• Molecular determinants of surface colonisation in diarrhoeagenic Escherichia coli (DEC): from bacterial adhesion to biofilm formation

      Ageorges, Valentin; Monteiro, Ricardo; Leroy, Sabine; Burgess, Catherine M; Pizza, Mariagrazia; Chaucheyras-durand, Frédérique; Desvaux, Mickaël; INRAE; European Union; RA-FEDER-Bpifrance; et al. (Oxford University Press (OUP), 2020-04-02)
      Escherichia coli is primarily known as a commensal colonising the gastrointestinal tract of infants very early in life but some strains being responsible for diarrhoea, which can be especially severe in young children. Intestinal pathogenic E. coli include six pathotypes of diarrhoeagenic E. coli (DEC), namely, the (i) enterotoxigenic E. coli, (ii) enteroaggregative E. coli, (iii) enteropathogenic E. coli, (iv) enterohemorragic E. coli, (v) enteroinvasive E. coli and (vi) diffusely adherent E. coli. Prior to human infection, DEC can be found in natural environments, animal reservoirs, food processing environments and contaminated food matrices. From an ecophysiological point of view, DEC thus deal with very different biotopes and biocoenoses all along the food chain. In this context, this review focuses on the wide range of surface molecular determinants acting as surface colonisation factors (SCFs) in DEC. In the first instance, SCFs can be broadly discriminated into (i) extracellular polysaccharides, (ii) extracellular DNA and (iii) surface proteins. Surface proteins constitute the most diverse group of SCFs broadly discriminated into (i) monomeric SCFs, such as autotransporter (AT) adhesins, inverted ATs, heat-resistant agglutinins or some moonlighting proteins, (ii) oligomeric SCFs, namely, the trimeric ATs and (iii) supramolecular SCFs, including flagella and numerous pili, e.g. the injectisome, type 4 pili, curli chaperone-usher pili or conjugative pili. This review also details the gene regulatory network of these numerous SCFs at the various stages as it occurs from pre-transcriptional to post-translocational levels, which remains to be fully elucidated in many cases.
    • Molecular Epidemiology of Campylobacter Isolates from Poultry Production Units in Southern Ireland

      O'Mahony, Emer; Buckley, James F.; Bolton, Declan J.; Whyte, Paul; Fanning, Seamus; Safefood; 04-RESR-04 (PLOS, 2011-12-06)
      This study aimed to identify the sources and routes of transmission of Campylobacter in intensively reared poultry farms in the Republic of Ireland. Breeder flocks and their corresponding broilers housed in three growing facilities were screened for the presence of Campylobacter species from November 2006 through September 2007. All breeder flocks tested positive for Campylobacter species (with C. jejuni and C. coli being identified). Similarly, all broiler flocks also tested positive for Campylobacter by the end of the rearing period. Faecal and environmental samples were analyzed at regular intervals throughout the rearing period of each broiler flock. Campylobacter was not detected in the disinfected house, or in one-day old broiler chicks. Campylobacter jejuni was isolated from environmental samples including air, water puddles, adjacent broiler flocks and soil. A representative subset of isolates from each farm was selected for further characterization using flaA-SVR sub-typing and multi-locus sequence typing (MLST) to determine if same-species isolates from different sources were indistinguishable or not. Results obtained suggest that no evidence of vertical transmission existed and that adequate cleaning/disinfection of broiler houses contributed to the prevention of carryover and cross-contamination. Nonetheless, the environment appears to be a potential source of Campylobacter. The population structure of Campylobacter isolates from broiler farms in Southern Ireland was diverse and weakly clonal.
    • Monitoring molecular composition and digestibility of ripened bresaola through a combined foodomics approach

      Picone, Gianfranco; De Noni, Ivano; Ferranti, Pasquale; Nicolai, Maria Adalgisa; Alamprese, Cristina; Trimigno, Alessia; Brodkorb, Andre; Portmann, Reto; Pihlanto, Anne; El, Sedef Nehir; et al. (Elsevier, 2018-11-14)
      In this work, the effects of maturation time and simulated gastrointestinal digestion on the molecular and peptide profiles of “Bresaola Valtellina” were assessed through the foodomics approach, in this case food proteomics and peptidomics combined to other analytical and biological assays, aiming at depicting a holistic food quality. Human digestion of this Italian cured meat product was simulated using an in vitro static protocol and the degree of proteolysis and the in vitro bioactivity of the soluble free compounds in the digestates were evaluated by biochemical assays, e.g. SDS-PAGE, size exclusion HPLC, HPLC/MS, 1H NMR, enzymatic and antioxidant activities. The obtained results demonstrated that in vitro gastrointestinal digestion contributed to a considerable release of myofibrillar proteins by the muscle tissue. Data from SDS-PAGE, peptidomic and size exclusion HPLC assays showed that the in vitro digestion largely degraded proteins of muscle tissue to peptides smaller than 250 Da. The released peptides were likely responsible for the inhibitory activity on amylolytic enzymes and for the antioxidant properties elicited by the gastric digestates of Bresaola. Overall, the results demonstrated the negligible role of ripening in making meat proteins more bioaccessible, whereas they confirmed the highly in vitro digestibility of meat proteins from Bresaola. This study represents a new approach merging proteomics and foodomics to evaluate the effect of ripening and in vitro digestion on the bioactivity and bioaccessibility of proteins and peptides of meat products.
    • Monitoring post mortem changes in porcine muscle through 2-D DIGE proteome analysis of Longissimus muscle exudate

      Di Luca, Alessio; Elia, Giuliano; Mullen, Anne Maria; Hamill, Ruth M; Department of Agriculture, Food and the Marine, Ireland; 06RDNUIG470 (Biomed Central, 20/03/2013)
      Background: Meat quality is a complex trait influenced by a range of factors with post mortem biochemical processes highly influential in defining ultimate quality. High resolution two-dimensional DIfference Gel Electrophoresis (2-D DIGE) and Western blot were applied to study the influence of post mortem meat ageing on the proteome of pork muscle. Exudate collected from the muscle following centrifugation was analysed at three timepoints representing a seven day meat ageing period. Results: The intensity of 136 spots varied significantly (p < 0.05) across this post mortem period and 40 spots were identified using mass spectrometry. The main functional categories represented were metabolic proteins, stress-related proteins, transport and structural proteins. Metabolic and structural proteins were generally observed to increase in abundance post mortem and many likely represent the accumulation of the degradation products of proteolytic enzyme activity. In contrast, stress-related proteins broadly decreased in abundance across the ageing period. Stress response proteins have protective roles in maintaining cellular integrity and a decline in their abundance over time may correlate with a reduction in cellular integrity and the onset of meat ageing. Since cellular conditions alter with muscle ageing, changes in solubility may also contribute to observed abundance profiles. Conclusions: Muscle exudate provided valuable information about the pathways and processes underlying the post mortem ageing period, highlighting the importance of post mortem modification of proteins and their interaction for the development of meat quality traits.
    • Multi-scale structure, pasting and digestibility of adlay (Coixlachryma-jobi L.) seed starch

      Chen, Jicheng; Chen, Yazhen; Ge, Huifang; Wu, Chunhua; Pang, Jie; Miao, Song; Marine High-Tech Industry in Fujian Province; Fujian Natural Science Foundation; Fujian Agriculture and Forestry University; [2004] 03; et al. (Elsevier BV, 2018-11-28)
      The hierarchical structure, pasting and digestibility of adlay seed starch (ASS) were investigated compared with maize starch (MS) and potato starch (PS). ASS exhibited round or polyglonal morphology with apparent pores/channels on the surface. It had a lower amylose content, a looser and more heterogeneous C-type crystalline structure, a higher crystallinity, and a thinner crystalline lamellae. Accordingly, ASS showed a higher slowly digestible starch content combined with less resistant starch fractions, and a decreased pasting temperature, a weakened tendency to retrogradation and an increased pasting stability compared with those of MS and PS. The ASS structure-functionality relationship indicated that the amylose content, double helical orders, crystalline lamellar structure, and surface pinholes should be responsible for ASS specific functionalities including pasting behaviors and in vitro digestibility. ASS showed potential applications in health-promoting foods which required low rearrangement during storage and sustainable energy-providing starch fractions.
    • Myosin-cross-reactive antigen (MCRA) protein from Bifidobacterium breve is a FAD-dependent fatty acid hydratase which has a function in stress protection

      Rosberg-Cody, Eva; Liavonchanka, Alena; Gobel, Cornelia; Ross, R Paul; O'Sullivan, Orla; Fitzgerald, Gerald F; Feussner, Ivo; Stanton, Catherine (Biomed Central, 17/02/2011)
      Background The aim of this study was to determine the catalytic activity and physiological role of myosin-cross-reactive antigen (MCRA) from Bifidobacterium breve NCIMB 702258. MCRA from B. breve NCIMB 702258 was cloned, sequenced and expressed in heterologous hosts (Lactococcus and Corynebacterium) and the recombinant proteins assessed for enzymatic activity against fatty acid substrates. Results MCRA catalysed the conversion of palmitoleic, oleic and linoleic acids to the corresponding 10-hydroxy fatty acids, but shorter chain fatty acids were not used as substrates, while the presence of trans-double bonds and double bonds beyond the position C12 abolished hydratase activity. The hydroxy fatty acids produced were not metabolised further. We also found that heterologous Lactococcus and Corynebacterium expressing MCRA accumulated increasing amounts of 10-HOA and 10-HOE in the culture medium. Furthermore, the heterologous cultures exhibited less sensitivity to heat and solvent stresses compared to corresponding controls. Conclusions MCRA protein in B. breve can be classified as a FAD-containing double bond hydratase, within the carbon-oxygen lyase family, which may be catalysing the first step in conjugated linoleic acid (CLA) production, and this protein has an additional function in bacterial stress protection.
    • N-3 Polyunsaturated Fatty Acids (PUFAs) Reverse the Impact of Early-Life Stress on the Gut Microbiota

      Pusceddu, Matteo M; El Aidy, Sahar; Crispie, Fiona; O'Sullivan, Orla; Cotter, Paul D.; Stanton, Catherine; Kelly, Philip M.; Cryan, John F.; Dinan, Timothy G.; Department of Agriculture, Food and the Marine; et al. (PLOS, 01/10/2015)
      Background Early life stress is a risk factor for many psychiatric disorders ranging from depression to anxiety. Stress, especially during early life, can induce dysbiosis in the gut microbiota, the key modulators of the bidirectional signalling pathways in the gut-brain axis that underline several neurodevelopmental and psychiatric disorders. Despite their critical role in the development and function of the central nervous system, the effect of n-3 polyunsaturated fatty acids (n-3 PUFAs) on the regulation of gut-microbiota in early-life stress has not been explored. Methods and Results Here, we show that long-term supplementation of eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) (80% EPA, 20% DHA) n-3 PUFAs mixture could restore the disturbed gut-microbiota composition of maternally separated (MS) female rats. Sprague-Dawley female rats were subjected to an early-life stress, maternal separation procedure from postnatal days 2 to 12. Non-separated (NS) and MS rats were administered saline, EPA/DHA 0.4 g/kg/day or EPA/DHA 1 g/kg/day, respectively. Analysis of the gut microbiota in adult rats revealed that EPA/DHA changes composition in the MS, and to a lesser extent the NS rats, and was associated with attenuation of the corticosterone response to acute stress. Conclusions In conclusion, EPA/DHA intervention alters the gut microbiota composition of both neurodevelopmentally normal and early-life stressed animals. This study offers insights into the interaction between n-3 PUFAs and gut microbes, which may play an important role in advancing our understanding of disorders of mood and cognitive functioning, such as anxiety and depression.
    • Nano- and microstructural evolution of alginate beads in simulated gastrointestinal fluids. Impact of M/G ratio, molecular weight and pH

      Gómez-Mascaraque, Laura G.; Martínez-Sanz, Marta; Hogan, S. A.; López-Rubio, Amparo; Brodkorb, André; Department of Agriculture, Food and the Marine; 15F 702 (Elsevier, 2019-07-26)
      Alginate microcapsules were prepared using three different alginate grades and incubated under simulated digestion conditions. Their micro- and nanostructural changes were studied using microscopy, laser diffraction and small angle X-ray scattering. Both the molecular weight and M/G ratio affected the size and nanostructural features of the capsules, but the changes in gastrointestinal conditions were mainly determined by the latter. All microcapsules swelled slightly in simulated gastric fluid (pH = 3) and swelled further in simulated intestinal fluid (pH = 7), particularly those with high mannuronic acid (M) contents. While high guluronic acid (G) beads maintained the nanostructural features characteristic of alginate gels (junction zones) in both media, these were rapidly disrupted in the M-rich capsules. Decreasing the pH of the gastric phase from 3 to 2 had dramatic structural impacts, resulting in a greater integrity of the microcapsules, thus highlighting the importance of the selected digestion protocol for rational microcapsule design.
    • A nationwide surveillance study on E.coli 0157:H7 and enterobacteriaceae in Irish minced beef products

      Duffy, Geraldine; Cagney, Claire; Crowley, Helen; Sheridan, James J.; Food Safety Authority of Ireland (Teagasc, 2003-04)
      A surveillance study on prevalence and numbers of E . coli O157: H7 in minced beef (unpackaged or packaged) and beefburgers (frozen, fresh and unpackaged or packaged) was carried out over a period of 12 months in the Republic of Ireland. A total of 1533 products were tested with approximately 15 products collected from each of the 26 counties every 3 months. Mince and beefburgers were collected from both supermarkets and butcher shop outlets. A standard analysis was conducted by sample enrichment, IMS extraction and plating onto SMAC agar with confirmation by PCR. The results showed that 43 retail beef products (2.8 %) contained E .coli O157:H7. The number of E .coli O157: H7 in 21 of these samples ranged from log100.51 - 4.03 cfu g-1 ( i.e. 3 to 10,700 bacteria per gram) while in the remaining 22 the pathogen was detectable by enrichment only. There was a seasonal effect observed with 33 of 43 positive samples detected in January (n = 8), April /May(n=20) and August (n=5) and the remaining 10 positive samples detected over the other 8 months. Of the beef products testing positive, 32 were purchased from supermarkets and 11 from butcher shops. E .coli O157:H7 was recovered from 2.8% (13 / 457) of fresh packaged mince and from 1.88 % (3 / 160) of fresh unpackaged burgers purchased from butcher shops. Of the 43 isolates recovered, 41 contained the virulence genes v t1, v t2, E aeA and H lyA while the remaining 2 isolates contained only one of the vtproducing genes (v t1or v t2).
    • Near infra-red spectroscopy in the food industry: a tool for quality management

      Downey, Gerard (Teagasc, 1999-03)
      Near infrared (NIR) spectroscopy is a rapid, non-destructive analytical technique which has been used in the food and agriculture industries for almost 20 years. Ireland was one of the first countries in the world to adopt this method for national trading purposes and the grain trade has used it for off-farm and in-process analysis since 1981. However, other sectors have been slower to realise its potential and as part of a process of demonstrating the role which it may play in monitoring quality in a range of food industry applications, a programme of research and development has been on-going within Teagasc and its predecessor An Foras Talúntais.
    • Near Infrared Spectroscopy in the Food Industry: A Tool of Quality Management.

      Downey, Gerard (Teagasc, 01/03/1999)
      Near infrared (NIR) spectroscopy is a rapid, non-destructive analytical technique which has been used in the food and agriculture industries for almost 20 years. Ireland was one of the first countries in the world to adopt this method for national trading purposes and the grain trade has used it for off-farm and in-process analysis since 1981. However, other sectors have been slower to realise its potential and as part of a process of demonstrating the role which it may play in monitoring quality in a range of food industry applications, a programme of research and development has been on-going within Teagasc and its predecessor An Foras Talúntais. NIR spectroscopy provides the food processor with information. This information may describe how much of a given substance is present in a mixture or how the overall quality of the substance compares to a reference material e.g. a previous batch of raw material, finished goods or a competitor’s product. This report provides some examples of precompetitive R&D on representative qualitative and quantitative problems in a range of foods and food ingredients. The use of NIR spectra collected within 24 hours of slaughter to predict beef tenderness 14 days later shows considerable promise. Non-destructive monitoring of flesh composition in farmed salmon has paved the way for the efficient use of expensive feed materials while the content of each species in binary mixtures of minced beef and lamb has been accurate enough to suggest the use of NIR spectroscopy as a rapid screening tool by regulatory agencies, food processors and retailers. Classification of a range of food ingredients (including skim milk powder and flour) into one of a number of functionally-discrete categories has been successfully achieved with levels of accuracy high enough to warrant immediate industry utilisation i.e. greater than 90% for skim milk powders and 97% in the case of flour. Species confirmation in a number of raw minced meats (chicken, turkey, pork, beef and lamb) has been achieved with over 90% accuracy in feasibility studies. Calibrations transferred from one NIR instrument to another lose accuracy because of differences in instrument construction, sample presentation and other factors. A research effort has recently been applied to this problem of transferability and results are available for both scanning and fixed filter instruments. The success achieved opens the way for using NIR results obtained in different companies or countries as an uncontested basis for trade.
    • New Insights into Cell Encapsulation and the Role of Proteins During Flow Cytometry

      Doherty, Sinead B.; Brodkorb, Andre; Irish National Development Plan 2007 to 2013; Irish Dairy Levy Research Trust; Science Foundation Ireland; NU518 (Intech, 13/06/2012)
      Modern approaches to science tend to follow divergent paths. On one hand, instruments and technologies are developed to capture as much information as possible with the need for complex data analysis to identify problematic issues. On the other hand, formulation focused, minimalistic approaches that gather only the most pertinent data for specific questions also represent a powerful methodology. This chapter will provide many examples of the latter by integrating Flow Cytometry (FACS - Fluorescence-Activated Cell Sorting) technology with high throughput screening (HTS) of encapsulation systems with extensive utility of one-dimensional (1-D) imaging for protein localisation. In this regard, less information is acquired from each cell, data files will be more manageable, easier to analyse and throughput screening will be significantly enhanced beyond traditional HTS analysis, irrespective of the protein concentration present in the background or delivery media.
    • New Product Development Opportunities for Irish Companies in the British Cheese Market

      Cowan, Cathal; Downey, Gerard (Teagasc, 01/11/2008)
      The primary objective of this research was to identify innovative cheese concepts appropriate for UK consumers and suitable for Irish industry to manufacture. It also aimed to identify personal, situational and market factors that influence consumers when purchasing cheese. This research study used existing market literature, in-depth interviews and consumer focus groups.
    • New product development opportunities for Irish companies in the British cheese market

      Cowan, Cathal; Downey, Gerard; Irish Dairy Levy Research Trust (Teagasc, 2008-11)
      The primary objective of this research was to identify innovative cheese concepts appropriate for UK consumers and suitable for Irish industry to manufacture. It also aimed to identify personal, situational and market factors that influence consumers when purchasing cheese. This research study used existing market literature, in-depth interviews and consumer focus groups.
    • A new sensitive method for the simultaneous chromatographic separation and tandem mass spectrometry detection of anticoccidials, including highly polar compounds, in environmental waters

      Mooney, D; Coxon, C; Richards, K.G.; Gill, L.W.; Mellander, P.-E.; Danaher, M; Science Foundation Ireland; European Union; Teagasc Walsh Fellowship Programme; Irish Centre for Research in Applied Geosciences (iCRAG); et al. (Elsevier, 2020-01-10)
      A sensitive and selective method was developed and validated for the determination of 26 anticoccidial compounds (six ionophores and twenty chemical coccidiostats) in surface and groundwater samples at parts-per-quadrillion (pg L−1) to parts-per-trillion (ng L−1) levels by ultra-high performance liquid chromatography with tandem mass spectrometry detection (UHPLC–MS/MS). A range of different analytical columns and mobile phase compositions were evaluated to enhance selectivity and retention of a number of highly polar and basic anticoccidials along with other non-polar coccidiostats. A combined separation, including these problematic polar compounds, was achieved on a phenyl-hexyl column, by binary gradient elution with water/acetonitrile using ammonium formate and formic acid as additives. The anticoccidial residues were extracted from raw, unfiltered, water samples (250 mL) using polymeric divinylbenzene solid phase extraction (SPE) cartridges, with subsequent elution (methanol:acetonitrile:ethyl acetate, 40:40:20, v/v) and concentration prior to determination. The method recovery (at a concentration representative of realistic expected environmental water concentrations based on literature review) ranged from 81% to 105%. The method was successfully validated for 26 anticoccidials, at four concentration levels, in accordance to Commission Decision 2002/657/EC and SANTE/11813/2017 guidelines. Trueness and precision, under within-laboratory reproducibility conditions, ranged from 88% to 111% and 0.9% to 10.3% respectively.
    • New technologies in the manufacture of low fat meat products

      Allen, Paul; Dreeling, Niamh; Desmond, Eoin; Hughes, Eimear; Mullen, Anne Maria; Troy, Declan J. (Teagasc, 1999-02)
      The objective of this project was to provide a sound scientific basis for the development of low fat meat products. The emphasis was placed on identifying the barriers to producing high quality, low fat meat products and providing a knowledge base for manufacturers to overcome these, rather than actually developing new products. Each partner had specific tasks and worked with traditional products of their country. A wide range of products was thereby studied including comminuted, emulsion, cured and dried fermented, so that the results are widely applicable.
    • New Weapons to Fight Old Enemies: Novel Strategies for the (Bio)control of Bacterial Biofilms in the Food Industry

      Coughlan, Laura M.; Cotter, Paul D.; Hill, Colin; Alvarez-Ordonez, Avelino; Science Foundation Ireland; 13/SIRG/2157 (Frontiers, 18/10/2016)
      Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc.), although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses the problems associated with bacterial biofilms in the food industry and summarizes the recent strategies explored to inhibit biofilm formation, with special focus on those targeting quorum sensing.
    • Nisin in Combination with Cinnamaldehyde and EDTA to Control Growth of Escherichia coli Strains of Swine Origin

      Field, Des; Baghou, Inès; Rea, Mary C.; Gardiner, Gillian E.; Ross, R. Paul; Hill, Colin; Science Foundation Ireland; SFI/12/RC/2273; 10/IN.1/B3027 (MDPI AG, 2017-12-12)
      Post-weaning diarrhoea (PWD) due to enterotoxigenic Escherichia coli (ETEC) is an economically important disease in pig production worldwide. Although antibiotics have contributed significantly to mitigate the economic losses caused by PWD, there is major concern over the increased incidence of antimicrobial resistance among bacteria isolated from pigs. Consequently, suitable alternatives that are safe and effective are urgently required. Many naturally occurring compounds, including the antimicrobial peptide nisin and a number of plant essential oils, have been widely studied and are reported to be effective as antimicrobial agents against pathogenic microorganisms. Here, we evaluate the potential of nisin in combination with the essential oil cinnamaldehyde and ethylenediaminetetraacetic acid (EDTA) to control the growth of E. coli strains of swine origin including two characterized as ETEC. The results reveal that the use of nisin (10 μM) with low concentrations of trans-cinnamaldehyde (125 μg/mL) and EDTA (0.25–2%) resulted in extended lag phases of growth compared to when either antimicrobial is used alone. Further analysis through kill curves revealed that an approximate 1-log reduction in E. coli cell counts was observed against the majority of targets tested following 3 h incubation. These results highlight the potential benefits of combining the natural antimicrobial nisin with trans-cinnamaldehyde and EDTA as a new approach for the inhibition of E. coli strains of swine origin.
    • Nisin in Combination with Cinnamaldehyde and EDTA to Control Growth of Escherichia coli Strains of Swine Origin

      Field, Des; Baghou, Inès; Rea, Mary; Gardiner, Gillian; Ross, R.; Hill, Colin; Science Foundation Ireland; 10/IN.1/B3027; SFI/12/RC/2273 (MDPI AG, 2017-12-12)
      Post-weaning diarrhoea (PWD) due to enterotoxigenic Escherichia coli (ETEC) is an economically important disease in pig production worldwide. Although antibiotics have contributed significantly to mitigate the economic losses caused by PWD, there is major concern over the increased incidence of antimicrobial resistance among bacteria isolated from pigs. Consequently, suitable alternatives that are safe and effective are urgently required. Many naturally occurring compounds, including the antimicrobial peptide nisin and a number of plant essential oils, have been widely studied and are reported to be effective as antimicrobial agents against pathogenic microorganisms. Here, we evaluate the potential of nisin in combination with the essential oil cinnamaldehyde and ethylenediaminetetraacetic acid (EDTA) to control the growth of E. coli strains of swine origin including two characterized as ETEC. The results reveal that the use of nisin (10 μM) with low concentrations of trans-cinnamaldehyde (125 μg/mL) and EDTA (0.25–2%) resulted in extended lag phases of growth compared to when either antimicrobial is used alone. Further analysis through kill curves revealed that an approximate 1-log reduction in E. coli cell counts was observed against the majority of targets tested following 3 h incubation. These results highlight the potential benefits of combining the natural antimicrobial nisin with trans-cinnamaldehyde and EDTA as a new approach for the inhibition of E. coli strains of swine origin.
    • Nitrofurans : measuring tissue-bound residues in meat

      O'Keeffe, Michael; Connolly, Anne; Nugent, Audrey (Teagasc, 2006-08)
      The aims of this project were to (a) develop a range of screening and confirmatory test methods that might be applied to effectively test for the illicit use of the prohibited nitrofuran antimicrobials, (b) study the persistence of nitrofuran antimicrobials as bound metabolite residues in edible tissues and (c) undertake a pan-European survey of the incidence of nitrofurans in retail pork.