneous Poisson the oretical interpretation; this is a gamma or a logno rmal true or population distribution for the unknown microbial concentration and a Pois s n measurement distribution that produces a discrete Poisson-gamma or a Poisson -lognormal distribution of observed plate counts. Two variants of random-effects regressions based o n the Poisson-gamma (m,1/k) and the Poissonlognormal (μ,σ) models were fitted to two microbial data sets of TVC (high counts) and Escherichia coli (low counts) on pre-chill beef carcasses s...
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The new Poisson-gamma modelling framework for low b acterial counts has been used to characterise... more The new Poisson-gamma modelling framework for low b acterial counts has been used to characterise withi nbatch and between-batch variability in Enterobacteriaceae in pre-chill sheep carcasses using counts data from five abattoirs sampled on four different occas ion . The negative correlation between the mean and dispersion parameters of the within-batch true dist ribu ions (gamma) was accounted by a correlated ran omeffects model. Since no assumption of within-batch constant variance was followed, all probability estimations could be performed with confidence inte rvals arising from the variability in the within-ba tch spread given a certain within-batch mean. The model was used in the assessment of the actual performan ce of the process hygiene criterion set by EC 2073/2005, and estimated that only 0.93% (95% CI: 0-4.08%) of the batches of pre-chill sheep carcasses produced in Ir eland would be found to be above the m limit of 1.5 log CFU/cm (~88 CFU/cm) and no batches would be fou...
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Zenodo (CERN European Organization for Nuclear Research), Nov 20, 2006
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13th World Congress of Food Science & Technology, 2006
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Journal of Food Engineering, Feb 1, 2008
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Food Microbiology, Jun 1, 2011
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Microbial Risk Analysis, Dec 1, 2016
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Food Control, Aug 1, 2011
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Food Control, May 1, 2012
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Zenodo (CERN European Organization for Nuclear Research), Sep 27, 2005
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International Journal of Food Microbiology, 2010
Bookmarks Related papers MentionsView impact
As part of a second-order model quantifying the risk of salmonellosis from consumption of fresh p... more As part of a second-order model quantifying the risk of salmonellosis from consumption of fresh pork sausage in Ireland, a separate sub-model was conducted to estimate the initial concentration of Salmonella Typhimurium in fresh pork sausage at retail using most probable number (MPN) results. This approach provided a more informed second-order distribution of CFU/g that would have been possible by the ordinary practice of fitting a distribution to the MPN/g.
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European Food Research and Technology, Feb 14, 2007
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Computers and Electronics in Agriculture, Dec 1, 2008
... To this aim, a longitudinal study was devised to observe the evolution of matching scores (ms... more ... To this aim, a longitudinal study was devised to observe the evolution of matching scores (ms) of lamb retinal images (n = 38) acquired from 1 to 22 weeks after birth. ... 2. Materials and methods. 2.1. Longitudinal study of lamb's retinal images. ...
Bookmarks Related papers MentionsView impact
Journal of Food Engineering, May 1, 2006
... Image segmentation is the first step of image analysis which aims at either a description of ... more ... Image segmentation is the first step of image analysis which aims at either a description of an image or a classification. Hundreds of segmentation techniques are present in the literature and almost all are ad hoc in nature (Fu & Mui, 1981). ...
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The objective of this article was to compare four Poisson-gamma regression models to assess the e... more The objective of this article was to compare four Poisson-gamma regression models to assess the effect of chilling on the concentration of coliforms from beef carcasses. A total of 600 carcasses were sampled before and after chilling at eight large Irish abattoirs, and the total coliforms were determined. With a coded variable (pre-chill/post-chill) as treatment, and extracting the variability of batches nested in abattoirs, random-effects models confirmed that chilling had a decreasing effect on the overall recovery of coliforms. Furthermore, the expected coliforms concentrations on pre-chill and post-chill carcasses were estimated on a CFU/cm2 scale, as well as their between-batch variability. This study introduced an alternative conceptual framework that can find interesting applications in stochastic risk assessment and in the design of more efficient sampling plans.info:eu-repo/semantics/publishedVersio
Bookmarks Related papers MentionsView impact
Foods
Listeria monocytogenes is a pathogen of considerable public health importance with a high case fa... more Listeria monocytogenes is a pathogen of considerable public health importance with a high case fatality. L. monocytogenes can grow at refrigeration temperatures and is of particular concern for ready-to-eat foods that require refrigeration. There is substantial interest in conducting and modeling shelf-life studies on L. monocytogenes, especially relating to storage temperature. Growth model parameters are generally estimated from constant-temperature growth experiments. Traditionally, first-order and second-order modeling (or primary and secondary) of growth data has been done sequentially. However, omnibus modeling, using a mixed-effects nonlinear regression approach, can model a full dataset covering all experimental conditions in one step. This study compared omnibus modeling to conventional sequential first-order/second-order modeling of growth data for five strains of L. monocytogenes. The omnibus model coupled a Huang primary model for growth with secondary models for growth ...
Bookmarks Related papers MentionsView impact
Earlier research has shown that the survivability of Enterobacteriaceae (ENT) and L. monocytogene... more Earlier research has shown that the survivability of Enterobacteriaceae (ENT) and L. monocytogenes (LM) in a Portuguese fermented sausage (linguiça) decreases during the ripening stage, and that such inhibition arises from the adverse conditions caused by the competition with autochthonous lactic acid bacteria (LAB) and the progressively lower water activity and pH. The objective of this work was to mathematically characterise the competition or interactions between LAB, LM and ENT that takes place in fermenting linguiça during ripening.info:eu-repo/semantics/publishedVersio
Bookmarks Related papers MentionsView impact
Whitepaper of The BioTrack Project: "Development of a protocol for biometric-based animal tr... more Whitepaper of The BioTrack Project: "Development of a protocol for biometric-based animal tracking and tracing". Biosystems Engineering, University College Dublin, Ireland.
Bookmarks Related papers MentionsView impact
In modelling risk management strategies (i.e., with in-lot batch testing, statistical process con... more In modelling risk management strategies (i.e., with in-lot batch testing, statistical process control), two basic assumptions have been normally made: that the true concentration of microorganisms are log-normally distributed within a batch, and that the variance of the samples is the same for a little or highly contaminated lot. These assumptions were evaluated by characterisin g the between-batch and within-batch variability in microbial counts within a heterogeneous Poisson the oretical interpretation; this is a gamma or a logno rmal true or population distribution for the unknown microbial concentration and a Pois s n measurement distribution that produces a discrete Poisson-gamma or a Poisson -lognormal distribution of observed plate counts. Two variants of random-effects regressions based o n the Poisson-gamma (m,1/k) and the Poissonlognormal (μ,σ) models were fitted to two microbial data sets of TVC (high counts) and Escherichia coli (low counts) on pre-chill beef carcasses s...
Bookmarks Related papers MentionsView impact
The new Poisson-gamma modelling framework for low b acterial counts has been used to characterise... more The new Poisson-gamma modelling framework for low b acterial counts has been used to characterise withi nbatch and between-batch variability in Enterobacteriaceae in pre-chill sheep carcasses using counts data from five abattoirs sampled on four different occas ion . The negative correlation between the mean and dispersion parameters of the within-batch true dist ribu ions (gamma) was accounted by a correlated ran omeffects model. Since no assumption of within-batch constant variance was followed, all probability estimations could be performed with confidence inte rvals arising from the variability in the within-ba tch spread given a certain within-batch mean. The model was used in the assessment of the actual performan ce of the process hygiene criterion set by EC 2073/2005, and estimated that only 0.93% (95% CI: 0-4.08%) of the batches of pre-chill sheep carcasses produced in Ir eland would be found to be above the m limit of 1.5 log CFU/cm (~88 CFU/cm) and no batches would be fou...
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