Moorepark Food Research Center
Moorepark Food Research Center
Ntemiri A.,University College Cork |
Chonchuir F.N.,Moorepark Food Research Center |
O'Callaghan T.F.,Moorepark Food Research Center |
Stanton C.,University College Cork |
And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2017
The potential of milk-derived glycomacropeptide (GMP) and lactose for modulating the human gut microbiota of older people, in whom loss of diversity correlates with inferior health, was investigated. We used an in vitro batch fermentation (artificial colon model) to simulate colonic fermentation processes of two GMP products, i.e., a commercially available GMP concentrate and a semipurified GMP concentrate, and lactose. Faecal samples were collected from healthy and frail older people. Samples were analyzed by Illumina Miseq sequencing of rRNA gene amplicons. The commercial GMP preparation had a positive effect on the growth of Coprococcus and Clostridium cluster XIVb and sustained a higher faecal microbiota diversity compared to control substrates or lactose. Lactose fermentation promoted the growth of Proteobacteria including Escherichia/Shigella. This work provides an in-depth insight on the potential of GMP and lactose for modulating the gut microbiota and contributes more evidence confirming the prebiotic activity of GMP. © 2017 American Chemical Society.
Mathur H.,Moorepark Food Research Center |
Mathur H.,University College Cork |
Fallico V.,Moorepark Food Research Center |
O'Connor P.M.,Moorepark Food Research Center |
And 7 more authors.
Frontiers in Microbiology | Year: 2017
Thuricin CD is a two-component bacteriocin, consisting of the peptides Trna and Trnβ, and belongs to the newly designated sactibiotic subclass of bacteriocins. While it is clear from studies conducted thus far that it is a narrow-spectrum bacteriocin, requiring the synergistic activity of the two peptides, the precise mechanism of action of thuricin CD has not been elucidated. This study used a combination of flow cytometry and traditional culture-dependent assays to ascertain the effects of the thuricin CD peptides on the morphology, physiology and viability of sensitive Bacillus firmus DPC6349 cells. We show that both Trna and Trnβ are membrane-acting and cause a collapse of the membrane potential, which could not be reversed even under membrane-repolarizing conditions. Furthermore, the depolarizing action of thuricin CD is accompanied by reductions in cell size and granularity, producing a pattern of physiological alterations in DPC6349 cells similar to those triggered by the pore-forming single-component bacteriocin Nisin A, and two-component lacticin 3147. Taken together, these results lead us to postulate that the lytic activity of thuricin CD involves the insertion of thuricin CD peptides into the membrane of target cells leading to permeabilization due to pore formation and consequent flux of ions across the membrane, resulting in membrane depolarization and eventual cell death. © 2017 Mathur, Fallico, O'Connor, Rea, Cotter, Hill and Ross.
Armaforte E.,University College Cork |
Armaforte E.,University of Bologna |
Curran E.,University College Cork |
Huppertz T.,University College Cork |
And 10 more authors.
International Dairy Journal | Year: 2010
Understanding the differences between the protein system of human milk and bovine milk is critical in the development of infant formulae. In this study, the proteins of bovine milk and a bovine-based whey-dominant infant formula were compared with those of human milk for infants born prematurely (pre-term) or at full term (term). The protein distribution of infant formula differed significantly from that of either type of human milk. A proteomic comparison between pre-term and term human milk showed a reduction of levels of β-casein and αs-casein and appearance of additional products, corresponding to low molecular weight hydrolysis products of the caseins, in pre-term milk. Pre-term milk samples also had higher total nitrogen concentration and plasmin activity, consistent with the proteomic data. These results suggest the operation of a physiological mechanism that may adjust enzyme and/or protein expression to modify protein digestibility, and may facilitate design of infant formulae, closer to maternal milk, particularly for premature infants. © 2010 Elsevier Ltd.
Marc Y.L.,UK Institute of Food Research |
Skandamis P.N.,Agricultural University of Athens |
Belessi C.I.A.,Agricultural University of Athens |
Merkouri S.I.,Agricultural University of Athens |
And 6 more authors.
Applied and Environmental Microbiology | Year: 2010
This study aims to model the effects of acid and osmotic shifts on theintermediate lag time of Listeria monocytogenes at 10°C in a growth medium. The model was developed from data from a previous study (C. I. A. Belessi, Y. Le Marc, S. I. Merkouri, A. S. Gounadaki, S. Schvartzman, K. Jordan, E. H. Drosinos, and P. N. Skandamis, submitted for publication) on the effects of osmotic and pH shifts on the kinetics of L. monocytogenes. The predictive ability of the model was assessed on new data in milk. The effects of shifts were modeled through the dependence of the parameter h0 ("work to be done"prior to growth) induced on the magnitude of the shift and/or the stringency of the new environmental conditions. For shifts acrossthe boundary, the lag time was found to be affected by the length of time fo which the microorganisms were kept at growth-inhibiting conditions. The predicted concentrations of L. monocytogenes in milk were overestimated whenthe effects of this shift were not taken into account. Th model proved to be suitable to describe the effects of osmotic and acid shifts observed bothwithin the growth domain and across the growth boundaries of L. monocytogenes. © 2010 American Society for Microbiology.
Kuchta-Noctor A.M.,Dublin City University |
Murray B.A.,Moorepark Food Research Center |
Stanton C.,Moorepark Food Research Center |
Devery R.,Dublin City University |
Kelly P.M.,Moorepark Food Research Center
Nutrition and Cancer | Year: 2016
Buttermilk is a rich source of milk fat globule membrane (MFGM) fragments assembled from bioactive polar lipids and proteins that originate from bovine mammary epithelial cells. The objective of this study was to examine growth-modulatory effects of experimental buttermilks varying in sphingolipid and phospholipid composition on a colon cancer cell line of human origin. Buttermilks were prepared from washed and unwashed cream using gravity or centrifugation. Compositional analysis showed that sphingomyelin (SM) (10.4–29.5%) and lactosylceramide (LacCer) (1.2–44.3%) were the predominant sphingolipids detected. Experimental samples inhibited in vitro growth of SW480 colon cancer cells in a dose-dependent manner. Antiproliferative activity was selective toward cancer cells. A fraction enriched in LacCer (44.3%), obtained by microfiltration induced caspase-independent cell death as evident by phosphatidylserine externalization, increased percentage of degraded DNA, and loss of mitochondrial membrane potential in SW480 cells. This fraction downregulated growth-signaling pathways mediated by β-catenin, phosphorylated Akt (serine/threonine-specific protein kinase), ERK1/2 (extracellular signal–regulated kinase), and c-myc. This study is to our knowledge the first to screen buttermilk samples that vary in polar lipid composition for antiproliferative activity in vitro. © 2016 Taylor & Francis Group, LLC
O'Beirne D.,University of Limerick |
Gleeson E.,University of Limerick |
Auty M.,Moorepark Food Research Center |
Jordan K.,Moorepark Food Research Center
Food Control | Year: 2014
The effects of severity of slicing and peeling, and of storage atmosphere and temperature on the survival of Escherichia coli O157:H7 at and below the cut surfaces of fresh-cut carrot discs were determined. Slicing with a blunt machine blade enhanced penetration of E.coli O157:H7 and its subsequent survival during storage at 8°C. Significantly (P<0.05) higher numbers of cells (0.5logCFUg-1) penetrated deeper (475-500, 725-750 and 975-1000μm) into carrot tissue sliced with a blunt machine blade compared to those sliced with a razor blade. Counts on Day 3 and Day 5 of storage remained higher in carrot tissue sliced with a blunt machine blade at all depths sampled. There were no significant effects of peeling method on penetration and survival. Storage of carrot slices in sub-optimal atmospheres (20%CO2/1%O2 resulted in increased survival of cells at the surface and within the tissue compared to storage in more optimal atmospheres (5% CO2/3% O2). Increasing storage temperature from 4 to 10°C resulted in growth of E.coli O157:H7 at all sample depths. For all experiments, E.coli O157:H7 cells colonising the surface generally survived better than cells that penetrated into the tissue. The data are relevant to improving microbial safety in the fresh-cut sector by demonstrating that cutting with sharp blades (e.g. during harvesting and processing) reduces the depth of potential contamination by E.coli O157:H7. This may also have implications for more efficient anti-microbial dipping and reduced pathogen survival during storage. © 2013 Elsevier Ltd.
Mateo M.J.,Moorepark Food Research Center |
O'Callaghan D.J.,Moorepark Food Research Center |
Everard C.D.,Moorepark Food Research Center |
Castillo M.,Moorepark Food Research Center |
And 2 more authors.
Food Research International | Year: 2010
This study focuses on the prediction ability of several optical sensing techniques, namely single wavelength (980 nm), broad spectrum and colour coordinates, for monitoring key syneresis indices during cheese manufacture. Three series of trials were undertaken in which milk gel was cut and stirred in an 11 L cheese vat. Three full factorial designs were employed with experimental variables consisting of: (i) three curd stirring speeds and three cutting programmes; (ii) three milk fat levels and three gel firmness levels at cutting; and (iii) two milk protein levels and three fat:protein ratio levels in the respective experiments. Models developed using the range of techniques investigated demonstrated that an on-line visible-NIR sensor was able to predict curd moisture content. However, the broad spectrum technique was the only one capable of predicting whey solids. The findings show that on-line sensing techniques can significantly improve the control of curd moisture content in cheese factories, across the range of experimental variables used in this study. © 2009 Elsevier Ltd.